of course, if you backed it down to about 3000 rpm the speed wouldn't
be much different, and the savings in fuel can be a better edge even
yet.

I've run my little Chris Craft with a 4 banger alpha 1 at 3000 and it
does rather well. at 3500 the fuel consumption goes up with little
speed change, and 4000 rpm the fuel really drops and doesn't gain
hardly much speed over the 3500.

I suppose you might say that the percentage of speed vs. consumption
really drops out of your favor the higher rpm you go.