Optimal Crusing Speed for 280 Sundancer 4.3 Mercruiser Bravo 3

[Boilermakerjay]

I have been trying to find the optimal fuel efficient cruising speed for my 2006 280 Sundancer with Twin 4.3 Bravo 3s. Tried boattest.com but search does not seem to be working unfortunately, not a lot available online. Thank you!

 

[Cap'n Scuba Steve]

Honestly, the best way to do this is with a bit of experimentation and it has a lot to do with your personal preference. With all the variables that affect fuel economy (wind, fuel amount, water amount, passengers, gear, current, hull growth), it's simply best to go out in the boat under the conditions you normally cruise in and make adjustments. Set your smart gauges to display Gallons per Hour and then get the boat up on plane and then make adjustments to drive trim, trim tabs and engine RPM to get the best performance you are able to dial in for the speed you would like to travel at. In the large majority of boats, the faster you go the more fuel you will burn - no matter the adjustments you make.

For most gasoline engines, somewhere between 3,400 and 3,800 RPM gives you a good combination of performance, fuel economy, and wear rate. The most optimal fuel efficient cruising speed is just above idle if you're mostly concerned about fuel economy. But most of us won't tolerate that slow of a speed!

 

[Boilermakerjay]

Did not even think of using the smart gauges, good info! Thank you!

 

[DWABoat]

Place to start your test would probably be just when your boat levels off on-plane. For my 2001 280 with twin 4.3’s and Alphas, it runs at about 3300/28mph at minimal planing speed. I don’t know if that is my most efficient speed, but I feel it handles best and gives me a comfortable ride, so that is where I try to stay.

 

[JimT]

I have always considered 3600 rpm to be the max RPM for long runs.

 

[Cap'n Scuba Steve]

I didn’t make this meme, so no judging for the to/too mistake!