Ijin Marine Limited

Ijin Marine Limited

Professional Supplier of Machinery & Hardware

7 types of anchor shackle

Anchor Joining Shackle Pear Shaped-Above

Anchor Swivel Shackle-above

Joining Shackle Type D-above

Joining Shackle Type Kenter-above


Type A Buoy Shackle

Type B Buoy Shackle


11 means of anchor chain connection

A.1 - Connection of two chain-cables

A.2 - Standard length with joining shackle

A.3 - Standard length with joining shackle and anchor shackle

A.4 - End length with joining shackle, swivel and anchor shackle

A.5 - Forerunner with joining shackle, swivel and anchor shackle

B.1 - Connection of two chain-cables

B.2 - Standard length with lugless joining shackle

B.3 - Standard length with lugless joining shackles and ordinary anchor shackle

B.4 - End length with lugless joining shackle, swivel and ordinary anchor shackle

B.5 - Forerunner with lugless joining shackle, swivel and lugless anchor shackle

B.6 - Three links adaptor piece

IJIN MARINE LIMITED-China's biggest rope and chain trader.
Mob:+86-15026636864  Web: ijinmarine(dot)net
E-mail: sales(at)ijinmarine(dot)com  Tel: +86-21-51699732
Add: 303,Block B,No.188 Zhangyang Road, 200122, Lujiazui, Shanghai,China
Linkedin:Bill Jia/
Twitter:ijinmarine / QQ:66895009
Supplier: Wire rope,Anchor,Chain,Pump,Life boat,Crane,Rubber fender,Winch,Propeller,Zinc Anode
Agent: In 80+ countries: Drydock, 
Repair, Fire-fighting, life saving, GMDSS, underwater, Bunker

What is Deck Machinery?

The introduction of winches
The winches are the small light weight lifting equipment to use the wire rope or chain rounding rolls or to upgrade or drag the heavy objects.
The winches have the following features: versatile, compact structure, small size, and light weight, have a significant, convenient to use the transfer. And they are widely used in construction, water conservancy, forestry, mines, docks and other materials, also can make modern electronically controlled automatic operation line equipment.
The winches' capacities range from 0.5 tons to 350 tons, and also divided into two kinds of fast and slow. The winches which are higher than for the large tonnage of 20 tons can be used alone, but also as a component part of crane, road building and mine hoist and other machinery. Because of simple rope around a large, mobile home convenient the winch are widely used. The main technical in dictators are rated winches load, to support the load, speed rope, rope capacity and so on.
In accordance with the power, the winches can be divided into hand winches, electric winches, and hydraulic. From the use of the classification can be divided into construction and boat winches
In accordance with the functions, the winched can be divided into: marine winches, project winches, mining winches and cable.
In accordance with the reel roll, there are single and double rolls winches。
Anchor windlass Introduction
Anchor windlass is a large deck on the ship machinery, used to receive, put anchors and anchor chains. Windlass is usually installed in the ship stern first on the main deck for the ship weighed anchor, anchor mooring during the event. Windlass and winch normally used in conjunction. Windlass mainly by the base, frame, anchor chain wheel, brake, sprocket, transmission, electronic control systems (except for manual windlass) and other components, electric windlass with electric motors, hydraulic windlass with hydraulic pump station. Windlass is based on vessel size and the size of anchors and anchor chain to the selection.
Anchor windlass drive in accordance with the form can be divided into: manual, electric, hydraulic, pneumatic, etc .
Anchor windlass diameter can be divided in accordance with φ12 - φ120mm several other specifications.
Anchor windlass drum in accordance with the distribution can be divided into unilateral and bilateral.
Anchor windlass chain of the major technical indicators including the diameter, the nominal anchor speed, rated load, to support the load, a few variable speed, power system and so on.
Anchor windlass installation on the ship anchor chain and sprocket to ensure the wrapping angle of 117-120 degrees.
Marine loading and unloading machinery introduced
There are lifts, hoists and conveyors. Boat lift is a vertical movement of the machine along the rails for lifting and down between decks used goods. Such as greater use of ro-ro deck lifts connect floors to transport goods. Ro-Ro on a scissor lift, chain and several species, its length is 9 to 18.5 meters, a width of 3 to 5 meters. Some also contained barge barge loading and unloading lifts, but the lifting capacity of greater than ro-ro. Elevator is in the vertical direction or tilt direction of the larger continuous delivery of goods. Conveyor is little gradient in the horizontal direction or the direction of continuous delivery of goods. These two machines is used in self-unloading ships or through side doors for loading and unloading of ships.
Special Crane Introduction
To accomplish a specific task and developed a special crane. For example: mechanized implementation of tactical and technical safeguards for the use of, or installed in off-road vehicle on the lift wheel armored rescue vehicle; to deal with road traffic accidents wreckers, etc., fall into this category.
Cranes Type: refers to how busy the crane and the degree of change of load parameters.
How busy working on the crane, the total time refers to the year, the crane's actual operating hours and the ratio of total number of hours; for institutions, it refers to an organization operating within a year, the number of hours and the ratio of total number of hours. In a working crane cycle, the percentage of institutions operating time, called the agency's duty cycle, by JC said.
Change of load, according to the design rated capacity of the crane in the actual operation, the crane lifting a load is often less than the rated capacity. This change in load lifting capacity utilization factor of k with that. k = the weight of the crane from the average annual actual / crane's rated capacity.
Work according to how busy the crane and load the degree of change, usually the type of crane work is divided into: light, intermediate, heavy and extra heavy duty class four levels.
Type of work and crane lifting capacity are two different concepts, lifting capacity, is not necessarily a heavy duty, since the weight is small, not necessarily light level. Such as hydropower with the crane lifting capacity of hundreds of tons, but with little chance, only if you install the unit, when the repair crew to use the remaining time stop there, so even though from the very heavy, but still is light level . Another example is the use of the station yard gantry cranes, although not from the weight, but very busy, are heavy duty type of work.
The type of work and crane safety performance has a very close relationship. Starting weight, span, crane lifting height of the same, if the type of work is different in design and manufacture, the safety factor is not taken the same, that is, spare parts, dimensions, specifications vary. Such as wire rope, brake as a result of different types, different safety factors (light-level safety factor is small, heavy duty safety factor), the selected model is not the same. Then, as is the 10t bridge crane, the type of work for the intermediate (JC = 25%) of the lifting motor power N = 16KW, and for heavy duty work type (JC = 40%) Lifting motor power was N = 23.5 KW.
Marine Boom equipment classification
Boom equipment can be divided into light and heavy categories. From the weight of 10 tons of equipment for light boom, more than 10 tons of heavy-duty boom for the device. The boom from the weight of the decision based on the use of the ship. General dry cargo boom light weight single lever operation from 3 to 5 tons, double-pole operation is 1.5 to 3 tons; ton dry cargo ships from the weight of a single lever operation up to 10 tons, two-pole operation up to 5 tons . Modern multi-purpose vessel to loading and unloading containers from the weight of the boom of the crane should be able to afford at least a 20-foot container (20 tons). Heavy-duty boom is used to handling large-scale machinery, locomotives and other heavy vehicles, large pieces of cargo, general cargo ships only set 1 ~ 2, since the weight mostly 10 to 60 tons, there are 60 to 150 tons, a small number of 300 tons . Every general dry cargo hold has two light boom; giant dry cargo for each cargo space is often set four light boom.
Mooring Winch Introduction
Mooring Winch with wire rope or chain winding drum or traction to enhance the small light weight lifting equipment, also known as the hoist. Winch can be used alone, but also as a crane, road construction and other machinery in the mine hoist component parts, because of simple operation, roping a large amount of displacement convenient and widely used. The product is highly versatile, compact structure, small size, light weight, major and easy to use transfer, lifting the ship's equipment to be used in flat or drag. There are two types of manual and electric winches. Manual rotation of the winch handle is equipped with a stopper drive mechanism (Ratchet and pawl), allows weight to maintain the desired position. Assembly or to enhance the heavy manual winch with safety handles and brakes should be set. Generally used in the manual winch from the weight of a small, disadvantaged or non-power facilities place. Electric winches are widely used in the heavy workload and the necessary traction to larger quarters. Electric single drum winch (Figure) of the motor through the reducer drive reel, between the motor and reducer input shaft equipped with a brake.  To meet the enhanced traction and rotation operations such as the need, as well as double-drum winch and multi-roll device.
Marine crane Instruction
Marine cranes are used for loading and unloading cargo ships owned the plant and machinery, there are boom gear, deck cranes and other handling machinery. In sea transport operations performed in the context of a special crane, mainly for the transport of goods between the transfer of ships, offshore supply, underwater launch and recovery equipment, and other important tasks. Specific application to marine ship crane control is a big challenge. On the one hand, similar to the land of underactuated crane equipment, the need to control the load generated during transport of the swing to ensure the accuracy of  its positioning and transportation efficiency; the other hand, this crane fixed on the ship and other sports platform, the platform itself Games of the strong impact load movement, and in many cases, the load lifting and landing point of the movement of the movement itself is inconsistent with the crane. Specifically, in the course of their work, crane ships and receiving ships will be pitching with the waves, roll and heave, the occurrence of these movements will cause the load swing; especially in the lifting process, the ship easily lead to such movement has been suspended the load from the deck again and collision, or to have been put down but not out of the load hook suspended again, these will threaten job security
In recent years, marine cranes, the control of the national military and civil marine engineering in general attention, and studies on the nonlinear, strong coupling of underactuated systems under the control of disturbances in particular have important theoretical value and universal significance.
All above machinery can be got from Ijin Marine Limited, a China hardware trader.


At Paradise

A winch is a device that is used to pull in or let out something that requires a specific tension. They have a huge variety of uses and can be many sizes. The simple version of a winch consists of a spool and a crank. The largest versions of winches are used in heavy industry and marine haulage. As well as the more basic hand operated winches, often used on small sailing vessels, winches can be incredibly complex items that use hydraulic, electric and gas powered engines to power the operation. This article explains a few of the more important uses for this very clever device.

More Uses For Winches

They can be used in theatrical productions for moving heavy items such as scenery construction without the need for a large amount of manpower. They are designed so a single person can shift a huge wait with very little effort indeed. They are very important on yachts and are used to trim the line, the member uses one hand to turn the line and the other to keep the tension regulated. Winches are also used for water and snow sports activities. Instead of requiring a boat to pull a water skier, the winch is set up in a circular track and can provide sufficient thrust to simulate the now redundant boat.

Snubbing Winch

A snubbing winch is similar to a conventional winch but does not use a crank handle to drive it. The winch line is controlled by pulling the tail line, and after the pulling operation is stopped, the winch can take the load without any effort required by the winch handler. These are used mainly for small sailing boats and dinghies, and they control the sails and lines as discussed previously. They can also be used in larger applications to support primary winch mechanisms.

Marine Winch

A marine winch is a very large construction that is primarily used for lifting heavy equipment onto a boat or a ship. They are also used for pulling in heavy industrial fishing nets and also cages from the bottom of the sea. The marine winch usually features a big spool connected to a hydraulic engine, they also use a gear system that changes the tension and power ratios used to pull these extremely heavy objects. The winch tends to be situated behind the captain’s house, away from the main deck’s activities. These winches are also used on dry land at the shipping docks. They are used when cranes are not available or they cannot access the remote docking areas.

Glider Winch

As well as many industrial uses, the winch is also used for some leisure activities, as well as the water sports previously mentioned, the winch plays an important part in gliding. The glider winch is attached to a large vehicle and is connected to the glider. The glider is towed by the vehicle and the winch slowly lets out the high tensile steel cable. When the glider reaches a height of approximately 1000-1600 meters, the glider is released to do its thing.

Attached Images: License: Creative Commons image source

Noel Williams, author of this post, works for Industrial and Marine Winch Hire which provides electric & diesel hydraulic power packs in Western Australia. He keeps himself up-to-date with the latest technology and blogs about various types of power packs and winches including tugger winches.

Ijin Marine Limited is trading and supplying above winches in China.

How to Adjust the Load Sensors on Mooring Winches?

Mooring winches are used to tie the ship to the berth when at a port. While loading and unloading the cargo on the ship, the mooring winches tighten or loosen suddenly. Any extra tightening or loosening of the mooring winches can lead to dashing of the ship with the berth or any other form of accident.

For this reason, load sensors are used on the mooring winches. Load sensors sense the tension on the mooring winches and adjust the tightening and loosing accordingly.

However, it is important that these load sensors are adjusted properly to get accurate results. The article will explain how to adjust the load sensors on the mooring winches.

Adjusting Load Sensor

Winches consist of strain gauges that sense the load. This strain gauge produces a small voltage when load is applied on it. The voltage produced will be different for different loading condition. This voltage is then calibrated to give out the readings on the panel of the winches. These gauges are required to be calibrated time to time and the procedure for the same is as follows.

1.      A tool is fabricated as shown in the diagram with the dimension specified. The dimension may vary with different size of the winches; proportional dimensions may be calculated accordingly.

2.       There are 2 holes in the rope drum and the measurement between the holes is 200 mm for the picture shown which may also vary with different winches.

3.      For fabricating cut 2 pieces of plates 10-15mm thick and weld a distance piece of 25 mm between them, and in the bottom a plate to be welded for placing the hydraulic jack as shown.

How to Fill in the Formula?

The following calculations and measurement has to be taken and put which is marked in blue.

The example given above is for the MW 300 EA winches.

The winch tension is noted, a winch MW 300 EA is pulling 300 KN, and a MW 120 EA 120 KN etc.

The drum diameter is checked and noted. It can be measured on the winch, or can be taken from the manual by checking the mechanical dimensions.

The rope diameter is measured and noted.

The distances from the center of the shaft to the position where the hydraulic jack is to be positioned is measured and noted.

Finally the jack piston area is to be calculated cm2.

Download your own formula calculator below.

Winches Formula Calculator



1.  After all the measured values are inserted we need to get the jack load and the maximum pressure to be applied by the hydraulic jack.

2.   Before adjusting safety precaution to be taken to avoid any accidents.

3.   Bridge is informed that you are working on the winches.

4.  Proper signs and placard are displayed for men at work so nobody will switch on the power by mistake.

5.  Electrical permit to work to be filled and instructions should be followed so you don’t miss any safety point and prevent accident.

6.  Switch off the power to the winch after putting the tool as seen in the picture.

7. The rope is made slack and a voltmeter is mounted between GND and SIGN. Trimmers P7 and P5 is adjusted until you have 0 V DC.

8.  The reading should be zero as there is no load on the gauges, but if it shows any reading then it should be adjusted to zero as specified in above point.

9.   Now engage the clutch and apply the pressure with the help of jack. The pressure applied is already calculated in the form above.

10.   When the maximum pressure is reached, check the reading in the voltmeter by mounting the two leads between SIGN and GND.

11. Now adjust trimmer P6 amplification by turning with a small screw driver until you have approximately 3 V DC and the value on the “Load meter” in the control panel is maximum.

12.  Release the hydraulic pressure and now the reading on the control panel should read approx. 0 V DC.

13. If reading is not zero then re-adjust trimmer P5 load sensor for fine tuning.

14. It is recommended to put back the pressure again to be sure that it goes back to max value.

We supply and trade marine mooring winches in China.So pls contact me if you are looking for a trader or supplier for your vessel.

All you need to know about lifeboat safety

Proper use and maintenance of lifeboats to prevent accidents and ensure your life saving boat is ready when your crew needs it

Lifeboat Safety photo courtesy of US Navy

Although lifeboats are of course, by design, meant to be used to get you out of trouble and potentially save you from a spot of trouble, they can sometimes be involved in accidents themselves. This is to be expected – accidents can happen to anything at any time – but it can’t help but feel a little ironic.

Most accidents in which lifeboats are involved occur during drills, thankfully, and tend to be down to one of the on-board mechanisms (like the release system) failing. Sadly, people do lose their lives in these accidents sometimes, and these people tend to be professional lifeboat crew members.

The Main Causes of Accidents

As stated before, the most common causes are down to malfunctions in the on-board equipment. Whether this is due to the on-load release system being incorrectly calibrated or simply because the launching gear hasn’t been looked after well enough, these accidents can be rather severe.

Also, most of the accidents take place during routine drills and inspections – because these are less “serious” activities, crew members may not take them as seriously as they should, and this might lead to failures in communication or even unsafe practices, both of which can cause mishaps to occur.

Davit Maintenance

If you want the lifeboat to release in a smooth, secure and overall safe manner, you need to make sure the davits are correctly maintained. Davits are safety systems which are used to lower the lifeboat from its mother vessel and to launch it into the water.

You should examine the davits closely to see if there are any visible signs of corrosion or deformation, then lubricate any moving parts, including sheaves and wires.

Any electronic devices, like limit switches and hydraulic mechanisms, should be routinely checked over to make sure they’re working properly.

Lifeboat Maintenance

If you want to avoid any nasty accidents occurring, regular lifeboat repair and maintenance is vital. Ensure everything on board the boat is functioning correctly, whether it’s fixed or loose, and give the boat itself an inspection; the engine, the power supply, the propulsion, the steering and the bailing mechanism should all be given the once over.

Everything should be inspected – this includes the sprinkler system and the air supply. If anything is failing or malfunctioning, replace it as soon as possible.

Accident Prevention

All lifeboats are fitted with a hook release system; it is important to ensure that every crew member is familiar with it, and has a thorough understanding of how it works. By doing this, you will be able to prevent the majority of lifeboat accidents.

When drills are being conducted, keep the personnel numbers to the absolute minimum necessary – this allows the lifeboat staff to concentrate more effectively and avoids any potential crowding incidents.

You should also make sure that your boats are kitted out with FPDs, also known as fall prevention devices. These handy gadgets stop the on-load release systems from being inadvertently activated.

GUEST POST: This article was brought to you buy Jamie King writing on behalf of ShipServ, the marine e-market place.

Ijin Marine forward this post this text for telling you we are a trader and supplier of lifeboat,liferaft in China.

Sacrificial Anodes - Frequently Asked Questions


Q. What do sacrificial anodes do?

A. All metals immersed in an electrolyte (sea water for example) produce an electrical voltage. When two dissimilar metals are in contact (electrically connected) they produce a galvanic cell (like a battery), with the less noble metal (a bronze propeller for example) forming the anode and the more noble metal (stainless steel shaft) forming the cathode.

Aluminum anode alloy provides more protection and lasts longer than zinc. It will continue to work in freshwater and is safe for use in salt water. Aluminum is the only anode that is safe for all applications.

                        Galvanic Corrosion

If you want to protect both metals you need to connect a third metal that is more active than the first two. The most active metal (zinc for example) becomes the anode to the others and sacrifices itself by corroding (giving up metal) to protect the cathode - hence the term sacrificial anode.



Q. What metals are sacrificial anodes made from?

A. The three most active materials used in sacrificial anodes are zincaluminum and magnesium. They have different properties and uses.

The first property to consider is their electrical potential. All metals generate a negative voltage (as compared to a reference electrode) when immersed in water. The lower – the more negative - the voltage, the more active the metal is considered to be, for example:

    Magnesium generates -1.6 Volts, i.e. negative 1.6 volts.
    Aluminum sacrificial anode alloy generates  -1.1Volts
    Zinc,  -1.05 Volts

In order to provide protection, the highest practicable voltage difference possible is required between the sacrificial anode and the metal to be protected.

For example, if zinc is used to protect a bronze propeller, a “driving or protecting voltage” of negative –0.75 volts will be available, i.e. zinc at -1.05 volts minus bronze at -0.3 = - 0.75 volts.

If aluminum anodes are used this increases to -0.8 Volts.

Magnesium anodes increase this to -1.3 volts.

The bigger the difference in voltage, the more protection you get. But, beware, some materials (aluminum) can be “overprotected” – more about that later.

The second property that is important is the current capacity of the anode material. The anode generates a voltage difference and this drives a current between the anode and the protected metal and through the water. It’s like having a bigger battery, the more capacity you have the longer it will keep protecting. Incidentally, for a particular anode, the rate of current flow is dependant on the surface area of the anode and the longevity depends on the mass. For the same size anode the relative capacities are:

    Zinc: 100 (Taken as a datum e.g. this could be 100 days)
    Magnesium: 30
    Aluminum anode: 130 – 150 (Different manufacturers quote different ranges)

So if you used a magnesium anode in place of the “100 day” zinc anode it would only last 30 days.

The aluminum anode would last between 130 and 150 days.

For convenience we provide the "Zinc Equivalent Weight" (ZEW) in some of our product listing pages. This is the amount of zinc that the aluminum anode is equivalent to in terms of capacity.

The third property is Quality of the Anode Alloy

A word of caution about the metals used !!

Not just any zinc or any aluminum will work. Beware ! There are some imported anodes which are of questionable quality.  It is important to ensure that the anodes you buy are made to the appropriate military or marine specification. Installing cheap or sub-standard anodes will undoubtedly cause increased and potentially very expensive corrosion problems. The most common material specifications are:

    Zinc: MIL-A-18001K
    Aluminum: MIL-A-24779(SH)
    Magnesium: MIL-A-21412


Comparison of Properties

                    ANode Poperties


Q. What anode material should I use on my boat?

A. The type of boat that you have will determine how careful you need to be. A fiberglass hull with an inboard engine will need much less protection than an aluminum hull or a boat with an aluminum sterndrive for example. Some simple guidelines:

Inboard boats with mainly bronze and stainless metal parts can be protected using zinc or aluminum anodes. Don’t worry about overprotecting them. You are only overprotected when the weight of the anodes is so great that your boat sinks! The voltage generated by zinc or aluminum anodes will not cause any damage – no matter how much anode material is added, the maximum voltage that can be generated is the voltage of the anode itself. You could also use magnesium in freshwater locations on fiberglass-hulled boats. Be careful using magnesium on aluminum or wooden hulled boats since you can overprotect them. Steel hulls can also be overprotected to the point where excessive protection voltage rapidly lifts the paint off the hull.

Sterndrives and Outboard Motors require a little more care. The sacrificial anodes have a difficult task, since they have to protect what is already a very active aluminum assembly. Initially the anodes for these units were made of zinc, but in response to corrosion problems, Mercury and Johnson/Evinrude/OMC started selling the aluminum anodes in the early 1990’s. Other manufacturers are switching to aluminum too. The small increase in protective voltage helps ensure that the sterndrive is protected. If you use zinc anodes you may even invalidate your warranty!  Again, be careful using magnesium anodes since you can overprotect your sterndrive or outboard.


Q. What anodes should I use in freshwater?

A. Where possible Navalloy™ (aluminum/zinc/indium alloy) anodes are recommended over zinc. Zinc anodes can become inactive after only a few months due to the build up of an insulating film of zinc hydroxide. Aluminum anodes will remain active. Don't take our word for it though, ABYC(American Boat and Yacht Council), who set the standards for the industry, clarified their recommendations on anode materials in the Standards and Technical Information Reports for Small Craft (July 2008-2009):

         ABYC Recommendations

As you can see, the only anode type that is recommended for all water types is aluminum (Navalloy).

This chart summarizes the anode choices based on type of boat and water type:

                Which Anodes?


Q. What factors increase corrosion?

A. The voltage difference between the two metals will affect the rate of corrosion. For example a stainless steel prop, which is a relatively noble metal, will cause more corrosion of a set of zincs than a bronze prop. Corrosion will increase the saltier the water is. Increasing temperature will also increase the conductivity of water and the resulting corrosion. The corrosion rate doubles with every 10 degrees Celsius (18 degrees Fahrenheit) increase in temperature. Pollution can also increase corrosion. For example, many freshwater lakes have been contaminated by acid rain, which increases the conductivity of the water and therefore corrosion rates.

Galvanic Scale


Q. When should sacrificial anodes be replaced?

A. Anodes should be changed, at least, on an annual basis (including anodes in fresh water) or when they have corroded to half their original size. Performance Metals “Premium” anodes include the exclusive patented “wear indicator.” When the red spot appears it is time to change your anode!


Q. What precautions should I take when installing new anodes?

A. Make sure they make good electrical contact with the metal that is being protected. Remove any paint and clean the metal surface that will be in contact with the anode. DON’T paint anodes! They can’t work if they are covered up.


Q. What else should I do to help protect my sterndrive?

A. Keep paint (on engines, sterndrive units etc.) in good condition. A small scratch will corrode rapidly. Leave the sterndrive unit immersed in the water. If you don’t the anodes can’t work. Don’t use anti-fouling paint containing copper or mercury on a sterndrive unit. The metal in the paint will increase galvanic corrosion. Don’t mix zinc anodes on the hull with aluminum anodes on the drive. The aluminum anodes will protect the zinc anodes in addition to the unit.

Q. How can Navalloy™ (aluminum) anodes protect aluminum outdrives?

A. Because the Navalloy™, aluminum anode is a combination of aluminum, zinc and indium. It is like comparing steel and stainless steel - they have very different properties. The zinc and indium make the metal more active and prevent the anode from forming an oxide coating.

This article is from below website.


As a hardware supplier,Ijin Marine Limited has delivered tons of zinc anodes, aluminium anodes onto vessels visiting China.

What is screw pump and how it works

Introduction to Screw Pump

Screw pump has a  structure same like a screw. I mean the whole  construction of the spindle is like a  archimedes screw and this spindle is responsible for the pumping action of the pump. It has been observed over the years that this pump requires least maintenances and therefore, is a potential device for increasing the pressure. As other pumps, screw pump too takes the mechanical or you can say the rotational energy from external means like a motor or any type of arrangements which provides the rotary motion. Sulzer and kirlosker pumps are very famous. So let’s discuss about this pump little more detail.


Construction of the Screw pump

Construction of screw pump is coherent and very straight forward in its making. See the  diagram for construction details.  Screw pump is having three screw spindles, one of which is driver and other two are driven. There is a fine clearance between these screws and this fine clearance is responsible for the pumping action of the fluid. Drive to the main screw is given through the motor which is coupled to this by proper coupling.
screw pump working, screw pumpm overhaulling, screw pump suction, repair screw pump
Pumps have a casing which has a proper inlet and outlet. Inlet is always preferred at the bottom and the outlet is preferred at the upper part of the pump. This is all we have in the construction of this pump. One more thing which I forget to tell is that this pump is having a relief valve fitted at the end of the outlet.

Working of the Screw Pump

Screw pump is having the simplest working on the entire pumps. Let’s  start with fluid coming at inlet at the bottom most part of this pump. Now since driver screw is rotating and other two drive screws are also rotating but in different directions, they tend to build up the suction pressure at the bottom part. This suction pressure makes the fluid to move upward. Fluid passes through the small clearance between these screws and also the centrifugal force is experienced by this fluid. Both of these factors contribute towards providing the force which in turn results in the development of pressure in the fluid.
This pumped oil get out of the pump, with pressure but before going out of the pump, it has to pass through the monitoring of the relief valve. A  relief valve is a mechanical device or mounting which guarantees that fluid is given by the pump in the limited pressure range. If the pressure of the fluid increases, then automatic relief valve will direct the excess pressure oil into the inlet side or we can say the suction side.

Problem and maintenances required on Screw pumps

Generally we have very less problems associated with this pump but yes some problems occur. To make things simpler, let’s discuss the problems which may occur on this pump.
  1. The clearances between the screws increases, which results in a decrease in pressure.
  2. Bearings may wear out.
  3. The relief valve does not function properly.


So these were some of the problems which we face in screw pumps.Let’s discuss the maintenances which are done with this pump.
  1. Checking the clearance between the screws and rectifying it.
  2. Bearings lubrication and oiling.
  3. Checking and testing the relief valve.


Material used in making different parts of the screw pump

Followings parts are made with the  metals described below:
Casing: Generally made of cast iron.
Screw shafts: Made of high grade carbon steel.
Bearings: High speed steels.

Applications of Screw pump

Normal the screw is used for pumping the high viscous fluids. They are also used for  draining out the tanks having high vapor pressure liquids. They are used to take the  water from the stern tube area, if there leakage there. So these are some of the uses of the screw pump.
In China, you can find almost any pumps if you contact Ijin Marine Limited.

What is the problem with anchor-chain swivel connectors?

Swivel connectors have become popular with their use quite widespread, but they are not free of drawbacks.
Often they are simply unnecessary. Their purpose is to prevent the chain twisting if the boat swings, but unless a boat is anchored for a long time and its chain is very short, it is very unlikely that the chain’s twisting will become a problem. They are also designed to help straighten the anchor on board more easily if it was twisted when raised, but the fact is it will straighten out anyway even if it did not turn, and the chain will not have twisted more than half the turn (because even if the chain turned several times, it would have untwisted while the anchor was being raised).
There are many ways of ensuring that the anchor is correctly retrieved aboard. For example, on the points where the length of the extended chain, every ten metres, are marked, you could mark one side of a link with paint or tape to indicate whether the chain is correctly positioned or not, helping you correct it if necessary before the weight of the anchor complicates the operation.
The biggest problem with swivel connectors is not that they are often superfluous, but that they may in fact be dangerous. If the anchor and the chain are aligned, i.e. in their normal working position, there is normally no problem with them. The problem arises if the boat swings and the chain starts to pull sideways. If this happens, too much stress is being exerted on the swivel connector and may break in some cases. It should be remembered that if the anchor is very embedded, a great deal of force is required to reposition it, with the situation even more difficult if the anchor is fouled. Even better quality swivel connectors, which normally include a ball that allows the chain to pull laterally up to 30°, are not equipped for the chain to pull perpendicularly to the shank.
If you consider a swivel connector necessary, we strongly recommend you do not install it on the anchor directly, and leave a section of chain (which can be larger in diameter) between the anchor and the swivel connector.
Ijin Marine Limited is able to provide better product.

To Swivel or to Twist, That is The Question

By Captains Alex & Daria Blackwell

To a cruiser, anchoring tackle is perhaps one of the most important pieces of gear – second only to the boat itself. As such, any mention of the pros or cons of any particular component or configuration will inevitably lead to some pretty strong opinions. We should know, having written Happy Hooking – the Art of Anchoring, though highly acclaimed and as impartial as we felt able to make it, our book, and subsequent articles have stirred up the occasional hornet’s nest of ‘discussion’.

So it was with our chapter on swivels. To date we have shunned them, viewing swivels as an unnecessary weak link in the components connecting the sea bed to our boat. Yes, we have swung at anchor for weeks at a time while cruising. Where the wind was heavy, our anchor veered as a good anchor should. In light wind situations we did note that our chain was occasionally twisted, but this always corrected itself when we weighed anchor. The twist cannot get past the toothed wildcat on our windlass, so there is no chance that the twisted chain would find its way into our chain locker. The anchor simply spins while coming up and any twist is straightened out.

Another reason many people opt for a swivel is that they fear that the protruding shackle pin might get stuck on the bow roller when deploying or weighing anchor. Unless the bow roller assembly has been very poorly designed, this should not be an issue. We have literally anchored thousands of times sometime two or three times in one day and have never seen this happen.

