A winch is a mechanical device that is used to wind up a rope or wire rope (also called "cable"). In its simplest form it consists of a spool and attached crank. The spool can also be called the winch drum. More elaborate designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. Some may include a solenoid brake and/or a mechanical brake or ratchet that prevents it from unwinding.

Besides industrial applications (e.g. in cranes), winches are used for towing cars, boats, or gliders. There are several winches on almost every boat or ship where they are used to pull anchor or mooring lines, halyards, and sheets.

The rope is usually stored on the winch, but a similar machine that does not store the rope is called a capstan. When trimming a line on a sailboat, the crew member turns the winch handle with one hand, while tailing (pulling on the loose tail end) with the other to maintain tension on the turns. Some winches have a "stripper" or cleat to maintain tension. These are known as "self-tailing" winches

Winches are frequently used as elements of backstage mechanics to move scenery in large theatrical productions. Winches are often embedded in the stage floor and used to move large set pieces on and off.

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