My boat has mid-boom traveler system. Sheeting in the main requires a winch . Is there a way to improve the purchase? The boat currently has the typical three-block (plus mainsheet block) system.
Dan Dickison responds:
Thanks for your question. There are a number of things that you can do if you'd like to eliminate the winch from the equation. I would consider getting rid of that winch as an improvement because a winch takes up space, requires a winch handle to operate, and is generally rather heavy.
The principal change that you'd need to make is to add purchase to the system to make up for the loss of the winch. If you understand purchase systems, then you can see that a five-to-one system would make it easier to pull the mainsheet than a three-to-one. Your current system, with three blocks plus the the mainsheet block (I'm guessing that you've got two on the boom and one on the traveler) is likely a four-to-one system. You can increase that to six-to-one by simply changing two of the blocks. One of the upper blocks will need to be a double block, and the lower one will need to be a double with the final throw of line leading to a block and cam cleat arrangement. Boats as large as 35 and 36 feet make do without winches for their mainsheet systems. Even larger boats have been known to use a simple block and tackle system to control the mainsheet, so it is indeed possible. If your boat is larger than 45 feet, you'd probably better stick with the winch.
Here's hoping that I haven't confused you with this talk of ratios. Have a look at the block and tackle mainsheet systems listed in the SailNet Store and you'll get a better idea of what I'm talking about.