There is one place we do have a swivel – on our mooring. There is a fairly stiff tidal current where our boat is moored. Our boat thus swings a lot. As our mooring cannot veer, it is conceivable that our riser, which is part chain and part arm thick nylon, would become twisted over the course of the year. We have therefore incorporated a heavy galvanised swivel in the riser, which we do replace every year. So, one cannot say that we are anti-swivel.

Swivel failure

We were cruising in company with some friends one weekend a while back. When our two boats reached the destination, we dropped our hook and got to work preparing the cocktails we had promised our friends. We heard a shout and found our friends had brought their boat alongside ours. They wanted to raft up. This was odd, as we had discussed anchoring separately, so that our respective boats would be secure for the night. It turned out that they had lost their shiny stainless steel anchor (of which we had been quite envious) from their bow when a stainless steel swivel failed while underway.

Two things became evident as we looked at their problem. There was some corrosion (rust) on their ‘stainless steel’ swivel – yes, stainless steel will rust. And there was significant evidence of rust on the swivel shaft, which was hidden from view, as is the case with many of the ‘nicer’ swivels on the market today.

The problem with all of these swivels is that their shaft is hidden from view. Should the shaft rust, which would seem to be likely as the space around it will remain moist, then it will no longer be as strong as it once was.

Some of these swivels have a threaded shaft with a nut welded onto it to hold the two bits together. First of all, a threaded bar (as with the one above that snapped) is inherently weaker than a solid bar of the same diameter. Then there is the issue of the welds not holding, as happened in the swivel shown here.

The other problem we found was that our friends were in the habit of bringing their anchor in tight to the bow roller using their windlass – their chain was thus bar taut. They did this so that their anchor would not bounce around while underway. Given the fact that there will inevitably be movement as the boat pounds through waves, this will undoubtedly put undue strain on the swivel, any shackle, and on the windlass.

Our friends quickly purchased a new anchor and swivel and were once again the envy of the fleet. A few short weeks later, both were gone. Having reflected on what had happened, they now have a galvanised anchor and no swivel. They also tie their anchor off to a cleat leaving their chain loose on the foredeck. We just heard that they have been successfully using this same setup for several years now.

Photo John Harries

Another reported failure of this type of swivel occurs when the boat veers strongly to one side and then comes up short. In this instance something has to give. These lateral loads can be so great as to bend the anchor shaft. They can also cause the swivel to be bent open with the screw thread being stripped out as is shown in the photo to the left. Alternatively the swivel shaft may shear or, as in the example to the right, the internal retaining pin may break. Of course this lateral load is also applied as the anchor is hauled over the bow roller – often with some gusto, so that the anchor bounces with the swivel on the roller as it rotates into the correct orientation.

A solution to this is to position the swivel some way up the chain as is suggested by Craig Smith (Rocna.com). A short piece of chain is thus shackled to the anchor with the swivel connecting it to the rest of the chain rode. But this leaves you with the shackle that some wish to eliminate.

The other option is to design the swivel so that it can indeed move laterally as well as twist. One such example is shown here, where the manufacturer has designed in what amounts to an extra chain link. It would appear that the lateral forces would still be exerted on the jaws attaching to the anchor and on the swivel shaft – not to mention that the shaft remains hidden from view and subject to rusting.

Following the adage that simple is better, one might also consider a simple shackled on swivel. The one we saw here could move laterally if sized correctly. Its only downside is, of course, that the shaft is still obstructed from view.

For anyone thinking they need a swivel, and that they need to attach it to the anchor, there is one option we had the pleasure of taking out cruising for the past several months. It is the Ultra flip swivel manufactured in Turkey by Boyut Marine. It incorporates a flipping nub to assist anchor alignment, a durable Teflon-coated ball for easy rotation, and a back bridge that supports the anchor as it travels over the roller. The back bridge also looks like it would add extra strength to the already beefy swivel. This swivel also has virtually no hidden places that cannot be inspected and for moisture to collect causing corrosion. The other part we liked was that this swivel not only twists, but will articulate to all sides reducing the danger of the lateral load. Like the beautifully styled Ultra anchor, Boyut has again produced a lovely looking piece of equipment as well.

A note on stainless steel shackles and swivels.

Stainless steel looks great. We were indeed very envious of our friend’s lovely shiny tackle particularly when next to our own dull galvanized anchor and chain. Even our shackles are dull, boring looking galvanized iron. On the other hand stainless steel, even the top grade 316, is more brittle, and thus not as strong as so called mild steel. Another chief characteristic of stainless steel is that it is smooth (and shiny). Galvanized shackles are rough and will bind when tightened properly. They can be difficult to open and are thus quite unlikely to ever open when they shouldn’t. Stainless steel shackles, on the other hand, do not bind and may come undone when least expected. This happened to me at the top of the mast when the shackle connecting my climbing gear to the halyard opened (but that is another story). Stainless steel shackles must thus always be seized with wire.

As mentioned previously, stainless steel does corrode. This may occur internally, weakening the overall piece of hardware. Rust will also occur in hidden crevasses which will stay wet, as in the above mentioned swivels.

So, where does this all leave us?

With the Ultra swivel we have indeed been shown a swivel that appears to have very elegantly solved all the arguments we would put forward in opposition of using a swivel on an anchor rode. It obviates the need for a shackle, it has no hidden parts, it looks to be very strongly (and beautifully) constructed, and it moves laterally as well as twisting.

Does this mean that it is advisable to add a swivel to an anchor rode? The way we see it, not really. As mentioned, we have on occasion spent months at anchor with wind and tide shifts. Our rode certainly had twists in it, but they all came out as we weighed anchor. With a permanent mooring, that is certainly a different matter, and a local mooring contractor would be the best to advise on this.

In the final analysis, it remains up to the individual boater. There is good quality equipment available. So, if you feel you must go this way, then go you may!

Ijin Marine Limited, we deliver more service for your vessel or boat in China.

Different Cargo Handling Equipments Used on Container Ships

Containers are the most transported method of cargo form in the world as they are transported by all the three transportation systems available i.e. land, air and water. The aspect of cargo handling of the containers on ships become very critical as they are subjected to harsh weather and strong wind in the mid sea.

A research states that every year more than 10,000 containers fall overboard and spill their cargo into the ocean; 50 % of this happens due to negligence in the cargo handling.

Different types of cargo handling equipments are used to secure containers to the ship and to other containers stacked on top of other. The details of these equipments are given in cargo securing manual (CSM) present onboard.

Some of the important container cargo handling equipments are:

Base Twistlock: As the name suggests, it is used on deck and is mounted on the socket provided on the deck. The shipping container is loaded over the base twist lock and it is to be installed as per the procedure in CSM. After loading ensure that the wire handle is in lock position.

Locked position.

To remove pull the wire all the way, tilt the twist lock backwards and lift the twist lock from the socket.

Semi Automatic Twistlock: This twistlock are used in between the containers i.e, when a container is loaded on top of other container to form a stack. A semi automatic twist lock is inserted in between them. They are not used for the position of midlocks.


Midlocks: They are used on deck between the 20 ft containers.

Semi Automatic Base Twistlock: They are also used on deck on the lowermost tier except for the position of midlocks.

Hanging staker: A hanging staker is equipment which holds for 20 ft containers on all the four sides.

Lashing Rods: Lashing rods are rods of different lengths to hold the containers from one end and are tied up to the deck surface from the other end.

Turnbuckle & Bottle screw: They are used in combination for tensioning the lashing of the container so that they won’t get loose.

Spammer: A spanner or a tightening tool must be available for tightening the bottle screws and turnbuckles.

Emergency tool: It is a tool which is used when a twist lock cannot be unlocked by pulling the wire handle. It is used in such a way that the emergency tool is in a position that will keep the twist lock open and the container can be then lifted along with the tool.

Grease: It is an anti seize compound that should be applied to all the lashing equipment as required so that they are well maintained and in operational condition.


A brief list of equipments used for container handling on ports:

  • Port equipment includes straddle carriers for container transportation on berth


  • Tractors and trailers/semi-trailers for back up transportation and movement within a terminal area,
  • Stacker cranes and side loaders to assist in cargo handling.
  • The cargo handling equipment used for ship during cargo operations are gantry cranes on the pier.
  • Gantry cranes are especially used for container handling. These cranes are fitted with spreaders that can be adjusted for twenty foot, forty foot and forty-five foot containers. Some of them can also be adjusted for twin lift.
  • Some ships are fitted with cranes, which can also be used for container handling. These cranes are operated by trained and experienced personnel.

It should be noted that the lashing should not be over tightened as they are pre tensioned.  Excessive tightening may lead to excessive loading on the containers and may damage them during rolling.

Hence lashing should be tightened with only the spanner with slight force. Also the lock nuts on the turnbuckle should be locked in position.

Ijin Marine Limited supply above items for your vessels visiting China.

Understanding Sacrificial Anodes on Ships

Corrosion is one of the greatest enemies of the ship and its machinery. It is also the toughest enemy to fight against for the people working on the ship. Iron is one substance which is used in abundance on the ship. From the main body of the ship to the smallest equipment used in operations, iron makes its presence felt in almost every type of equipment used on board the ship.

A ship is continuously in contact with water and moisture laden winds which makes it highly susceptible to corrosion. The other body of the ship (mainly hull) is continuously in contact with water, making it extremely vulnerable to corrosion. It is for this reason sacrificial anodes are used to protect the parent material. In this article we will have a look at the working of sacrificial anodes on ship.

It is to note that the sacrificial anodes which are protecting the parent material should lie higher in the electromotive series or galvanic series of metals.

How Sacrificial Anodes Work?

Sacrificial anodes works on the principle similar to electrolysis, according to which if an anode and a metallic strip are dipped in electrolytic solution, anode electron will dissolve and deposit over the metallic strip and make it cathode.

In the case of a ship, sea water acts as an electrolyte and transfers the electrons from the anode by oxidizing it over the steel plate and making a protecting layer. If the metal is more active it will be easily oxidized and will protect the metallic compound by making it act as cathode. The anode will corrode first sacrificing itself for the other compound and it is thus called sacrificial anode.

Electromotive series or galvanic series metals

Anode materials

Zinc (Zn)

It can be seen from the table that for protecting iron any material above in the series are useful. These metals are preferred because they are easy and cheap to replace the anodes rather than complete a large sheet of metal.

anodes attached to hull

These anodes are used in various applications such as :

1) Protecting the ship’s hull.

2) Protecting the ballast tanks corrosion.

3) Protecting the heat exchangers.

4) Sea chests

The most common metals used for sacrificial anode is zinc.

Frequency for Changing of Anodes

The frequency for changing of anodes depends on the application where the anodes have been used.
In case the anodes are attached to the ship’s hull, then they are to be checked during dry dock which takes place after 2 to 3 years. If the anodes are found completely corroded then anodes of bigger size should be fitted, for fully corroded means that the material used was of poor quality or a large amount of material is required to protect the hull. Generally, sacrificial anodes are changed at every dry dock.

If sacrificial anodes are used for heat exchangers and it is found during inspection that the anode left is only 10% then also it has to be changed.

How to Assess if the Anodes are Working Properly or Not?

During the inspection of heat exchangers or sea chest, if the condition of anode is same as it was installed then it indicates that the sacrificial anodes are ineffective.

The main reason for this is that the electrical continuity between the parent materials is not made. Because of this the parent metal starts getting corroded instead of the anodes. It is therefore important to check the electrical continuity during installation.

Contact Ijin Marine Limited to know the price of above items.

Video-How it Works: Chain Hoist?

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How to Adjust a Turnbuckle

Open Body Turnbuckle W/ Swage Stud and Toggle

Open Body Turnbuckle W/ Swage Stud and Toggle

The concept of how to properly adjust a turnbuckle seems to sometimes elude most people. This is understandable as I didn’t used to spend my days thinking about tightening cables, like I do now. So let’s take a moment to discuss how this is done properly.

There are generally three different styles of turnbuckles. Yes, there are a few more styles, however these concepts should give you the gist for any turnbuckle.

Open Body Turnbuckle with a Toggle Jaw at Each End

Open Body Turnbuckle with a Toggle Jaw at Each End

First things first, always make sure that you start by taking out the cotter pins and removing any old tape. Generally, to tighten or loosen turnbuckles it is the reverse of what you have learned your whole life, “righty-tighty, lefty-loosey” is now “lefty-tighty, righty-loosey”.

OPEN BODY TURNBUCKLES: The open body style turnbuckle is the most common style in today’s sailboat market and will require either an adjustable wrench and a spike (a ‘beefy’ screw driver should do), or a second adjustable wrench. If you have a turnbuckle that has a swage stud at the top end, then look closely and locate the wrench flat which will be either machined or pressed into the stud by the manufacturer.

DOUBLE JAWED TURNBUCKLES: You may also have a double jawed turnbuckle which accepts an eye fitting attached to the end of the stay. In this situation it is important to keep the upper jaw/eye end from spinning by using either a spike or screwdriver. Also, please note: these turnbuckles are often installed upside down and not consistently. So figuring out which way is tight and which way is loose can be a doozie and may vary from stay to stay. It may be worth the extra time to make sure they are all configured in the same fashion matching up with aforementioned tightening/loosening method (“lefty-tighty, righty-loosey”).

MECHANICAL STUDS AND ROD STUDS : It is also possible that your rigging utilizes a mechanical stud at the top end of the turnbuckle. This is a similar product to that used for open body rod turnbuckles, and the same directions should be followed. Be careful in this situation as the mechanical stud will have two wrench flats, one is to tighten the cap of the mechanical stud (this is NOT the one to use and may cause the fitting to become undone!) and one is to hold the stud in place while turning the turnbuckle body. This wrench flat will sometimes  be less noticeable, but if you look closely you will be able to determine which ‘flat’  holds the stud and not the cap.

Mechanical Stud, Similar to Rod Stud

Mechanical Stud, Similar to Rod Stud

TURNBUCKLES THAT UTILIZE RIGGING SCREWS (ROD AND WIRE): Next we have the rigging screw style turnbuckle, typically provided by Navtec. This looks like an open body turnbuckle, but in reverse. Instead of one body and two studs, there are two bodies and one stud. This is another typical turnbuckle found on rod rigged boats and you should follow these same guidelines here as well. Again, care must be taken to ensure that the upper end of the turnbuckle does not spin. In this case it is the upper body portion that will need to be either held in place by an adjustable wrench or a spike. Then use another wrench to turn the rigging screw by using the wrench flats.

Rigging Screw Style Turnbuckle

Rigging Screw Style Turnbuckle

COQUILLE OR STEM BALL TURNBUCKLES: You have probably noticed by now that I keep making the point of always holding the upper end of the turnbuckle in place, be it a stud, jaw, or body. Well, that is because in most situations the bottom of the turnbuckle is kept from spinning by the way it is pinned to the chainplate. EXCEPT, when the chainplate isn’t conventional. Beneteau and Jeaneau are notorious for these types of chainplates. They use what is called a coquille style chainplate, that means essentially, that the connection of the turnbuckle at the deck is a ball and socket type (which means it can spin freely at the deck). Here you need to perform a bit’ of a magic trick or grab a friend. Both the top and bottom screws will try to spin in this case, so you will need to hold both upper and lower studs by their wrench flats. I like to use large vise grips to grip the lower stud, I will then place my knee near it (as I am in the crouched position) so that the vise grips become wedged up against me as they begin to spin. Then, I will go about holding the upper stud with an adjustable wrench and turning the body with my spike as usual. This maneuver can be a bit tricky, but with a little body contortion and the right tools, it can be done. OR…… simply grab a friend and have them help you ;-0)

Coquille Style Turnbuckle, Popular on Beneteau's and Jeaneau's

Coquille Style Turnbuckle, Popular on Beneteau’s and Jeaneau’s

When you are done make sure you line up the cotter pin holes in the studs so that the turnbuckle can be pinned. If cotter pins aren’t present then there should be locking nuts of some sort. A turnbuckle ALWAYS needs to be secured so that it cannot become undone.

TIP: No matter what type of turnbuckle you are adjusting make sure the wire, rod or whatever type of stay material you may have, does NOT turn, or is in any way able to become distorted.This can lead to shroud failure!

Remember, if in doubt you can always ask Ijin Marine Limited to know more. We are in China, where are you?

Safety tips for steel wire rope slings


Find out the weight for the load to be lifted.

Examine all slings before use and discard those are defective

Protect sling from sharp corners by packing suitable material such as rubber or wood.

Use protective gloves when handling steel wire rope.

Keep wire rope slings in dry place when not in use.


Do not use the sling for any load exceeding the stated SWL.

Do not use a sling that contains kinking, crushing, birdcaging or other damage   which distort the original rope construction.

Do not use wire rope slings with 10 randomly broken wires in one rope lay, or 5  wires in one strand in one rope lay.

Do not use wire rope slings with severe wear, abrasion or scraping, metal loss of  1/3 of the diameter of individual outside wires should be discarded.

Do not bend splice over corners.

Do not exceed 120 degrees when using multi-legged wire rope sling.

Do not drag wire rope slings along the floor.

Never allow the load to be carried over the heads of other people.

Never ride on the load.

Never join wire rope slings by knotting, always use a shackle.

Never shorten wire rope slings by knotting.

Wire rope derating

The strength of steel wire rope is reduced by bending. The derating is related to the diameter of the bend as follows (d = diameter of the steel wire rope):

        6d = 100%

        5d = 85%

        4d = 80%

        3d = 70%

        2d = 65%

        1d = 50%

From Mak Kee Internationl

Ijin Marine limited is a Chinese hardwar supplier

Video-How to make wire rope?

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How to Use Portable Ladder?


What should you know about portable ladders before using them?

Falls from portable ladders are a major source of serious injury. Be aware of the hazards and take proper precautions to prevent falling.

What should you do before using a portable ladder?

  • Inspect the ladder before and after each use.
  • Reject and tag any ladders that have defects. Have faulty ladders repaired or thrown out.
  • Use a ladder designed for your task. Consider the strength, type, length and the Canadian Standards Association (CSA) approval.
  • Get help when handling a heavy or long ladder.
  • Keep ladders away from electrical wires.
  • Tie off ladders at the top and secure bottom to prevent them from slipping.
  • Set up barricades and warning signs when using a ladder in a doorway or passageway.
  • Before mounting a ladder, clean the boot soles if they are muddy or slippery. Avoid climbing with wet soles. Ensure that footwear is in good condition.
  • Face the ladder when going up or down and when working from it.
  • Keep the centre of your body within the side rails.

Refer to safety regulations for specific measurement requirements.

What should you avoid when using a portable ladder?

  • Do not use a ladder in a horizontal position as a scaffold plank or runway.
  • Do not carry objects in your hands while on a ladder. Hoist materials or attach tools to a belt.
  • Do not work from top three rungs. The higher a person goes on a ladder, the greater the possibility that the ladder will slip out at the base.
  • Do not use items such as a chair, barrel or box as a makeshift ladder.
  • Do not use a portable ladder when other equipment is available. Replace a ladder with a fixed stairway or scaffold.
  • Do not join two short ladders to make a longer ladder. Side rails are not strong enough to support the extra load.
  • Do not paint wooden ladders. Defects may be hidden by the paint. Wood preservatives or clear coatings may be used.


How should you set up the ladder?

  • Place the ladder feet 1/4 of the ladder's working length (e.g., foot to top support point) away from the base of the structure (e.g., for every 1.2 m (4 ft ) high, the base of the ladder should be out 0.3 m (1 ft); that means one horizontal foot from the support point).
  • Extend the ladder at least 1 m (3 ft) above the landing platform.
  • Place the ladder on a firm, level footing. Use a ladder with slip-resistant feet or secure blocking. Brace or tie the bottom of the ladder.
  • Rest both side rails on the top support and secure ladder to prevent slipping.


What should you know about climbing portable ladders?

  • Check for overhead electrical wires before setting up a ladder.
  • Clear area around base and top of the ladder of debris, tools and other objects.
  • Tie off yourself with a safety harness when working 3 m (10 ft) or more off the ground or when working with both hands.
  • Ensure that only one person is on a single-width ladder. Only one person is allowed on each side of a double-width ladder.
  • Maintain three-point contact by keeping two hands and one foot, or two feet and one hand on the ladder at all times.
  • Grasp the rungs when climbing a ladder, not the side rails. If your foot slips on a ladder, holding onto rungs is easier than holding onto the side rails.

3 Point Contact

  • Wear protective footwear with slip-resistant soles and heels.
  • Ensure that all electrical equipment used during ladder work is in good condition and properly grounded.
  • Rest frequently to avoid arm fatigue and disorientation when the work requires you to look up and reach above your head.
  • Drape your arms over a rung and rest your head against another rung or side rail if you become dizzy or panicky. Climb down slowly.

What should you avoid when climbing portable ladders?

  • Do not use a ladder in passageways, doorways, driveways or other locations where a person or vehicle can hit it. Set up suitable barricades or lock the doors shut.
  • Do not place a ladder against flexible or moveable surfaces.
  • Do not straddle the space between a ladder and another object.
  • Do not erect ladders on boxes, carts, tables, scaffold or other unstable surfaces.
  • Do not use ladders on ice.
  • Do not stand a ladder on any of its rungs. Ladders must rest on both side rails.
  • Do not allow anyone to stand under a ladder.
  • Do not overreach from a ladder; move as required.
  • Do not use any type of ladder near electrical wires.
Watch for Wires
Ijin Marine Limited,China

How to inspect ladders?


When should you inspect ladders?

  • Inspect new ladders promptly upon receipt.
  • Inspect ladders before each use.
  • Check the condition of ladders that have been dropped or have fallen before using them again.

What should you look for when inspecting any ladder?

  • missing or loose steps or rungs (they are loose if you can move them by hand)
  • damaged or worn non-slip feet
  • loose nails, screws, bolts or nuts
  • loose or faulty spreaders, locks, and other metal parts in poor repair
  • rot, decay or warped rails in wooden ladders
  • cracks and exposed fibreglass in fibreglass ladders
  • cracked, split, worn or broken rails, braces, steps or rungs
  • sharp edges on rails and rungs
  • rough or splintered surfaces
  • corrosion, rust, oxidization and excessive wear, especially on treads
  • twisted or distorted rails. Check ladders for distortion by sighting along the rails. Using a twisted or bowed ladder is hazardous.
  • missing identification labels

What other things should I look for when inspecting stepladders?

  • wobble
  • loose or bent hinges and hinge spreaders
  • broken stop on a hinge spreader

What should you look for when inspecting extension ladders?

  • loose, broken or missing extension locks
  • defective locks that do not seat properly when ladder is extended
  • sufficient lubrication of working parts
  • defective cords, chains and ropes
  • missing or defective pads or sleeves

What should you do after inspecting any ladder?

  • Tag any defective ladders and take them out of service.
  • Clean fibreglass ladders every three months. Spray lightly with a clear lacquer or paste wax.
  • Protect wooden ladders with a clear sealer or wood preservative.
  • Replace worn or frayed ropes on extension ladders.
  • Lubricate pulleys on extension ladders regularly.

What are some things you should not do after inspecting ladders?

  • Do not make temporary or makeshift repairs.
  • Do not try to straighten or use bent or bowed ladders.
  • Ijin Marine Limited help you know more about ladders. In China, we also help more people to know more about hardware use,maintenance,etc.

How to safely use fixed access ladder?

When should you inspect fixed ladders?

  • Inspect the fixed ladder before each use.
  • Inspect fixed ladders periodically, once every three months.
  • Report any defect promptly.
  • Keep the record of every inspection.

What should you check for when inspecting access ladders?

  • loose, worn and damaged rungs or side rails
  • damaged or a corroded cage
  • corroded guard, bolts and rivet heads
  • damaged or corroded handrails and brackets on platforms
  • broken or loose anchorages
  • weakened or damaged rungs on brick or concrete slabs
  • defects in climbing devices, including loose or damaged carrier rails or ropes
  • slippery surfaces from oil and ice
  • clutter obstructing the base of ladder or platform

What should you do when climbing a fixed ladder?

  • Wait until the other person has exited before ascending or descending.
  • Use the appropriate safety devices (e.g., restraint belt, traveling fixture).
  • Maintain three-point contact by keeping two hands and one foot, or two feet and one hand on a ladder always.
  • Face ladder and use both hands to grip the rungs firmly.
  • Place feet firmly on each rung.
  • Wear footwear with heels. Ensure that footwear is in good condition.
  • Clean muddy or slippery boot soles before mounting a ladder.
  • Rise or lower tools and materials using a hand-line.
Fixed access ladder
Wear appropriate safety devices

What should you avoid when climbing a fixed ladder?

  • Avoid climbing with wet soles
  • Do not carry tools or materials in your hand while climbing. Carry small tools in a tool pouch.
  • Do not jump from a ladder. Check footing before descending a ladder.
  • Do not hurry up or slide down a ladder.

Use of Extension Ladder

What should you do to safely secure extension ladders?

  • Place ladders on a firm, level surface and ensure the footing is secure.
  • Erect extension ladders so that the upper section rests on (e.g., in front of) the bottom section. This means the bottom section "faces" a wall or other supporting surface (see figures below).
  • Place the ladder feet so that the horizontal distance between the feet and the top support is 1/4 of the working length of the ladder. The ladder will be leaning at a 75 degree angle from the ground.
Extension ladder
  • Raise and lower ladders from the ground. Ensure that locking ladder hooks are secure before climbing.
  • Erect ladders so that a minimum of 1 m (3 ft) extends above a landing platform. Tie the top at support points.
  • Brace or tie off the ladder near the base. If there is no structure to tie off to, use a stake in the ground.
  • Leave all tie-off devices in place until they must be removed before taking the ladder down.
  • Maintain the minimum overlap of sections as shown on a ladder label. Refer to safety regulations.

Note: When working 3 metres (10 feet) or more above ground, wear a safety belt or harness with the lanyard tied appropriately to the structure.

Extension ladder parts


What should you avoid when using extension ladders?

  • Do not use ladders near electrical wire.
  • Do not set up or take a ladder down when it is extended.
  • Do not overextend. Maintain minimum overlap of sections.
  • Do not climb higher than the fourth rung from the top of a ladder.
  • Do not use ladders on ice, snow or other slippery surfaces without securing ladders' feet.
  • Do not extend top section of a ladder from above or by "bouncing" on a ladder.
  • Do not leave ladders unattended.


What should you do to avoid overexertion while setting up an extension ladder?

When setting up an extension ladder, use the following method to avoid straining muscles or losing control of a ladder. With ladders weighing more than 25 kg (55 lb), or where conditions complicate the task, have two persons set up a ladder, step by step, as follows:

  • Lay a ladder on the ground close to intended location.
  • Brace ladder base using helpers' feet.
  • Grasp the top rung with both hands, raise the top end over your head and walk toward the base of a ladder. Grasp the centre of the rungs to maintain stability.
  • Move the erect ladder to the desired location. Lean it forward against the resting point.
Lay the ladder on the ground
Brace ladder using helper's feet

One person can erect a short ladder, step by step as follows:

  • Place the bottom of a ladder firmly against the base of a building or stationary object.
  • Lift the top of ladder, and pull upwards to raise a ladder to a vertical position.
  • Transfer a ladder to its required position when it is erect.
  • Keep a ladder upright and close to the body with a firm grip.
Placing ladder
Ladder upright and close to the body with a firm grip
Do not hold ladder away from the body

The method for lowering any ladder is the reverse procedure of erecting it.

How to Use Materials Hoist?


When should you inspect the materials hoists?

  • Schedule a detailed inspection of all hoists.
  • Follow the manufacturers' recommended maintenance schedules.
  • Inspect hooks, ropes, brakes and limit switches for wear and damage every working day.
  • Replace items not operating properly. Tag defective items and remove from service for repair by a competent person.
  • Post the safe load limit on the hoist.
  • Inspect the hoist before lifting a load. Check the upper and lower hooks to see that they swivel. Replace any worn chain or wire rope immediately. Tag any defective chain or rope and remove from service.
  • Keep wire ropes and chains lubricated.

How should you use a materials hoist safely?

  • Hoist from directly over the load. If not centered, the load may swing when lifted.
  • Hang hoists solidly in the highest part of the hook area. Rigged this way, the hook support is directly in line with the hook shank
  • Lever operated hoists can be used to pull in any direction, but a straight line pull must be maintained. Side pulling or lifting increases wear and sets up dangerous stress levels on hoist parts. Only one person should pull on hand, chain and lever hoists.
  • When loading the lower hook, place the load directly in line with the hook shank. Loaded this way, the load chain makes a straight line from hook shank to hook shank.
Lever Operated Hoist
  • Pushing a loaded hoist is safer (A). If it must be pulled, use a rope (B).
Pushing a loaded hoist is safer
If you must pull the hoist use a rope
  • Stand completely clear of the load.
  • Seat the load properly in the hook.
  • Move hoist controls smoothly. Avoid abrupt, jerky movements of the load. Remove slack from the sling and hoisting ropes before lifting the load.
  • Remove all loose materials, parts, blocking and packing from the load before starting the lift.
  • Make sure everyone is away from the load before starting to hoist.


What should you avoid when using material hoists?

  • Do not use hoisting equipment for lifting people.
  • Do not pass a load over workers.
  • Do not tip a load. The load is unstable and harms the hook and hoist.
  • Do not insert the point of the hook in a link of the chain.
  • Do not hammer a sling into place.
  • Do not leave slings dangling from the load hook. Place sling hooks on the sling ring when carrying slings to the load.
  • Do not raise loads higher than necessary to clear objects.
  • Do not exceed a hoist load limit.
  • Do not leave suspended loads unattended.
  • Do contact Ijin Marine Limited to choose quality material hoist made in China.

What is Synthetic Web Slings?


What should you know about using synthetic web slings?

Synthetic web slings are a good choice where highly finished parts or delicate equipment must be protected from damage. The synthetic material has stretch and flexibility to help the slings mold to the shape of the load, gripping securely, while cushioning and absorbing shock more than a wire rope or chain.

  • They are lightweight and very easy to handle.
  • They are non-sparking, non conductive and can be used safely in explosive atmospheres.
  • Synthetic slings are typically not affected by grease, oil, moisture and certain chemicals. Check with the manufacturer to determine which conditions apply to the exact material you are using.
  • Synthetic web slings are easily cut and have poor abrasion resistance when compared with chain and wire rope slings. Protect webbing from sharp corners, protrusions, or abrasive surfaces.
  • Protect slings from heat sources such as steam pipes, open flame and welding splatter.
  • Nylon slings are damaged by acids, but resist caustics.
  • Polyester slings are damaged by caustics but resist acids.
  • Sunlight, moisture, and temperatures above 90°C (194°F) damage both nylon and polyester slings.
  • Use slings made of the right material for the job.
  • Check the manufacturers' slings for their code number and the rated capacity. Reference charts showing slings and hitch rated capacities are available from manufacturers.
  • Inspect slings before using them.
  • Keep an inspection record for each sling.

What should you check when selecting slings?

  • Refer to the manufacturer's reference chart for the capacity rating.
  • Check a sling before using it.
  • Determine the weight of the load.
  • Prevent loading more than the rated capacity by considering sling angle.
  • Ensure that the sling choking action is on the webbing, not the hardware.
  • Have slings repaired by a sling manufacturer only.

