View Full Version : boat fuel mileage
flyingd
06-23-2008, 02:50 PM
Just curious what you guys think a 23' deep vee hulled boat with a 350 chevy should/would get for fuel mileage.
And what would be the most economical RPM to run at.
I guess it would be in gallons per hour???:passout:
Thanks
Tinman
06-23-2008, 03:20 PM
Just a wild guess would be 2 miles per gallon in the ocean at cruising speed.
A rule of thumb says that gallons per hour (at wide open throttle) is equal to horsepower divided by 10. Example: a 200 hp motor would burn 20 gallons per hour at wide open throttle.
carb - 2 MPG sounds about right, EFI - maybe up to 3. Best mileage will most likely be at 1000 RPM, then at somewhere around 3000 - 3300.
bigredapes
06-24-2008, 10:03 PM
I've got a 22ft with aluminum 18degree hull.
Chevy 305 EFI/MPI Alpha-I IO drive to a prop
I get a hair over 3 miles/gallon cruising on the rivers
Most efficient on plane is about 3200rpm for me, burning around 8 gph (based on internal engine computer)
Surprisingly, the miles/gallon efficiency doesn't change much from 2600rpm (just barely on plane) to 4000rpm. It's that last 4200-4600rpm that really eats up the fuel bill for me.
however, once I'm out in the ocean I'm getting closer to 2mpg (except for those rare really flat days.