Burn rate at different speeds: 31 TE with twin CATS

[SonoraWind]

A friend is considering buying a 31 TE with twin CATS. This seems to be a very rare configuration and I am having trouble finding much info on the 31 with these engines.

I believe they are 3116 engines. Were there other CAT engines put into the 31 by Albin?

Anyone out there with one that can tell me what this vessel will burn at troll, at cruise and at WOT?

Also interested in the speed is at cruise and WOT.

[SonoraWind]

I have learned that they are the 300hp versions.

[RicM]

You might want to try www.boatdiesel.com

[SonoraWind]

There is plenty of info over there on the engines themselves. I was looking for something more specific to the boat, itself.

Thank you for the recommendation.

[RicM]

The boat has little to do with it other than what it weighs. Take the engine burn rate from the charts, multiply by 2 and that's pretty much it.

[SonoraWind]

So, planing or semi-displacement hull is immaterial? Only knowing weight is all I need? I would have thought otherwise.

I'll check over there.

[RicM]

The hull shape and design will effect how far you TRAVEL in that one hour of running at say, 2200RPM. You didn't ask for MPG. The engines will burn X amount of fuel with each revolution of the crankshaft. The crankshaft will revolve a certain number of times per hour. How well that gets transferred into forward motion is up to the prop, the hull, the density of the water, current, weather etc etc. If you look up your engine model many manufacturers publish charts of fuel burn rates so you can determine the sweet spots on plane and in displacement mode. The biggest determinate of efficiency (MPG) is usually weight (displacement) and yes, once you get the boat up on plane you are pumping less water from the front to the back of the boat each time you move forward one boat length.

If you are boat shopping and trying to determine operating costs and that's a factor, stick with single engine 31 TE's and you'll be MUCH happier. It's not only the fuel burn, it's service and maintenance that doubles with twin anythings. There are multiple threads on this forum about single VS twins, lot's of good reading.