vertical battens
I just took delivery on a vertical-batten mainsail built by the UK loft in Sweden. It has roach similar to any full-batten main, which is a great improvement to the scalloped leach on the OEM main that came with the boat. Although I've only sailed a couple days with this technology, the performance boost is incredible. I have more power and yet am significantly less tender. The sail is easier to trim and has a wider slot in which it is "in trim." A buddy of mine with an h380 ordered his vertical batten main at the same time that I did, and we spent this past Saturday sailing his, waiting to try mine out until Sunday. Both boats showed similar performance gains. Part of this is that we replaced poorly built OEM sails made of low-grade dacron with well-built, laminate sails with a tri-radial design. But vertical battens are the way to go, in my opinion, whether you race your boat or not.