CHAPTER 5


Creating power Winching


A winch delivers additional power to the pull on a rope in two ways. First, there is the basic leverage aspect. If the winch barrel is 5cm in radius and the winch handle is 25cm long, a mechanical advantage is achieved equal to 25 ÷ 5, or five times. Most winches include a gearing system whereby the handle turns more times than the winch barrel for a given input of effort. This is called a velocity ratio and works in exactly the same way as gears on a pedal cycle. If you wind the winch round five times on the handle to gain a single turn of the barrel, the ratio is 5:1 and the power is commensurate. Factor in the handle length and you have a power delivery of 5 x 5, or 25 times what you are putting in with your strong arm. Many larger winches are two or even three-speed, with power rising accordingly. The winch only works so long as there is enough friction to stop the rope slipping on the barrel. This is supplied by having an appropriate number of turns, and keeping them tensioned either by tailing the end as it comes off the winch, or by using a self-tailing winch top.


Loading a winch


Never use a winch without a full round turn on the barrel. Depending on how effective the lead onto the winch may be, you may or may not be able to apply more turns initially. If the lead is not good, extra turns may ride over one another and lock up. A good lead can allow up to four turns to be clapped on then rattled round as you gather in the slack. If in doubt, use a single turn to grab the slack, then lay on more turns as the load begins to build. Four turns is enough for most situations on all but the largest yachts.


Tailing manually


When you can no longer pull in the rope around the winch, it’s time to begin winding. The tension on the turns must now be maintained. If you’re strong enough, you can do this with one hand while winding with the other, working the tailing hand along the rope to keep it near the winch barrel. Where two hands are needed for full power, a second crew person must tail the winch, unless it is a ‘self-tailer’.


Self-tailing winches


These have a circular device on the top to grab the bight of a rope fed into it off the barrel. The bight strips off after it has been round once, allowing the winch to feed continually through the ‘jaws’ of the self-tailer. It is common practice to leave a loaded line in a self-tailer rather than belay it on a cleat as one would with a conventional winch. This is slack practice, since it can be knocked out of the jaws. The best answer is to flip an additional ‘safety turn’ over the top once cranking has finished.


Self-tailing winch


MANUAL OF SEAMANSHIP | 53


Ropes and ropework


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