A ship fender protects the vessel's sides from collision damage when lying alongside.
The ship fender protects large ships when they lie alongside one another. It is also used at port terminals, general cargo docks, Ro-Ro docks, container ship terminals, etc.
The ship fender is a large, air-filled cylinder. It consists of various layers of rubber which are sometimes covered by a tire and chain net. It flexes when squeezed between the sides of two ships. Size varies greatly, from one to nine meters long. Those more than 2.5 meters in diameter usually have a pressure relief valve.
Choice will depend primarily on the size and displacement of the vessel. Fenders that compress slowly are preferred when ships of great size come alongside one another.