A winch is a spool-shaped device used to aid in bringing in the sheets on larger boats. The sheet is wrapped around the winch, which is cranked using a detachable handle connected to the top. The winch is made to turn in only one direction and the handle acts like a socket-wrench in that it can be moved back and forth and will only “catch” in one direction. It can also be spun 360°, but short back-and-forth movements give the most leverage.
To load a winch, the sheet is wrapped three times around in the active direction (usually clockwise). The sheet can still be pulled in by hand and the winch will spin freely. When the sheet becomes difficult to bring in further, the winch handle can be attached and cranked while tension is kept on the sheet. When the sail is trimmed, the sheet is cleated behind the winch.
Some winches are “self-tailing” which means there is a cleat built into the top of the winch. These make things easy by automatically keeping tension on the sheet while the winch handle is used, and by eliminating the need for the cleat behind the winch.
To loosen up the sails using a winch, the sheet can simply be uncleated – but not unwrapped from the winch – and let slip slightly until the desired sheeting angle is achieved, at which point the sheet is cleated again.
