Views: 3 Author: Site Editor Publish Time: 2021-06-15 Origin: Site
An efficient fender system will protects 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.
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.
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.