My Wild Cat is a 1977 wooden top Mark 2 (near to the last of the pretty – but more expensive to maintain – wooden tops?). Wild Cat’s draught is about 1.5m. I would think that any less than that would be very uncomfortable unless there is substantially more ballast. Mine rolls quite enough in rough seas. Perhaps the shallower keel is in the Mark 1 which has a coach roof on the aft cabin instead of the raised poop deck.