What should you avoid when using slings?

  • Do not drag slings across floors or other abrasive surfaces.
  • Do not drop slings with metal fittings.
  • Do not set loads down on top of slings.
  • Do not pull slings from under loads when the load is resting on the sling.
  • Do not weld anything hung from a sling.
  • Do not lengthen or shorten slings by tying knots.
  • Do not place stitch patterns (laps) on hooks, around sharp corners, or at choker bearing points.

What kinds of damage make a synthetic web-sling unusable?

  • Increased stiffness of sling material.
  • Acid or caustic burns.
  • Melted, burned or weld spatter damage.
  • Holes, tears, cuts, snags.
  • Broke or worn stitching.
  • Excessive abrasive wear.
  • Knots in any part of the sling.
  • Crushed webbing or embedded particles.
  • Bleached sling colour.
  • For more information about synthetic slings,pls contact Ijin Marine Limited. We will provide more not only in China but the whole world.

Slinging on overhead crane hook


How should you sling a load onto a crane hook?

  • Make clear signals according to standard signals.
  • Signal the crane operator from only the one slinger who is in charge of lift. The only exception is a stop signal. (A slinger or rigger is the person who hooks loads onto cranes using various types of slings.)
  • Determine the weight of the load to be lifted.
  • Select the right sling for each job using the manufacturers' tables. A slinger must be familiar with these tables showing the safe capacities of slings.
  • Inspect each item of lifting equipment before and after lifts.
  • Protect slings from damage by sharp edges with corner saddles, padding, or wooden blocks.
  • Warn all people out of the load area before starting the lift.
  • Protect your hands and fingers: when slack is being taken out of a sling, keep them from between the sling and load so they will not be trapped and crushed. Step away before the lift is made.
  • Make sure a load is high enough to clear all objects before signaling for the crane to move.
  • Walk ahead of the moving load and warn people to keep clear. Use guide ropes to prevent rotation or other uncontrolled motion.
  • Hook unused sling legs to the sling ring.

What should you avoid when slinging a load?

  • Do not exceed the capacities of slings, fixtures and cranes.
  • Do not twist or tie knots in slings or use bolts, nails or pieces of wire to shorten slings.
  • Do not splice together broken slings.
  • Do not ride on hooks or loads.
  • Do not allow workers to walk or work under a load.
  • Do not attempt to pull or push loads to a spot that is not under the hoist.
  • Do not drag slings. Avoid pulling slings out from under loads by crane. Set down loads on blocking, never directly on a sling.
  • Do not leave unused slings, accessories, or blocking lying on the floor. Hang on racks or store in a proper place.
  • Do not carry a load by inserting the point of the hook into a link of the chain.
  • Do not hammer a sling into place.
  • Do not leave loose materials on a load.
  • Do not use slings that are stretched, broken, or defective. Tag them as defective and dispose of any damaged slings.
  • Do not leave suspended loads unattended.
  • from Canadian Centre for Occupational Health & Safety
  • Ijin Marine Limited edited all above material from China.

Plate Clamp Inspection and Use


What should you inspect the body of a clamp?

  • Follow the clamp manufacturers' maintenance recommendations.
  • Inspect internal and external surfaces for forging or weld fractures, wear and distortion.
  • Check all pin holes for wear.
  • Inspect the throat (clamp opening) width. At zero grip, the cam should be in full contact with the pad.
  • Measure the width of the throat. If the measurement at the base, where the pad is located is greater than at the top, the body has been overloaded. Replace the clamp; tag the defective clamp and remove it from service.
Throat Width
  • Check all pin holes for wear.
  • Inspect the throat (clamp opening) width. At zero grip, the cam should be in full contact with the pad.
  • Measure the width of the throat. If the measurement at the base, where the pad is located is greater than at the top, the body has been overloaded. Replace the clamp; tag the defective clamp and remove it from service.


How should you inspect the internal parts of the clamp?

  • Soak overnight in a degreasing solvent to remove all dirt and grease that prevent proper inspection of components. Degreasing solvents should be used in appropriately well ventilated areas. Handle the wet clamp parts while wearing gloves made of material that is chemically resistant to the solvent.
  • Remove the body pins or bolts and slide out the complete internal mechanism.
  • Check each body pin or bolt for wear or bending due to overloading.
  • Check each spacer, rivet, bolt or internal part for play or wear.


What should you know about the spring, cam, lock and pads?

  • The cam spring should be strong enough to hold the cam against the pad.
  • The locking spring should give initial pressure at near zero grip without material in the clamp.
  • There should be "definite tension" in the locked position.
  • The spring should not be bent or distorted.
  • The lock assembly should rotate freely without binding and must rest fully on the stop pin.
Spring Cam and Lock
  • Cams and pads are vital parts of a clamp and are exposed to wear. Use on one size plate thickness will cause wear only in one area of the cam working surface. Replacement is required sooner than when a cam is used to handle different plate thicknesses.
  • Examine the cam surface. If the teeth are flattened by 50% or more, replace the cam and pad.
  • Teeth must be sharp and free of foreign material.


How should you use plate clamps safely?

  • Refer to the manufacturers' operating instructions.
  • Inspect clamps visually before each lift.
  • Use the correct clamp for a job.
  • Use two or more clamps to balance a long or flexible load.
  • When using a vertical type of plate clamp, use a locking device to prevent accidental loosening.
  • Use horizontal types of plate clamps in pairs.
  • Use clamps within their rated capacity and flange width.
  • Lock a clamp closed before lifting a load.
  • Use a sling between the clamp and the crane or hoist hook.
Vertical Type
Horizontal Type


What should you avoid when using plate clamps?

  • Do not lift over workers.
  • Do not stand near a load. Position yourself away from and fully clear of the load.
  • Do not lift from the side with a vertical clamp.
  • Do not lift more than one plate at a time with a vertical clamp.
  • Do not lift plate from the bottom of a plate stack.
  • Do not grind, weld or modify a clamp.
  • Do not use a clamp having a minimum jaw opening larger than the thickness of the load.
  • Do not leave suspended loads unattended.
  • Ijin Marine Limited will provide more hard ware and deck machinery in China.

How to lift with eye bolt?


How should you select the right bolt?

Eye Bolts are marked with their thread size NOT with their rated capacities. Make sure you select the correct eyebolt based on its type and capacity for the lift you are conducting.

  • Use plain or regular eye bolts (non-shoulder) or ring bolts for vertical loading only. Angle loading on non-shoulder bolts will bend or break them.
  • Use shoulder eye bolts for vertical or angle loading.
Eye Bolts
Eye Bolts
Eye Bolts


How should you use eye bolts safely?

  • Orient the eye bolt in line with the slings. If the load is applied sideways, the eye bolt may bend.
  • Pack washers between the shoulder and the load surface to ensure that the eye bolt firmly contacts the surface. Ensure that the nut is properly torqued.
  • Engage at least 90% of threads in receiving a hole when using shims or washers.
  • Attach only one sling leg to each eye bolt.
Attach only one sling leg to each eye bolt
  • Inspect and clean the eye bolt threads and the hole.
  • Screw the eye bolt on all the way down and properly seat.
  • Ensure the tapped hole for a screw eye bolt (body bolts) has a minimum depth of one-and-a-half times the bolt diameter.
  • Install the shoulder at right angles to the axis of the hole. The shoulder should be in full contact with the surface of the object being lifted.
  • Use a spreader bar with regular (non-shoulder) eye bolts to keep the lift angle at 90° to the horizontal.
    • Use eye bolts at a horizontal angle greater than 45°. Sling strength at 45° is 71% of vertical sling capacity. Eye bolt strength at 45° horizontal angle drops down to 30% of vertical lifting capacity.
    • Use a swivel hoist ring for angled lifts. The swivel hoist ring will adjust to any sling angle by rotating around the bolt and the hoisting eye pivots 180°.

What should you avoid when using eye bolts?

  • Do not run a sling through a pair of eye bolts: this will reduce the effective angle of lift and will put more strain on the rigging.
  • Do not force the slings through eye bolts. This force may alter the load and the angle of loading.
  • Do not use eye bolts that have been ground, machined or stamped.
  • Do not use bars, grips or wrenches to tighten eye bolts.
  • Do not paint an eye bolt. The paint could cover up flaws.
  • Do not force hooks or other fittings into the eye; they must fit freely.
  • Do not shock load eye bolts.
  • Do not use a single eye bolt to lift a load that is free to rotate.
  • Do not use eye bolts that have worn threads or other flaws.
  • Do not insert the point of a hook in an eye bolt. Use a shackle.
Use a shackle

How to maintenance hoist wire ropes?


Who should inspect wire ropes and when?

  • Only trained personnel should carry out an inspection of wire ropes.
  • Inspect a wire rope when installing it.
  • Visually inspect wire ropes every working day and at the start of each shift.
  • Keep records of daily inspections.

How do you visually inspect wire ropes?

  • Use the "rag-and-visual" method to check for external damage. Grab the rope lightly and with a rag or cotton cloth, move the rag slowly along the wire. Broken wires will often "porcupine" (stick out) and these broken wires will snag on the rag. If the cloth catches, stop and visually assess the rope. It is also important to visually inspect the wire (without a rag). Some wire breaks will not porcupine.
  • Measure the rope diameter. Compare the rope diameter measurements with the original diameter. If the measurements are different, this change indicates external and/or internal rope damage.
  • Visually check for abrasions, corrosion, pitting, and lubrication inside rope. Insert a marlin spike beneath two strands and rotate to lift strands and open rope.
How to Check Rope
Checking Rope for Wear


When should you stop using the rope and remove it from use?

Assess the condition of the rope at the section showing the most wear. Discard a wire rope if you find any of the following conditions:

  • In running ropes (wound on drums or passed over sheaves), 6 or more broken wires in one lay length; 3 or more broken wires in one strand in one lay.
  • In pendant standing ropes, 3 or more broken wires in one lay length.
  • Wear of 1/3 of the original diameter of individual outside wires.
  • Kinking, crushing, cutting or unstranding, bird caging or other physical damaged that has distorted the shape of the wire rope.
  • Heat damage (check for burn marks, discoloration of the metal).
  • Excessive stretch or sharp reduction in the rope diameter.
  • Knots or splices (except eye splices) in a wire rope.


What can cause a wire rope break?

  • Wear on areas in contact with hoist sheaves and drums.
  • Corrosion from lack of lubrication and exposure to heat or moisture (e.g., wire rope shows signs of pitting). A fibre core rope will dry out and break at temperatures above 120°C (250°F).
  • Fatigue from repeated bending even under normal operating conditions.
  • Overloading the safe working load limit. Follow manufacturers' charts.
  • Mechanical abuse - crushing, cutting or dragging of rope.
  • Kinks from improper installation of new rope, sudden release of a load or knots made to shorten a rope. A kink cannot be removed without creating a weak section. Discarding kinked rope is best.
A Kinked Rope
Ijin Marine Limited,China

What is crane and hoist hand signals?

When should the crane operator follow hand signals?

A crane operator should always move loads according to the established code of signals, and use a signaler. Hand signals are preferred and commonly used.

Who can give the hand signals? or Who can be a signaler?

  • A person qualified to give crane signals to the operator.
  • There should be only one designated signaler at a time.
  • If signalers are changing between each other, the one in charge should wear a clearly visible badge of authority.
  • A crane operator should move loads only on signals from one signaler.
  • A crane operator must obey STOP signals no matter who gives it.


What should you do when in charge of signaling?

The signaler must:

  • Be in clear view of the crane operator.
  • Have a clear view of the load and the equipment.
  • Keep persons outside the crane's operating area.
  • Never direct a load over a person.


What are examples of some common hand signals?

Hoist: With forearm vertical, forefinger pointing up, move the hand in a small horizontal circle.

Lower: With an arm extended downward, forefinger pointing down, move the hand in small horizontal circles.

Multiple Trolleys: Hold up one finger for block marked "1" and two fingers for a block marked "2." Regular signals follow.

Multiple Trolleys
Multiple Trolleys

Bridge Travel: Arm extended forward, hand open and slightly raised, make a pushing motion in direction of travel.

Trolley Travel: Palm up, fingers closed, thumb pointing in direction of motion, jerk the hand horizontally.

Stop: Arm extended, palm down, hold the position rigidly.

Bridge Travel

Bridge Travel
Trolley Travel
Trolley Travel

Emergency Stop: Arm extended, palm down, move the hand rapidly right and left.

Magnet Is Disconnected! : Crane operator spreads both hands apart, palms up.

Dog Everything: Clasp hands in front of the body. Means PAUSE. This signal can be used on potentially risky occasions such as when it has started raining, when the load doesn't fit the space for which it was planned, or when a bystander gets too close to the action.

Emergency Stop
Emergency Stop
Magnet is Disconnected!
Magnet is Disconnected!
Dog Everything 
Dog Everything


What are some common hand signals for crawler, truck and locomotive cranes?

Use Main Hoist: Tap fists on head; then use regular signals.

Use Whip Line (Auxiliary Hoist): Tap elbows with one hand; then use regular signals.

Raise Boom: Arm extended, fingers closed, thumb pointing upward.

Lower Boom: Arm extended, fingers closed, thumb pointing downward.

Swing: Point with a finger in direction of swing of a boom.

Use Main Hoist
Use Main Hoist
Use Whip Line
Use Whip Line
Raise Boom;  Lower Boom; Swing
Raise Boom; Lower Boom; Swing

Raise the Boom and Lower the Load: Arm extended, fingers closed, thumb pointing upward, other arm bent slightly with forefinger pointing down and rotate hand in horizontal circles.

Lower the Boom and Raise the Load: Arm extended, fingers closed, thumb pointing downward, other arm with forearm vertical, forefinger pointing upward and rotate the hand in horizontal circles.

Move Slowly: Use one hand to give any motion signal and place the other hand motionless in front of the hand giving the motion signal. (Hoist Slowly shown as example.)

Raise the Boom and Lower the Load
Raise the Boom and Lower the Load
Lower the Boom and Raise the Load
Lower the Boom and Raise the Load
Move Slowly
Move Slowly

Retract Boom (Telescoping Booms): Both fists in front of body with thumbs pointing toward each other.

Extend Boom (Telescoping Booms): Both fists in front of body with thumbs pointing outward.

Retract Boom
Retract Boom
Extend Boom
Extend Boom

What are some signals for crawler cranes only?

Lock Track: this side as indicated by raised fist.

Turn Travel Track: this side in direction shown by revolving fist.

Travel Both Tracks: forward or backward by revolving fists.

Lock Track - Turn Travel Track
Lock Track
Turn Travel Track
Travel Both Tracks
Travel Both Tracks

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Document last updated on January 4, 2008

How to do crane pre inspection?

What should you check for before operating a crane?

  • Rope appearance - lubrication, kinks, cuts, breaks, corrosion, reduced diameter, broken strands of wires or other signs of wear or damage.
  • A rope drum - position of cable in groove tracking, means of anchoring and drum wear or damage.
  • Sheaves - alignment of ropes, guides, dead ends, wear in sheave groove.
  • Hooks - cracks, twisting, straightening, hook throat opening or other signs of wear or damage, bent safety latch and broken spring.
  • Slings - appropriate type of sling, legible and appropriate capacity ratings, holes, with no cuts, crushed webbing and other damages.
  • Lights - burned out, broken.
  • Mechanical parts and guards - loose, bent, broken, and missing.
  • Rails - broken, chipped, cracked.
  • Wheels - worn (showed by bumpy riding).
  • Bearings - loose, worn.
  • Brakes - shoe wear.
  • Bridge bumpers and a trolley end stop - loose, missing, improper placement.
  • Controllers and collector shoes or bars - worn, pitted, loose, broken, or faulty operation.
  • Control buttons - labeled to indicate their function, properly function, immediately releases without sticking.
  • A foot walk - condition of the boards, railings, and ladders.
  • Gears - lack of lubrication or foreign material in gear teeth (indicated by grinding or squealing).
  • A fire extinguisher must be in the crane cab.
  • Make sure that no one is on or around a crane before closing the main or emergency switch, even when starting on regular duty.
  • Before closing the main switch, make sure that all controllers are in the "off" position.
  • Inspect oil only after opening and locking out the main switch.
  • Make sure no overhead power lines are obstructing the crane operation.

What should you inspect a moving crane for?

Before lifting any load you should start the crane and inspect it when it is moving. Look for:

  • Smooth play out of wire rope to and from a drum.
  • Sheaves turning without binding or jerking as a rope passes over them.
  • Proper alignment where ropes enter sheaves.
  • Ropes not rubbing on rope sheave guards.
  • Rubbing, scraping, or clattering noises during operation.
  • Jerky movements.
  • Proper operation of controls and brakes.
  • Test the limit switch. Slowly raise the hook block with no load attached to the hook. If the switch is defective, make sure the block does not strike the cable.
  • In China,Ijin is waiting for you to provide quality product and impressing service.

How to do crane maintenance?

What should you check for when inspecting a crane?


  • Use maintenance checklists and record problems clearly in the maintenance logbook.
  • Follow the company requirements and the manufacturer's manuals.
  • Complete maintenance checklists while the engine is off and then again when the engine is on. Engine off checks helps to find any obvious problems and correct them before starting the engine and possibly harming others.

Wire Rope

  • Lower hoist to unload rope sheaves.
  • Unwind all wire rope from the hoist drum to expose all parts of a rope, making sure that the rope does not rewind in the reverse direction.
  • Inspect sheaves, sockets, dead-ends, thimble joints, and all wire rope hardware.
  • During rope changes, check the sheaves for worn bearings, broken flanges, proper groove size, smoothness, and contour.
  • Inspect all parts of the cable, cleaning wire rope only as required to complete an inspection. Excessive removal of lubrication will lead to damage.
  • Re-lubricate rope to prevent corrosion, wear, friction, and drying out of the core.
  • Check for ropes that may have been operated dry (unlubricated). Replace dry ropes. There may be hidden damage that is not detected by visual inspection.
  • Compare the rope length and diameter with the original dimensions. Lengthening accompanied by diameter reduction is often an indication of interior core defects.

Establish a schedule of rope replacement to change wire rope before it breaks. Periodic replacements do not take the place of inspections. If rope breaks or inspections reveal abnormal wire breakage or defects, reduce the time between replacements. Do not make wire rope slings from used wire rope.

Crane Structure and accessories

  • Visually examine the crane structure for deformed, cracked or corroded members in the structure and boom.
  • Check for loose bolts or rivets.
  • Check for excessive wear on brake and clutch system parts.
  • Check for deformed wedges.
  • Check for defective cotter keys, pins and guardrails.
  • Ensure all mechanical components of the crane is in good working order (gear box, hydraulics, etc.).

Hydraulic systems

  • Check for deterioration or leakage in air or hydraulic systems.
  • Check for safe and effective operation on hoses, pumps and motors.
  • Check levels of fluid.
  • Check air cleaners for replacement or cleaning.

Control Mechanisms and Monitoring Devices

  • Check all control mechanisms such as cables, brakes and levers for poor adjustment or excessive wear.
  • Check accuracy of marking on the load/radius indicator over full range.
  • Check for proper operation of load moment indicator, boom angle indicator, boom length indicator and anti two-block system according to the manufacturer's manual.


What are some things to remember when repairing a crane?

  • Enter all service inspections and repairs in a crane logbook or file.
  • Take a crane to a location where repairs will least interfere with other cranes.
  • Ensure that all controllers are placed in the "off" position, and the main switches are open and locked.
  • Place on the switch a standard warning tag stating "DO NOT START." The tag must be filled out and signed.
  • Place rail stops or make other safety provisions when another crane operates on the same runway.
  • Use fall protection equipment.
  • Do not carry anything in your hands when going up and down ladders. Items that are too large to go into pockets or belts should be lifted to or lowered from the crane by a rope.
  • Prevent loose parts or tools from falling to the floor.
  • The area below the crane must be cleared and a barrier erected to prevent injury from a falling object.
  • Replace all guards and other safety devices before leaving a crane.
  • Remove all stops, tools, loose parts and other material and dispose of them before completing the repair job.
  • Keep your equipment clean including batteries, cab and windows, wheels and tracks, deck and car body.
  • Try Ijin Marine Limited to know more about crane and hardware.Not only a supplier,Ijin also tell you more about hardware from China.

4 Q&As helps you know more about chain slings

When should you inspect chain slings?

Inspect chain slings and accessories before each use and before placing into storage. Check for visible faults in links and hooks and distortion of fittings.


How should you check chain slings during inspection?

A competent person should inspect chain slings periodically, according to the manufacturer's recommendations. For record keeping purposes it is useful if each chain has a metal tag with an identification number and load limit information. Information about the chain length and other characteristics and an inspection schedule should recorded in a log book.

  • Clean sling before inspection.
  • Hang the chain up or stretch the chain out on a level floor in a well-lighted area. Remove all twists. Measure the sling length. Discard if a sling has been stretched.
  • Make a link-by-link inspection and discard if:

a) Wear exceeds 15% of a link diameter.

Curved Chain Sling

Cut, nicked, cracked, gouged, burned, or corrosion pitted.

Damaged Chain Sling

c) Twisted or bent.

Twisted or Bent Chain Slings

d) Stretched. Links tend to close up and get longer.

Stretched Chain Sling
  • Check master link, load pins and hooks for any of the above faults. Hooks should be removed from service if they have been opened more than 15% of the normal throat opening, measured at the narrowest point, or twisted more than 10° from the plane of the unbent hook.
  • Manufacturers' reference charts show sling and hitch capacities. Record manufacturer, type, load limit and inspection dates.


How should you use chain slings safely?

  • Always know how to properly use the equipment, slinging procedures before attempting the lift operation.
  • Inspect the slings and accessories before use for any defects.
  • Replace broken safety latches.
  • Find out load weight before lifting.
  • Check whether chain slings fit freely. Do not force, hammer or wedge chain slings or fittings into position.
  • Keep hands and fingers from between load and chain when tensioning slings and when landing loads.
  • Ensure the load is free to be lifted.
  • Make a trial lift and trial lower to ensure the load is balanced, stable and secure.
  • Balance the load to avoid overstress on one sling arm or the load slipping free.
  • Lower working a load limit if there may be severe impact.
  • Pad sharp corners to prevent bending links and to protect the load.
  • Position hooks of multi-leg slings facing outward from the load.
  • Do not leave suspended loads unattended.
  • Cordon off the area.
  • Reduce the load limit when using chain in temperatures above 425°C (800°F).
  • Store chain sling arms on racks in assigned areas and not lying on the ground. The storage area should be dry, clean and free of any contaminates which may harm the sling.


What should you avoid using chain slings?

  • Avoid impact loading: do not jerk the load when lifting or lowering the sling. This increases the actual stress on the sling.
  • Do not drag chains over floors or attempt to drag a trapped sling from under a load. Do not use a sling to drag a load.
  • Do not use worn-out or damaged slings.
  • Do not lift on the point of the hook.
  • Do not overload or shock load a sling.
  • Do not trap slings when landing the load.
  • Do not splice a chain by inserting a bolt between two links.
  • Do not shorten a chain with knots or by twisting other than by means of an integral chain clutch.
  • Do not force or hammer hooks into place.
  • Do not use homemade connections. Use only attachments designed for the chain.
  • Do not heat treat or weld chain links: the lifting capacity will be reduced drastically.
  • Do not expose chain links to chemicals without the manufacturers approval.
  • Contact Ijin Marine Limited for more information about chain slings,wire rope slings, PP slings,etc.Ijin,China help you to get quality products with reasonable prices.

How should you select the proper wire rope sling?

  • Follow the manufacturers' charts and tables on sling types, angles, and rope diameters and select a proper sling which suits the load and the slinging method that you are going to use. Sling types can be endless, single, two, three or four leg.
  • The sling must be both long enough and strong enough for the load and the slinging method.
  • Follow the manufacturers' recommendations on clips and clamps of suitable size and design for ropes of different size.
  • Consult the manufacturer or supplier when wire rope slings come into contact with acids or chemicals.
  • Attach using methods outlined by the manufacturer.
  • Remember that a socket and clip fittings used to attach the rope determine the sling's load limit. Fittings have 75% to 100% of the breaking load of the rope.
  • Remember that the safe load limit of a sling also depends on the hitch (method of applying a sling to the load). The type of hitch depends on the kind of material to be lifted, the safe load limit of the sling, the presence (or absence) of lugs on the load, the headroom, and other factors. Check with the manufacturers instructions.
Wire Rope Slings

How should you use wire rope slings safely?

  • Be sure you know the correct use of the equipment, the slinging procedures and the sling strength factors to be applied before lifting.
  • Use wire rope slings at rated limits.
  • Check the manufacturer's chart for sling properties.
  • Examine slings for wear, fatigue, crushed or broken wires, kinking, ballooning or "bird-caging", heat damage, etc. Check both before and after using slings to detect any damage or defects.
  • Attach the sling securely to the load and appliance and position hooks to face outwards.
  • Inspect and tighten fittings regularly.
  • Ensure the load is balanced and will not tilt or fall.
  • Center the sling load to prevent the load from shifting suddenly and causing a high impact load.
  • Ensure that the load is free to be lifted.
  • Keep fingers and toes clear when tensioning slings and when landing loads.
  • Make a trial lift and trial lower to ensure everything is working in a safe manner.
  • Reduce rope stress with slow starts and stops.
  • Position hooks of multi-leg slings facing outward from the load.
  • Back hook free legs to the master link to avoid lashing legs which might accidentally become engaged.
  • Keep wire rope slings well lubricated and inspect them often. Use non-acidic lubricants.
  • Remove damaged slings from service and tag appropriately.
  • Store slings on racks in a clean, dry place and protect from corrosion.


What should you avoid when using wire rope slings?

  • Do not bend slings around sharp edges. Protect them by using corner saddles, padding, or wood blocks.
  • Do not force, hammer or wedge slings or fittings into position. They must fit freely.
  • Never join wire rope slings made from different lays of rope together as it can seriously affect the lifting capacity.
  • Do not use slings with knots.
  • Never attempt to shorten or tie wire rope slings.
  • Never shock load wire rope slings.
  • Do not slide the load along a rope.
  • Do not use a single leg hitch on a load that cannot be controlled. Rotation of a load can undo the wire rope strands and weaken the rope.
  • Ijin Marine is always trying to supply quality wire rope slings from China.Never mind which country you are from, Ijin is able to deliver slings to location you expect.Contact sales@ijinmarine.com for more information.

What are the types of shackles that you can choose?

Anchor (bow type) and chain ("D" type) shackles are used with screw or round pins.

  • When selecting the right shackle, refer to manufacturers' tables for the safe working loads of the shackles.
  • Shackles are sized according to the diameter of the bow section rather than the pin size. Never use a shackle if the distance between the eyes is greater than listed in the manufacturers' tables.


How should you inspect shackles?

  • Inspect shackles regularly.
  • Inspect the shackle eye and pin holes for stretching (elongation) and wear. Elongation means the metal is being overloaded.
  • Inspect the shackle body for bending. A bent shackle indicates excessive side-loading.
  • Inspect all shackle pins for distortion, surface blemishes, wear and fractures.
  • All pins must be straight and all screw pins must be completely seated. Cotter pins must be used with all round pin shackles.
  • Replace shackles that are bent, show excessive wear by more than 10% of the original diameter, or have an elongated eye or shackle pin holes.


What should you avoid when using shackles?

  • Do not replace the shackle pin with a bolt or unidentified pins. A load will bend the bolt.
Do not replace the shackle pin with a bolt
  • Do not allow a shackle to be pulled at an angle. The legs will open. Pack the pin with washers to center the shackle.
Pack the pin with washers to centre the shackle
  • Do not use screw pin shackles or fit pins in contact with moving parts if the pin can roll and unscrew. If the load shifts, the sling will unscrew the shackle pin.
Do not use screw pin shackles if the pin can roll and unscrew
  • Do not use shackles with bent pins or deformed bodies.
  • Do not force, hammer or wedge shackles into position.
  • In China,if you need any hard ware for industrial use or shipping use, just contact Ijin Marine Limited, reliable supplier.

What are shackles? From Wikipedia.

shackle, also known as a gyve, is a U-shaped piece of metal secured with a clevis pin or bolt across the opening, or a hinged metal loop secured with a quick-release locking pin mechanism. The term also applies tohandcuffs and other similarly conceived restraint devices that function in a similar manner. Shackles are the primary connecting link in all manner of rigging systems, from boats and ships to industrial crane rigging, as they allow different rigging subsets to be connected or disconnected quickly. A shackle is also the similarly shaped piece of metal used with a locking mechanism in padlocks.

carabiner is a variety of shackle used in mountaineering.



Pin shackle

A pin shackle is closed with an anchor bolt and cotter pin, in a manner similar to a clevis. It is for this reason they are often referred to, in industrial jargon, as clevises. Pin shackles can be inconvenient to work with, at times, as the bolt will need to be secured to the shackle body to avoid its loss, usually with a split pin or seizing wire. A more secure version used in crane rigging features the combination of a securing nut (hardware) located alongside the cotter pin. Pin shackles are practical in many rigging applications where the anchor bolt is expected to experience some rotation.

Threaded shackle

A moused shackle

The pin is threaded and one leg of the shackle is tapped. The pin may be captive, which means it is mated to the shackle, usually with a wire. The threads may gall if overtightened or have been corroding in salty air, so a liberal coating of lanolin or a heavy grease is not out of place on any and all threads. A shackle key or metal marlinspike are useful tools for loosening a tight nut.

For safety, it is common to mouse a threaded shackle to keep the pin from coming loose. This is done by looping mousing wirethrough the hole in the pin and around the shackle body. For pins that have a cross-hole in the threaded end a cotter pin can be used. One disadvantage is that mousing can introduce galvanic corrosion because of material differences; it is especially bad when used in places where the shackle is exposed to air and water.

Snap shackle

As the name implies, a snap shackle is a fast action fastener which can be implemented single handedly. It uses a spring activated locking mechanism to close a hinged shackle, and can be unfastened under load. This is a potential safety hazard, but can also be extremely useful at times. The snap shackle is not as secure as any other form of shackle, but can come in handy for temporary uses or in situations which must be moved or replaced often, such as a sailor's harness tether or to attach spinnaker sheets. Note: When this type of shackle is used to release a significant load, it will work rather poorly (hard to release) and is likely to have the pin assembly or the split ring fail.

A snap shackle spliced to a line



Also known as a chain shackle, D-shackles are narrow shackles shaped like a loop of chain, usually with a pin or threaded pin closure. D-shackles are very common and most other shackle types are a variation of the D-shackle. The small loop can take high loads primarily in line. Side and racking loads may twist or bend a D-shackle.

Headboard shackle

This longer version of a D-shackle is used to attach halyards to sails, especially sails fitted with a headboard such as on Bermuda rigged boats. Headboard shackles are often stamped from flat strap stainless steel, and feature an additional pin between the top of the loop and the bottom so the headboard does not chafe the spliced eye of the halyard.

