Best Fuel Economy Twin Screw

[DKramer]

I have an 1999 Albin 35 TE with twin Cummins 6BTA5.9-M3 370 horsepower engines. I am trying to figure out my best economy/long range power setting. Does anyone know how I can figure this out?

[RobS]

I guess you're looking for an answer other than the obvious - displacement speed. I attach the performance specs. You need to record your speed (SOG) at the rpm increments listed. Based on the printed fuel consumption at those rpm's, calculate your MPG (SOG/GPH). There is one VERY important piece to this puzzle - is your boat propped so those engines can easily make 3,100 - 3,150rpm WOT fully loaded as you use the boat? If so, you can bank on those printed fuel burn specs. If not, all bets are off...

[DKramer]

Thanks for that, very helpful!

About displacement speed, I figure that is probably a good rule of thumb but what exactly is the definition?

[RobS]

Thanks for that, very helpful!

About displacement speed, I figure that is probably a good rule of thumb but what exactly is the definition?

You could research and read, read and read some more on that...........But for your hull type lets simplify it as much as possible and say that it is the speed before your boat wants to start thinking about climbing up onto plane.

[WillieC]

MPG=(SOG/GPH). Don't you love simple algebra? What a concise way to put it!
Thanks, Rob.