Used to have a 7.5hp kicker on my old 16ft fiberform trihull and it did just great pushing that boat around at trolling speeds. One day while fishing the outer bar at possesion my main motor would'nt start so I had to come back in on my kicker. 15 miles against the tide! 4 hrs later I was back in everett - lots of cavitation at WOT with that short shaft. My next kicker was a fourstroke 15hp longshaft. Much better at putting that boat up on a plane when you have to and still being able to troll waaay down.