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Old 08-10-2013, 02:59 AM   #1
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Lehman sp 275's fuel consumption

Hi.
We just bought a loop boat with twin lehman 275's
( president 43) we have the fuel consumption curves but I don't believe they mean very much in the reality
I'm a cheap bugger, and plan to go as slow as possible to conserve fuel, possibly running on one engine where allowable.
Are there any cruisers out there with these engines who have an idea of their real gph consumption.
Any input would be really appreciated.
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Old 08-10-2013, 06:19 AM   #2
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There is little you can do to make what exists better at a worthwhile cost.

Re-prop for a couple of grand to save 5% is a waste of time.

The throttle is your fuel cost.

Usually operating at the SQ RT of the LWL (known as SL) times .9 to 1.15 is the cheapest operating range.

Happily this formula is in K and ICW , loop,and inshore nav is in statute mules so 5K = 6 stat MPH makes it easier on your head at trawler speeds.

Single engine operation inshore is seldom worth the extra hassles.

Relax and enjoy the ride , be sure the auto pilot is working and has a remote you can use slouched , feet up in the PH as the world slowly goes by.
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Old 08-10-2013, 08:09 AM   #3
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Quote:
Originally Posted by Submarine deckhand View Post
Hi.
We just bought a loop boat with twin lehman 275's
( president 43) we have the fuel consumption curves but I don't believe they mean very much in the reality
I'm a cheap bugger, and plan to go as slow as possible to conserve fuel, possibly running on one engine where allowable.
Are there any cruisers out there with these engines who have an idea of their real gph consumption.
Any input would be really appreciated.
If you want real fuel economy...and it only becomes truly meaningful if you are burning enough to really matter (the loop would certainly be that case)...

Buy a Fuel Scan fuel monitoring system (or equivalent)....hooked to a GPS and giving realistic NMPG will give you the best answer you want and allow you to ADJUST to whatever you want real time.

After about 1000 miles on my first "serious" trip...I had my boat/engine figured out to a nice set of AVERAGES...but at any given moment of bottom fouling, prop dings, current, windage, etc..etc...I couldn't really tell you if I was going the most "economical" and other times it didn't matter because I was in no hurry, or trying to make a bridge opening or dock before nightfall.

So bottom line is how accurate do you want to be and where in the fuel burn range is acceptable for you.

Daddyo on this forum runs twin Lehmans in a Defever and puts lots'o miles on every year. His engines are 120's I believe and he might have better info because he's twins. He's way down on the RPM numbers and sips fuel...if you ran down there I bet you would be close.
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Old 08-11-2013, 03:36 AM   #4
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Thanks for your input.

Thanks mostly for not giving me a hard time about posting in classifieds
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Old 08-11-2013, 01:21 PM   #5
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If you're real cheap, always run with a fair tide. If the current is against you stop and wait for the swing.

You said you were real cheap, you never said you were in a hurry.

A 3-4 knot current will really make a difference in your MPG but wont matter to your GPH rate.
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