Cross Posted in Diesel Forum: I know this sounds wierd, but I have a Universal 5411 that produces 11 hp. I'm using the standard 2 blad prop that came with the boat. What I find interesting is that I can achieve the same speeds as other are getting with 18-20 hp with my "little engine that could". 
I cruise at 5.5-5.7 and top out near 6.3 knots. Humm... OK, what's up with you all that are having problems with 2x as much power? Any comments on this would be greatly appriciated. I was thinking of repowering with a bigger engine, but from what I've heard here, stepping up to 20 hp really won't get me any more speed. What I really want is to be able to cruise under power near hull speed and have something left over for powering into a strong headwind and still keep that turn of speed. So what's that going to take? It seems like going to 20 won't be enough. Would I need 30? 40? At that point it become pointless, as those engines would never fint in a Cat 30 and right now the engine I have sips less than 1/4 gal per hour at cruise speed. So is my thought of cruising at near hull speed a "pie in the sky?"
I cruise at 5.5-5.7 and top out near 6.3 knots. Humm... OK, what's up with you all that are having problems with 2x as much power? Any comments on this would be greatly appriciated. I was thinking of repowering with a bigger engine, but from what I've heard here, stepping up to 20 hp really won't get me any more speed. What I really want is to be able to cruise under power near hull speed and have something left over for powering into a strong headwind and still keep that turn of speed. So what's that going to take? It seems like going to 20 won't be enough. Would I need 30? 40? At that point it become pointless, as those engines would never fint in a Cat 30 and right now the engine I have sips less than 1/4 gal per hour at cruise speed. So is my thought of cruising at near hull speed a "pie in the sky?"