[C320-list] Maxprop RPM v. boat speed

[Jeff Church]

Hi Dick,

Yanmar strongly recommends (it's a warranty issue) that the prop is 
pitched so that the the engine can reach about 100 rpm above its 
one-hour loaded rpm rating. If anyone wants to confirm that, here are 
the phone numbers for two of the largest Yanmar distributors; Mack 
Boring Co. 847-526-9700, and Mastry Engine Center 800-545-4574. They 
were both very helpful when I had questions prior buying props for my 
320 and 387.

JeffC


Richard A. Walker wrote:
> To Low a pitch.
>
> I get 7.1 kts at about 2800 RPM with my AutoProp.  It is self pitching so
> does not harm the engine.
>
> I have about 750 hours on the engine over 9 years.
>
> Cheers,
>  
> Dick Walker
> C-320 (687) WindWalker II
> 740 Olive Ave.
> Coronado, CA 92118-2136
> 619.435.8986
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Sea Chalet
> Sent: Wednesday, April 01, 2009 5:07 PM
> To: C320-List at Catalina320.com
> Subject: [C320-list] Maxprop RPM v. boat speed
>
> I've got a Maxprop on my 2001 C320 with the 3GM30 engine.  I'm wondering 
> if I have the pitch set properly to achieve maximum boat speed and 
> engine RPM.
> This is what I measured (avg. of opposite directions):
> 2000 rpm - 4.3 kn
> 2500 rpm - 5.3 kn
> 3000 rpm - 5.8 kn
> 3200 rpm (max.) - 6.1 kn.
> How does this look?   Should I be getting higher speed with higher max. 
> rpm?  Are there any other resources out there to check?
> Thanks, all.
> Pete Peterson
> Sea Chalet
> #815
>
>
>