单项选择题 （）is placed in the front of the ship under the water,which eases berthing or ma-noeuvering sideways at slow speed.

单项选择题 （）is a roud-shaped underwater part in the front of the ship.The purpose is to cre-ate less friction with water so that the ship moves more easily.

单项选择题 （）is used to moor the ship to the seabed to keep it sationary.