Whoa, Bill I said the 2 HP was adequate for the ComPac 16 and the Montgomery 15. I pushed Eugene's M17 up river against the outgoing tide on the Thames in New London, CT, but the general consensus among the M17 owners is that a 4 HP is the size you want. Of course, that is all a function of where, when and how you are using your boat. On a lake with no current to contend with, and only for getting in and out of a slip a 2 HP would suffice. But, if your boat is loaded, you have wind and tide against you and you want to do more than 1 knot, then more horse power is needed. So it all depends on the sailing area: tides? winds? load in boat? if the wind pipes up do you sail or drop the sails and motor? Answers to these questions determine what you need of a motor size. Connie