Hi Joe,
SC stands for Supercat; therefore a SC 17 is a 17ft long beach cat, no boards. This boat has the lowest PN, is rated the fastest by US Sailing, of any 17ft boardless beach cat.
If I wanted to know how to tune up a H17, I would call/write Bob Curry. He is a past H17 National Champion. Bob must know his stuff about the H17.
Bill