you agument doesn't hold water.<br />An air plane is a difert anamal than a boat.<br />a plane would require as much hp as the main.<br />but on a boat a 5hp kicker could keep you from capsizeing you may not beable to wait for help.<br />even the newest well manitained engine can fail<br />and what hapens when you hit a log and break your lower unitIf you don't have confidence in your engine, get it fixed and maintain it. Lots of airplanes have only one engine!