Wouter,

Thanks so much for sharing so much great information.
I really learned a lot (as always) from your post.
I've got a lot to look forward to learn!

Regarding the twist vs flat sail vs power issue:

I understand what you are saying and was trying to extrapolate from my experience with a stiffer mast (Hobie 17) which is totally different; in that case tensioning the leach doesn't really flatten the sail at all, it just powers up the leach. I look foreward to experiencing what you describe on the superwing mast.

The only thing I'm still trying to come to grips with is that in windsurfing (whose sails share a lot in common with square top bendy mast catamaran rigs) in high wind, after applying a lot of downhaul, what you get is a bent mast which flattens the sail AND produces a lot of twist and it is this combination that gives the best control, CE stability, lowest drag, highest speed, and best gust response. So I'm still not clear on why with a high performance catamaran rig why you wouldn't be best off using DH (+/- prebend) to bend the mast and flatten the sail and still allow moderate twist. On windsurfing rigs, the twist does not add power and in fact it reduces power significantly along with lowering drag. It also effectively reduces sail area since as you bend the mast the twist increased both further into the body of the sail from the leach and also further down the sail, which really is analogous to reefing in a sense. Plus, it lowers the sail's CE reduding heeling forces in big winds. Have you tried getting a flat sail with just DH (+/- prebend) in big winds while using moderate twist and if so how did it compare?

Thanks again for sharing so much great experience and insight.

Jerry