Using the Orma 60 footers and AC cup boats are a poor example, the C Cats and A Cats are probably the most developed of the boats using C Foils nearest our water line length and they really are not convinced.
The other factor no one really has mentioned yet is what happens in normal sailing wind speeds around the, 8 -12 knots band, small foils such as the F20 uses are in no mans land, neither creating enough lift to reduce wetted surface and yet must be creating drag, ( you cannot get lift without creating drag ), I do accept there must be benefit once boat speed gets to a point but in general that cannot be the norm. I do accept that the T foils on the Stealth for example can sort of defy logic.
I am a foil convertee however and I do believe all new design boats will go down this path and the more the likes of the AC and C Cats develop the foils we can only benefit in the smaller, size wise, classes.
Wayne, you just keep coming back with stuff that's simply wrong! The F20C is performing at its biggest advantage in the 8-12kt range. The foils are working to lift the boat and the leeway is minimal. As an Example here are some time from a recent regatta in NED:-
3 laps W/L
1st. F20c elapsed time:- 44.39
2nd. F18 elapsed time:- 54.30
I was there and can tell you the worst thing about the F20c's performance in that race was the long wait for the rest of the F18's to finish!
Did you see Steve Clark's boat in the first race in Newport? (before the crash..) that thing was smoking fast..
And to discount the development in bigger boats seems a little silly, There have been a lot of things developed in the AC that scale down very well, Have a look at the Hulls on the F20C and compare them to the floats on USA17.