[PUP] :PPM-propeller efficiency

[John Marshall]

Interesting... that's phenomenal fuel efficiency.

Does that still give you enough excess power to deal with big seas?   
Can the engine be run at long periods at 1750 rpm?

Another way to ask... what are the downsides to the overpropping?

John
On Nov 23, 2008, at 11:31 AM, Kevin Kearney wrote:

> I recently repowered with a non-turbo Deere 80HP-the torque peak is  
> at 1200-1400rpm-twisting a 34 inch prop at 500rpm-Overpropped since  
> the engine "stalls" at 1750rpm-out of a 2400rpm redline-but  
> operating at 1200-1400rpm fuel economy is sub 1gph my sl is 1.125 at  
> 7.5 knots and the torque the twisting action of the engine is at is  
> max 220ft pounds demiinishing to 170ish ft pounds over 2000rpm as  
> the fuel consumption goes over 4gph.
>
> Deere would not warrenty an engine so overpropped- but it works well/ 
> better when you match cruising speed to the torque peak of the engine'
>
> Kevin Kearney/Jolie/Baltimore
>
> --- On Sun, 11/23/08, Patrick Gerety <alohaboat at yahoo.com> wrote:
> From: Patrick Gerety <alohaboat at yahoo.com>
> Subject: Re: [PUP] :PPM-propeller efficiency
> To: "Passagemaking Under Power List" <passagemaking-under-power at lists.samurai.com 
> >
> Date: Sunday, November 23, 2008, 1:35 PM
>
>> but does that give us maximum efficiency (fuel
>>
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