OK, I saw some of them up close in Key Largo, looked very neet but I am still unclear as to exactly what they are supposed to do. Do they help lift the hulls in all conditions, upwind and down, for less drag, or just downwind? And when sailing upwind on one hull, how is the leeway vs. a "normal" deep, straight, board?

Full disclaimer, I don't own an A cat but am intereted in any good, cheap, speed developments you guys come up with! I'm still drooling over Ben's wing, I think that could be further developed and be faster than a regular sail in flat water. Not sure about all the pitching in waves though.