How is a "leech line" on a sail used?
- Thread starter mherrcat
- Start date
Slick470
Member III
I'll give it a go. As the sail material stretches along the leach, it will start to flutter in increasing breeze. You put on just enough tension on the leach line to make the flutter stop. My understanding is any more than the minimum required tension can add stretch to the leach and make the problem worse, eventually cupping the leach and disturbing the flow over the sail. At that point, it's time to visit your favorite sailmaker.
HughHarv
Hugh
flapping equals friction!
I think I read once that the flapping causes disturbed air flow at the trailing edge which may rob some boat speed, along with premature wear and tear on the leech?
I think I read once that the flapping causes disturbed air flow at the trailing edge which may rob some boat speed, along with premature wear and tear on the leech?
Last edited:
Morgan Stinemetz
Moderator
Leech line tension...
Whomever said "tension it enough to take the flutter out" had it right. Make sure you also have telltales (one each) on the top three batten pockets. Otherwise, you cannot determine when the flow off the main. The tendency is to over trim the main. "When in doubt, let it out."
Morgan Stinemetz
Whomever said "tension it enough to take the flutter out" had it right. Make sure you also have telltales (one each) on the top three batten pockets. Otherwise, you cannot determine when the flow off the main. The tendency is to over trim the main. "When in doubt, let it out."
Morgan Stinemetz
Slick470
Member III
If you haven't noticed and you don't have brand new sails, try taking all of the tension off the leach line and trim your sails and you should notice some flutter. If not, you're lucky. It's much more noticable with the leach on genoas. The battens on mainsails will help control the leach tension more.