About the sailboat winch. Every boat design is different, each has differing requirements based on the sail plans, and every deck winch manufacturer has similar tables to help you compute what you require based on several criteria. You start with plain top deck winches and then you have self tailing winches. Then there are what are known as snubber winches usually used on smaller boats. Each have a purpose and as we get into plain top and self tailing deck winches it’s all about achieving mechanical advantage to make life easier.
Modern yachts have a sail plan that consists of a small number of large and powerful sails, which is less complex and more efficient than more smaller sails as seen in older boats. The forces generated on sails mean that a deck winch is the only way to handle things. The maximum loads generated are usually encountered when beating to windward in a good breeze. The effects as you all know, especially in protracted offshore situations, is severe boat motion, and the compounded effects this has on any activity. Try going to the toilet or cooking a simple meal in a good seaway. It doesn’t take long to wear down and fatigues you and that’s when a good winch comes to the rescue. Select your deck winch for maximum worst case scenarios and reap the advantages when it’s not too strong out there.
So how does a deck winch work? A deck winch is effectively a rotating lever. The winch handle is the lever arm and the barrel axis becomes the fulcrum with load application being on the winch barrel face. When you divide distance between the fulcrum and barrel face into the handle length, this equates in an ungeared winch as the amount of advantage attained. As most modern deck winches have internal gearing in 2 and 3 speed models, this effectively shortens or lengthens the lever arm, with the ability to change gears for greater leverage when increased loads are applied. This gearing increases the leverage. When you wrap several turns of sheet around the winch barrel it becomes the same as reeving with the grip of the rope on the winch drum allowing the application of force.
It
is important when using a winch that the sheet angle onto the drum is correct, this
is typically in the range of 95 – 100 degrees angle with the winch drum. If
this is not correct you run the risk of experiencing a wrap or override and
then the winch is effectively seized up.
This is a very bad situation and I know because I have been there,
because you can end up being unable to release the sheet from the drum quickly. Some smart sailors use a turning block
fastened to a lifeline stanchion to ensure that the sheet angle to the drum is
fair. I read about the use of shock cord being tied between the block becket and
a lifeline stanchion to stop the block falling down and getting fouled up when
there is no line tension. It works as simple ideas do as have tried the same.
Before you start, leave the handle off the winch before you start sheeting in or hoisting. Throw 3 or 4 wraps around the drum (make sure you get the right direction), and then take in the line slack by hand, arm over arm. Make sure you are not too close to the drum so you have some line should the wraps start slipping. When tailing the line make sure no loops are forming under your feet that you can get fouled in. I always have a winch handle socket near winches, so when slack is out then drop the winch handle into position. In a self tailing winch make sure the rope is in the tailing and start cranking. For maximum effort and cranking efficiency ensure your weight is centered over the winch handle and crank using both hands. In two speed self tailers you start at the higher speed and then go to the lower speed. More to learn about the sailboat winch and sail handling.