"Rick Cortese" wrote...
Slow in the group so I figured I'd waste some bandwidth. Checked the mileage
and my boat with an 18hp two stroke only makes 2-3 mpg. I figure it is mostly
because I usually go sailing with my son so WOT for 7-10 miles to get where
the winds are to his liking and same drill coming back after the winds die.

Just my guesstimate but we seem to make ~5 knots at 1/3 throttle and ~6 knots
at WOT. My GPS went down for the count so I have to get a new one before I can
get good data.

Is this about right for a hull that is in sore need of a bottom cleaning?

It appears you're wasting fuel at WOT. Is it really worth all that extra fuel
to save 20 minutes? I suspect you could get half the difference (5.5 kt) with
1/2 to 2/3 throttle. You might get double that by cleaning the bottom!

My SeaPearl 21 with a Honda BF2 4-stroke got around 45 mpg at 5-5.5 kt and 1/3
throttle. Half throttle got another 1/4 kt at the cost of a lot more noise.