Dave Stadt wrote:
wrote in message
ups.com...

The key is speed. A boat runs most efficiently at "hull speed" which is
a function of length. If you want to push the hull faster than that,
fuel consumption goes up ridiculously, even worse than with airplanes.

Only true when talking about displacement hulls. Has nothing to do with
planing hulls which include the vast majority of power boats. Planing hulls
burn a tremendous amount of fuel untill they reach planing speed.

A planing hull can still be driven more efficiently (in MPG terms) at
hull speed than at or above planing speed. It is true that a planing
hull is least efficient at the speeds above displacement but below
planing, but even up on the step you'll get lower MPG. Even on a boat
like a Cigarette which has a hull and drive system optimized for
nothing but go-fast, you'll get better mileage running at hull speed:

http://powerandmotoryacht.com/boatte...te/index2.html

Likewise, hulls designed for planing are vary bad when you get serious
weather. The very characteristics which allow them to go so fast also
make them prone to pitchpoling and broaching.

-cwk.