Twist shackle

A twist shackle is usually somewhat longer than the average, and features a 90° twist so the top of the loop is perpendicular to the pin. One of the uses for this shackle include attaching the jib halyard block to the mast, or the jib halyard to the sail, to reduce twist on the luff and allow the sail to set better.

Bow shackle

With a larger "O" shape to the loop, this shackle can take loads from many directions without developing as much side load. However, the larger shape to the loop does reduce its overall strength. Also referred to as an anchor shackle.

Ijin Marine Limited is a hardware supplier in China.

A Guide to Different Types of Boats

A boat is a small vessel which has been specifically designed for navigating in near-shore areas or inland waterways. Though there is a thin line between a ship and a boat, there are quite a few differences which set both of them apart.

Apart from recreational purpose, boats have also served an integral purpose in the commercial world by allowing active transportation of both passengers and cargo, wherever short distances are concerned. In this article, we will take a look at the main types of boats that are used around the world.

Technically, there are several types of boats and it’s impossible to list down all the types. However, boats can be classified into three  main sections as follows:

  1. Unpowered or man-powered (like rafts, gondolas, kayaks, etc.),
  2. Sailboats (sail-propelled)
  3. and Motorboats (engine-powered)

A few chosen instances of these categories of boats may include the following:

1. Fishing Boats

As the name suggests, these type of boats are used for fishing activities. Fishing boats are used on both salty and fresh water bodies. The immediate qualities include stability, strength and durability to survive the fishing ventures across various kinds of waterways.

fishing boat

The all-purpose fishing boats generally include features such as a front bow, rod lockers, a trolling motor system, an outboard power and live wells. On the other hand, the aluminum fishing boats weigh less and are highly durable. Fishing boats can be both manned and un-manned types.

2. Bass Boats

The bass boats are designed with slim profiles, and consist of 2-3 anglers on board,and are used for fishing. The common specimens are built of aluminum with 25-150 horsepower, and the length varies between 16 and 18 feet.

bass boat

Similarly, the tournament bass boats utilize 150-250 horsepower and are more than 18 feet, lengthwise. Live wells, and electric trolling motors are compulsory features.

3. Bowrider Boats

The bow area of these type of boats has been constructed in special way to allow a spacious seating arrangement. Moreover, these runabout-style vessels contain a swim platform for putting on wake-boards, or for swimming activities.


The usage of stern drive power is the typical rule, but the demand for outboard engines is increasing at a high rate.

4. Catamaran Boats

The power or sailing style catamarans comprise of multiple hulls and are excellent for fishing purposes and even for leisurely cruising abilities.


A boat consisting of three hulls are also referred to as a trimaran boat.

5. Cuddy Cabins Boats

This type of boat is well-suited for fishing, yachting, sailing and other water sports. Also, the presence of a closed deck over the boat’s bow allows a convenient storage space and also easy navigation.

cuddy cabin

The cuddy cabin boats are usually built of fiber glass and aluminum, and the minimum length is around 4.75 meters.

6. Centre Console Boats

The Centre Consoles are ideal for sport fishing and work in harsh offshore waterways where there is plenty of ocean fish.

center console

The basic equipment consists of bait wells, gunwale rod holders, fish lockers and outriggers, to name a few. The deck provides a powerful insulation system for icing the fish storage.

7. Dinghy Boats

A dinghy is a small inflatable boat usually made of rubber and comprises of cross thwarts and rowlocks that act as seats and oars, respectively. Dinghies are popularly known as sailboats, rowboats or simply inflatables.


These boats team up with larger vessels and come in handy when the mother ship is unable to navigate in narrow areas. These rowboats can also be utilized as companion boats and are taken to camping expeditions or for fishing in shallow waters.

8. Houseboats

These boats offer the luxury of living on water and provide excellent recreational and holiday accommodation facilities.


House boats incorporate broad flooring and modern amenities such as entertainment, fine dining and proper sleeping arrangements. The boats offer fun activities like relaxed cruising, water sports, family sailing etc.

9. Trawler Boats

The main advantage of trawlers is that the presence of a displacement hull allows them to smoothly maneuver through the water bodies without exhausting much horsepower or consuming excessive fuel.


This quality makes the trawler a brilliant option for participating in long-range cruising activities, as all modern facilities can be found.

10. Cabin Cruiser Boats

These boats are apt for relaxed sailing and include a galley and a berth. All modern comforts like heaters, air conditioners, and power generators are enclosed in the arrangement.

cabin cruises

The Cabin Cruisers employ an easy shaft drive mechanism plus rudder steering, and therefore is mainly suited for movement in salty water.

11. Game boats

These fiberglass boats are generally large in measurement, powered by diesel or petrol engines, and are useful for the game fish pursuit, especially pelagic fishes like tuna and marlin.

game boats

Sleeping berths, plumbing system, cooking galleys, allow the boats to remain waterborne for a couple of days or more.

12. Motor yacht Boats

The motoryachts have a standard length of 12m and above, with one or two diesel engines as per navigation requirement in the bigger river systems or the oceans.

Motor Yacht

The motoryachts can vouchsafe for an enjoyable family trip, for a long period of time that it sails on water.

13. Personal Watercraft Boats

The PWC boats are customized for adventurous individuals who all are seeking thrilling expeditions.


The PWCs allow one to explore the waters at their own ease, not only during solo rides but also during family trips. Games such as waterskiing, sport fishing, tubing are comfortably carried out.

14. Runabout Boats

The movement of these open boats is controlled by a steering wheel and forward controls, as located behind a windscreen.

runabout boats

Cabin space is not required. Runabouts are usually declared entry-level vessels for casual sports and boating activities.

15. Jet Boats

The structure of a jet boat is quite similar to that of a bow-rider, as it offers a lot of seating area along with a swimming platform.

Jet Boats

The advanced propulsion system is securely enwrapped in the hull, to protect it from any external damage. The jet boats are really fast, yet easy to manage.

16. Wakeboard/ Ski Boats

The wakeboard boats and the ski boats look quite the same, but differ in their fields of action.

Wakeboard Boats

The inboard ski boats require a powerful range of acceleration and the shape of the engine and propeller accentuates it. Contrarily, the inboard wake boards need a V drive engine system, deep hulls, and a huge wake to set in motion.

17. Banana Boats

It is a boat that is solely utilized for recreational activities and simply for family entertainment.


As the name suggests, it is banana-shaped and inflatable and easily floats on water. It does not have an inbuilt motor system. A banana boat has a capacity to seat around three to ten people.

18. Life Boats

In emergency situations, lifeboats come to the rescue! These are mainly attached to bigger vessels like cruises and their main function is to carry passengers to a secure area, if the concerned vessel is met with an accident.

life boats

The lifeboats are well-equipped with immediate food and water supplies, and other necessities to pacify the frightened voyagers in case of a shipwreck.

More Types of Boats:

1. Hydrofoil boats

2. Cigarette boats

3. Cuddy Boats 

4. Tug Boats

5. High Speed Crafts

6. Bumper Boats

7. Pilot Boat

8. Fire Boat

9. Well boats

10. Kayak 

Apart from the above mentioned ones, several other types of boats exist in the market such as Bay or Flat Boats, All-Purpose fishing Boats, Deck Boats, High Performance Boats, Rafts, Surf boats, Narrow boats, Folding Boats, Log Boats, Go-fast Boats, Catboats, Junk Boats, Ferry Boats, Canoe Boats, U-boats, Dory boats etc.

References: boatsdepotdiscoverboatingmyboatinglife

Image Credits: discoverboating, gogetadventureseamagicsail-worldtrendszine,yachtchartersinmiami

Safe anchoring - planning and operational guidance for cargo ships

Planning for Anchoring
Master shall Identify a suitable anchoring position before entering the anchorage area. Conduct a planned approach including speed reduction in ample time and orienting the ships head prior anchoring to 
(a) Same as similar sized vessels around or (b) Stem the tide or wind whichever is stronger 
Decide on which method of anchoring to be used and the number of shackles depending on the depth of water, expected weather and holding ground. A simple rule in determining length of cable to use:
Standard condition: 
Length of cable = [(Depth of water in meters * 2) + 90 ] / 27.5 
When good holding power can not be expected: 
(e.g. Strong Wind, Strong Current, Harder Sea bottom) 
Length of cable = [(Depth of water in meters * 3) + 140 ] / 27.5
It is suggested the use of radar parallel indexing technique, an effective tool in maneuvering approach to anchoring position. A fix reference point is necessary in establishing the intended anchoring position relative to this fix point. 
Preparation for Anchoring 
The Chief Officer (or another experienced officer in lieu) must supervise letting go or weighing the anchors and should only assign experienced crew members to anchor work.
Prior to Anchoring, the Chief Officer should be aware of:
a. Approximate anchoring position
b. Method of approach
c. Which anchor to use
d. Depth of water
e. Method of Anchoring
f. Final amount of Cables
Procedure of the Introduction to Anchoring 
At the Forecastle:
Check brakes are on and clear the voyage securing devices
(Anchor Lashings, Bow Compressed Bar etc.)
a. Start Hydraulic(Source of) Power of Windlasses 
b. Check Anchor Shape / Light
c. Check Communication with the Bridge
d. Check Lighting on Forecastle including torch , at night time
e. Ensure all personnel are wearing Safety Helmets, Safety Shoes and Goggles. 
Before Letting Go Anchor :
The Chief Officer shall confirm that there is no craft or any obstacle under the bow and inform to the Bridge.
The Master shall ensure that the vessels GPS speed at the time of anchoring is near-zero or indicates a slight sternway. 
The speed should be verified by visual transits and/or Radar ranges of Landmarks, if available or other fix conspicuous targets. 
Where means of communication between Bridge and the Anchoring party is by Portable radio, the identification of the ship should be clear to avoid misinterpretation of instructions from other user of such equipment in the vicinity. 
Routine Anchoring Operation
There are 2 methods for Anchoring according to depth of the water:
Method 1 (Preferable for Container Ships / Depths up to 50m )
a. Walk out the anchor to Half a shackle above the sea bottom
b. Hold the cable on the brake and take the windlass out of gear
c. Stop the vessel over ground
d. Drop the anchor
e. Control the speed of cable flow by the brake , while not allowing pile-up
f. Bring anchor cable direction forward and confirmed anchor holds its position.
If the brake fails, or there is too much speed over ground, the cable will run out to the bitter end with consequent damage. The brake lining could also be damaged due to this Dynamic load (the Static load on brakes to restrain movement of an anchored vessel is much less). 

Method 2 (Suggested for Tankers / Depths over 50m )
a. Stop the vessel over ground
b. Walk out the anchor under power until the complete length of required cable is paid out and anchor holds it position on the seabed. 
c. Bring anchor cable direction forward and confirmed anchor holds its position.
Vessel must be completely stopped to avoid major damage to Windlass. 
Particular Caution for VLCCs 
VLCCs, because of their inertia require great caution while anchoring. 
They can suffer equipment failure if attempting to anchor whilst moving at speeds as low as half a knot over the ground. 
Hence, the vessel must be nearly stopped not only in the linear direction but axial too, meaning the bow should not be swinging much either while anchoring. 
The depth at which the vessel can safely anchor is about 110m or less, beyond which the windlass may have extreme difficulty in recovering the anchor.
Emergency Anchoring
Anchors should be ready for letting go on arrival and departure port, when in anchoring depths. At least, any wire lashings are to be removed and the anchors held on brake. In critical situations, to arrest the movement of the vessel, after stopping/reversing the main engine , it is preferable to let go both anchors simultaneously instead of one. 
Anchor retrieval
For weighing in the anchors, to reduce the load on the windlass, and keep the cable near vertical ,as required, short movements to be given on the main engine (and Bow Thruster used, where is applicable) 
The stay and direction of the cable and the residual shackles are to be continuously reported to the bridge. 
Anchor Wash to be run to clean the chain and the anchor.
When anchor is fully hove, the brake is to be applied and the windlass taken out of gear. 
The bow stopper is to be put when it is deemed safe to do so. 
If it does not engage properly on the chain, then it is to be lowered across the chain as far as possible and lashed down in this position in such a manner, that if the cable does slip, the bar will fall into place across the chain.
Anchor watch
An anchor watch is to be always kept when the ship is at anchor.

Ijin Marine Limited is always welcome all ship owner to purchase anchor,anchor chain and deck equipment,etc from us. We are a leading deck hardware supplier and trader in China. Anchor chain,mooring rope,wire rope,ladder,winch,lifeboat,etc can be supplied by Ijin Marine Limited.

14 Common Reasons for Stow Collapse

improper lashing caused container stowfall

Container stows often fail due to:
• Container stacks being too heavy and too high overall, exposing the lower containers to excessive transverse racking and compressive forces due to the tipping effect. Such an anomaly may occur if the ship is unable to calculate the forces acting on stow with precision. The Cargo/Container Securing Manual is limited in this respect as the examples of container weight distributions shown may not cover all permutations and eventualities. Software programs have the advantage of taking into account all known variables.

• Containers at the top of the stack being significantly heavier than those below. 
• The wind force acting on the outboard stacks not being taken into account. 
• Loose lashings allowing the stacks to tilt and arrest sharply as the slack is taken up. This causes the securing system to experience a sudden shock load which may exceed safe working limits by a considerable margin. 
• Two 20 foot containers placed in a 40 foot slot, leaving insufficient space for lashing rods to be fitted to the inward facing ends. This arrangement should be avoided unless the containers are either lightly loaded or empty and the stack height is low, or if the Cargo / Container Securing Manual allows. 
• Rogue twist locks (e.g. right-hand locking mechanism) finding their way aboard a vessel equipped entirely with twistlocks of a different type (e.g. left-hand locking mechanism). 
• If manual twist locks are used, screening checks should be carried out whenever possible in order to ensure that rogue devices are not present. 
• High cube boxes stowed cumulatively, resulting in the highest container extending well above the top of the cell guides. 
• Wherever possible, the vessel should scrutinize pre-plan details for the presence of non-standard containers. If the pre-plan shows that out of gauge boxes are to be loaded in unacceptable positions, more suitable stowage options should be discussed and agreed with the terminal as soon as possible. 
• Securing equipment not applied correctly, not tightened or not applied at all, contrary to the provisions of the Cargo/Container Securing manual. 
• Stevedores should be given detailed instructions regarding the positioning of the lashings and equipment to be used and, as far as practicable all arrangements should be checked thoroughly by the crew before sailing. 
• Portable and/or fixed securing equipment in damaged or worn condition. 
• Extreme weather conditions. 
• The movement of inadequately secured heavy cargo within a container during adverse weather, resulting in damage to the container walls and/or framework and leading to the eventual collapse of the stack. 

Pls send e-mail to us if you need any lashing materials from China. Ijin Marine Limite is trading and supplying all kinds of container lashing materials such as twist locsk,turnbuckles,lashing rods,stackers,etc.

Anchor & chain damage handled as GENERAL AVERAGE

When anchor and chain damage resulted from the following causes, they can be covered by insurance as 'General Average' sacrifices loss. The Master shall in such cases secure witness statement from external sources if Possible.
a. When the anchor and chain were damaged by Dropping in an emergency in order to avoid an Urgent Danger such as Collision with another ship at sea. 

b. When the weather suddenly changed to extraordinary Rough Weather while the vessel was in port and the anchor chains were cut intentionally as an urgent measure to avoid a danger because there was not sufficient time to heave the anchor. 

c. When the Main Engine was started in order to avoid an Urgent Danger at anchor, knowing that the anchor could be sacrificed, and consequently, the anchor and chain were cut by an excessive force applied to them. 

Damage to the anchor and chain resulting when Re-floating the stranded vessel by making use of the holding power of the anchor. Note: 

To effect the 'General Average', the anchor must have been abnormally used for common safety. Therefore, the following cases do NOT effect the general average. 

Ex.1 As the vessel was carried away by a strong current while maneuvering the vessel at an anchorage, it was anchored in order to avoid grounding, and as a result, the chain was cut. (This is not regarded as an abnormal use of the anchor) 

Ex.2 An abrupt storm was encountered while anchoring and vessel tried to shift to a safe anchorage, but the chain got entangled with an obstacle on the seabed and could not be heaved. In order to avoid a common danger, the chain was cut and vessel shifted to a safe anchorage. (Principle of the general average: There can be no sacrifice of an already destroyed substance.) 
Send e-mail to sales@ijinmarine.com to get more information about anchor,anchor chain,etc from IJIN MARINE LIMITED,the leading anchor,anchor chain trader in China.

How to Choose Container Securing Equipment and Materials? Part 2

  Determining the securing forces

Again, a recipe is quicker, simpler and more precise. Four distances must be measured and the MSL of the weakest load securing element must be determined. The friction coefficient must be determined or estimated.

Securing forces Calculation
Vertical securing Effective vertical component / effective length x MSL
Additional frictional forces Effective vertical component / effective length x MSL x μ
Lateral securing including additional frictional forces Effective lateral component / effective length x MSL + effective vertical component / effective length x MSL x μ
Longitudinal securing including additional frictional forces Effective longitudinal component / effective length x MSL + effective vertical component / effective length x MSL x μ

Calculated example:
A doubled, single-use webbing belt is used for securing as previously. For reasons of caution, the MSL is not assumed to be 70% but only 30% of the breaking load. The sketch below shows all the data needed.

Calculated example: Determining the securing forces


Securing forces Calculation
Vertical securing 0.65 m / 1.65 m x 2,300 daN = 906 daN.
frictional forces
0.65 m / 1.65 m x 2,300 daN = 906 daN x 0.3 = 271.8 daN
Lateral securing including 
additional frictional forces
0.95 m / 1.65 m x 2,300 daN = 1,324 daN + 271.8 daN = 1,595.8 daN
Longitudinal securing including 
additional frictional forces
1.30 m / 1.65 m x 2,300 daN = 1,812 daN + 271.8 daN = 2,083.8 daN

As far as the overall securing is concerned, it should always be borne in mind what lashings are subjected to loads under what circumstances:

  Package secured with four diagonal direct lashings


Upward 4 x vertical securing = 4 x 906 daN 3,624 daN
Longitudinally, to the left The longitudinal components of b and c restrain 4,167.6 daN
Longitudinally, to the right The longitudinal components of a and d restrain 4,167.6 daN
Laterally, upward The lateral components of d and d restrain 3,191.6 daN
Laterally, downward The lateral components of a and b restrain 3,191.6 daN

It can be concluded that the lashing arrangement would not be not homogeneous if the load in the example were loaded on a flatrack transported using fore and aft stowage on a container ship, where acceleration forces of 0.4 g occur longitudinally and acceleration forces of 0.8 g occur laterally. In this instance, the lashings would need to have been arranged so that the lateral component was twice the size of the longitudinal component:

  Lateral components twice as large as 
longitudinal components

If it is assumed that the flatrack is transported using fore and aft stowage on a container ship and transported during precarriage and/or onward carriage on a road vehicle, longitudinal and transverse acceleration forces of 0.8 g should be assumed for the lashings

The decision in this instance is simple: both components must be the same size.

  Transverse and longitudinal components same size

If the flatrack is transported during precarriage or onward transport on a freight car in multimodal operations, longitudinal acceleration forces of 1 g are assumed. If lateral acceleration forces of 0.8 g are assumed, the longitudinal components must be 25% larger than the lateral components or the lateral components can be 20% smaller than the longitudinal components:

  Longitudinal components 25% larger than lateral components

Using tie-down lashings also produces angles which cause a reduction in the MSL. The effects are not very dramatic because they are the cosine of half the opening angle between the ends of the lashing. It does not really matter whether angles are measured and forces are calculated or lengths are measured. It is easier for people familiar with mathematics to calculate using the trigonometric function than to measure distances - provided a pocket calculator with trigonometric functions or a relevant table is available. Both methods are feasible. Anyone who is familiar with a the shape of a cosine wave or has certain values in their head, can also make a good estimate.

  Angle which is too large to be permitted

The angle γ is 121.552°, but who can ever determine an angle as precisely as this? Half this angle is 60.776°. The cosine of this angle is 0.488. This makes it obvious that this type of securing is ineffectual. The mathematically calculated part only generates securing forces which are less than half. It would have been better to have secured the cargo with a single-strand direct lashing. The cosine of 60° is 0.5. It is therefore clear that lashings are only worthwhile if their opening angle - i.e. the complete γ - is significantly less than 120° and γ/2, significantly less than 60°. The same could have been determined - possibly more quickly - by taking measurements:

  As previously: Angle which is too large to be permitted

The effective length of one end of the lashing is 197.5 cm, the effective lateral dimension is 96.5 cm. This is less than half. Both ends of the lashing together are thus less than 1. It can also be seen and proved from this that this lashing is not worthwhile.
This does not apply here:

The opening angle here is γ 27° (γ/2 is thus 13.5°). The cosine of 13.5° is 0.973 - i.e. close to 1. This means that this securing aid achieves nearly double theMSL, or to be precise 1 times the MSL of a single strand.

  Angle used for tie-down 
lashings in practice

Measuring would have produced approximately the same results:

If - using our recipe - the smaller measured value is divided by the larger measured value, the result is 0.973. That means, the lashing secures 2 x 0.973 times, i.e. 1.946 times the MSL of a single strand.

  As previously: Angle used for 
tie-down lashings in practice

To be precise, the angle between the ends must be measured in 3D space, since lashings which are attached to separate lashing points form an "oblique" angle to each other. These problems should not occur during measuring, even if one end comes from the top and the other end comes from the bottom.
Here are the rough guideline values for the MSL at different estimated angles:

Estimated angle MSL of the lashing
120° 2 x MSL of a single strand x 0.50 = 1.0 x MSL of a single strand
90° 2 x MSL of a single strand x 0.70 = 1.4 x MSL of a single strand
60° 2 x MSL of a single strand x 0.87 = 1.7 x MSL of a single strand
40° 2 x MSL of a single strand x 0.92 = 1.8 x MSL of a single strand
30° 2 x MSL of a single strand x 0.97 = 1.9 x MSL of a single strand
< 30° 2 x MSL of a single strand x 1.00 = 2.0 x MSL of a single strand

Ijin Marine Limited exports lashing materials for timber vessel,container,ro/ro,etc in China.Not only exporting,Ijin Marine also is able to deliver lashing materials on board within China's ports.The materials contain dovetail twistlock,lashing rod,d ring,turnbuckle,slings,wire ropes,etc.Same as other products,the lashing materials can be approved by CCS,DNV,LR,ABS,KR,etc.sales@ijinmarine.com is our contact detail for your reference.

How to Choose Container Securing Equipment and Materials?Part 1

This section of the Container Handbook deals with how to determine the maximum securing load of materials used for load securing using simple rules of thumb and explains some basic principles for practical work.

  Steel wire rope Lashing point Steel strap


  Inspecting and measuring lashing equipment

Note: Sections in italics have been reproduced from seminar material by kind courtesy of Captain Hermann Kaps, professor at the University of Applied Sciences in Bremen.
Fundamental terms
kilonewton (kN) is a unit of force useful for describing for instance the breaking strength or breaking load of load securing material. It has replaced the previously common metric ton which is the unit reserved for describing mass according to the SI standard. The conversion is easily learned: 1 kN ≡ 0.1 t or 100 kg.
Anyone who was used to calculating mass in kilograms can use the unit decanewton (daN) as a unit of force.
The following English terms are in common use in maritime transport across the world.
Securing element is an individual item of equipment on board ship which is used for load securing, e.g. a shackle, a deck ring, a turnbuckle, chain or wire rope.
Securing device is a suitable combination of elements which together form a means of load securing, e.g. lashing or bracing.
Securing Arrangement is a reasonable arrangement of load securing means with the aim of securing a cargo item or a cargo block.
Breaking Load (BL) is the nominal breaking load, generally specified by the manufacturer. However, it can also be estimated using rules of thumb.
Maximum Securing Load (MSL) in kN, is the greatest permissible force which can be applied to a load securing element or device.
Calculation Strength (CS) in kN, is an arithmetic force determined by reducing the MSL by the formula: CS = MSL / 1.5. CS values are only used to assess the efficiency of securing arrangements as per Annex 13 of the CSS code.
The relation between Breaking Load and Maximum Securing Load is shown in Annex 13 by the following table:


Material MSL
Shackles, rings, deck eyes, turnbuckles of 
mild steel
50% of breaking strength
Fiber ropes 33% of breaking strength
Web lashing 70% of breaking strength
Wire rope (single use) 80% of breaking strength
Wire rope (re-useable) 30% of breaking strength
Steel band (single use) 70% of breaking strength
Chains 50% of breaking strength
lumber 0.3 kN per cm⊃2; normal to the grain


Table: Determining the  MSL  from the breaking load

Lashing elements and lashing materials There are no international standards on tie down lashings. It is to be expected, however, that manufacturers or dealers will provide information on or certification of the nominal breaking load on purchase. It is, however, generally unclear how this value was determined and under what conditions it is valid. No reference is made to any other properties, such as elasticity and fatigue strength.
The table below provides a list of the most important materials and elements with the usual characteristic values. An accepted rule of thumb is used for the breaking load.

If millimeters are chosen instead of centimeters for the dimensions, the breaking load values will be in decanewtons [daN] instead of kilonewtons.

Material/element Breaking load [kN] Notes
Natural fiber ropes (manila, sisal, hemp) 6 x d⊃2; d = diameter of rope in cm. Natural fiber ropes are sensitive to decay, acids and alkalis. All fiber ropes are sensitive to chafing from sharp edges. Knots on synthetic fiber ropes can slip open. Heavers of sufficient thickness should be used to tighten them and these in turn should be secured to prevent them from unwinding.
Polypropylene 12 x d⊃2;
Polyester 15 x d⊃2;
Polyamide 20 x d⊃2;
Hercules (sisal) 6 x d⊃2;
Hercules (polypropylene) 12 x d⊃2;


Material/element Breaking load [kN] Notes
Wire rope 6 x 9 + 1 FC
Wire rope 6 x 19 + 1 FC
Wire rope 6 x 37 + 1 FC
50 x d⊃2; d = diameter of rope in cm. Producing conventional wire rope lashings with turnbuckles and rope clips is technically demanding and can give rise to a number of potential problems. More detailed notes are provided after this table.
Wire rope 6 x 9 +7 FC
Wire rope 6 x 12 +7 FC
Wire rope 6 x 15 +7 FC
25 x d⊃2;


Material/element Breaking load [kN] Notes
Shackles 20 x d⊃2; d = diameter of bolt in cm. The breaking load formula only applies to shackles made of standard strength steel.
Turnbuckles 20 x d⊃2; d = diameter of thread in cm. The breaking load formula only applies to turnbuckles made of standard strength steel.


Material/element Breaking load [kN] Notes
Untreated steel strap
Blued steel strap
70 x w x t
85 x w x t
w = width of strap in cm
t = thickness of strap in cm.


Material/element Breaking load [kN] Notes
Long- and short-link chains with different tensioners See manufacturer's specifications Tie down lashing chains are always made of higher strength steel to save weight. Calculation of the breaking load is therefore dependent on the manufacturer's specifications.


Material/element Breaking load [kN] Notes
Deck eyes and eye plates 20 x d⊃2; d = diameter of eye material in cm. The breaking load formula only applies to material made of standard strength steel.


Material/element Breaking load [kN] Notes
Synthetic fiber lashing belts See manufacturer's specifications Lashing belts are produced in a number of different grades. They are highly elastic but can become permanently deformed when subjected to threshold stresses greater than 50% of the breaking load and therefore quickly become loose. They must not be knotted. They are sensitive to external influences in the same way as synthetic fiber ropes.


Material/element Breaking load [kN] Notes
Weld joints subjected to shear loads MSL = 4 kN per cm Single-layer weld, 4 mm thick.
MSL = 10 kN per cm Three-layer weld, 10 mm thick.


Material/element Breaking load [kN] Notes
Softwood used forbracing MSL = 0.3 kN per cm⊃2; Compressive load perpendicular to the grain
Softwood used for bracing MSL = 1 kN per cm⊃2; Compressive load parallel to the grain


Material/element Breaking load [kN] Notes
Special equipment forro/ro ships - Trailer horses, trailer jacks, wheel chocks; breaking loads usually unknown
Special equipment for container ships See manufacturer's specifications Lashing rods, turnbuckles, twist locks, D rings, sockets, bridge fittings, tie plates, etc. Strength and material properties as per the requirements of the relevant classification society

For economic reasons, it is advisable to try to homogenize load securing equipment and load securing arrangements.

    Homogeneous load securing equipment comprises elements which where possible have the same  values.
    A homogeneous load securing arrangement comprises load securing equipment which are arranged in such a way that, when subjected to extreme loads, they bear the part of the load appropriate to their strength.

To summarize the problems of load securing, some examples are provided below as a sort of "recipe" how to calculate the number of securing devices required, what such a device can withstand and what can be expected of it.
Example: Tie-down lashing:

  Use of tie down lashings

Let us assume that the wooden case on the flatrack has a weight of 12,000 daN. Without taking into account the risk of this overheight case tipping, the package must be secured for overseas shipment. Lateral acceleration forces of 0.8 g can be expected. This means that lateral forces of 12,000 daN x 0.8 or 120 kN x 0.8 i.e. 9,600 daN or 96 kN can be expected.
The single-use webbing belts used in the figure on the left have a breaking load of 3,433 daN. This equates to 2,403 daN at an MSL no greater than 70% of the breaking load. No more than half of this, i.e. around 1,200 daN, may be used as the pretensioning force. It should be noted that in practice this value can neither be achieved nor maintained throughout the entire voyage.
The effective length of the belt from its attachment to the lashing point to the edge of the case (red line) is 3.0 m. The effective height (green line) is 2.93 m, a very high vertical component (97.6%). This component can be determined for any load by dividing the effective height by the effective length. Multiplying this by the pretensioning force gives the force with which the tensioned side of the load is pulled onto the flat. In the example, this is 97.6% of 1,200 daN, or 1,171 daN. If we assume ideal conditions and this force were completely transmitted to the other side, a total pretensioning force of 2,342 daN per lashing can be assumed. Assuming a friction coefficient of 0.3, a single tie-down lashing can achieve a securing force of around 703 daN. 13.65 belts are theoretically required to secure the case (9,600 daN/703 daN). In reality, the webbing belts used would be able to maintain a maximum pretensioning force of around 100 daN through 200 daN during the voyage. This means that a single belt is able to maintain a long-term securing force of 30 daN through 60 daN. To have really "secured" the case, somewhere between 160 and 320 belts would have to be provided!!!

Note: Tie down lashings only provide 
securing forces of the vertical component of the pretensioning force multiplied by the friction coefficient.


Note: The pretensioning force must never be greater than 50% of theMSL 
of the weakest securing element.

This recipe is simpler and more precise than a calculation which uses the lashing angle α, since in practice distances are easier to measure than angles. If the vertical component of a lashing is to be calculated using the lashing angle, the permissible lashing force must be multiplied by the sine of the lashing angle: vertical component = MSL x sin α.
The smaller the lashing angle, the smaller the vertical component will be. At a lashing angle of 90° it will be 100% ( sin 90 ° = 1), at 75° 97% (sin 75 ° = 0.9659), at 60° 87 % (sin 60 ° = 0.866), at 45° 71% (sin 45 ° = 0.7071), at 30° 50% (sin 30 ° = 0.5), at 15° 26% (sin 15 ° = 0.2588) and at 0° 0% (sin 0° = 0).
Example: Direct lashing:
The main difference between direct lashings and tie-down lashings is that with direct lashings, the pretensioning force can and should be kept as low as possible.

