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post #4 of Old 04-27-2009
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Originally Posted by huguley3 View Post
My mainsheet currently uses a dock cleat to secure it. It seems kind of scary to me to use something like that for a sheet so I am looking at replacing it with a rope clutch. I will need to move the winch and possibly the sheave. Also planning to move the main halyard back to a second clutch so its not on the mast. I have a pretty good plan for doing all of that.
You should be using a cam cleat, clam cleat or something similar for a main sheet. A rope clutch doesn't always release under load, nor does it release anywhere near fast enough to be safe on a mainsheet.

I am wondering about the size of line for the mainsheet? I have looked for some kind of sizing chart but they are all based on boat size which seems like you would end up with a line that may be off. My traveler is about in the middle of the boom so I am guessing the boom will be generating more leverage on the sheet than if it was toward the end of the boom. Or is it just a rule of thumb and if the sheet breaks you get a stronger line next time? I was just going to replace the line with a similer diameter but I had Mack sails out to replace my main halyard and they said it was oversized(was 7/16 replaced with 3/8) and replaced it with a smaller diameter line. The larger line is easier to hold onto but harder to keep tidy. Always a trade off but I would rather only have to buy the rope clutch once. The current mainsheet is 1/2 inch.

If I could replace the 1/2 inch mainsheet with 3/8 or 7/16 then I can get a single double clutch. 7/16 can get up to 6100 lbs in strength while 1/2 inch is 8700 lbs. The current line on the mainsheet is very old and has not broken yet. I don't know what kind it is but it is ready to be retired.

Anyway long post for a simple question about how strong of line I need for a 30' sailboats mainsheet.
Depends on the amount of purchase/leverage your mainsheet gives you as well as what line you're using. On a 30' boat, a 1/2" polyester double braid is quite common... but if you go up to a spectra or dyneema based line, you might be able to drop down to a 3/8" or 7/16" line. One advantage of a smaller line is that they generally run out with less friction—smalller diameter==> less friction. One disadvantage is that they're harder on your hands.


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Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
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