I have the Mr. Darby from Dumas and it weighs in at 75lbs. Using a pair of dumas 12v motors is perfect power for it. I would guess that with your much lighter weight boat the power would be good. I've never built a crew boat but I believe their supposed to move at a good pace so the extra power in a lighter weight boat should give you a scale appearance. If its to fast the just keep your foot out of it.

Tim