Note: The pretensioning force should be as low as possible on direct lashings. However, slack must never be able to develop in lashings.

The pretensioning force must, however, be sufficiently high to prevent a lashing from becoming slack. The reason for this is that the lashing may be loaded up to its MSL under stress and the vertical components resulting from this produce additional frictional forces.

  Direct lashing with chains

For those who enjoy mathematics, the relevant lashing forces can be calculated by first measuring the lashing angle α (47.5°) and then the sine and cosine of this angle to determine the vertical and horizontal components and using these in conjunction with the permissible lashing force of the chain.
Using another recipe, it is unnecessary to determine this angle or its sine and cosine. Basic arithmetic will suffice. The following lengths are determined by using a tape measure or meter rule: the effective length of the lashing chain (red line = 3.61 m), the effective vertical component (green line = 2.66 m) and the effective horizontal component (blue line = 2.44 m). Using rules of thumb or the manufacturer's specifications, the breaking load and the MSL of the 13 mm link material diameter high-tensile chain. This corresponds to 10,000 daN. Checking the size of the lashing point gives a steel diameter of 28.3 mm. This gives a breaking strength of 16,000 daN and an MSL of 8,000 daN. This value represents an upper threshold if the chain components have a higher MSL.
Vertical securing force: 2.66 m : 3.61 m x 10,000 daN = 7,368 daN. A lashing chain secures the package against vertical movement with a force of 7,368 daN. But this is not so important. This force becomes effective when the package is moved horizontally causing the chain to be tightened; the package is then pulled toward the floor with this force. Assuming a sliding friction coefficient of 30% (μ = 0.3), the package is secured by a lashing in all directions with a force of 7,368 daN x 0.3 = 2,210 daN.
Shortfall in securing force: 2.44 m / 3.61 m x 10,000 daN = 6,759 daN. A lashing chain directly secures the package laterally with 6,759 daN. To this are added the frictional securing forces of 2,210 daN as previously determined. The calculated chain lashing secures the machine component against movement laterally towards the right with a force of 8,969 daN. 
Since no longitudinal components exist, a chain only secures the machine component longitudinally with the frictional forces produced by the vertical component of 2,210 daN.

  Different components on a diagonal 
lashing with lashing angles

To calculate the longitudinal, transverse and vertical securing forces using the lashing angles α and β, use the following method:

Component Calculation
Vertical component MSL x sin α
Horizontal component MSL x cos α
Additional frictional forces Vertical component x μ or MSL x sin α x μ
Pure lateral component Horizontal component x sin β or MSL x cos α x sin β
Pure longitudinal component Horizontal component x cos β or MSL x cos α x cos β

Since the additional frictional forces produced by the vertical component may be added to the forces produced by the lateral and longitudinal components, the securing forces produced are:

Securing forces Calculation
Vertical securing MSL x sin α
Lateral securing MSL x cos α x sin β + MSL x sin α x μ
Longitudinal securing MSL x cos α x cos β + MSL x sin α x μ


Ijin Marine Limited exports lashing materials for timber vessel,container,ro/ro,etc in China.Not only exporting,Ijin Marine also is able to deliver lashing materials on board within China's ports.The materials contain dovetail twistlock,lashing rod,d ring,turnbuckle,slings,wire ropes,etc.Same as other products,the lashing materials can be approved by CCS,DNV,LR,ABS,KR,etc.sales@ijinmarine.com is our contact detail for your reference.

Positioning and securing of containers on board


Introductory remarks
This section is intended to provide the interested layperson with some basic information about how to stow and secure containers on board ocean-going vessels, so as to give him/her a better idea of the problems involved and possibly of how to select the appropriate carrier. Those actually involved with securing containers on board ships should refer to other specialist literature.
General on-board stowage
On most ships which are specially designed for container traffic, the containers are carried lengthwise:
  Containers stowed lengthwise fore and aft stowage on board a ship

This stowage method is sensible with regard to the interplay of stresses in rough seas and the loading capacity of containers. Stresses in rough seas are greater athwartships than fore and aft and the loading capacity of container side walls is designed to be higher than that of the end walls. 
However, on many ships the containers are stowed in athwartships bays or are transported athwartships for other reasons. This must be taken into consideration when packing containers and securing cargo.
  Containers stowed athwartships 
(athwartships stowage)
 on board a ship

This stowage method is not sensible with regard to the stresses in rough seas and the loading capacity of containers. Stresses in rough seas are greater athwartships than fore and aft but the loading capacity of container end walls is lower than that of the side walls.
  Containers stowed both ways on board ship

Even unusual stowage methods like this, where some of the containers are stowed athwartships and others fore and aft, are used, but they require greater effort during packing and securing operations. 
The above two pictures show how important it is to find out about the various carriers and their way of transporting containers, either in order to rule out certain modes of transport or to be able to match cargo securing to mode of transport. If the method of transporting a container is not known, then packing and securing have to be geared to the greater stresses.
General securing information
When securing containers on board, the stresses resulting from the ship's movements and wind pressure must be taken into account. Forces resulting from breaking-wave impact can only be taken into account to a certain degree. All the containers on board must be secured against slippage and toppling, with care being taken to ensure that the load-carrying parts of the containers are not loaded beyond admissible levels. 
Except in the case of individually carried containers, securing is effected by stacking the containers in vertical guide rails or by stowing them in stacks or blocks, the containers being connected together and fixed to parts of the vessel.
Securing in vessel holds by cell guides alone
  Cell guides in an all-container ship

Virtually all all-container ships are provided with cell guides with vertical guide rails as securing means for hold cargoes. The greatest stress the containers are exposed to stems from stack pressure. Since the containers are not connected together vertically, lateral stress is transmitted by each individual container to the cell guides When positioned in such cell guides, individual containers are not usually able to shift. If the corner posts of one of the containers at the bottom of a stack collapse under excessive pressure, containers stowed above it generally suffer only slight damage. The risk of damage to containers in adjacent stacks is kept within tight limits.
  Guide rails of two adjacent slots

The containers are guided by these rails of the cell guides during loading and unloading. The photo shows clearly that the upper ends of the guide rails each take the form of insertion guides. 
Securing in vessel holds by cell guides and pins
Feeder ships, multipurpose freighters and container ships in certain regions have to be particularly flexibly equipped, in order to be able to carry containers of different dimensions. To this end, convertible stowage frames have been developed, in which 20', 24', 30', 40', 45', 48' and 49' containers may be stowed securely without appreciable delay.
Most of these frames are produced as panels which are brought into the required positions by cranes. At the bottom they mainly have fixed cones, which engage in pockets welded into the tank top area. At the sides, the frames are secured by pins, which engage in bushes which are let into the wing bulkheads. Such frames are often man-accessible, so that the containers can be locked in place by means of pins. 
If it is necessary to be able to carry containers 2,500 mm wide, the frames are arranged on the basis of this dimension. To secure standard containers of normal width, closure rails are then fitted on both sides of the guide rails by means of screw connections. If necessary, these adapters may be removed.
Removable container guides have also been developed and constructed for multipurpose freighters, reefer vessels and the like. Such guides allow containers to be carried in regular or insulated holds without any risk of damage to the holds themselves. If other cargoes are carried, the stowage guides may be removed using ship's or shore-based loading or lifting gear and deposited in special holders on deck.
Securing in vessel holds by conventional securing and stacked stowage
On older, conventional general cargo vessels and multipurpose freighters, stacked stowage methods are used in the hold, combined with various securing methods:
  Example of stacked stowage with conventional securing

The lower containers stand on foundations capable of withstanding the stack pressures which arise. Dovetail foundations, into which sliding cones fit, are provided to prevent slippage. The containers are connected together by single or double stacking cones or twist locks. The entire stack or container block is lashed using lashing wires or rods and turnbuckles. This system entails a lot of lashing work and material and, moreover, is less secure than securing in cell guides.
Securing in vessel holds by block stowage and stabilization
This securing method is found less and less frequently, but it is still found on some conbulkers and other multipurpose freighters. Containers are interconnected horizontally and vertically using single, double and possibly quadruple stacking cones. The top tiers are connected by means of bridge fittings.
  Fastening containers together

To the sides, the containers are supported at their corner castings with "pressure/tension elements".
  Examples of block stowage method with stabilization

This type of container securing has two marked disadvantages:
  • If an individual container breaks, it is not just one container stack which is affected, but the whole container block.
  • Due to dimensional tolerances and wear and tear to the stacking cones, the entire block can move constantly in rough seas. This causes the intermediate stacking cones to break and an entire block may collapse.
Securing on deck using container guides
On some ships, containers are also secured on deck in cell guides or lashing frames. Some years ago, Atlantic Container Lines used only cell guides on deck. Certain ships belonging to Polish Ocean Lines had combined systems. In other ships, cell guides can be pushed hydraulically over the hatch cover as soon as loading below deck is completed and the hatches have been covered up.
Securing on deck using block stowage securing
This method was used a lot in the early days of container ships, but has been used less and less in recent years for economic reasons.
  Example of block stowage securing on deck

The containers in the bottom layer are positioned in socket elements or on fixed cones. Double stacking cones are used between the layers and the corner castings of adjoining containers are connected at the top by bridge fittings. The containers are held together over the entire width of the ship or hatch cover by cross lashings. A distinct disadvantage of this method is reduced flexibility when loading and unloading, since adjoining containers have always to be moved as well if access to a particular container is required.
Numerous variants, not listed any greater detail here, are available for attaching the lashings. Sometimes the lashings from different stacks cross one another.
  Crisscross lashings from different container stacks

This securing method is being used increasingly in very large container ships. 
Instructions for lashing on board ships are displayed in obvious places.
  Lashing system for 40' and 45' containers

  Lashing system for 20' containers from the lashing bridges of the end hatches

  Lashing system for 20' containers from the hatch covers of the middle hatches

Securing on deck using stacked stowage securing
This securing method is the one used most frequently. Cargo handling flexibility is its key advantage. The containers are stacked one on top of the other, connected with twist locks and lashed vertically. No stack is connected with any other stack. The container lashings do not cross over the lashings from other stacks, except for the "wind lashings" on the outer sides of the ship.
  Principle of stacked stowage securing

  Securing of on-deck containers with lashing rods and twist locks Securing of on-deck containers with twist locksand chains

  Securing of a 3-tier stack on board a semi-container ship

Obviously, a container stack of this kind can topple if it is not adequately secured. 
An absence of special equipment for securing containers and unfavorable stowage spaces increase the risk for container cargoes. "Sloppy" carriers should be avoided wherever possible. This applies quite generally, not only to the operators of aging ships. Timely information about as many as of the circumstances and procedures encountered during carriage as possible can be extremely useful.


Types Of Rope Fibers Used In Ships

  • written by: Raunekk • edited by: Lamar Stonecypher • updated: 10/14/2009

    Learn about all the main fibers that are used to make different types of ropes on board a ship.

    • Introduction

      Ropes have a variety of usages on board a ship. Ropes were the most highly seen equipment on a ship’s deck in the olden days. Though technology has reduced their usage to a certain extent, ropes still have many important applications in a ship’s operation.

      Different types of ropes are used for different applications on a ship. The thickness, strength and length of the rope depend on the rope’s usage. The material from which ropes are made can be both, man-made and natural. It is on the basis of the characteristics of these materials that the selection of rope type is done for a particular use.

      If we go back to our ancestral age, ropes were widely used in almost all the day to day activities. All these ropes were built from materials found in the natural environment. In those days, fishermen and boaters used ropes made from natural fibers such as helm or sisal. However, presently these materials have been substituted by the modern synthetic materials, which are stronger and durable.

    • Materials

      However, choosing a material for a particular rope is a difficult task because each and every material has its own negative and positive points. Knowing the characteristics of a material helps a sailor or boater to choose a rope for specific uses and operations. The different characteristics of materials that one needs to keep in mind are cost, strength, elasticity, durability and resistance to chemicals, water and sunlight.

  • Let’s take a look at the most common materials of ropes.

    Rope materials can be classified into two main categories:

    • Natural
    • Manmade
  • Natural Materials

    Though obsolete on commercial vessels, natural materials are still used for making ropes by many fishermen and small vessel owners. In the olden days, ropes were made from materials such as sisal, hemp and cotton. The main disadvantage of natural fibers is that they are shorter in length, which makes them weaker and more brittle. This also makes the rope surface harder and difficult to handle. Also, for higher strengths the diameter of the rope needs to be larger. Moreover, all the natural materials have a tendency to absorb more of moisture, which makes them freeze. These materials also have a tendency to decay and degrade from insects, rot and fungus infestation.


  • Manmade Materials

    Synthetic ropes have substituted almost all the natural material ropes. These ropes are used in a variety of applications because of the long length of their fibers, which increases the strength and durability of the materials. The different types of synthetic materials are:


    This is one of the most widely used fibers because of its strength and high resistance to load and degradation. Having very low elasticity, polyester does not stretch and is thus less affected by wear and tear. It also has a high resistance towards chemicals, acids, water and sunlight. The ropes made of polyester do not float and are generally used for mooring applications.


    This is the only manmade fiber that is affected by sunlight and thus needs various additives during making. Polypropylene can be made from a single filament fiber or a multi filament-fiber. A polypropylene rope is not used where more of friction is there. Resistant to most of the chemicals, the ropes made from these materials are lighter and float on water.


    Generally used for making light weight ropes, this plastic easily wears and tears. The rope made out of this material is a bit difficult to tie in knot. Due to the light weight of the material, the rope made out of it floats on water.


    Also known as nylon, it is one of the strongest manmade materials for ropes. It is elastic, durable and is not affected by chemicals or water. Though the material loses strength when wet, it has a high ability to absorb loads, tension and shocks. Ropes made from nylon float on water.

    nylon ropes

  • References



    As a hardware supplier, Ijin is able to provide mooring rope in all ports of China. The mooring ropes we can supply contain Polymide /Polyamide /Nylon /PA /Polymide fiber rope, Polypropylene/PP rope, Polythylene /PE rope, Polyethylene terephthalate (PET) rope,etc.We can provide ABS,LR,NKK,CCS,DNV,etc certificate for your vessels.Not only supplying in China, Ijin also can deliver above mooring ropes in your countries.Pls send me e-mail sales@ijinmarine.com for more information.

How to Clean SW Pump Chest?

  • On a ship the main propulsion engine is cooled by fresh water which is in turn cooled by sea water in the huge central coolers. Know how to clean the sea suction filters and how the fishes and crabs have to be taken out of the sea suction filter in the engine room.

    • Overview of marine sea water pumps and system

      The main propulsion & other auxiliary machineries generate heat due to the combustion and other processes involved in performing of their operations. This heat has to be transferred to some other medium, so that the machineries can function properly within the safe operating parameters. The ships main & auxiliary machineries are cooled by fresh water (as sea water causes corrosion), and this fresh water is in turn cooled by the seawater in huge heat exchangers. Thus the heat is extracted from the machineries and heat balance is maintained. For the extraction of heat, the sea water has to be conveyed at a particular pressure and volume. This is done by having 2 or more main sea water pumps in the engine room. The sea water pumps sufficiently cater the needs for the proper cooling of the fresh water and in turn the machineries. Some of the components of the sea water system are

    general cooling sea water system1. High & Low sea suctions.

    2. Sea suction Filters and corresponding isolation valves.

    3. Main sea water pumps.

    4. Heat Exchangers.

    5. Temperature adjusting valve(auto/manual) &

    6. Overboard valve.

    Some systems may be different but these above mentioned components are common for all types.

    Attached here with, is the simple main sea water circulating system, onboard a ship.

    engine fresh water cooling systemThe system consists of usually 2 sea suctions. One is high and the other is low sea suction. These act as a gate so that sea water enters the engine room through pipelines & valves in a controlled manner. Then after the respective isolation valves, the sea water line has a filter called as "sea suction filter", to filter out the fishes, weeds, Plankton, shells etc..These organisms when they enter into the sea water system, they cause fluctuation in the sea water pressure and erosion of the impeller of the sea water pumps. They also chock the central coolers, causing heat imbalance, making the parameters of the engine to exceed its limit. Thus it is highly essential to filter out all these marine organisms so that the sea water cooling efficiency is maintained at optimum always. After the filter, ships generally have various lines branching out for various shipboard services. But the main huge line goes to the main sea water pumps.


    cetral cooling system



  • The main SW pumps

    a typical cooling water pumpThese are high capacity centrifugal pumps, two or three in number, circulate the sea water throughout the plant, and responsible for throwing out the same sea water after it extracts the heat from fresh water(from the engine). Thus these centrifugal pumps have to develop a minimum pressure of at least 2 bar (a value which is minimum level onboard almost all ships, where we get low pressure alarm at 1.8 bar). These pumps have their own isolation valves, which can be used to isolate the pump to carry out maintenance on it. These pumps are capable of running in parallel and individually, depending on the heat balance requirement. One of these pumps, sometimes may act as dual purpose pumps, used as General service or even Ballast pump.

    One of the important aspect of the capacity of the sea water pump is decided based on the "Emergency Bilge Suction". An Emergency Bilge Suction, is a valve, which is connected to the suction line of the main plate type heat exchangersea water pump, thus when it is opened, the sea water pumps taken suction from the engine room. This valve is distinguished by marking it with red/orange color, and kept locked as this must be used only in emergency situation of engine room getting flooded.




  • Sea water usage in ship's engine room

    sea water pipeline branchesSea Water is typically used for various purposes in the engine room. It is the only source which is always available with no extra cost. They are used for

    1. Cooling for fresh water in central coolers,

    2. Cooling of condensate (return steam) in auxiliary/atmospheric condensers,

    3. Cooling of exhaust/gland/condensate steam from the turbines(cargo pumps),

    4. Cooling of air conditioning/refrigeration condensers,

    general arrangement5. Cooling of lubricating oil/ stern tube oil/ intermediate shaft bearing oil ,

    6. Sea water feed for the production of fresh water in fresh water generators,

    7. In Oil Tankers, sea water is used in scrubber towers & deck seals,

    8. The main use is for the Fire main line, for fire fighting purposes. . and many more...!!


  • Cleaning procedure for sea chest filters

    sea chest filter & isolation valvesSince there are two or more sea suctions, before opening a sea suction for maintenance, other sea chest must be put in use with proper isolation of valves. After change over, the sea water pressure has to be monitored for any abnormality. If everything normal, the sea chest can be opened up and filter element can be taken out and cleaned.

    1. Put the unused sea chest in use by opening the valves in proper sequence.( purge the sea chest out of air by keeping the vent open)

    2. When all the air is purged, after ensuring sea water coming out of the vent, then close the vent and open the other valve to put the sea chest in use.

    Opened Sea Chest filter3. Isolate the sea chest on which the maintenance is to be carried out.

    4. Open the vent and drain valve on the sea chest.

    5. Then with proper tools,equipments & lifting gears open the top cover of the sea chest and pull the filter element out. Take out all the debris like fish, shell, sea weeds, barnacles etc..

    6. Put back the filter element and properly close the top cover. Tighten the cover by tightening the bolts of exactly opposite side.

    sea chest filter7. After tightening, shut the drain and keep the vent open to purge all the air out of the sea chest by opening the sea chest valve.

    8. After purging, shut the vent and keep the cleaned sea chest as stand-by.


  • References/Image Credits





    Marine Auxiliary Machinery by McGeorge

    Introduction To Marine Engineering by D.A.Taylor.

    Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps.

Top 3 Reasons for Lifeboat Accidents On Board a Ship

  • written by: Raunekk • edited by: Lamar Stonecypher • updated: 3/14/2010

    Lifeboat accidents have claimed many lives and injured many more on board ships. Though the most probable reason for these accidents have been thought of as human error, the investigation has often lead to something else. In the following article, find out the main reason for lifeboat accidents.

    • Introduction

      It is extremely ironical that lifeboats, which are meant to save lives of people on board a ship during emergency times, have been the cause of several deaths of both crew members and passengers in the past. People have often claimed human error as the main reason for lifeboat accidents; however systematic research has found that faulty lifeboat mechanism has been the root cause for maximum number lifeboat accidents in the past. In this article we will learn about the main causes of lifeboat accidents.

    • Human Error

      This is the most probable and expected reason for any types of lifeboat accidents on board a ship. For many crew members, operating and lowering a lifeboat into the water is still a complex task. Also, the mechanical advancements in the launching system have overcomplicated the lifeboat launching mechanism system. Lack of training and awareness, along with the unclear user manuals, have also been the reason for such accidents. Many a times it has also happened that crew members have neglected the manuals, as they have been written in some other language and even the procedures provided by the company have not been concise and correct.

    Apart from this, poor maintenance of lifeboat release mechanism and other parts of the lifeboat by the crew members have resulted into unwanted mishaps, which have even led to several deaths. Some of the ship’s crew has also been seen following risky practices such as having personnel in the lifeboat while lowering or raising.

  • Lifeboat Mechanism Failure

    In the last few decades more people have been killed during lifeboat drills than being saved by it during actual emergency situations. Also when found out, maximum of these accidents was a result of failed lifeboat releasing mechanism. It is a known fact that many of the accidents in the past occurred because of the problems related to the release of lifeboat hooks. Earlier, lifeboat hooks couldn’t be released unless they were under load. The pre-requisite became extremely difficult to attain, especially during rough sea often leading to jamming of the hooks. In such conditions, the crew members used any possible method to un-hook the lifeboat, risking their lives and leading to accidental situations. A series of accidents resulted because of this problem, until IMO came out with a rule that required lifeboats to be equipped with hooks disengaging gear that could be operated both on-load and off-load. However, the occurrences of lifeboat accidents didn’t stop.

    After that, though lifeboats with hook disengaging mechanism were provided on all boats, seafarers somehow had little confidence in the system. For this reason, they started using metallic wires for spanning the hooks manually to prevent the boat from falling incase the hook released unknowingly. However, these wires were used only during drills and thus a spate of accidents followed as a result of premature release of boats. For this reason, mechanical and hydrostatic interlocking systems were introduced in the lifeboats. But instead of making the process simpler they rather complicated the lifeboat launching system. The most surprising thing after the implementation of this system was that many lifeboat accidents took place mainly during the training exercises and drills which were carried out under the supervision of qualified officers. These accidents proved that many of the accidents occurred as a result of over-complicated launching systems, which required extensive training for operating it, and not because of human error or incapability in handling emergency.

  • Design Issues

    Investigations of many lifeboat accidents have found that though many of the launching mechanisms satisfied the IMO regulations, they were still unsafe and suffered from technical flinches. Many launching system designs are still considered over complicated and instable. Several accidents took place in the past when the hooks came off on their own under the life boat’s own weight, leaving very little room for the crew members to do anything in the situation.

    Presently, the technical advancement has allowed launching of the lifeboat remotely and without the involvement of crew members. However, there is still a risk as crew members board the lifeboat before the automatic launching system is operated. Moreover, if the crew members decide to board the lifeboat using a ladder after it is launched in the water, then that also itself is an inherently risky operation.

    Thus, the risk of lifeboat accidents will continue to haunt the seafarers unless and until some drastic steps are taken to revamp the current lifeboat launching systems and prevent unnecessary risking of the lives of innocent and hardworking crew members.

  • References

    The Lifeboat Imbroglio by Captain Paul Drouin MNI


    There are many different types of lifeboat and rescue boat. They are divided into free fall lifeboat,totally enclosed lifeboat,partially enclosed lifeboat,etc according to use, structure,lauching type.Ijin cooperated with China's famous boatyards such as Beihai Shipyard,Dalian Mingzu,Songliao,Haihong,Jiangyin Beihai,Wuxi Wenjiao.All lifeboats,rescue boats can be delivered directly on board in China's ports,dockyards,anchorage,etc.Ijin can provide CCS,DNV,LR,ABS,NK,KR,etc class certificate for all lifeboat.In more than 300 ports of 80 countries, Ijin is also able to do annual inspection,five years inspection for your lifeboat and rescue boat.Contact our representitive for more information,sales@ijinmarine.com

Water Tight Doors & Ship Safety

written by: Ricky • edited by: Lamar Stonecypher • updated: 7/8/2009

A ship certainly needs to be safe from the very water on which is floats for obvious reasons. One of the ways to keep sea water at bay is to use water tight doors.

  • Introduction

    ship floats in water during a major part of its lifetime except when it is in a drydock or when it is ultimately broken down into pieces. Since water is a good friend but a dangerous enemy, there are always chances of flooding of the shipand I am sure you remember what happened to the fateful Titanic on its maiden voyage. Hence ship safety is of ultimate importance and every care is taken at design and conception stage to ensure that various parts of the ship, especially the hull and the engine room are safe from flooding.

  • Water Tight Enclosures

    Apart from strengthening the ship’s hull using stiffeners and frames, it is important to have water tight enclosures especially at places where it is important to have a door in a bulkhead for access purposes but it is necessary to maintain water tightness as well. There could be several such situations for example such as the shaft tunnel access from the engine room is via a water tight door.

    This may seem to be a minor requirement but just imagine a ship stuck in rough waters due to weather conditions or any other damage due to grounding or collision and the importance of having water tight arrangement in such situations cannot be overemphasized.

    • Working of the Water Tight Doors

      The concept and working of a water tight door in a bulkhead on board a ship can be best explained with the help of a diagram which is shown here. The various parts of the water tight door and bulkhead arrangement have been clearly labeled in the diagram and these include the following.Water Tight Door Arrangement


      • Hydraulic cylinder which is necessary for mechanical operation of the door to open and close it.
      • Hand pump which is necessary in case of failure of the mechanical system so that there is always a manual option for operation of the door.
      • The necessary monitors and controls in the form of alarm and control valve which get activated for safety purposes.
      • A remote switch from where the door can be operated as desired in case of emergency or any other situation where direct access is not possible. An indicator at this remote location which shows the status of the door as either being open or closed.


      Depending on the location and situation these doors could either open through sliding or like normal hinged doors. The material of construction of these doors is strong and durable material which could be either mild steel or cast steel. It is also required that these doors can operate without fail even when the ship is listed to around 15 degrees which is necessary to ensure safety in an actual emergency situation.


      In the actual manufacturing yard, the testing of the door is done either by applying high hose pressure of water and checking for water leakage at the other side or by submerging the door under the required pressure of water before it is actually fitted on to the ship.


      It is also worth noting that since cutting of the door in the bulkhead leads to reduction of strength, it is important to counter this effect by providing extra stiffeners and frames to reinforce the same, otherwise water may not get through the water tight door but might rupture the bulkhead itself which would defeat the very purpose of having a water tight door.


    • Sources and Images

      Advanced Marine Engineering Knowledge Volume III by Gokhale & Nanda. EnGee Enterprises Publishers

      Ijin Marine Limited draws on its many years of dedicated experience in the marine equipment supply sector, to provide a range of high quality Ship Doors which form an integral part of the company's ship access equipment range. 
      "Providing critical protection against flooding due to collision or grounding, our watertight doors are designed specifically to clamp tightly and promote excellent flood containment" .Send e-mail to sales@ijinmarine.com for more support.

How to Do Load Testing of Life Boat Davit?

  • written by: Willie Scott • edited by: Lamar Stonecypher • updated: 2/11/2010

    Dynamic load testing of lifeboat davits is carried out using test weights simulating their Safe Working Load (SWL) and a proof load. These load tests can be carried out onshore during the construction phase using test weights, with a Load Test Certificate being issued following a successful test.

    • Load Testing of Lifeboat Davits


      Offshore oil and gas platforms are dangerous places to work, and accidents can happen very easily. To alleviate any accidents due to failure of mechanical lifting equipment, these components are load tested using weights at percentages above their Safe Working Load (SWL). These weights are known as the Proof Load.

      The equipment to be tested consists of runway beams and padeyes which are static load tests and lifeboat davits and pedestal cranes which are a combination of both static and dynamic load tests. These are all tested according to Safety of Life At Sea (SOLAS) and Lifting Operations and Lifting Equipment Regulations (LOLAS)

      All tests are carried out by a qualified person and witnessed by the Certifying Authority and sometimes by the platform’s client.

      The tests are carried out during the construction phase when there is plenty of room to maneuver the large, heavy weights around the structure.

      This article is another in the series of Marine Offshore Oil and Gas and is written from my experience as a mechanical engineer in the offshore construction yards, from which I retired in 2000.

    It may therefore be a bit dated but the methods used to load test and certify mechanical equipment will not have changed that much, although the legislation may well have, so it is best to check the current versions of these documents.

    We shall start by looking at the procedures involved in the load testing of lifeboat davits, the test weights used and how these are fabricated and certified.


  • Installation of Davits


    These are a vital component of the lifesaving equipment on board an offshore structure.

    Normally the davits are delivered with the winches sheaves and wire ropes, these being stored until required.

    Once the deck has been fabricated and all supports in place the davits can be fitted.

    This is carried out by welding the steel pads on the bottom of each davit section to under-deck supports after cutting away the surrounding deck plate, rather than welding them just to the steel deck plate.

    The winch which includes the motor, gearbox and drums is welded to the deck supports by the same method that was used for welding the davits down.

    The wire ropes are then reeved onto the winch drums. They run from here through several sheaves which have been fitted to the deck. These sheaves are used to guide the wire rope horizontally along the deck to the bottom of the davit arms. The wire ropes are then fed upwards along the davit arms through another set of guide sheaves, to the end sheave where the ropes drop downwards over the last sheave hanging vertically. This final section which hangs down is known as the lifeboat davit falls.

    The bottle screws are fitted to the wire rope end rings to enable final adjustments when the lifeboat is fitted. The ring on the other end of the bottlescrew is used to connect the falls to the lifeboat quick-release mechanism.

  • Testweights

    Certified testweights can be hired or fabricated and certified at the construction yard. I used a steel trough filled with concrete with lifting eyes at each end, one testweight for the Safe Working Load and one for the Proof Load. The weights of the testweights were checked using a load cell, which must have a current calibration certificate.

    The whole operation is witnessed by the Mechanical Engineer, Lloyd’s or DNV surveyor then certified.

  • Load-test Procedure

    Before any testing is carried out, a thorough examination of the sheaves, wire ropes, winch and attachments should be carried out to ensure all these components are in working order and well lubricated and greased.

