Paul and Wouter,

Thanks for your confirming my cruder calculations.
It's always nice to see how the problem should be solved correctly!

Regarding limited performane gains, I suspect you are right, but then again that is only important racing (for which it would not be used). My experience with wings on the H17 for recreational sailing is that the reserve leverage they provide "feels" like much more than 10%; even if it doesn't let you go 10% faster, it feels like you have much more control in higher winds (almost like having a lightweight crew along).

Thanks,

Jerry