Well, that would certainly account for the hull I have being called "SK". It is very low-deck above the water line, with little freeboard, like a low-deck flat bottom, but with a shallow vee in front and a very shallow vee in back, with two chines and then a flat horizontal runner at the edges. The middle is rounded, not flat like a bass boat, so it could be for increased comfort in chop. From what I have gathered, the SK describes a racing class, and several hull styles have been allowed, not restricted to flat bottom, but being biased towards flat bottom for speed, at least in the early years.
Thanks!