Dave Yeah, the 15 was Perry's largest project to date (32 feet long) and had a big prop and a pair of 10 hp mains to drive it to 6 knots. It's in the books, of course. The little boat is a chunk of the forward hull section with the domes installed. The sub has a pair of 2 & 1/2 hp thrusters mounted aft on a rail just above the centerline of the aft hemisphere. Vance