    The supporting welds between the deck and the davits are tested using a Non-Destructive Test (NDT)

    Once these examinations have been carried out, and welds have been passed the relative positions of the davits are measured using a theodolite, testing can commence in the following sequence,

    1. The Safe Working Load (SWL test) weight is attached to the davit ropes and the winch operated to raise the weight to the normal height that the lifeboat would be stowed.
    2. The winch brake is released and the weight allowed to free-fall a few meters before being applied again. The weight should stop and not creep downwards. Any deviation from this will require the winch brake to be adjusted.
    3. The positions of the davits are again measured and any deflections recorded.
    4. The SWL test weight is removed
    5. This procedure is repeated, this time using the proof load weight. (The proof load is 2.2 times the weight of a fully laden boat including equipment, plus the weight of the max number of persons it can carry.)
    6. The weight is removed from the davit ropes.
    7. The positions of the davits are again recorded using the theodolite and any deflection noted.
    8. The supporting welding is then subjected to post test NDT, and the data recorded.
    9. It usually takes 24 hours for the certificates of the various tests to be completed, and once they are obtained and checked they will be placed in a davit load-test certification package which will form part of the lifeboat and davit commissioning package. This will go offshore with the structure at sailaway.


  • Certification Package Contents

    This consists of the following,

    • A dynamic load-test certificate for the davits, signed by the mechanical eng and surveyor.
    • The deck structural drawing showing the location and Equipment I/D. of the davits.
    • The certification for the testweights and load cell
    • A sketch showing position of davits before, during and after load-test
    • A NDT report showing the condition of the supporting welding before and after the load-test.

    A certain amount deflection of the davits is expected but they should return to their original position once the loads have been removed. The NDT report should confirm no cracks in the support welds, and a thorough visual check of the winch, sheaves, and ropes should be carried out.

  • Loadtest Diagrams

    Load-testing of Lifeboat Davits Davit & Wire Rope Fitting
  • Internet Sites Visited


    Lift boat davit is usually referred to "davit". It is designed for unloading lifeboat or work boat of special equipment. According to the launching modes of operation, it can be divided into roll out type, wave inverse and gravity type. With the requirements of SOLAS (Convention on the Safety of Life at Sea) norms, now lift boat davit is divided into drop type, gravity fall arm type, four connecting rod type, platform, single arm cranes, etc. Located on both sides of the ship deck, lift boat davit is usually inside the ship's rail. When it is used, the davit extends out, lifts the boat and puts it down. According to your requirements, Ijin Marine is able to propose the best solution for standard applications, even some special tailor-made solutions.In China, Ijin is waiting for your contact via sales@ijinmarine.com

Types of Mechanical Seals for the Centrifugal Pumps and Selection of the Mechanical Seal

written by: Haresh Khemani • edited by: Lamar Stonecypher • updated: 3/19/2010

This article describe various types of mechanical seals like pusher, unbalanced, conventional, non-pusher, balanced, and cartridge types. It also serves the guidelines for selecting the correct mechanical seal.

  • Mechanical Seal Types


    There are various types and arrangement of the mechanical seals being used for the centrifugal pumps. Some of the commonly used ones are described below:

  • 1) Pusher Type of Mechanical Seals:

    The pusher type of mechanical seals move axially along the rotating shaft or the sleeve to maintain the contact with the faces of the seal. This feature of these seals helps compensate for the wearing that may occur at the seal face, and wobbling due to misalignment. The pusher types of mechanical seals are used commonly, are less expensive and are easily available in the market in wide range of sizes and designs. The only disadvantage of these seals is that they tend to hang up and sometimes there is fretting of the shaft.

    Pusher type of mechanical seal

  • 2) Unbalanced Type of Mechanical Seals:

    The unbalanced types of mechanical seals are used under drastic conditions where there are vibrations, misalignment of the shaft, and the problem of the cavitation of the fluid. These mechanical seals are inexpensive, allow lesser leakage of the fluid and are highly stable. However, these seals can operate only under low pressure range and if the force of the fluid exceeds certain limits the lubricating film between the faces squeezes out and the seal fails.

Unbalanced type of mechanical seal

  • 3) Conventional Mechanical Seals:

    These are relatively simple mechanical seals that have to be properly set and aligned on the shaft or the sleeve of the pump.

    Conventional mechanical seals

  • 4) Non-pusher Type of Mechanical Seals:

    As the name suggests, the non-pusher or bellow type of mechanical seals don’t have to be moved axially to maintain their contact with the faces. These seals can work under low temperature and high pressure applications. The bellows used in these seals should be upgraded so that they can work under the corrosive environments.

    Non-pusher type of mechanical seals

  • 5) Balanced Mechanical seals:


    The balanced mechanical seals have the ability to sustain higher pressures across the faces and they generate lesser heat thus they are suitable for handling liquids that have low lubricating capacity and hydrocarbons that have high vapor pressure.

    Balanced type of mechanical seals

  • 6) Cartridge Mechanical Seals:


    The major advantage of the cartridge seals is that they don’t require complicated setting during the installation as required by the conventional seal. This helps reducing errors associated with seal setting and eventually also reduces the maintenance required.

    Cartridge type of mechanical seals
  • This part of the article is the guide for selecting the suitable mechanical seal from the various types described above. The factors to be considered when selecting the mechanical seal are type of liquid or fluid to be pumped, pressure and temperature of the liquid, nature of the liquid and the safety and environmental regulations.
  • Selection of the Mechanical Seal for the Centrifugal Pumps

    There are various types and arrangements of the mechanical seals available in the market. It is very important to use appropriate mechanical seal for the required application. If the incorrect mechanical seal is selected there are chances that the fluid would start leaking from the pump and the very purpose of installing the expensive mechanical seal will be destroyed. In addition there would be loss of time, manpower, resources and also some safety hazards.

    When selecting the mechanical seal for any applications consider the following factors:

    1) Liquid or fluid to be pumped: The first and the most important factor to consider while selecting the mechanical seal for the centrifugal pump is the liquid or the fluid to be pumped. If ordinary liquid like water is to be pumped, then conventional mechanical seal with ordinary materials can be selected. In fact in many water pumps ordinary glands are used as the sealants since any leakage of water to the external atmosphere is not dangerous. But you can always see the water dripping from the pumps using ordinary glands.

    If the pump has to handle corrosive liquids like acids, it is very important to select corrosion resistant materials for the mechanical seals. Some of these materials can be stainless steel, bronze or hastelloy. The mechanical seals also comprise of the mating surfaces and these should also be made up of corrosion and wear resistant materials like ceramic, silicon or tungsten carbide, carbon etc. For the corrosive environments the materials for the stationary parts of the mechanical seal can be Teflon, Buna, EPR or Viton.

    Choosing the correct materials for the hazardous liquids is very important else there will all the chances that the materials would fail and the liquid would leak to the atmosphere. This can be very dangerous to the people moving around the pumps and also to the atmosphere.

    2) Pressure of the liquid: The liquid enters the pump at certain pressure and the pump has to increase its pressure to certain level so that it reaches certain height. The total pressure on the seal decides whether one should opt for the balanced seal or the unbalanced type of seal.

    3) Temperature of the liquid: Some pumps handle liquids at high temperatures and others handle the liquids at low temperature. The materials and mating surfaces used in mechanical seals should be able to sustain the temperature of the fluid.

    4) Nature of fluid: The liquids to be handled by the pump may be having ordinary flow, but there can also be chemical solutions that have high viscosity and slow flow, there can be precipitates, there can be abrasive liquids and so on. These types of fluids usually cause more wear and tear of the parts of the mechanical seals and in such cases it is advisable to use double seals.

    5) Safety and Environmental concerns: The safety of human being handling the pump is of prime importance so are the permissible emission standards. To be on the safer side it is always better to used double seals that work as the better sealants and are more reliable.

  • Images Courtesy and Reference

    Goulds Pumps

    Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps-sales@ijinmarine.com

How Does A Bilge Pump Work on Board Ship?

  • written by: Raunekk • edited by: Lamar Stonecypher • updated: 4/11/2009

    It is important to empty ship's bilge wells at regular interval of times to prevent flooding of the engine room. Bilge pumps are used for this purpose.It is important to know the construction and working of these pumps as they are used in emergency situations and also often face technical problems.

    • Introduction

      We learnt what is bilge water, oily water and use of oily water seperator. Now we will talk a look at these pumps used on board various types of ships and boats and see how does a bilge pump work . A bilge pump found on a ship is generally a reciprocating type or a centrifugal type. The rate of flow provided by a reciprocating type is lesser than that of the centrifugal type. Also, the mechanism and construction of a reciprocating pump is extremely complicated for a pump used for such important purpose.

      All the bilge pumps that are generally used on ships are placed below the sea level. Though this helps them to gain extra suction pressure, they often require priming before the start. Reciprocating pumps are self-priming but due to the drawbacks mentioned earlier, their use is getting reduced day by day.

      Nowadays centrifugal pumps are generally used as bilge pumps as they provide greater output rate and take lesser time for the pumping process. The only drawback of these pumps is that they don't have a self- priming system. This has not been an obstacle in their use and the problem is compensated by using an external priming system.


    • Construction of Bilge Pump

      A centrifugal pump consists of an impeller. The impeller is fixed at the center with a help of a shaft.It has vanes which are fixed radially and are strategically located.

    Around the impeller, a diffuser or volute is fixed. A diffuser is a ring which also has fixed blades that are strategically placed and are used to increase the speed and convert the kinetic energy of the liquid into pressure.

    The impeller and diffuser are contained in a casing or the main frame which also supports the motor of the pump.

    Thus there are three main parts of a centrifugal pump :

    • Impeller
    • Diffuser
    • Casing

    A sealing arrangement is provided around the shaft to prevent leaking of fluid. The sealing arrangement might consist of a gland or a mechanical seal.

    centrifugal pump


  • Working of Bilge Pump

    The liquid enters the pump through the center of the impeller also known as the eye of the impeller. The liquid after entering flows radially out and enters the vanes of the impeller. Due to the rotation of the impeller the velocity of the liquid increases. This high velocity liquid then enters the diffuser or the volute casing where the kinetic energy of the liquid is converted to pressure. This pressurized liquid is pumped out through the pump discharge.Many centrifugal pumps have more than one impeller for increased velocity.


  • Priming arrangement

    As centrifugal pumps are not self priming, they require some additional arrangement to get rid of the air in the suction line. When the liquid that is to be pumped is at a level higher than the pump, then the air in the suction line can be removed by opening an air cock fitted at the pump suction. This will automatically allow the liquid to flow due to gravity.Bilge Pump Priming

    If the pump is located below the sea water level and there is a provision made to utilize the pressurized sea water, then priming can be done by opening the sea water cock and the air cock simultaneously.

    Alternate priming systems can be an external air pumping unit that provides pressurised air to different pumps simultaneously.

  • How to prime the bilge pump

    So you want to prime a bilge pump before starting. How would you do it? Given below is the step by step procedure of doing it in the right way.

    1. Before starting the pump , open the suction valve and close the discharge valve.
    2. Start the priming unit to the suction line
    3. Start the motor
    4. Keep a watch at the priming process ( It will start when you start the pump)
    5. Once priming is done, open the discharge valve slowly , turn by turn.
    6. Adjust the amount of flow with the help of the suction valve.
    7. Keep the desired output flow by adjusting the discharge valve
    8. While stopping, stop the motor first and then close the discharge and suction valve.
  • References

    Introduction to marine engineering by D.A Taylor

    Image Credits





    Introduction to marine engineering by D.A Taylor

    Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps-sales@ijinmarine.com

How to Maintain and Repair Centrifugal Pump?

written by: Willie Scott • edited by: Lamar Stonecypher • updated: 11/1/2011

Centrifugal pumps have been used in industry for a hundred and fifty years or more. They are used to convert the energy from the pump driver to kinetic and potential energy into the fluid, via the impeller. They are used aboard ships to circulate seawater and freshwater cooling for the main engine.


    ship's engine room contains several different types of pumps including centrifugal pumps. In the next few sections, the maintenance of centrifugal pumps is explained. Here we will have a look at the procedure to strip, inspect and reassemble a centrifugal pump, forming part of the planned maintenance schedule on board ships for the purpose of maintaining the equipment in optimum operating condition.

    The first section gives an overview of a typical centrifugal pump operation

  • Overview

    As we saw earlier; the centrifugal pump was developed in the mid 1800’s, although it was used in a crude form before then. The main design change was by John Appold in 1851; he replaced the impeller straight vanes by curved blades.

    The pump converts mechanical energy from the drive to kinetic energy, with this being transferred to the fluid as pressure.

    This takes place due to the two main components of the pump: the impeller and the volute. The rotating impeller converts the input of mechanical energy to kinetic energy, while the stationary volute converts this to pressure.

    The fluid to be pumped enters the pump through the suction pipe nozzle, where it is drawn directly to the impeller “eye” located in the center of the impeller. The impeller spins the fluid tangentially and radially with centrifugal force outwards. The curved blades create a low pressure at the eye that allows more fluid to be drawn from the suction nozzle to the impeller.

    • So basically, the pump operates on the transfer of mechanical energy from the drive motor from where it is converted to kinetic energy that is transferred to the fluid as pressure energy. The rotation of the impeller with its curved vanes draws the fluid from the suction nozzle; throwing it outwards, expelling it through centrifugal force from the discharge nozzle.

      A sketch of a horizontal pump is shown below.


      Centrifugal Pump Sketch

    • Removal of Pump for Inspection and Maintenance

      1 Isolate pump electrical circuit breaker on main switch board and attach a warning notice. (Do Not Operate-Men at Work).

      2. Switch off and lock pump supply at its local supply panel. Attach a warning notice to pump local supply panel.

      3. Close suction and discharge valves, chain and lock hand wheels.

      4. Open pump suction and discharge pipe drain valves to bilge and when water ceases to flow; crack open the pipes / pump flange joints carefully to ensure that pump has drained off and is safe for opening.

      5. Fix a shackle to lifting pad eye above pump and hang chain block; ensuring SWL of block, slings and shackles are satisfactory.

      6. Use a center-punch to match/mark coupling and casing, then remove the coupling bolts.

      7. Disconnect, fix i/d tag and remove motor supply cables; taping over bare ends with insulating tape.

      8. Connect shackle and sling to motor eyebolt and lift motor clear of pump using overhead chain block. Lay motor on its side out of harm’s way, protecting machined surfaces on both pump and motor coupling halves against damage. (Cardboard and masking tape is quick and efficient method.)

      9. Disconnect all external fittings from pump casing e.g. cooling pipe, pressure gauge, oil reservoirs and air cock.

      10. Remove bolting from top cover and remove cover. Scrape off old gasket and check mating surfaces, and renew gasket on assembly. (Light smear of grease on gasket / faces)

      11. The pump shaft with impeller can be lifted out of casing.

      12. Dismantle the impeller, and remove the wear ring.

      13. Remove the gland packing and disregard; replacing it on rebuild. Remember to cut ends of packing at 45° and stagger joints when repacking gland.

    • Centrifugal Pumps Fitted on Board (Images Taken from National Center for Appropriate Technology Website)

      centrifugal pump centrifugal pump
    • Inspection Procedure for Pump and Motor


      1. Impeller, pump shaft and internal volute/casing can now be inspected for erosion, pitting and wear.

      2. If required rectify pitting or erosion in the impeller and casing with two – part alloy epoxy putty. (See my article in the Reference section)

      3. Check main drive shaft bearings and thrust bearings for wear and replace if required.

      4. Check wear ring clearance using feeler gauges; in my day at sea it was general practice is to replace with new rings at major overhaul.

      5. Check impeller / shaft key and keyways for damage and undue wear, Unscrew impeller shaft securing nut and check threads are in satisfactory condition; retighten to manufacturers torque settings.

      6. Give all parts a good clean removing any dirt/ medium residue before re- assembly using new parts as required.

      7. Enter date of overhaul and parts renewed in the pump maintenance record card.

      Drive Motor

      1. Grip motor drive shaft /coupling firmly and check for excess axial and longitudinal movement. Rotate shaft at speed by hand, allowing it to run to a stop whilst listening for excess noise from bearings. Any doubt on either counts, the bearings should be replaced.

      2. Megger check motor windings to ensure no dampness is present and windings are in good condition. Any suspect readings indicate a full motor strip to check condition of rotor and stator.

      3. If these checks are satisfactory, grease bearings as required. Some bearings are now sealed for life and will not require greasing.


    • Procedure to Start the Pump

      1. Unlock and remove chains from inlet/outlet valve wheels and open both valves full.

      2. Open air cock and expel air from line and pump while checking for any leaks

      3. Turn the shaft coupling and ensure shaft is free to rotate.

      4. Reconnect motor.

      5. Remove danger notices from pump power supplies and reinstate breakers.

      6. Start and record current drawn by the motor under starting and running conditions. Check and record the discharge pressure.

      Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps-sales@ijinmarine.com


How to Repair Boiler Feed Water Pump? About Seal Replacement

written by: guruvignesh • edited by: Lamar Stonecypher • updated: 6/28/2010

This article will provide information about repairing the boiler feed water pump and seal replacement. Boiler feed water pumps are multistage centrifugal pumps which build up high pressure and to provide the sealing, we use a mechanical seal arrangement.

  • Introduction:

    The boiler feed pump is a multistage centrifugal pump used to increase the discharge pressure of the feed water to the boiler. To deliver the feed water into the boiler steam drum, it has to raise the pressure beyond the boiler steam drum pressure. Because of the high pressure and temperature involved, boiler feed water pumps are made up of cast steel casings and shafts along with an impeller made up of stainless steel.

    To achieve this condition, the multistage centrifugal pumps are used where the discharge of the first stage becomes the suction of the second stage. Such pumps are provided with the diffuser rings around each impeller that serve to increase discharge pressure. This type of pump is thus often referred as a "turbine pump."

    The shaft is protected in the way of bearings by stainless steel sleeves, where we normally use a mechanical seal to the high pressure for liquid handling. So we provide a separate lubricating arrangement. The oil within the seal chamber is maintained constantly one bar above the discharge pressure by an accumulator containing a plunger which is operated by air or nitrogen pressure.

  • Multistage Centrifugal Pump as Boiler Feed Pump

    Boiler feed pump assembly Multistage Centrifugal Pump
  • Mechanical Seals are used in Boiler Feed Water Pumps

    It is preferable on a vertical pump to have shaft sealing at the pump upper end only. Mechanical seals are spring loaded to hold the sealing faces together. It is important that cooling and lubrication liquid is led to the mechanical seal from the lowest point on the pressure side of the pump to ensure that some liquid reaches there even when priming.

    • Special header tanks have been installed for seal lubrication in some applications. They must not run dry, and care must be taken to prevent ingress of foreign matter. Many mechanical seals incorporate a carbon face, and there is a possibility of electrolytic action in the presence of sea water. Normally this does not take place in boiler feed water pumps because we use the fresh water treated dosed with corrosion preventing chemicals as the boiler feed.

      In the case of sea water pumps, we do not use the mechanical sealing arrangement- instead we use a soft packing arrangement. Stuffing box type glands may be packed with soft or metal foil type packing. The pump internal bearings may be lubricated and cooled by pumping liquid that is always available when the pump is running. A lubricator for the application of grease is also fitted in some circumstances.

      The image below shows a mechanical seal arrangement. (Click to enlarge and then use the Back button in your browser to return to the same place in this article.) In the image, elements d1 and a1 bear and slide on each other, creating a seal at their interface. One group of parts is connected to the rotating shaft and the other to the machine's case. The spring keeps the elements tight against each other, maintaining the seal and allowing for wear.

    • Mechanical Seals

      Mechanical Seals:
    • Repairing Boiler Feed Water Pump - Mechanical Seal Replacement

      Tools Required for Dismantling of the Boiler Feed Water Pump:

      1. Open end spanner, box spanner, and ring spanner of required size.
      2. Allen key set
      3. Bearing puller
      4. Vernier caliper
      5. Hammer

      Precaution to Be Taken Before Opening the Boiler Feed Pump:

      1. Switch off the power and put a board on electrical banner “work in progress.”
      2. Drain all the water inside the pump.
      3. Close the suction and discharge side valves.

      Dismantling Procedure of the Boiler Feed Pump:

      1. By using spanner, slacken all the bolts.
      2. Then open all the bolts of the outer casing diagonally.
      3. Remove the bearing by using the bearing puller.
      4. Take out the impeller of the first stage and remove the diffuser ring of the first stage.
      5. Remove the other impeller along with its diffuser rings.
      6. Place the shaft on shaft holder.
      7. Open the mechanical seal using the special tool. Care must be taken while removing the spring arrangement of the seals.
      8. Check for the impeller clearance using the vernier caliper.
      9. Check the wear ring is in good condition or not.
      10. Check the trueness of the shaft.
      11. Shaft should be clearly examined especially in the area of mechanical seal arrangement if excessive wear has taken place the quality of packing used should be investigated and a larger amount of lubricant should be used while running.
      12. Check for bushes and bearing of the pump.
      13. Check for pump casing any traces of corrosion or pitting.

      Assembling Procedure of Boiler Feed Pump:

      1. Put back the new bearing if needed.
      2. Replace a new wear ring for the impeller blades.
      3. Replace a new mechanical seal on the shaft.
      4. Assemble the impellers and diffuser rings, check for impeller clearances.
      5. Then place a wear ring in place.
      6. Next place the outer casing of the pump.
      7. After that tightening the casing of the pump by using spanner diagonally.

      Checks to Be Made Before Staring the Boiler Feed Pumps:

      1. First check the priming of the pump is done or not.
      2. Check the lubrication for the seals.
      3. Open the suction valve and air cocks. After all the air has escaped close the pump’s air cock.
      4. When the pump has reached the correct speed, open the discharge valve.
      5. Check all gauges to see that a proper pressure is being developed.

      And this is how the boiler feed water pump is repaired and the seals are replaced.

      Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps-sales@ijinmarine.com

What is Boiler Feed Pump?

written by: engineerbiz • edited by: Lamar Stonecypher • updated: 12/21/2008

Boiler Feed Pump as the name suggests, finds application in boiler or reactor vessels to feed water and also control the amount of water fed to the boiler. It has got significant role in the operation of boilers.

  • Selection of Boiler Feed Pumps

    Boiler Feed Pump is selected depending on the capacity of the boiler. The operation of the pump may be continuous or intermittent and depends on the liquid level control of the boiler. A float type switch is provided in boilers with capacity 10,000 lbs/hr or lesser which ensure the programmed level of water in the boiler and this is a classic intermittent operation.

    The boilers having capacity higher than 10,000 lbs/hr will have modulating feed water regulator to feed the water continuously at diverse flow rates to satisfy the need of maintaining designed water level in the boiler and this is a continuous operation.

    Now when we discuss about the capacity of the boiler feed pump which is nothing but the quantity of water to be pumped, it is designed taking into account the evaporation rate of the boiler. The on-off operation would be 2 times of the evaporation rate of the boiler considering the safe factor whereas with modulating level control, a factor of 1.3 times of the evaporation rate of the boiler plus recirculation is suggested.

    Boiler Feed Pumps can handle temperature upto 220°F but higher temperature is made possible with the help of external water cooling. The deaerator pump used in power plants is also designed for higher temperatures.

    • Boiler Feed Pumps in Power Generation

      Most common pump is a multistage centrifugal in power plants for feeding water to boilers. The main parts of this pump are impeller, stainless steel 2-piece twin volute and stage pieces, combination of balancing drum & disc, shaft and gland packing. A heavy cylindrical forged steel barrel is an integral part for the stages to be stacked and closed at one end by a bolt on the head. The stages inside barrel casing are split radially. In few pumps, the stages are also split axially.

    • The advantage of barrel type feed pump is it has smaller number of joints to be sealed against the high pressure action and this minimise leaking of pumps which is an added feature for power plants.

      As the stages multiply, the boiler feed pump has an increased length and to attain radial rigidity, bigger shaft is designed and installed for reliability. Although, in these pumps where the stages are less, the reliability is high but efficiency is affected the reason being increase in diameter of the shaft.

      In view of reliability, the bearing used in these boiler feed pumps is ‘Kingsbury Thrust’ or ‘Journal’ type bearing because roller contact bearings are not believed to be of substantially dependable.

      Categorically, In low pressure installations, horizontal single stage volute type centrifugal pumps are more in use. For medium pressure below 100 bars, split case multistage twin volute diffuser pumps are common because of the difficulties found in sealing the case joint surfaces.

      The seals used in boiler feed pumps are generally stuffing box type and injected condensate to avoid leakage of feed water. Asbestos gland packing is out dated due to health hazards and off late are replaced by non-asbestos braided gland packings which include Graphite, PTFE, GFO, Aramid or in combination due to their self lubricating properties. Hence the scoring of shaft is avoided, leakages are reduced and the life of shaft is also enhanced. The selection of gland packing depends on the temperature, flow rate etc. In power plants, especially in nuclear, mechanical seals are also used but rubbing speed is always a problem due to the large diameter and high speed shafts.

      The required spares whose inventory should always be maintained for boiler feed pumps are set of casing wearing rings, balancing device which is usually made of stationary and rotating parts, set of diffuser bushings, 2-4 sets of shaft sleeves, gland packing rings in several sets and thrust bearings.

      Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps-sales@ijinmarine.com

Fluid Pumps: Classification and Types

  • written by: naveenagrawal • edited by: Lamar Stonecypher • updated: 4/26/2010

    Classification of fluid or hydraulic pumps is based on fluid flow pattern through pumps and fluid supplied by pumps. Pumps can be classified as intermittent flow Positive Displacement Pumps and continuous flow Roto-Dynamic or Turbo Pumps. Read more on criteria of classification and different types.

    • Classification Criterion

      The most basic classification criterion for differentiating the pumps, whether it is for purpose of analysis or for commercial purpose, is the fluid flow pattern. There are also other important classifications based on the power rating range and fluid discharge rate. The flow supplied by a pump can be intermittent or continuous. The pumps with intermittent flow are all positive displacement pumps and pumps with continuous flow are all Roto-Dynamic pumps. These classifications of the pumps does not end here, these two broad categories have further different types of pumps having varying characteristics. To sum up the classification criterion:

      Broad categories based on Flow Pattern:

      1. Intermittent - Positive Displacement Pumps
      2. Continuous - Roto-Dynamic or Turbo Pumps
    • Positive Displacement Pumps

      Positive displacement, as the name suggests, is displacing something positively, that is, certain fixed quantity is displaced. In case of the fluid pumps that “something” is fluid for sure. Positive displacement of a fluid is that a closed volume of the fluid is moved from one part of the machine to the other part. The construction of the positive displacement pumps is such that the moving parts along with the fixed ones inside it can form moving enclosed volumes. They open on one side, take the fluid, enclose it and open on the other side, discharging the fluid.

    Positive Displacement pumps can further be classified under subcategories according to the motion pattern of the enclosed volume forming parts.

    Reciprocating Positive Displacement Pumps

    In the reciprocating positive displacement pumps the moving part forming the enclosed volume for fluid displacement has a reciprocating motion. Reciprocating pumps are mainly of two types based on the reciprocating part.

    • Piston Pump
    • Diaphragm Pump

    Each type of these reciprocating pumps is available with various different features. Different variants of positive displacement pumps reciprocating pump are single discharge, double discharge, duplex and triplex.

    Rotary Positive Displacement Pumps

    Rotating positive displacement pumps have rotating parts which form the moving cavity for carrying the fluid from one side and discharging it at the supply side. Rotary positive displacement pumps are of mainly two types based on the number of rotors.

    • Single Rotor
    • Multiple Rotor

    Each of these two types of Rotary Positive Displacement Pump has pumps available with different design features. Screw Pumps and Gear Pumps are most common Rotary Positive Displacement Pumps.

  • Roto-Dynamic or Turbo Pumps

    Roto-Dynamic or Turbo Pumps are similar in construction as the Hydraulic Turbines just the functioning is opposite to them. Turbo Pumps has rotating impellers with blades or vanes fixed to a rotating shaft. The flow is continuous through the Turbo Pumps. Like turbines turbo pumps are also mainly of two types based on flow direction.

    Centrifugal Pumps

    Axial Flow Pumps

    The coming articles on fluid pumps will provide information about each type of pumps their construction, working and different features.


Fluid Pump or Hydraulic Pump is a machine which transfers the energy from its moving parts to the fluid passing through the machine. The energy transferred from the Pump to the fluid appears as the pressure and velocity of the fluid. Know more about Fluid or Hydraulic Pumps in this article series.
Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps-sales@ijinmarine.com

What is a Capstan on a Ship?

written by: Raunekk • edited by: Lamar Stonecypher • updated: 7/5/2010

A capstan is a type of device used on ships to wound the cables and ropes during anchoring. Capstans are to old wooden ships what windlasses are to modern ships. Read this article to find out the difference between a capstan and a windlass.

  • Introduction

    ship is a giant structure which needs big ropes and strong cables to tame her when at sea. These ropes are of various types with some thicker than the diameter of your arm. Moreover, the ship also uses massive anchor chains that are attached to the ship's anchor.

    The process of handling these cables and ropes on board a ship has been a cumbersome task since they were first used. Even though the sizes of ships during the days of wooden sail ships were not as big as those present today, handing the ship’s anchors and sails have always been a tough task. To handle this difficult task a device known as capstan is used. Capstan is one of the simplest yet important devices on the ship. Gradually, the mechanical capstan gave way to the currently used device known as windlass in big ships and electrical capstans for the smaller boats.

    In this article we will learn about the evolution of the primitive capstan into the modern day windlass and electric capstans. We will also find out how capstans and capstan winch are useful in ship handling operations.

    What is a Capstan?

    • A ship’s capstan is a drum shaped device that is used for hoisting weights or for winding ship’s anchor cable. A capstan is similar to a windlass, but unlike windlass, it rotates in a horizontal plane and around a vertical axis.

      The term capstan was generally used in the days of wooden ships, when the ships were smaller in size. Capstans were used to weigh the ship’s anchors using anchor cables or for hoisting the sails. However, as the size of the ships went on increasing, the size of the anchor cable also became longer. Instead of anchor cables, messenger cables were then used to wound it around the capstan in a continuous loop. The messenger cables were attached to the anchor cables using small lines known as nippers. When the cables were not in use, the nippers were removed to let the cables enter the holds. All these capstans were manually operated by means of wooden bars, attached to slots made in the upper portion of the capstan. The drum was rotated by means of pushing these wooden bars in a clock wise direction.

      capstan parts800px-CapstanCrewModel

    • Capstan Vs Windlass

      As time passed, capstans were completely made from iron and steel. Gears were used at the head of the capstan to provide a mechanical advantage when the bars were pushed anti-clockwise. Even though things improved, capstans still used to be driven by human power, making their usage stressing and difficult.

      However, in the modern ships, the traditional capstans are replaced by hydraulically or pneumatically operated windlass. A windlass is a complex device meant for the same purpose as that of capstan, but comprised of different parts, which together make the anchorage process smoother and easier. A capstan differs from a windlass only in the matter of the axis on which the rope or cable is wound (for a capstan it’s vertical axis, whereas for a windlass it’s horizontal)


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What Is Role Of Pilot Ladder On Ships

written by: Ricky • edited by: Lamar Stonecypher • updated: 9/17/2009

This article explains about the arrangement used by pilots to board the ship and disembark upon mission accomplishment

  • Introduction

    We have studied about pilots in context of a ship and know that it refers to an expert navigator used locally by ships where navigation by the normal navigating officers on board would be bit risky and could lead to grounding or collision. But if you have noticed one thing that a pilot always boards a ship at sea and also during departure from port, the pilot gets off at sea.

