Fuel Consumption - Initial Figures

[Seahope]

Hi all,

I know a number of people wonder how much fuel diesel engines use so I thought I would publish my figures.

Yesterday, I filled the tanks which were filled just before the delivery trip. My usage has been roughly 50% planing and 50% displacement speed through Portsmouth harbour. I have just used Google Earth to calculate the nautical miles for all the actual journeys we have done and ignored a couple of days worth of 'pontoon bashing' instruction so the consumption is probably better than I've calculated which is ..

2 x Yanmar 4LHA diesels have used 4.5 ltr per nautical mile travelled or 0.82 UK gallons/nm.

 

[Ripster]

When I had my Monte 250CR with a single 240 4HLA I used to reckon about 2-2.5mpg depending on conditions and the trip dynamics etc - wt on board, no of peops, conditions etc. Mostly cruising about 20-22k.

 

[thefatlady]

4.5 ltr per nautical mile travelled or 0.82 UK gallons/nm.

Something wrong with one of those figures. 1 gallon = 4.55 litres

John

 

[Deleted User YDKXO]

Agree with thefatlady. 4.5 ltr per nm is as near as dammit 1.0nm per imperial gallon. Even this figure I find odd as any planing boat with 2 x 240hp (?) diesels should be doing better than that. What kind of boat do you have any does it have shafts or sterndrives?

 

[rubberduck]

My Abs 41 with 2 x volvo D6 330 gets about 1.4 mpg, so those figures sound poor to me.

 

[Nickcf]

My Abs 41 with 2 x volvo D6 330 gets about 1.4 mpg, so those figures sound poor to me.

sound poor to me as well- I get about 1 mpg from 2x480hp Volvos. Maybe the OP is pushing it in displacement mode as this drinks fuel but doesn't get you anywhere, tickover or planing speed is best.

 

[Deleted User YDKXO]

How sure are you that the tank(s) were absolutely full before your delivery trip? It is often difficult to know when the tanks are full as, on some boats, you get fuel blowback well before the tanks are full, particularly if the pump has a fast delivery. IMHO, it's better to calculate fuel consumption over a whole season to get an accurate idea of fuel usage than on one fill up

 

[Nick_H]

Seahope, weren't you having some planing problems? If boat was struggling to get on the plane you would be burning lots of fuel, so that could explain the very poor figures you've achieved. You should be getting about 2 mpg, not 1.