A boat trailer winch is a device used to load a boat onto a trailer. Consisting of a cranking mechanism, a spool of cable and a hook, the boat trailer winch is attached to a steel ring on the bow of a boat. As the cable is cranked back onto the spool, the boat is pulled onto the trailer. There are two basic designs of boat trailer winch: a manual type that incorporates a hand-cranked winch to spool the cable, and an electric model that uses an electric motor to crank the cable onto the spool.