Do you mean the blade type?. In which case yes, I tried them on a naval patrol boat, they generate drag as much as lift and were used to steer this particular vessel which did 42 knots on jet drives. They will not provide much lift at low speeds which is when you most need it on a planing boat to get onto the plane and I am convinced that the conventional flap type give better results for most applications.
Steve /forums/images/graemlins/confused.gif