On Sun, 06 Apr 2008 00:31:52 GMT, Jere Lull wrote:

On 2008-04-05 09:48:23 -0400, Bruce in Bangkok said:

I suspect, but can't prove that yacht engines are seldom run at maximum
continuous horsepower settings for any length of time while most
commercial engines are.

Talking around the docks, and here, I find that most 'yacht' engines
are also either at idle or 80+% of designed revs.

I'm a bit unusual that I normally power at less than 80% of the
engine's max revs to maximize fuel economy. At 70-75% of max revs, we
get 25-30 mpg. 80% has us pushing against hull speed. Full revs push us
over hull speed, and I've only done that twice in 15 seasons.

Most sailors run at high power when they motor. If they turn the motor
on, they're by definition in a hurry.

Your engine is too big, simple as that :-) By the way, how do you
calculate miles per gallon? No tides in the Chesapeake?

Over in the dry (N.E. monsoon) season you motor when there isn't any
wind, which is usually when the land breeze dies about 11:00 every
morning.

Bruce-in-Bangkok
(correct email address for reply)