How to Use Sailing Winches

The mighty deck winch is an underrated tool. Here's how to use sailing winches as safely and efficiently as possible.

June 14, 2013


The most common mistake when it comes to winch safety is not having enough wraps around the drum, which can cause numerous problems. With the proper number of wraps (as pictured), easing and trimming the sheet is both safer and more efficient. Marianne G. Lee

Sailing winches are almost always taken for granted, yet these compact pieces of mechanical machinery are incredibly powerful. Even the winches on a 30- or 40-foot sailboat are capable of pulling 2 tons or more. The thing about winches is that they’re so reliable that most sailors rarely pay much attention to them—until something goes wrong. Using sailing winches correctly should always be a priority.

To understand the capability of winches, let’s crunch some numbers. Say your boat has a “number 42” primary winch, which is an industry standard. The “42” represents a 42:1 power ratio. If an average person applies 50 pounds of load using a 10-inch winch handle, the result will be 2,100 pounds of pull (42 x 50 = 2,100). That figure puts the power potential into suitable perspective. With this much power in play, you must consider whether you’re operating your winch safely.
When it comes to sailing winches, the most common mistake is not having enough wraps around the drum to hold the line load safely. In most cases, three wraps just aren’t enough. With too few wraps, several issues can arise.

For example, say that you’re coming out of a tack with a little load on the new sheet. It’s still easy to grasp, so you lock it into the self-tailer. But as the wind freshens and the jib fills, the sheet load greatly exceeds what it was coming out of the tack. Now you want to bear away and ease the sheet. But with only three wraps on the drum, just releasing it from the self-tailer may suck your fingers into the winch. This is a very painful way to learn about winch loads.


Furthermore, beyond the personal hazard, higher loads and few wraps can also equal a damaged winch, as those greater sheet loads will be transferred to the self-tailing arm rather than to the drum. Replacing a bent or broken self-tailing arm is not an inexpensive proposition.

On the flip side, to err on the side of caution can also present problems. For instance, easing a sheet with too many wraps might result in an override that takes some time to unjam. The takeaway message here? There’s a fine line between too many and too few wraps. As is often the case in sailing, you can “feel” when it’s right. So pay attention to the loads on the winch, respect the powerful consequences, and wrap accordingly.

Sending someone up the mast? This requires even greater winch safety, as a life is literally in your hands. It’s a good idea to have an experienced sailor demonstrate for new crewmembers how to send someone aloft properly. Once again, it’s important to have a sufficient number of wraps to hold the person, yet not so many that the halyard overrides. Whenever possible, instead of trusting the self-tailer, always have a second person tailing the halyard. When lowering the mast climber back to the deck, ensure a smooth ride down by taking one or two wraps off the drum. You want to avoid bouncing and jerking the person the length of the spar.


Whenever you’re grinding a winch, if the load becomes excessive or extreme, simply stop cranking. This is especially important with winches powered electrically or hydraulically; with such winches, the operator can’t actually feel the increased tension. Take the time to observe the line. If it stops moving, this almost always means that something is jammed somewhere. A 2,100-pound load on a sheet that’s tangled around a deck hatch can quickly become a major problem if it isn’t immediately addressed.

With power winches, the loads are even greater. A small, electric winch motor can produce about 9 pounds of load, but because such engines spin so fast, the speed needs to be reduced. Enter a 24:1 reduction gear. However, the gear not only reduces the speed of the motor but also increases the torque—in this instance, to 216 pounds. Now multiply that by our previous 42:1 power ratio; suddenly, in theory, that little powered winch should be able to pull 9,072 pounds. (We say “in theory” because with a proper circuit breaker, the amperage draw should trip well before that load is reached. Also, the parts in a 42 winch are really designed to handle loads only produced by a sailor working a winch handle. If something does fail, it’s better if it’s a winch part and not anything more critical—like the mast.)

Of course, proper technique is only one part of winch safety. The other is making sure that they’re properly maintained. The little clicking noise you hear deep inside a working winch comes from the ratchet pawls. The pawls lock the drum in place to keep it from moving backward, and they essentially bear the entire load placed on a winch. When servicing a winch, it’s important to inspect the pawls to make sure they aren’t packed with gunk or cracked, which will cause them to stick in the socket. When that happens, there’s nothing to bear the load; essentially, it’s the same as trying to hold the jib sheet with a bare hand. At least once a season, check the pawls.


The winch’s mounting bolts also require periodic inspection. Over time, a surprising number of such bolts do loosen up, some to the point that they can be retightened by hand. Get in the habit of inspecting those bolts each spring, and while you’re at it, also test the deck section on which the winch is mounted. On older boats with cored decks, water may seep through the fastening holes and cause rot. In most cases, simply tapping the deck with a screwdriver tells the tale. A soft deck will make a different, easily distinguished sound from that made by a solid one. A rotten deck core won’t hold winch loads very long. Deck surgery is then required.

Remember: A single winch can generate huge loads, and these are often larger than most sailors realize. So always apply the correct number of wraps, avoid or correct jams, and keep up with basic maintenance. Treat your sailing winch with respect, and you’ll get plenty of trouble-free service from it.

Mike Lee is a marine-industry pro with over 25 years of technical and sailing experience.


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