Quote:
Originally Posted by lakewinnie
I'm not sure how this equates to MPG, but I get around 5 GPH at 30 MPH in my 24 foot Four Winns bowrider with the 5.3 liter Volvo Penta. That seems to be the sweet spot.
|
Just divide the MPH by the GPH to get MPG. 30/5=6 so 6 MPG.
6MPG in a 24 foot bowrider seems pretty optimistic though.
Assuming you have a 300 HP 5.3, I'd expect the top speed to be close to 50 MPH. Since drag is a function of the square of speed we can calculate the HP needed to go 30MPH if the boat tops out at 50MPH
50x50=2500 2500/300=8.33
30x30=900 900/8.33 = 108 HP
It takes roughly .08GPH to make 1 HP so 108 HP would require 8.64 GPH so I think you are getting around 3.5 MPG, 30/8.64= 3.5