    So how does a pilot get on the ship because if you are not familiar with ship, it is a giant structure and sometimes it might not be steady due to rough weather conditions?  This is an interesting topic in itself as we will learn about pilot ladder construction and arrangement in the following sections.

  • Pilot Ladder Construction

    Pilot LadderA pilot normally embarks and disembarks from a ship using a special ladder known by what else but the pilot ladder due to obvious reasons. You can best understand about the pilot ladder by taking a look at the sketch of such a ladder in the image below. The image shows the pilot ladder hanging down from the ship side. As you can make out, the ladder has the following parts

    Manrope – this is a rope which is present on both sides for physical hold of the person climbing or descending from the ship.

Sideropes – these are used to hold the steps and take the weight of the climbers and the steps. Regulations say that this rope cannot be less then 20 mm in diameter.

Spreaders – these are used at regular intervals of the pilot ladder and help to ensure that the ladder does not get twisted which would cause difficulty to the pilot. They are normally 2m in length and are made of some kind of hard wood that could be oak. The maximum interval of a spreader can be 9 steps.

Treads/steps – the steps obviously need to be made of non-slippery material and are also normally made of same material like the spreaders, except the last 3 steps which are made out of hard rubber as they would more often come in contact with the sea water.

It must be remembered that the pilot ladder has to be made from a continuous length only and cannot be made of two or more lengths joined together. This is simply to ensure strength as you wouldn’t want the pilot to be in a dangerous situation.

But do you realize how the ladder is fastened at the top where it reaches the main deck of the ship. Well it can be done in either of the two ways depending on the exact situation at the top. The pictures below show two situations where the ladder goes over the bulwark and directly onto the main deck. The images are self explanatory and you can see that in either case, the handrails are provided for grip of the climber at the top of the ascent. Also the ropes are secured safety with some arrangement at the deck which is very important.

Securing the Pilot Ladder


There are lot of technical details regarding pilot ladders and their rigging but I will not include them here. Just note that during night time there should be sufficient light for the pilot to see around, plus there need to be arrangements for lifebuoy and related safety gear in case anything goes wrong so that immediate action can be taken.


Maximum Height

Obviously the job climbing a pilot ladder is not easy so there is a maximum limit to which the pilot is supposed to climb. This is necessary since the regulators cannot expect pilots to have the skills of Tarzan or Superman, so anything more than 9 meters in height needs to be provided access using accommodation ladder or some automated means of hoisting. We will learn about these various types of pilot arrangement in our next articles.

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Traveling Gantry Cranes

  • written by: Willie Scott • edited by: Lamar Stonecypher • updated: 10/21/2011

    Traveling gantry cranes are one of the most widely used cranes for movement of heavy loads in shipyards, industrial workshops, and container terminals. They can be supported on overhead and ground level steel rails or run on rubber tires enabling them portable and easily maneuvered on the ground.

    • There are numerous types and sizes of gantry cranes in use all over the world for many purposes. They all basically consist of a hoist that is attached to an overhead trolley, the trolley being fitted to single or double steel I beam supported of a building's structure or vertical steel legs.

      In the next few sections we will examine the operation and applications of several types of gantry cranes. The first section gives a brief overview of this type of crane.

    • Overview

      The cranes have been used for many years. Demag Cranes and Components Company iscredited with the design of the first one that was steam driven. I well remember seeing some old, but perfectly working examples of these steam cranes in the Belfast Docks, with a mixture of steam and coal smoke emitting from the small stack-pipe sticking out the roof. I also noticed a few of these still nimbly dodging about on their three small rubber wheels on the quayside of the ships outfitting channel in the shipyard of Harland and Wolff in the early sixties whilst serving my apprenticeship. These are such a far cry from the massive Samson and Goliath cranes that span the dry-dock and that are visible from miles around the shipyard.

      There are several bodies in the US that support the manufacture of overhead material handling cranes. Crane Manufacturers Association of America and Hoist Manufacturers Institute are the main ones.

  • Components of Gantry Cranes

    We shall examine the components of a typical gantry crane running on steel overhead rails mounted inside a building.

    1. Steel Rail

    These are manufactured in various lengths from cast iron having a bottom flange that is drilled for high tensile bolts and nuts used to fix the rails to the building’s main steel work. There are two methods of fitting the bolts.

    a) Bolts inserted downwards with the nuts fitted to the bolts from underneath. This prevents the bolt falling to the ground should the nut slacken off. However there is no visible warning of a nut missing until it hits the floor (or your head)!

    b) Bolts inserted upwards with the nut fitted from above. This method allows the operator to notice right away that the bolt is missing as the bolt hole will be visible. However some of these bolts are quite large and heavy. This combined with the height of the rails are also capable of inflicting injury should one fall and hit a worker.

    2. Wheels and Drive Motor

    The long-travel wheels are also cast having steel flanges and double ball bearings. Two of the wheels are driven by electric motors and two are normally free running. These are contained in the end carriages that are fitted to each side of the crane beam(s).

    The electric drive motors may be mounted directly onto the driven wheels or mounted on the cross-beam and driving the wheels via a drive shaft.

    It is very important to have these long-travel drive motors synchronized to stop and start at the same time as any time lag at all will result in the crane “crabbing” (the name given to the ‘Z’ action that the crane adopted on starting).

    I was engineer at an aluminum smelter here in the North of Scotland for many years. The cast shop had four overhead gantry cranes of 50T & 20T capacity. The 50 tonners were used to transport molten aluminum in steel crucibles to the holding furnaces, prior to casting. One particular crane was prone to crabbing, which was a dangerous situation to be in when travelling up the shop with a crucible of molten metal hanging from the hook!

    We tried numerous times to get the motors synchronized to start together at the same time. One quite weekend nightshift, I operated the crane and the electrician and fitter observed the drive motors as I stopped and started the travel. We suspected backlash in the drive gears and shafts, but eventually we traced the fault to the magnetic brake on one motor that was lagging ever so slightly behind the other one. Once we adjusted the clearance and greased the linkage, the crane worked satisfactorily.

    Some years later the smelter closed and the cranes and the equipment were sold to a smelter in Dubai. I applied for an engineer’s post out there and was flown to the plant for final interview.

    I was being shown around their cast shop and lo and behold; up above me was one of our old overhead cranes. I mentioned this to the plant manager and he said they were excellent cranes (Vaughn’s I think they were) except for their crabbing! I was able to tell him how to put this right. In the end I was offered the engineer’s job, but turned it down accepting an alternative position with a local oil and gas offshore construction company.

    Anyway, this is one thing to look out for that can be very dangerous when lifting and transporting heavy loads; especially when maneuvering in tight locations.

    3. Cross Travel Bogie/Trolley

    The bogie is electrically driven and houses the main hoist. It is under-slung on a single beam or suspended between two beams in a double beam design. The electric drive motor enables the bogie to cross-travel along the beams.

    4. Hoist

    The hoist is mounted on the cross travel bogie and consists of a steel drum around which the coils of wire rope are wound. It is electrically driven and has the normal magnetic brake that operates on raising or lowering the crane hook, whether loaded or unloaded.

    5. Operator's Ca

    Accessed by a set of vertical looped ladders, the cab is located at one end of the overhead beams and gives all-round vision to the crane operator. The long travel, cross travel, and hoist are normally hand operated from a control panel convenient to the operator’s seat, with an emergency long travel hydraulic foot brake on the floor of the cab.

    A sketch showing the components follows.


    Gantry Crane

  • Application of Gantry Cranes

    We shall examine the application of three types of gantry cranes.

    Mounted and operating on fixed overhead steel rails

    These are normally mounted inside buildings and have the steel overhead rails bolted to the building walls or supporting steelwork. The crane has end carriages attached to each end of its overhead beams and these contain the drive wheels. This arrangement allows the crane to travel along the full length of the building with the cross-travel trolley giving access across the width of the building.

    The cranes are used to lift, transport, and lower heavy items around the building floor area.

    Mounted and operating on fixed parallel ground level steel rail

    These use the same type of hoist and travelling system as the previous overhead crane except the rails are at ground level and the crane beams are supported on vertical steel legs.

    This allows for loading and unloading train cargo/freight with the crane straddling the railway line and the carriages located under the crane. A typical example is shown below.

    Modern shipyards use this type of crane straddling a dry-dock where large fabricated sections of ships hulls are joined together. These are transported by the crane from the fabrication shops to the bottom of the dock and hold them in position while the sections are welded together forming the hull.

    An example of this from my old shipyard of Harland & Wolff Belfast is shown below.

    Operate on the ground on rubber tires.

    These are extensively used in container terminal storage yards for locating, shifting, and stacking containers. The main beam(s) and hoists are supported on vertical steel columns that have rubber tired wheels at the base. These wheels are driven by electric motors; two of them being used to steer the cranes.

    There are examples of the above types of cranes in the References section at the end of the article.

  • Images

    Samson & Goliath Cranes
    Lift boat davit is usually referred to "davit". It is designed for unloading lifeboat or work boat of special equipment. According to the launching modes of operation, it can be divided into roll out type, wave inverse and gravity type. With the requirements of SOLAS (Convention on the Safety of Life at Sea) norms, now lift boat davit is divided into drop type, gravity fall arm type, four connecting rod type, platform, single arm cranes, etc. Located on both sides of the ship deck, lift boat davit is usually inside the ship's rail. When it is used, the davit extends out, lifts the boat and puts it down. According to your requirements, Ijin Marine is able to propose the best solution for standard applications, even some special tailor-made solutions.In China, Ijin is waiting for your contact via sales@ijinmarine.com

Types of Shipboard Cranes

This article will give you the clear picture about the various shipboard cranes, their working, maintenance, and safety cut-outs.

  • Introduction:

    The duty of winches and cranes is to lift and lower the load by means of fixed wire ropes or wrap pins to lower or higher positions by derricks. All cranes should be able to perform the following functions:

    1. Lift the load at a suitable speed.
    2. Hold the load from running back.
    3. Lower the load under control.
    4. Take up the slack on the slugs without induced stress.
    5. Drop the load smartly on the hold.
    6. Allow more power when overloaded on starting up again and automatically lower the power when the load is relieved.
    7. Have good acceleration and retardation.

    In addition to these, when the crane is electrically driven, the following requirements should be satisfied:

    • Prevent any over speed which will damage the motor armature.
    • Stop the load from running back if the power fails.
    • Prevent the winch starting again when the power is restricted until the controller has put back to the correct position.

    Cranes are basically classified by their method of working:

    1. Cargo Winches or Derricks
    2. Jib Cranes
    3. Gantry Cranes
  • 1. Cargo Winches or Derricks

    Cargo winches are used with the various derrick systems arranged for cargo handling. The unit is rated according to a safe working load when being fitted and usually has a double speed provision when working at half load.

    In a cargo winch, a spur reduction gearing transfers the motor drive to the barrel shaft. A warp end may be fitted for operating the derrick toppings lifts (the wire which adjusts the derrick height). Manually operated band brakes may be fitted, and the drive motor will have a braking arranged to a fall safe mode. That is it will hold the load if power fails or the machinery is stopped.

    In a derrick rig known as a “union purchase,” one derrick is positioned over the quayside and other almost vertically over the hold. Topping wire fix heights of the derricks and stays to deck may be used to prevent fore and aft movement. Cargo handling wires run from two winches and join the hook. A combination of movements from the two winches enables lifting, transferring, and lowering of cargo. This is only one of several possible derrick arrangements or rigs. Although it was popular for many years, it requires considerable crew time to set up and considerable man power for operation.


  • 2. Jib Cranes

    Cranes have replaced derricks on many modern ships. Positioned between the holds on platforms which can be rotated through 360 degrees, deck cranes provide an immediately operational unit requiring only one man to operate it. Double gearing is a feature of most designs, providing a higher speed at lighter loads. Various types of cranes exist for particular duties, for example, a general duties crane uses a hook and a grabbing crane is for use with bulk cargoes.

    A general cargo crane has three separate drives that provide the principal movements:

    1. A hoisting motor for lifting the load.
    2. A luffing motor for raising or lowering the jib.
    3. A slewing motor for rotating the crane.


    In the movement of jib up and down, the limit switch works when:

    • Jib is limited to certain angle of inclination.
    • The movement of the jib above this limit is prevented by luffing limit switch; this stops the motor and luffing drum.


    The up and down movement of the hook from the jib by means of running wire; the hoisting limit switch works when:

    • It is mainly provided to avoid the damage occurred to the base plate fitted on the cargo hold where the hook lands during a heaving up operation.
    • The hoisting motor will stop at a distance before the hook block touches the base plate.


    The rotation movement of whole crane through 360o with all the machinery; the aft most crane near to the accommodation can be rotated only 180o and it is provided with a slewing limit switch.

    Slack wire limit

    If the operators by mistake pay more wire rope, which is lowering, the wire gets slack. Then the slack wire limit switches activate and stop the hoisting operation by stopping the hoisting motor and drum.

    This is to avoid winding of the wire irregular in the drum while heaving and causes damage to the drum, supporting brackets, and other parts related to the hoisting. The operator’s cab is designed to provide a clear view of all cargo working areas so that the crane operator can function alone.

    Using Two Cranes Together

    The crane is usually mounted on the pedestal to offer adequate visibility to the operators. For occasional heavy loads arrangements, two cranes are made to work together, i.e. twinning. This can be done with a single operator using a master and slave control system in the two cranes. A common revolving platform will be necessary for this arrangement. The operating medium for deck crane motors may be hydraulic or electrically operated.


    jib cranes

  • In this you can get all the information on gantry cranes it construction, working, maintenance, and safety cut outs.
  • 3. Gantry Cranes

    Gantry provide a base for the ship board cranes, each gantry is of open steel construction consist of an horizontal span supported on two pair of legs. The gantry straddles the ship’s holds each pair of legs resting on rails switch run the length of the deck to port and starboard at the hatch cover.

    The gantry is equipped with extension (wings or arm) of each end of the horizontal span. When extended telescopically, they project over the ship sides. A top platform with cabins beneath is situated on a bogie and able to travel the length of the span. Also on the platform is the winch with four hoist wires on grooved barrels, each driven by an electrical motor. The wires have at their lower ends the lifting head which can be used with a grab or hook. The operator can raise or lower the load and can rotate it in some cases through 360 degrees. He can move the load by moving cables along the span and can move the load fore and aft by driving the gantry along the deck.

    Movements along the deck are driven by rack and pinion gears, but the weight of the system is borne on the railway-type wheel running on rail tracks. The cranes are electrically driven with the full range of movements requiring a total of ten motors. Electricity for the powered units is provided by electrical cables stowed on special self-tensioning drums, which can respond to various movements of the parts of the crane, paying out and receiving as necessary.

    The extending and retracting of the gantry arms is achieved hydraulically when jacking up the cranes before they are parked or stowed for sea. Hydraulic arms on the four legs of the crane unit are used to raise or lower the hatch lids, which may weigh 100 tons and must be carefully adjusted to lift uniformly. When raised a hatch lid is moved to another hatch and stacked on the top of the lid for that hatch.

    Each crane fitted aboard a 42,000 dead weight vessel weighs about 360 tons without load and may have a safe working load (SWL) of 32 tons. When not in use, the gantries are stowed in the position aft-most against the bridge front with their arms retracted.

    Gantry crane

  • Manual Safety Stops and Cut Outs

    Bells and flashing lights are fitted to each leg to give a warning when they are moved. They should be regularly checked. Manual safety stop buttons are provided and situated at the base of each leg of the crane and also on the top platform and in the driver's cab.

    They are clearly marked and are to be used in an emergency such as someone getting in the way of the moving crane. They have the effect of instantly cutting of the power from the hoisting and crane moving motor. Once the safe stop buttons have been operated, they must be reset by ship's staff in the main power house of the crane.

    Safety cut outs are fitted at the ends of the gantry arms to stop the cab and hoisting gear from going off the end of the arm. Cutoffs are fitted for the fires and aftmost movement of the gantry crane to stop the crane from collision with one other or with the accommodation housing or the end line buffer pads.

    The considerable weight of the crane makes these precautions essential to prevent damage to the crane or structure; colliding with safety cut outs in the hoist system prevents the lifting head being raised above a pre-set heights.

  • Maintenance of Cranes

    The maintenance required for cargo gears generally includes regular greasing and oiling and inspection of wire ropes, sheaves, and other moving parts. The gantries must be kept free as a loose scale could fall on the deck and injure someone passing below.

    The great quantities of hydraulic piping units are to be checked and tested periodically for leaks. Since hydraulics are used for the rigging and unrigging of the gantry and are not required during cargo work, hydraulic repairs are done immediately only when they can be done without interrupting cargo handling or when they are causing immediate problems.

    Normally they are completed during the first removal interruption to cargo to avoid any delay which could be blamed on the ship. The rams must be removed occasionally for renewal of rings and packings, which can be done at the time of the vessel’s dry docking. Since each crane uses ten motors, there is a need for a great deal of high quality electrical maintenance. The drive motor in each of the four legs incorporates a set of disc brakes that also need regular inspection and maintenance.

    Lift boat davit is usually referred to "davit". It is designed for unloading lifeboat or work boat of special equipment. According to the launching modes of operation, it can be divided into roll out type, wave inverse and gravity type. With the requirements of SOLAS (Convention on the Safety of Life at Sea) norms, now lift boat davit is divided into drop type, gravity fall arm type, four connecting rod type, platform, single arm cranes, etc. Located on both sides of the ship deck, lift boat davit is usually inside the ship's rail. When it is used, the davit extends out, lifts the boat and puts it down. According to your requirements, Ijin Marine is able to propose the best solution for standard applications, even some special tailor-made solutions.In China, Ijin is waiting for your contact via sales@ijinmarine.com

What Kinds of Deck Machinery Are We Trading?

  • Deck Crane
  • Deck Crane

    A deck crane is a kind of machine, usually equipped with a hoist, wire ropes (chains) and sheaves. It can be used to lift and lower materials and also to move them horizontally. This ship crane is mainly used for lifting heavy things and transporting them to other places. Deck crane adopts one or more simple machines to move loads beyond the normal capability of a man, thus it creates a mechanical advantage. 
  • Mooring Winch
  • Mooring Winch
    A mooring winch is a piece of marine device to hold a boat in place. The winch contains a drum divided into working part and storage part. Sailors can wrap rope, chain, or cable around the drum. There are single drum and double drum mooring winches with or without auto-tension device. Non-asbestos band brake and warping head are fixed on the main shaft. It is also designed with fully or partially enclosed gears. 
  • Anchor Windlass
  • Anchor Windlass
    An anchor windlass is a machine that restrains and manipulates the anchor chain or rope on a boat, allowing the anchor to be raised and lowered. A notched wheel links the chain or the rope. A brake is provided for control and a windlass is usually powered by an electric or hydraulic motor. Our anchor windlass is available in single or double execution. 
  • Lift Boat Davit
  • Lift Boat Davit
    Lift boat davit is usually referred to "davit". It is designed for unlading lifeboat or work boat of special equipment. According to the launching modes of operation, it can be divided into roll out type, wave inverse and gravity type. With the requirements of SOLAS (Convention on the Safety of Life at Sea) norms, now lift boat davit is divided into drop type, gravity fall arm type, four connecting rod type, platfor...
  • Deck Fitting
  • Deck Fitting
    Deck fitting is a type of ventilated attachment that must be screwed tightly to the deck of the vessel for sturdy transport. For boaters, it is referred to pieces of hardware. These metal pieces are used to secure various items to the deck, including fishing rods, ropes and rigging, tarps and sails, railings, life preservers and steering wheels. These fittings come in many shapes and sizes. 

Deck machinery is also called ship deck machinery. As an important part of the ship, it is a kind of mechanical machinery installed on the ship’s deck. Deck machinery is also a necessary mechanical equipment or device for ship docking, loading and unloading cargo, passengers’ getting on and off. This can ensure that ships navigate normally. Ship deck machinery mainly includes anchor windlass, winch, fairleader, mooring bollard, lift boat davit, deck fittings, etc. Our deck machinery have received foreign authentication, such as CCS, ABS, DNV, BV, GL, RINA, NK, KR, SGS, etc.

Operation Cautions of Deck Machinery:
1. Before Operation
1) Take down the canvas cover on the deck machinery, then check whether there are some obstacles around and the control crank is in neutral position or not. This can prevent oil motor from suddenly moving when hydraulic pump is started.
2) Check and confirm that the hydraulic tank’s oil level is normal.
3) Forbid the use of shore power control hydraulic ship deck machinery.
4) After the first start or maintenance, we should check whether the steering pump is consistent with the arrow direction on the pump case. Don’t keep the hydraulic pump reversal to avoid damaging the hydraulic pump. Check whether pipeline has leakage and there is abnormal sound and vibration or not during pump’ running.
5) Confirm all the above normal, and then release the dog driver from the reversing handle of deck machinery.
2. During Operation
1) When operating in the navigation bridge (if already long-time no use), spin the bypass valve on the remote console to the bottom towards the operation direction, and then connect the reversing valve rod of the ship deck machinery with the actuating mechanism of remote control oil cylinder.
2) When operating the warping winch, push the control handle to the warping position. While heaving up the anchor, loosen the chain cable stopper and hand brake band, and then push the clutch handle to the heave away anchor position.
3) Pay attention to the pressure gauge of the remote control box during running. If the pressure exceeds the rated pressure, we must stop operation.
4) When the remote control handle is in the neutral position, cable crane hydraulic brake cylinder should be in brake position. If the red light of the remote control station is on, it means that the brake system works well.
3. After Operation
1) Brake the anchor machine brake tightly, close the chain stopper, open the clutch, put the control handle in neutral position, release the actuating mechanism of remote control oil cylinder, and then use the dog driver to lock the handle.
2) Put the remote control handle of the navigation bridge in the neutral position, spin the bypass valve to the bottom towards the BYPASS direction, and then close the pump power.
3) Use canvas cover to cover the deck machinery.

An anchor windlass is a machine that restrains and manipulates the anchor chain and/or rope on a boat, allowing the anchor to be raised and lowered. A notched wheel engages the links of the chain or the rope. A "trawl windlass" is a similar machine that restrains or manipulates the trawl on a commercial fishing vessel. The trawl is a sort of big fishing net that is wound on the windlass. The fishermen either let-out the trawl or heaves-up the trawl during fishing operations. A brake is provided for control and a windlass is usually powered by an electric or hydraulic motor operating via a gear train.Ijin try to provide reliable winches for all vessels coming into China.Contact Ijin Marine Limited for more info:sales@ijinmarine.com

What Is an Accommodation Ladder?

Accommodation ladders are simple pieces of equipment used with many different types of boats and ships. Designed as a portable device rather than a permanent fixture, this type of nautical ladder can be hung over the side of a boat or ship with relative ease, making it possible for passengers to climb into or out of the vessel with relative ease. The dimensions of the accommodation ladder vary, depending on the size of the boat or ship.

A typical accommodation ladder is constructed with lightweight metal that is capable of supporting the average weight of one or two people at a time. As with most ladders, the basic design is two poles or sides that are connected with a series of evenly spaced rungs. One characteristic that distinguishes an accommodation ladder is a hook design on the top of each pole, which makes it possible to securely position the ladder on the side of the boat when and as needed.

Some designs of the accommodation ladder are retractable, making it easy to fold them for easy storage. A ladder designed for use with a smaller boat, such as a powerboat or yacht, would likely be a simple solid piece that does not fold in any manner. Still, the ladder would be relatively small and easy to store in some nearby compartment, where it could be accessed and put into use with very little effort.

A hanging accommodation ladder is usually considered a staple of onboard equipment for smaller pleasure vessels, like yachts and powerboats. The devices make it relatively easy for passengers to enjoy swimming near a boat that is anchored in a lake, and regain access to the boat when and as desired. They also can make disembarking from the boat after it is docked at a pier much less hazardous, especially for people who are not used to getting on and off a boat.

An accommodation ladder may or may not include handrails and a platform as part of the design. Ladders for smaller vessels are less likely to include these features, while accommodation ladders for larger vessels will often include at least one landing or platform as well as handrails that run the length of the device. The design for larger boats may also allow the ladder to be placed parallel to the vessel, or run in a rectangular fashion to the board of the ship. While older versions of the accommodation ladder were once made with wood steps, many designs today are primarily made of metal components, with some of the ladders designed for use with smaller boats including heavy duty plastic as well.

Ijin Marine Limited is working with Chinese ladders manufacturers to provide quality ladders in China.The ladders contain hatch access ladder,crossover platform ship ladder,ship gangway ladder,pilot ladder,Accommodation ladder,etc.Not only just trading the ladders to the location you expect in the world,Ijin is also able to deliver them on board within China's water.Never mind where you are from,dockyard,shipyard,supplier,ship owner,ship manager,Ijin is always welcoming you to conatct us via sales@ijinmarine.com

A Chief Officer was hit by hook of wire rope while mooring operation

A Chief Officer was hit by the hook of a parted mooring wire rope 

while undertaking mooring operation on board "Shun Hong Hai 11" (順宏海11) 
at To Kwa Wan, Kowloon on 1 September 2002

1.  The Incident 

1.1 At about 0815 hours on 1 September 2002, while the sand carrier "Shun Hong Hai 11" (順宏海11) was in the process of mooring to a barge berthed at the Hing Wah Sand Wharf at To Kwa Wan, the starboard mooring line made fast to the barge "Chi Lee" parted where it passed around the bollard. A hook used to secure the mooring line on the bollard bounced back to the vessel, hitting the Chief Officer who was standing at the port aft of the foredeck taking charge of the mooring operation. The Chief Officer suffered severe injuries to his left hand and chest and was admitted to the Queen Elizabeth Hospital for treatment. Five days later on 6 September 2002, he died in the hospital.

1.2 In the incident, the starboard mooring line was a wire rope of about 16 mm in diameter. It was led from the starboard mooring winch situated athwart at the starboard aft of the foredeck and passed through two fairleads, one at the starboard side and the other at the starboard bow before reaching the port aft bollard on the barge. Unlike the port mooring line which ended with a loop, the end of the starboard mooring line was joined by a shackle with a grommet strop (Fig. 1) on which a hook was carried. The size of the grommet strop could not be ascertained as it was lost in the incident. However, according to the sailors, the grommet strop was about 1 m in circular length and 12 mm in diameter. After stretched to form double wires, the grommet strop was passed around the port bollard of the barge and its end was hooked onto the mooring line by means of the hook it carried.

2.   Findings 

2.1 The most probable cause of the accident is the failure of the grommet strop used to fasten the starboard mooring line during the mooring operation, as a result of a substantial reduction in strength induced by severe bending of its wire rope in passing through the shackle and the hook. The hook released from the parted grommet strop bounced off and hit the deceased working on the foredeck of the Vessel. If proper seamanship practice using a looped mooring line over the bollard had been adopted, the accident would have been avoided.

3.   The Lesson 

3.1 Important lesson should be learnt from this incident :- 

(i) In mooring operation, attention should be paid on the importance of observing the safe seamanship practice associated with mooring wire.

 Grommet Strop


Ijin Marine Limited has supplied hundrend tons of wire ropes in the past year.In most ports of China, Ijin have the capability of delivering ropes direct on board.The wire ropes can be made of steel,stainless steel,plastic covered,etc ,according to China national standards such as GB8919, GB/T20118, GB/T20067 and also international standards ISO, ASTM, EN, JIS and API etc.They are extensively used in crane,davit,winch,elevator,etc for mooring,lifting,transporting,lashing.Different ends are available in our warehouse such as wedge socket,thimble,sleeve,ferrule,mechanical spiced eye,and so on.Also there are IWRC,FI,WS,SES,etc construction available.Pls send me e-mail sales@ijinmarine.com for more information.







Pilots welcome new international rules to enhance safety of boarding ladders

Sep 26, 2012 11:06 AM

New international standards for pilot ladders and related gear should make the most dangerous part of a pilot’s job a bit safer.

The new rules, which took effect July 1, were originally adopted by the International Maritime Organization (IMO) in 2010 as revisions to SOLAS, the International Convention for the Safety of Life at Sea.

John Gormley

Capt. Dave Germond of the Portland Pilots ascends the pilot ladder and prepares to transfer to the accommodation ladder on an asphalt tanker arriving in Portland, Maine, for bunkering.

In a newsletter to its members, the American Pilots’ Association summarized some of the most significant changes:
• Mechanical hoists are now banned.

• Accommodation ladders used with pilot ladders must be secured to the side of the ship to prevent the ladder from swinging.

• Pilot ladders must be certified by the manufacturer as complying with international standards.

• Records of ladder inspections and maintenance must be kept.

• Pilot transfer gear must be inspected as part of the ship’s safety equipment and no safety inspection certificate can be issued or renewed if the equipment has not been inspected.

Capt. Henry Mahlmann, the New York president of the Sandy Hook Pilots, said he welcomed the changes but hinted that more could be done to protect pilots when they are going up or down the ship’s side.

He said that the International Maritime Pilots’ Association had worked very hard with the IMO to get these changes, but noted that there is always an opportunity to improve safety. “The changes are enough, until they are not,” he said.

The most significant change, Mahlmann said, is the requirement that accommodation ladders be secured to the side of the ship. He said that having a railing or hand hold on trap-door platforms at the end of the gangway will also save lives. On many platforms the ladder simply comes up through the platform opening without anything to grab onto.

Another key improvement he pointed out is the requirement that any door on the side of the hull open inward.

“Opening outward is very dangerous. It could hit the pilot or clip the launch,” he said.

Capt. Brian Hope, a member of the Association of Maryland Pilots since 1970, said he has seen all manner of boarding gear during his career: “We board in all conditions and I have even boarded ladders with nothing but chain to hang on to.”  Hope said that one of the biggest improvements to safety mandated by the new requirements has been the installation of secure stanchions at the top of the bulwarks.

“Without stanchions, there is nothing to grab onto as you come over the rail. It is even worse going down the ladder because you have to step over the rail with nothing to grab,” he said.

The revised requirements do not call for any additional equipment or retrofitting of existing ships, but do provide guidelines for correcting especially hazardous arrangements.

The International Maritime Pilots’ Association, in cooperation with the International Chamber of Shipping and other industry groups, has prepared a five-page brochure outlining the new requirements. The brochure is published by Marisec Publications, based in London, and an electronic version is available free of charge at:www.marisec.org/pilotladders and www.impahq.org/downloads.cfm.

Pumps and Pumping Basics

A Primer on Pumps and Pumping for Shore and Vessel Applications

Pumps are used extensively throughout the maritime industry. Vessels and shore installations utilize a wide range of pumps and pumping techniques to transfer and distribute fluids and slurries of all types.

Types of Pumps

All common types of pumps use a source of energy to move a liquid through a confined space. The energy may be applied by mechanical force directly on the liquid or by using an energy carrier like compressed air.

Pumps for general applications are mostly direct mechanical pumps. Specialized pumps use a variety of techniques to appropriately handle whatever material is being transferred. Liquids that are highly viscous or flammable need special equipment to be transferred quickly and safely.

