The existing mainsail had a problem with a fluttering leech, in almost all wind conditions. I had the leech tightened up by a sailmaker during the 2000 season, but the problem was still evident.
To solve it, I took in two of the upper seams, increasing their overlap by 1/2". This definitely requires guts to do -- blithely ripping seams on your only mainsail almost ranks up there with drilling holes below the waterline!
With the sail now recut, I also added a leechline, with Gransegel cleats installed above the clew and both reef cringles. This allows adjusting the leech tension even with a reef in.
The cleats are installed such that if the leechline is cleated with a reef in, the line will uncleat when it is adjusted, after the reef has been shaken out. This is really difficult to explain -- I'll put some photos online of my new mainsail, once I've completed its assembly.
© 2018 Melissa Goudeseune