External to the ship’s mechanical or electrical systems, there is one of the primary factors that come in to effect while berthing a vessel is the marine fender system. An efficient marine fender system saves the ship or vehicle from external damages that would have otherwise occurred to the hull or to the pier or jetty, which comes on contact with the steel plates of the ship or vehicle.
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 exponential 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.
While 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.
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 Marine Fenders
Now the question arises what is the type of marine 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 turnaround 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 (JCO)
• Cell fenders (JSC)
• Arch fenders (JDA)
• Cylindrical fenders (JCY)
• D type fenders (JD)
• Leg fenders (JUE)
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.
(Partial contents of the above are quoted from marineinsight)
Arch Fender
JIER manufactures two types Arch Fenders, JDA-A and JDA-B. The JDA-A fender has a rubber contact face ideal for all general purpose applications...
Cylindrical Fender
Cylindrical Fenders are simple to install and operate which makes these units an economical solution for remote locations and for multi user berths...
Cone Fender
All Cone Fenders are single piece mouldings so they are robust, long lasting and easy to install. UHMW-PE faced steel frontal frames are generally used...
Super Cell Fender
Cell Rubber Fender here mentioned is improved over the ordinary type. It has high absorption energy per unit weight and low tilt compression performance...
D Fender
D Fenders can be pre-curved, chamfered and drilled to aid installation at a relatively low cost and can also be cut to the length required ...
Wing Fender
JIER Wing Type Rubber Fenders are developed on the basis of D Type Rubber Fenders. They can be fixed with double line anchors which greatly ...
Square Fender
Square Rubber Fenders offer similar advantages to D fenders and are typically used where a stiffer fender is required. Square Rubber Fenders...
Unit Element Fender
Unit Element Fenders are a high performance, modular system. Element Fenders can be combined in unlimited permutations of length, orientation and Energy...
Roller Wheel Fender
Roller and Wheel Fenders are commonly used on the berth corners and dock entrances, also widely installed along the walls of dry docks and other...
Tug Fender
Tug fenders must work harder, for longer and under more adverse conditions than any other fender type. Tug fenders can be divided into three main types...
Pneumatic Rubber Fender
Pneumatic Rubber Fenders have been in use for around 50 years. The development of the Pneumatic Fender has progressed through ...
Foam Filled Fender
Foam Filled Fenders are versatile, robust and suitable for almost all applications. The manufacturing process allows for virtually any size of fender to be...
Keyhole Fender
Keyhole Fenders are made of high abrasion resistance rubber. They are specially designed for tugboats and workboats.
Rubber Ladders
Rubber Ladders Fenders are very robust. They are flexible to reduce accidental damage and help protect the wharf from small craft berthing.
Rubber Pads
Rubber Pads (Plates) are designed and produced for the protection of barges, tugboats, water locks and quay walls.Contact Us
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