How does the leeway angle compare with standard raceboards? I imagine it must be a good bit better. Did you find any need for an adjustable control foil?
The changing immersion of the foil must do some interesting things to the lift/drag characteristics. Have you looked at ways to optimize the foil and other elements of the design for more consistent immersion?
I suppose, that the efficiency of my foils could slightly be ahead (but certainly not yet) of those of kite boards (being an asymmetric hydrofoil rather than symmetric and only one high AR foil rather than three smaller ones, as current standard in raceboards), and with it probably the leeway angle.
I have experienced stall (from about 12knts onwards), probably induced by the changing immersion of the foils, which I could feel in advance and probably could easily have been avoided by a rudder.
I wouldn't want to complicate things, however, by implementing a rudder(as the thing self steers very well) and think, that the problem could also be resolved by using tapered and/or possibly twisted foils(but to engineer those is beyond my skill level).
Even without a rudder, I can change the angle of attack of the foils by two different ways: 1. changing the angle of the lever arm (which I do to shift the helm) 2.changing the angle of the foil itself (which in fact makes it a front rudder),
both can be done while riding, but none of it fast enough thus far(needed more engineering) to react to waves and to prevent stall.