On Sat, 09 Apr 2005 21:34:42 GMT, Dan Krueger
wrote:

Roughly 1-22 gph. There are too many variables: Alpha 1, Bravo 1,2, or
3, Volvo Penta, prop selection, load, fuel & water on board, sea
conditions, etc. The most important variable is your speed. You can
burn 1-2 gph at a crawl and about 20-22 at WOT.

If you want to economize - and your post hints to that - you *should*
buy a fuel meter. A boat running 2500 rpms at 21 knots can burn 6 gph
with that engine. That same boat at 3500 rpms and 34 knots can burn
around 12 gph - about double or half of the fuel economy. A fuel flow
meter can help you find your sweet spot, or cruising speed, to get the
best bang for your buck and pay off that meter in a short period of
time. Here's a boat with a Volvo 5.7 that was tested...

RPM MPH Knots GPH
650 3.7 3.2 0.9
1000 5.8 5.0 1.2
1500 8.1 7.0 3.4
2000 15.6 13.6 5.1
2500 24.4 21.2 6.0
3000 31.7 27.6 8.2
3500 39.6 34.4 11.8
4000 45.3 39.4 13.5
4500 49.9 43.3 17.2
4750 54.1 47.0 22.6

Dan


Thanks Dan, I should have mentioned it has an Alpha I outdrive. It looks like
trolling (8-900 rpm) will burn about 1 gph and cruising (usually about 3200 rpm)
will burn about 10gph. Guess I better spend more time fishing and less time
playing!
--
John H

"All decisions are the result of binary thinking."