Positive Displacement Pumps

Positive displacement pumps fill a chamber with fluid from an inlet then compress the fluid to eject it from the outlet. One example of this is the internal combustion engine which fills a cylinder with an air and fuel mixture and then empties the cylinder when the mixture has burned and expanded. Of course this is being done with gasses rather than liquid, a device that moves gasses is usually called a compressor.

The method of displacement can be achieved by several different means.

  • Piston and Cylinder – This is the same as our example of the internal combustion engine above. One variation on this method is called diaphragm pumping. In these types of displacement pumps a flexible diaphragm moves back and forth to change the displacement in the pump chamber in place of the usual piston.
  • Rotary Displacement – A spinning device pushes water using fins or lobes which fit tightly against the walls of the pump chamber. The operation is similar to old fashioned water wheels that ran industrial equipment before other forms of power became available. The difference is that the wheel is enclosed within a housing which allows it to operate at a much higher speed and efficiency.

Centrifugal or Rotary Velocity Pumps

This type of pump spins a device called an impeller inside a chamber which causes the liquid being transferred to be pushed to the outer edge of the chamber by centrifugal forces. An outlet along this outer edge gives the compressed liquid a place to escape.

The action of the impeller on the liquid comes in two forms depending on the application. Centrifugal pumps designed for a variety of applications use a combination of these two methods to meet performance and efficiency goals.

  • Radial Flow – Fluids are transported around the pump chamber by the impeller. Energy is supplied to spin the impeller by a shaft or coupling which is at a right angle to the flow of the liquid.
  • Axial Flow – In this application the impeller moves the liquid along in a screw-like fashion. The rotating shaft that moves the impeller is parallel to the movement of the fluid. The impeller and shaft may be in the center of the pump chamber or offset to one side which exposes only one side of the impeller to the fluid being pumped.

Pump Variations

The two main types of pumps outlined above are the basis for a very large number of variations.

Valves come in many configurations that add performance or reduce manufacturing or maintenance costs. The types of valves, or lack of valves, also depend on the liquid being transferred.

Corrosive or flammable liquids need careful handling. Some pumps must move very hot or abrasive materials and operate without maintenance for extended periods of time. Valve design and material is essential to longevity of these pieces of equipment.

Materials that make up the pump chamber and impeller are important to many aspects of pump operation. Iron, bronze, and stainless steel construction are common in many maritime applications on board ship and on shore. This is a well-tested and familiar group of materials with known long-term performance characteristics.

Recently, pumps built from engineering composites have begun replacing the more traditional materials in the industry. Structural graphite pump construction offers high strength and fully corrosion resistant operation in corrosive environments.

The use of composites throughout the maritime industry is now seen by a growing number of manufacturers and operators as one of the best ways to reduce maintenance and the associated overhead costs.

Pump Design

Overall the most important aspect of pump performance lies in the design. Efficiency is best in a pump that is exactly sized for the job it needs to do. Many pump solutions advise to use a pump within a performance range that can be quite wide. A pump that operates at 10 percent less efficiency than an exactly sized pump will consume much more energy over its lifetime than one that is sized exactly for the job.

Factors influencing pump design are material being transferred, pump head, pump lift, volume of flow, amount of maintenance required, and many other variables that fill textbooks on fluid dynamics and engineering.

If there were three basic concepts to understand about pump design and fluid dynamics it could be narrowed down to volume of flow, pump head, and pump lift.

Volume of Flow is fairly simple; how big is the pipe that the pump is feeding and how fast must the fluid flow through the pipe to meet your goals for flow rate. This is where you need to brush up on your fluid dynamics to get the best possible balance between all the variables.

Pump Lift is the ability of a pump to draw a liquid up to itself through the inlet pipe.

The laws of physics show us that a liquid like water can only be drawn up to a certain height by a perfect vacuum. Since no pump draws a perfect vacuum it is only possible to draw liquids to a certain height with a pump positioned well above the liquid reservoir.

This height is variable according to the density of the liquid being moved.

Pump Head is the distance a pump can move a liquid vertically before the pressure of the liquid above the pump stops it from adding new liquid to the output side of the pump.

Pumps come in a wide variety of head efficiencies. As the height of the output rises the volume of the pump is decreased proportionally until no liquid flows from the outlet. Large pumps can have thousands of feet of head even with a large diameter pipe which decreases head because of the larger volume of liquid the pump mechanism is supporting.

What is the best type of pump?

This is kind of a difficult question but one that is asked often. It is kind of like asking ‘what is the best kind of dog?’ or ‘what is the best kind of car?’. The answer lies in the use of the pump or dog or car.

There are some pros and cons of centrifugal and positive displacement pumps in general but correct pump sizing is more important than pump type in most situations.

Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps:sales@ijinmarine.com

Why ship needs standby pumps?


Pumps are commonly found and the most used marine equipments on ships,regardless of the purpose of systems,nearly all of them have pumps serve specific purpose,especially when it comes to system closely related to water and oil.A standby pump is fitted along with the main pump in parallel arrangement,many people say that it is a waste of money,but the truth is not.

Take the fresh water cooling water system of ship engine for instance,you will always find two fresh water pumps on the schematic diagram,are they working together?The answer is no,it is only one fresh water pump running at a time,you may ask then what does the other pump used for,isn’t it used to help increase the water flow in the water circuit?In fact,if the system is designed to use two pumps,then one pump is sufficient to provide enough water for the system,the other pump is only a standby pump,it does not run while the other pump is running.Should failures occurs to the running pump the standby pump will be working instead.The fault pump will stop contributed to external logic protection.

Each pump can be set as a standby pump to the other one,when the discharge pressure falls below the preset value,it indicates something goes wrong with the running pump,the most common case is a clogged suction pipe,when the pressure signal is captured by the VCS and compared to the valve value,if the value is smaller than the preset value,the pump will stop running thereby starting the standby pump instead.Then the discharge pressure would most likely recover to normal,this is the exact moment for crew to find out what happened to the main pump.The diesel engine would stop running due to overheat if there’s only one pump and it is fault,then we can see why a standby pump is so important for a ship.

Standby pumps are also the main factor that makes a ship so expensive,the function of a standby pump has also to be tested immediately after its installation,as it would likely result in bigger trouble if the standby pump does not automatically start up when failure of the main running pump occurs.

Ijin Marine Limited is a supplier and trader company in Shanghai,China.Ijin mainly trades hardware and equipment for ships.There are many different series of marine pumps in China's market.But Ijin is sorting out all of them to satisfy different needs.Normally Ijin is trading below pumps.Horizontal Centrifugal Pumps,Vertical centifugal pumps,Multi-stage Centrifugal Pumps,Self-priming Non-block Sewage Pumps,Submersible Electrical Pumps,Sludge Discharge Pumps,Gear Pumps,Electrical Reciprocating Pumps,Hand Pumps,Crushing Pumps,Water Circulating Vacuum Pumps,Ejector Pumps.Contact Ijin Marine, you will get the wonderful pumps-sales@ijinmarine.com

What is a Dock Bumper?

In routine terms, a bumper is a ‘device consisting of bars at either end of a vehicle to absorb shock and prevent serious damage.’ A marine dock bumper is attached to the docks so as to prevent the boats from getting damaged if they hit the docks after they are moored properly.

Sometimes it so happens that even after a boat is docked they tend to get jostled or shoved against the docks. Since the boats are made of fibreglass material, such moving of the boat could result in the boat owner paying out huge amounts to repair the boat. A dock bumper solves this problem for the boat owner.

There are different kinds of boat dock bumpers. Some of the various types of boat dock bumpers can be explained below:

  • The most ordinary type of a marine dock bumper is a foam bumper. They are the cheapest variety of boat dock bumpers that are available in the market.
  • A steel-faced dock bumper is a very preferred variety of dock bumper that is available in the market. This type of boat dock bumpers offers not only longer life to the bumpers but also offers complete protection to the docks in every weather condition. There are different types of steel-faced bumpers that are utilised for the purpose of dock and boat safety. One such important type is the dura-soft marine dock bumper.

A dock bumper can be easily installed; however it is important to note the type of bumper that is to be used and the correct area of the dock where the bumper is to be fitted. The fitting of a dock bumper depends on the area where the boat could hit the docks with the most impact.  Excess fitting could lead to unnecessary expenses for the dock owner while limited fitting could lead to some area being left out and the boat getting damaged.

In order to install a dock bumper, all one needs is the appropriate screwdriver and screws. Sometimes, by using simple materials a dock bumper can be created by a boat owner himself. But the reliability of such bumpers will not be as much as of the company manufactured dock bumper.

A dock bumper is an important technological method that is helpful to everyone involved in the boat docking process.

Ijin Marine Limited,China, is a global leader in the trader and supplier of marine fenders. Marine fenders are a critical element of any commercial marine docking facility and provide the necessary protection between a large vessel and the docking structure itself. Ijin chosed marine fenders are utilized by a variety of clientele within several industries to include: ports and harbors, municipalities, private facilities and government/military facilities. These facilities are typically supported by Maritime via the engineering consultants and marine contractors that design, construct and maintain the docks and quays.Ijin offers numerous types of marine fenders for various applications, but is anchored by the large molded fender group  including: cone fenders, cell fenders, leg/element fenders and arch type fenders. All of the marine fenders are tested to the most rigorous standards per the latest international requirements.Ijin's contact detail:sales@ijinmarine.com

What are Marine Fenders?

Marine fenders are a type of marine equipment that are used to prevent boats, ships and other naval vessels from colliding against each other or against docks, wharves and piers. In other words marine fenders can be simply termed as a marine bumper.

Marine fenders are important marine equipment as they prevent loss to the body of a boat or a ship. The fender systems that are used in naval vessels have evolved continuously throughout the times and now are devised in such a way that the prevention process is almost faultless and foolproof.

Marine fenders, in today’s times are employed in such a way that they are kept on the hull or the head of a boat or a ship in order to prevent casualty to the hull or the head of the naval vessel if there is any collision happening between boats. However, at the same time, marine fenders are also employed in piers, docks, wharves and other regular boat entrance and exit points on a permanent basis.

This permanent fixing of marine fenders help because, in case there is a heavy traffic of boats passing through from a particular dockyard, and there is an accident or a collision then the casualty to the boat and the dockyard will be both minimised to a great extent.

Fender systems have been devised in order to protect all vehicles from damage caused due to accidents. When it comes to marine fenders, the marine equipment is one of the best technological advancements to have occurred in contemporary times.

Even in the earlier centuries, fender systems were used to prevent loss to a naval vessel’s torso but the concept and idea has evolved more in the modern times than in the past. Through successful innovations and initiations, there are a wide variety of marine fender systems available which act as excellent marine equipment.

There are various types of marine fenders which have emerged over the years and which provide excellent utility in the area of water transportation. The wide variety of marine fenders ensures that sufficient options are provided so as to enable a person or an authority to choose the best possible fender system or marine fender.

Some of the types of marine fenders are as follows:

Arch Fenders:

This type of marine equipment is used in order to provide aid and assistance to a type of marine fender known as the cylindrical fender. Since the maintenance aspect in arch fenders is absolutely zero, it is one of the best marine equipment and a best fender system. Arch fenders can be used for small and mid-ranged ships and boats and provide excellent quality service to the same.

Cylindrical Fenders:

They are the most basic and common fender systems used in today’s times. They can be used for all types of marine boats and ships and they are quite economical too when the aspect of fitting them up is taken into account.

W Fenders:

These type of marine fenders are used mainly to aid the larger ships and boats because they offer a high rate of resistance and thus better protection to the water-crafts in case of any accident occurring.

Other types of marine fenders are the I fender, Cell Fender, Cone Fender and the Pneumatic Fender which along with the other three marine fenders, help in providing a very viable and feasible solution to the problem of accidents and collisions of naval vessels.

Having a shipping conglomerate is a very important thing, but equally important is the preventive measure employed to safeguard the naval vessels in case of any collision. Fixing fender systems to one’s boats and ships therefore is the best idea and the best safety procedure that can be applied and used not just effectively but also productively.

Ijin Marine Limited,China, is a global leader in the trader and supplier of marine fenders. Marine fenders are a critical element of any commercial marine docking facility and provide the necessary protection between a large vessel and the docking structure itself. Ijin chosed marine fenders are utilized by a variety of clientele within several industries to include: ports and harbors, municipalities, private facilities and government/military facilities. These facilities are typically supported by Maritime via the engineering consultants and marine contractors that design, construct and maintain the docks and quays.Ijin offers numerous types of marine fenders for various applications, but is anchored by the large molded fender group  including: cone fenders, cell fenders, leg/element fenders and arch type fenders. All of the marine fenders are tested to the most rigorous standards per the latest international requirements.Ijin's contact detail:sales@ijinmarine.com

Cleats, Chocks, Bits, and Bollards; Securing Your Vessel


Do You Know the Difference Between a Cleat, Chock, Bit, and Bollard? Make Sure You Know the Differences and Specific Uses for Each of These Important Fixtures.

At some point early in your maritime career someone is going to ask you to tie a boat to something solid so it doesn’t float away.

There are specific fixtures on all vessels and docks made for this purpose. We will take a short look at four of the most common and save the specialty fixtures for a little later.


Cleats: These are fixtures found on docks and vessels. They are shaped like a very wide and short capital letter T.

Closed types have a solid base while open types have two closely spaced legs in the center. A line with a loop on the end can be passed through the legs and secured over the horns which is the name of the horizontal piece of the cleat.

This allows it to pull tight without the chance of working loose as it would if the loop were just placed over the cleat. Some Dock Masters frown on this because the line can abrade the dock.

The best way to tie to a cleat is with a hitch at the end of a line. They come in all sizes from the size of your little finger to the size of your leg.

Chocks: These are fixtures that hold a line rather than using it as a tie point. It is found near a cleat and keeps the line in position so it does not move laterally and chafe or abrade. They are flattened loops that have a narrow opening at the top to accept and remove the line. Like cleats, these come in all sizes but are usually found aboard vessels and not on docks.

Bits: These fixtures are a solid column which is sometimes square and sometimes cylindrical. They have a cross bar that is of a lesser diameter and forms a lowercase letter t. These are also called Samson posts because they are so strong. You tie to them with a hitch around the crossbar or they accept a looped line well.

Bits are mostly found on vessels near the bow and stern, they appear infrequently on docks but it isn’t unheard of if there is a need to use something taller than a cleat in order to accept large diameter lines.

Bollards: These are the things that look like short metal mushrooms. You can find them on docks and large ships and almost never on smaller vessels. They are made for a loop of line that is placed over the top and the slack is taken up on the other end to make the line tight.

Each of the fixtures above has a preferred method of tying. Some of the methods like passing the loop through the legs and over the horns of an open cleat is suitable for heavy weather situations with strong wind and waves. Other methods like a loop should be used in calmer conditions but a hitch can be used at any time.

If you want to learn more go to our maritime glossary where you can find more than a simple definition of a term and get some insight into the context and rich maritime history.

Ijin Marine Limited offers chocks and buttons in a wide variety of sizes and features. Ijin in China offer open and closed chocks, fabricated button chocks, throat button chocks, hawse chocks, and many other varieties.Our Panama chocks are used by military and industrial ships, operating effectively throughout the world.With certificates of CCS,LR,NKK,ABS,etc,Ijin Marine Limited is waiting for your contact via sales@ijinmarine.com

What Are Mooring Winches?

Learn about an important equipment of a ship's navigation system. No matter which era a ship belong to, a mooring winch is found on all the ships whether old or new. Find out about the construction and working of these winches

  • Mooring Winch

    A ship is a huge structure and when it comes to a port for any purpose such as cargo loading, discharging or bunkering; it needs to be "parked" properly so that it does not move from its position beyond a certain degree. This could lead to disruption of operations and also could mean damage or harm to life and nearby installations. It is very easy to tie up a small boat to the shore, but how do you go about securing a big sized vessel. Well, we will learn in detail about the "berthing operation" as it is called in navigational language, in a separate article. But for now, I will talk something about an important component of the mooring systems, namely a winch.

    Mooring winch is a mechanical device used for securing a ship to the berth. An equipment with various barrels used for pulling ropes or cables, mooring winches play an important role in berthing the ship ashore. The barrels, also known as winch drums, are used for hauling in or letting out the wires or ropes, which will help in fastening the ship to the berth.

    Mooring winches assembly comes in various arrangements with different number of barrels, depending on the requirement of the ship. The main parts of a mooring winch includes a winch barrel or a drum, a warp end and a driving motor. Modern mooring winches comprises of elaborate designs with various gear assemblies, which can be electric, pneumatic or hydraulic driven.

    • Construction and Working

      A mooring winch assembly consists of a winch drum which has cable or rope wound around it. The winch drum and warp end is driven with the help of a motor drive. All these parts are supported with the help of a substantial frame, which also support a band brake, clutch and geared drives.

      The motor drive is connected to the barrel and warp end using a spur gear transmission system. The transmission system is also provided with a clutch and a band brake. Thus, the spur gear transmission system controls both the barrel and the warp end. The warp end acts like a locking device, which prevents the rope from sliding off the barrel when pulled excessively. Warp end is extremely important for moving the ship along the berth for alignment purposes. This is done by fastening one end of the ropes or wires to the bollards on the shore and the other end around the warp end of the winch.

      Appropriate control of the drum movement is an important aspect of the mooring operation. For this reason, band brakes are provided to stop the drum whenever required. Also, it is important that the drum rotates smoothly in both reverse and forward direction. A controller arrangement of the drive motor facilitates forward and reverse direction as and when required, including selection of speeds as per the requirement.

      Most of the modern mooring winches help in avoiding the stress related to constant monitoring of the mooring winches when the ship is berthing at a port. It is essential to tension or slacken the mooring wires according to the flow of the tides and the change in the draught that takes place due to cargo operations. The modern mooring assemblies act as an automatic self tensioning unit, which provides for paying out or recovering wires when a pre-set tension is not present.








      An anchor windlass is a machine that restrains and manipulates the anchor chain and/or rope on a boat, allowing the anchor to be raised and lowered. A notched wheel engages the links of the chain or the rope. A "trawl windlass" is a similar machine that restrains or manipulates the trawl on a commercial fishing vessel. The trawl is a sort of big fishing net that is wound on the windlass. The fishermen either let-out the trawl or heaves-up the trawl during fishing operations. A brake is provided for control and a windlass is usually powered by an electric or hydraulic motor operating via a gear train.Ijin try to provide reliable winches for all vessels coming into China.Contact Ijin Marine Limited for more info:sales@ijinmarine.com

Marine Fenders and Ship Berthing

One of the primary factors -external to the ship’s mechanical or electrical systems – that come in to effect while berthing a vessel is the marine fender system. An efficient fender system saves the ship from external damages that would have otherwise occurred to the hull plates or to the berth or jetty, which comes in contact with the steel plates of the ship.

How Ship Berthing is done Using Marine Fenders?

Theoretically speaking, a ship is to be brought at a negligible speed to the berth. A small increase in speed will give rise to an marine fendersexponential jump in the momentum – which essentially is the product of mass and velocity. For example the displacement tonnage of 10,000 when multiplied by a speed of one knot has half the momentum when multiplied by a speed of two knots. The energy of impact is twice, thrice, four times and so on with every knot of increase of speed.

Now, when it comes to practice the speed always cannot be restricted to bare minimum, owing to certain conditions such as the tides, wind effects, tugs erratic pull, engine failures etc. A good marine fender system can save the day in such exigencies.

Ideally a marine fender system should be cost effective, with low maintenance cost and high durability. The material should be locally available should a case of replacement arise.

marine fenders foamWhile berthing, the navigator of the ship has to consider the amount of berthing energy involved. It is actually a product of various variants such as mass of the vessel or displacement, it’s approach velocity, the added mass co-efficient ( which is the mass of the water that is moving along with the vessel and is suddenly stopped at the point of contact), the eccentricity factor which is the rotational movement generated by a reaction force when the bow or stern comes in contact with the marine fenders at the berth, the berthing configuration factor which is the amount of energy absorbed by the cushion effect of the water between the quay wall of the berth and the approaching vessel, and the softness factor which is the energy absorbed by the deformation of the ship’s hull and the shore marine fender.

Abnormal energy is the energy that exceeds the normal berthing energy when berthing is done in abnormal conditions such as inclement weather, during human or technical error or an ominous combination of all three.

To neutralize this kinetic force imparted by the ship on the pier or berth, some work must be done by the quay wall and the shore structure upon the hull of the ship.

The reactive force of the dock installations increases dramatically, immediately after the impact of the ship’s hull upon it. As a result both the hull and the dock structure deflect according to their respective stiffness.marine fenders for ships

Herein the marine fender, which is fitted in their interface, becomes active. It deflects and reduces the berthing energy drastically without causing permanent damage to the hull of the vessel or concrete of the berth.  Naturally fenders should have high force absorption capacity without exerting a reactive force upon the quay.

Types of Fenders

Now the question arises what is the type of fender to be used in a specific berthing of ship?

Marine fender selection is important as it determines the safety of the personnel, cargo and body of the ship and its equipments. The turn around time of the ship can depend on the quality of the fender. One has to keep in mind the statistics of the heaviest and the largest vessel that reports to the dock before selecting and arranging the marine fender system.

Hollow wooden fenders of yester years are now giving way to various types of rubber marine fender, foam marine fender and pneumatic marine fenders Now fixed rubber fender systems comes in different varieties such as

  • Cone fenders
  • Cell fenders
  • Arch fenders
  • Cylindrical fenders
  • D type fenders
  • Leg fenders
  • Dock corner rubber fenders
  • Pie-type rubber fenders

marine fenders whiteFoam fenders contain chemicals such as Ethylene Vinyl Acetate (EVA), which are floatable and low in maintenance cost. A polyurethane spray or elastic-polymer sprays are used over these fenders to create near total wear resistant exterior.

Pneumatic fenders are air filled floating marine fenders which can be fitted on quay wall or ships hull according to the requirement. There are four types of pneumatic marine fenders

  • Sling type fender
  • Rib type fender
  • Rope net fender
  • China and tyre net.

Fenders are an integral part of safety system of the ship which reduces the shocks upon the quay or the hull. A wide range or variety of marine fenders is available in the market for different applications. They are not only used for merchant vessels, but also for boats, yachts, and other floating vessels.

The right choice of the marine fender to optimize the cost and the effectiveness is a matter which requires experience and expertise, not to say a thorough overall knowledge of the available varieties, requirements and the theory that goes with it.

Ijin Marine Limited,China, is a global leader in the trader and supplier of marine fenders. Marine fenders are a critical element of any commercial marine docking facility and provide the necessary protection between a large vessel and the docking structure itself. Ijin chosed marine fenders are utilized by a variety of clientele within several industries to include: ports and harbors, municipalities, private facilities and government/military facilities. These facilities are typically supported by Maritime via the engineering consultants and marine contractors that design, construct and maintain the docks and quays.Ijin offers numerous types of marine fenders for various applications, but is anchored by the large molded fender group  including: cone fenders, cell fenders, leg/element fenders and arch type fenders. All of the marine fenders are tested to the most rigorous standards per the latest international requirements.Ijin's contact detail:sales@ijinmarine.com

What equipment is there on forecastle deck of ship?

Equipment%20on%20forecastle%20deck%20of%20ship Equipment on forecastle deck of ship equipment

1 . Windlass
2. Chain cable compress
3. Hawse pipe
4. Anchor chain
5. Bollard
6. Fair leader
7. Mooring pipe
8. Deck end roller
9. Wire reel
10 . Cowl head ventilator
11 . Derrick boom
12. Boom support
13. Air and sounding pipe
14 . Flag staff
15. Anchor davit
16 . Stockless anchor
17 . Anchor shackle
18 . Anchor shank, Anchor shaft
19. Anchor crown
20. Anchor arm
21 . Anchor palm
22 . Anchor fluke
23 . Anchor light davit
24 . Open rail
25. Hand rail stanchion
26 . Hand rail
27 . Anchor recess
28 . Bow chock
29 . Bell mouth of hawse pipe
30 . Deck Flange hawse pipe

Equipment%20on%20forecastle%20deck%20of%20ship 1 Equipment on forecastle deck of ship equipment

Ijin Marine Limited offers a variety of high-impact composite roller fairleads from a single roller to 4-rollers. The roller fairleads will extend the life of your synthetic rope and cost less than stainless steel.Our deck fittings are used by military and industrial ships, operating effectively throughout the world.Contact us via sales@ijinmarine.com for more information.

The Construction of Life Boat

Life boat

Lifesaving%20appliance Lifesaving appliance equipment

Clinker system wooden boat

Lifesaving%20appliance 1 Lifesaving appliance equipment

Double skin system wooden boat

Lifesaving%20appliance 2 Lifesaving appliance equipment

Steel boat

Lifesaving%20appliance 3 Lifesaving appliance equipment

Alloy boat with hand propeller gear

Lifesaving%20appliance 4 Lifesaving appliance equipment


1 . Keel
2. Hog piece
3. Keelson
4. Bent frame, Timber
5. Garboard strake
6. Shell planking
7. Bilge rail
8. Seating plank
9. Filling piece
10. Topside planking
11 . Sheer strake
12. Capping gunwale
13. Gunwale
14. Rising
15 . Side benches
16. Thwart
17. Lower cross scat
18. Stanchion
19. Gang board
20. Buoyancy air tank
21 . Tank cleading
22. Bilge stringer
23. Life line
24. Life line handle
25. Lifting hook
26. Ring bolt
27 . Stern post
28 . Check piece
29 . Tiller
30 . Stem
31 . Thwart knee
32 . Mast clatch
33 . Rubber piece
34 . Seat chock
35 . Clutch socket
36 . Double skin diagonal
37 . Breast plate
38 . Deep floor
39 . Grating .
40 . Floor
41 . Stern frame
42 . Rudder plate
43 . Frame
44 . Handle lever
45 . Support point
46 . Bearing
47. Connecting rod
48. Gear box
49 . Universal point
50. Stuffing box
51 . Kawara, Siki
52. Nakadana
53 .Aori
54 .Uwadana
55 .Koberi
56 .Uwasuberi, Hunabuti
57 .Matura
58 .Komoti
59 .Sikiita, neda
60 . Tomo bari
61 . Deck
62. Lifting hook


towering & hoisting equipment for life boat

owering%20%2C%20hoisting%20equipment%20for%20life%20boat Lifesaving appliance equipment

Gravity type davit
Boat chock
Alloy boat
Radial davit
Davit span
Griping spar bracket
Cross head bitt

owering%20%2C%20hoisting%20equipment%20for%20life%20boat 2 Lifesaving appliance equipment

Steel boat
Drive tube
Rope drum

owering%20%2C%20hoisting%20equipment%20for%20life%20boat 1 Lifesaving appliance equipment

Luffing type davit
Griping pad
Stay to davit
Turning out gear

There are many different types of lifeboat and rescue boat. They are divided into free fall lifeboat,totally enclosed lifeboat,partially enclosed lifeboat,etc according to use, structure,lauching type.Ijin cooperated with China's famous boatyards such as Beihai Shipyard,Dalian Mingzu,Songliao,Haihong,Jiangyin Beihai,Wuxi Wenjiao.All lifeboats,rescue boats can be delivered directly on board in China's ports,dockyards,anchorage,etc.Ijin can provide CCS,DNV,LR,ABS,NK,KR,etc class certificate for all lifeboat.In more than 300 ports of 80 countries, Ijin is also able to do annual inspection,five years inspection for your lifeboat and rescue boat.Contact our representitive for more information,sales@ijinmarine.com

Different types of valves in shipping industry



gate%252520valves Types of valves ship machine equipment


gate%252520valves 1 Types of valves ship machine equipment



globe%252520valve Types of valves ship machine equipment


globe%252520valve %2525201 Types of valves ship machine equipment


globe%252520valve %2525202 Types of valves ship machine equipment


plug%252520valves Types of valves ship machine equipment

plug%252520valves 1 Types of valves ship machine equipment


ball%252520valves 1 Types of valves ship machine equipment


butterfly%252520valves 1 Types of valves ship machine equipment

ball%252520valves 2 Types of valves ship machine equipment

butterfly%252520valves 2 Types of valves ship machine equipment


butterfly%252520valves 3 Types of valves ship machine equipment


diaphragm%252520valves 1 Types of valves ship machine equipment


check%252520valves 1 Types of valves ship machine equipment

check%252520valves 2 Types of valves ship machine equipment

check%252520valves 3 Types of valves ship machine equipment

check%252520valves 4 Types of valves ship machine equipment

check%252520valves 5 Types of valves ship machine equipment


Butterfly valve

Butterfly%20valve Types of valves ship machine equipment

1.valve liner
2.valve blade,
3.valve body,
4.upper seal,
5.valve spindle,
7.upper bearing,
9.lower bearing,
10.lower seal,

Retention valve, non-return valve, check valve

1) when the disc is not attached to the spindle, the globe valve is considered to be a screw-down nonreturn valve (SDNR).

Butterfly%20valve%201 Types of valves ship machine equipment
2 bonnet,
3 gland flange
4 gland,
5A disc (stop type),
5B disc (piston SDNR),
6 disc stem nut,
7A stem (stop type),
7B stem (piston SDNR),
8 bonnet gasket,
9 gland packing,
10 bonnet studs,
11 bonnet stud nuts,
12 yoke bush,
13 handwheel,
14 handwheel nut, tack weld, stellite,

2) without a stem to screw down the flow interrupting component, the non-return valve is of the freelifting type.
Note : the flow-interrupting component may be a disc (see figure) or may be a bail (ball check valve),

Butterfly%20valve%202 Types of valves ship machine equipment
flap check valve, flap valve, swing check valve,
plug valve, ball plug valve, ball valve,cylindrical plug valve,
cock, bib, bib-cock, faucet, tap,
3 guides cast integral with body,
cover studs,

sleeve-packed cylindrical plug cock

Butterfly%20valve%203 Types of valves ship machine equipment

lever bolt
split ring
packing sleeve
tightening nut

valve classification according to…


full way valve, full bore valve (e.g. gate valve, butterfly valve)
throttle valve (e.g. globe valve, needle valve, piston valve)


straight-through valve, in-line valve, angle valve


dump valve,
flow diversion valve,
relief valve, safety valve, sea suction valve etc.

in the gate valve,

closing by interposing a flat or tapered element (gate or wedge) transversely across the axis of the opening.

in the globe valve,

closing by pressing a disc or plug axially against the opening.

The valves are made of cast iron,cast steel,stainless steel,etc.Ijin trades and supplies globe valve,angle valve,stope valve,butterfly valve,etc in China.These valves are approved by class societies such as DNV,LR,ABS,NKK,KR,CCS,etc.In more than 50 ports of China,Ijin can deliver above valves on board.With reasonable prices,Ijin won more clients and become a reliable hardware supplier for shipowners.The more suppliers Ijin have,the more confident Ijin is when sending you a quotation.Our contact detail is as below:sales@ijinmarine.com

All Equipment Used When Mooring

Overview of Anchor and Mooring Gear

Anchor windlass on general purpose shi