Complex sentence: The term was first used for the capstan on a ship, which is used to control ropes that are wound around it one or more times, but not stored on it--that arrangement is usually called a winch.
Split into simpler sentences: The term was first used for the capstan on a ship, which is used to control ropes that are wound around it. The rope is wound around one or more times, but is not stored on a capstan--that arrangement is usually called a winch.