I think hulls are canted so that when the boat has a slight heel, the leeward hull will be more perpendicular to the water. This allows the underbody (hull for asymmetric hulls or boards and rudders for symm) to generate more "bite" in the water and more lateral resistance.

I don't know if there are drag penalties or bonuses here.

D. Ho
TheMightyHobie18 1067