Moderation in all things,
or...
..small changes can make a big difference.
David,
I can see your point in wanting a sail which is as balanced (weight-wise) as possible. Slieve McGalliard also has a focus on this. His Split Junk sails are both balanced for hoisting and lowering, but also come out with very light sheet forces.
I haven’t had the same focus on that. When I looked at many Chinese junks (the real ones), it appeared that this didn’t bother them, so I just followed on.
However, Johanna’s rig (2002) ended up as an extreme case of broad chord and little balance, with AR=1.87 . To make it worse, the mast was too short for a decent halyard drift. The result was that the forces needed in the YHP and THP ended up quite high (though not needing winches). The AR=2.15 sail I built for my Oslodinghy, Broremann in 2009, gave some useful hints. Here the forces in the parrels were very light, or hardly needed. I thought this had with AR alone to do.
When I made Ingeborg’s sail (2015), the AR again dropped to 1.90, and I planned to set it as Johanna’s sail, with about 10% balance. However, this time I had built a plenty tall mast, so the halyard could be moved 5% aft of the middle of the yard, and the YHP could be moved even further aft and up the yard.
After two test trips I found that Ingeborg had too much weather helm, so I moved the whole sail forward to about 13-15% balance. This turned out to be a double success:
The helm balance was improved, but surprisingly, the forces on the YHP and THP also dropped a lot. I still use them to position the sail and remove the diagonal wrinkles, but the forces involved are so light that I claim it is no longer a drawback of this sail planform.
Arne
PS: The only line I have to touch between reefing or un-reefing, is the sheet. I don't need to alter the set of the YHP and THP when falling off to a run or heading up for close-hauled sailing. What more can one ask for?
PPS: The throat hauling parrel, THP, is just another word for a luff hauling parrel, LHP, after having moved it up a couple of battens.