Our 37' overall 34' running surface twin Yanmar 260 diesel boat gets 2 litres (0.528 US Gallon) per mile at between 65 and 70mph, works out to 1.9 miles per USG, more if it's a British Gallon - 2.27 MPG!

I like that mileage.nice

Nice build. Hope the back feels better! Good Luck in the future races

we get 2 mpg @ 80 mph in the skater v with diesels, that is with all the safety gear and a few hundred gallons of diesel and two of us in it. When we had 600 gallons in it to average 2 mpg we had to drop speed to 75.

http://www.youtube.com/watch?v=gq0WiMKhlJY

http://www.youtube.com/watch?v=zu98_yPg6aQ

http://www.youtube.com/watch?v=Of1RY4M8VqM

That boat has the 5.9L cummins or the 6.7L are they 480HP or 550HP? I want to build a Skater cat with the exact same powertrain you have but with the 6.7L 550HP cummins. What kind of mpg do you get with a light setup at ideal speeds?

I get a best of 2.6 or 2.7 mpg in my 37 Spectre center console going 33mph light on fuel with just me on board, same setup gets me 2.5mpg at 40mph. But normal load and passengers is between 2 and 2.3 depending on seas, wind, and load on board. It usually is only a tenth or two worse going 40mph vs 32mph so I usually go faster. I get 2mpg all the way to 50mph, then it starts to drop slightly and bottoms out at 57mph top speed around 1.8 or 1.7 mpg. My boat is heavy with a big t-top and conventional bottom.

Are we talking "Nautical miles" or "Miles".
Just wonder, as we always talk "Nautical miles and "Knots" here in Sweden.

I am talking US Gallons and statute miles for speeds and mpg.

Ok. Sorry to mix things up...
Means that my earlier figures should be corrected as I was talking Nautical miles.

1,43 mpg at 80 mph and 1,26 at WOT(85-88 mph depending on fuelload).
Never more than 1,65 mpg at any speed.

Should be:

1,65 mpg at 80 mph and 1,45 at WOT(85-88 mph depending on fuelload).
Never more than 1,9 mpg at any speed.

Love to see all these new Diesel Projects popping up..

Took me a while to understand what Joe's been preaching also, but he's spot on when it comes to the prop speed being key. HP is the easy part with the diesels, but just because they say you can turn them 4k doesn't mean your gonna do it all day long. Diesels work off of heat and compression, the harder ya run the more heat they will build.

My built Duramax can run safely at 2600R's for hours, but push it to 3600R's and the heat builds quick, and that time drops to a couple minutes before the gauges start peaking. Best every day example of a hot diesel boat setup is pulling that same boat up an endless hill with your diesel truck. Push the throttle down for an uphill mile and watch your gauges. That's a diesel boat every day run...

Thinking of starting another double Dmax build, and a 2-speed "overdrive" trans is the FIRST part that will be fit to each engine. 3500R's at the prop while turning 2500R's at the crank is my ultimate performance goal.

Nice Build.

-K

PS. Did 120 miles running on Cumberland and Dale Hollow couple weeks ago on just 24gal of fuel. 5mpg..

Chapeau bas 7075T6.

Very nice project.

In my opinion the best mix: aluminium, diesels, multi-speed gearbox and surface propellers!