Ship's crane, also known as a DAVIT, is a mechanical device used to lower and raise cargo, equipment, or people from one level to another. It is typically used on ships, but can also be found on docks and other structures. Davits are usually made of metal and consist of a base, a boom, and a winch. The boom is used to lower and raise the cargo, while the winch is used to control the speed and direction of the movement.