In article .com,
"Dennis" wrote:

I've got an interesting problem. The 10.5hp diesel engine in my
28footer sailboat only pushes at about 3.5knots cruising speed at
around 3600rpm, which is the max. RPM that is recommended for the
engine.

We have a fairly modern Yanmar. We use an effective 5-6 HP to drive us
along at 5+ knots. At idle, we move at about 3 knots.

I believe your prop is under-sized. I would increase diameter to the max
your boat can accommodate before considering pitch, then max that out.


--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's NEW Pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/