Notes: Accoring to literature, the S2 22 is a refinement of the S2 6.9 with a winged keel, which in turn, was a development of the S2 6.7, designed by S2 in-house designer, Don Wennersten. The S2 22 was built of solid glass (deck and hull), differing from the balsa core used in it's predecessors. (Thanks to Bob Proctor for providing updated information on this yacht.)