On Fri, 19 Oct 2007 16:53:13 +0000, Richard Casady wrote:

On Thu, 18 Oct 2007 11:22:19 -0700, druid
wrote:

Hi,

My new-to-me boat (Crown 28) has a Volvo 10hp MD6A, and it's way
overpropped with a Campbell Sailor 11x6 3-blade (gets 1500 WOT instead
of 2400). The Campbell Sailor dealer says his calcs recommend a 12x8
(ie much MORE pitch). Now, my experience with CS props is you take the
calculated pitch and subtract 2", but I donno...

Engine IS very "tired" but it pushes the boat at 5+ knots with the
over-pitched prop, so it can't be TOO bad.

Those with MD6A's - what prop do you have on it?

What other people do with their boats may or may not impart something
useful. You have your very own performance figures, and they are
telling you less pitch. Maybe less diameter. Perhaps both, but
whatever, you want one that is easier to spin. Did the engine turn up
more RPM when it was new? I mean you can run a worn out car in a lower
gear because it lacks the suds for a higher one, but it isn't really
the answer.

Casady

OK, here's the Deal: I've already decided to take 2" pitch (or at least 1
1/2" ) out of my prop. What I WANT to know is what other MD6A folks are
spinning so I can get a feel for how tired my engine is. Yes, I will take
into account things like the "boosted" CS thrust, differences in boat
size/weight/LWL, possible differences in gear ratios, phase of the moon...

I just wanna know, ok?

druid
http://www.bcboatnet.org