Fuel Figures

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yarradeen

Veteran Member
Joined
Jul 18, 2017
Messages
79
Location
Australia
Vessel Name
Yarradeen
Vessel Make
Harriscraft 48
Peoples

Just returned from a trip down southwest Western Australia, nice travels, This is my first long trip. I would like to share my fuel consumption figures to see how the compare with others on similar boats.

Total distance in nautical Miles = 329
Total Fuel usage for generator and main = 1188L or 314US Gallons

Mostly at 10knots 1250 rpm = 21 hours
other time spent at 1850 rpm for about 18Knots racing ahead of weather.

Boat is SD at 48feet single screw 825hp FPT tier IV

I am pretty happy with these numbers.
 

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I think those numbers are excellent considering genny plus a sprint for a bit. Overall a shade over 1 nmpg. The boat must be relatively light?

I am 50' SD hull with 2 x 200HP, displacement a bit under 30 tonnes. I can get 1.5 nmpg (US Gallons) if I run at 8 kn. Running at 8.5 or so I drop to 1.2. I rarely run at 10kn, and would be under 1 in that case.
 
My 45' 45,000 pound semi displacement trawler could cruise at 14 knots with a 1.5 gallons per mile fuel burn. Originally it had a 450 HP Cummins. Repowered with a tier 2 135 Hp John Deere and now cruise 7 knots at 3.5 MPG.

Ted
 
Ted, did you ever measure the fuel burn with the stock engine at 7K/
 
Ted, did you ever measure the fuel burn with the stock engine at 7K/
3.5 to 4.0 GPH or <2 MPG at 7 knots. I think Ski's boat does a lot better with the same engine at that speed because he displaces a lot less. Before I changed the prop, I was getting 2 GPH with the John Deere. It seems to me that the Cummins was real inefficient at 1,200 RPM.

Ted
 
I've got the dyno data for the 450C and down at like 40-60hp it is certainly not as efficient as the Deere 4045 making the same hp, but it is not that much worse. I can look it up and crunch numbers if desired but if I remember right it is about 15hp/gph. Not stellar, but not horrible.

I tolerate the less than stellar BSFC for hull speed running as a good bit of my travels are at 200-250hp, right at the sweet spot of the engine making a solid 20hp/gph and running in the 20kt range. Depends on how much money I feel like burning!!!
 

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