2 min read · Updated 27 June 2026
A winch is a geared drum that multiplies a sailor's pull. Turned by a removable handle, with gears inside and the grip of rope wraps on the drum, it lets a crew trim heavily loaded sheets and hoist sails that no person could haul by hand. Along with the block and tackle, it is how the enormous loads in a rig are handled.
How a winch works
The principle is simple:
- You take several wraps of rope (usually about three turns) around the metal drum.
- The friction of those wraps grips the loaded line.
- Cranking the handle turns the drum through internal gears that multiply your force.
- Ratchet pawls let the drum turn one way only, so it holds the load between pulls and cannot unwind.
The wraps must go around the drum the same way it turns — clockwise on almost all winches — or the rope won't feed. Too few wraps and the line slips; too many and you risk an override, where the wraps cross and jam.
Self-tailing winches
A plain winch needs two people: one to grind the handle and one to tail (pull the loose end to keep tension). A self-tailing winch solves this with a spring-loaded jaw on top that grips the tail itself, so one sailor can grind and hold tension at once. Most modern winches are self-tailing, though some race boats keep plain winches with a dedicated tailer for outright speed.
Two-speed winches
Bigger winches have two gears:
- Turn the handle one way for a fast, low-power wind — to take up slack quickly.
- Turn it the other way to drop into a lower gear that winds slowly but with much more force — for the final, heavily loaded trimming.
So the crew grinds fast to take up the slack, then reverses to grind slow and powerful as the load comes on. On big boats, winches are ganged to grinding pedestals so several crew can put their whole bodies into it.
Where winches fit
Winches are the top of the force-multiplying ladder: tackles handle the moderate loads, winches handle the big ones, and together they let a crew control the sail trim that drives the boat. For the vocabulary, see the sailing terms glossary.
Frequently asked questions
- How does a sailing winch work?
- A winch is a metal drum turned by a removable handle, with gears inside that multiply the force you apply. You take several wraps of rope around the drum; the friction of those wraps grips the loaded line, and cranking the handle winds it in with far more force than you could pull by hand. Internal ratchet pawls let the drum turn only one way, so it holds the load between pulls and cannot unwind.
- What is a self-tailing winch?
- A self-tailing winch has a spring-loaded jaw on top that grips the tail of the rope, so the winch holds the line itself instead of needing someone to pull the tail while another person cranks. This lets one sailor both grind the handle and keep tension, freeing up crew. Most modern cruising and racing winches are self-tailing, though some race boats use plain winches with a dedicated tailer for speed.
- What is a two-speed winch?
- A two-speed winch has two gears. Turning the handle one way gives a fast, low-power wind for taking up slack quickly; turning it the other way engages a lower gear that winds more slowly but with much greater force for the final, heavily loaded trimming. The sailor grinds fast to take up the slack, then reverses direction to grind slow and powerful as the load comes on.
- How many wraps of rope go around a winch?
- Usually about three turns around the drum, though it varies with the load and the rope. Enough wraps are needed so the friction grips the loaded line without the rope slipping, but too many can cause an override, where the wraps cross and jam. The wraps must go around the drum in the same direction the winch turns — clockwise on almost all winches — or the line will not feed correctly.
- Why do sailing boats need winches?
- Because the loads on sheets and halyards are far greater than a person can pull directly. A winch multiplies human effort many times over through its gears and the friction of the rope on the drum, letting a sailor trim a heavily loaded genoa or hoist a mainsail by hand. On big boats the winches are ganged to grinding pedestals so several crew can put their whole bodies into turning them.