[C38] Propeller issue follow up

[eyriepg at comcast.net]

Charles,

Can you still reach rated rpm with the new prop.  The reason that I ask is that I was overpropped for 4 years before replacing my propeller.  As a result, I couldn't reach max rpm under full throttle and I burned a lot of oil.  Consumption was about 1 quart every 10 hours.  I think that it was also bad on the engine.  With the new prop I can now reach max rpm, but don't go quite as fast at 80% rpm.

I just hauled Que Linda last week and amazed at how much difference in boat speed a little grass/slime on the bottom of the boat and on the prop makes.  We went from a little over 5 knots to 6.5 knots at the same rpm.

Phil Gay
C38 049 Que Linda
Everett, WA

-------------- Original message -------------- 
From: Charles Finn <charles at finn.ws> 

> Based upon our discussions a few months back, I purchased the Campbell 
> Sailor prop (15 x 9 three blade). I have the Universal 5424 and have 
> only been able to obtain 5-6 knots at 2400+ rpm. I had a two-blade 
> fixed prop. In addition, I had awful "prop walk" and the boat would 
> "thrum" at higher rpms that was wearing over any long motoring. 
> 
> I talked with the Norm Ross at West by North Enterprises and he made 
> three promises: 
> 1. The boat will go faster at reduced rpm and will not load the diesel. 
> 2. The "thrum" is due to the two-blade prop as it is completely covered 
> by the keel vortex, so it is essentially grabbing more water when it is 
> outside the keel shadow and then relieved when within. 
> 3. Prop walk would be significantly reduced. 
> 
> Well, he was right on all three promises! I now get about 6.5 knots at 
> 2000 rpm. The engine is a lot quieter and the thrum is gone. I still 
> have prop walk, but it is not nearly as bad. The prop looks very 
> different from the Michigan Wheel design. My last test of course will 
> be how the drag will affect sailing, but I suspect I won't seem much 
> (the weather in my area has been absolutely awful for the last 6-7 weeks). 
> 
> Charles Finn 
> Mighty Quinn, #114 
> Lake Champlain 
> 
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