No power into the wind

[RussNorman]

I would like to know if anyone knows what I can do to get more power out of my boat. My yanmar engine is completely rebuilt and puts out a whopping 13Hp. A fellow sailor told me I need a different prop. Has any one found the right prop to help out this situation. I have the orignial prop.

Thank you.

 

[Ed A]

may be a prop problem but we have way to little info to make any kind of decision.

You need to know how many rpm the engine is turning to tell if your getting proper rpm. then you could have an obstructed exhaust elbow, a fuel problem or an air problem.

It is pretty hard to diagnose.

has it run properly before?
how fast is it going on what kind of boat.
does it smoke

those are great little engines but you cant expect them to really go fast.

My old pearson flyer would motor hull speed on a calm day.

You also need to know the water line length of your boat to tell how fast hull speed is for your design.

 

[Johnb]

Before I started hiring a diver, my prop got growth on it and the effect was amazingly bad.

 

[RussNorman]

I run at 2500 to 2700 RPMs. My exhaust is fine. My engine was rebuilt 3 years ago and is pristine. The problem is either the size, pitch or both of the prop. It has never had much power. When heading into a 25 knot wind I am barely able to make 1 to 2 knots. Very scary. Any suggestions would be appreciated. Other owners of 1983 vintage Hunter 30's with the same small engine must have the same problem. I just wonder how they fixed it.

 

[wufibugs]

My 86 Hunter 31 has the 2GM20F and goes quite well at 2300 rpm. However, when checking the shaft movement under sail, you would be more than surprised at how fast that shaft is turning and how much wear that imposes on the engine mounts. That, plus performance has convinced me to move to a Flexofold. For under a grand, I'm hoping for noticeable performance gains in gear and under sail. Had I not comitted to making that change, I would have had to figure a way to harness all that wasted energy. A shaft driven alternator maybe?