On Jun 21, 7:24 am, R Swarts wrote:
Over the years I've seen very little written about fuel economy in
boats. If anyone has good data I would like to see it. I am particularly
concerned with optimal speeds for planing hulls. Is it in the
displacement range? Or on the plane? Does it increase monotonically with
decreasing speed? Not in gallons per hour, but in miles per gallon. If
one has a twin screw boat, does fuel economy increase or decrease in
running only one prop? Is diesel always more economical than gas? And
anything else that bears on the problem.

Bob Swarts

The reason we measure boats in gallons per hour and not miles per
hour? Wind and current make miles per hour impractical. With the
current against you, the engine can be running at 6000 RPM for an hour
and you have only covered two miles. I have seen that in the Inside
Passage around the Fraiser River. Too big of a veriable there. RPM's
and fuel used can be realistically monitored.

Tom, the trouble with using gallons per hour is that it doesn't measure
fuel economy. If I burn twice the gallons per hour, but go three times
as fast, then burning at the higher rate yields greater economy.

I will grant that if you are comparing identical boats at identical
speeds then gallons per hour would give the desired result.

BS


tomdownard wrote:

The reason we measure boats in gallons per hour and not miles per
hour? Wind and current make miles per hour impractical. With the
current against you, the engine can be running at 6000 RPM for an hour
and you have only covered two miles. I have seen that in the Inside
Passage around the Fraiser River. Too big of a veriable there. RPM's
and fuel used can be realistically monitored.

The only measure that makes sense is miles per gallon, drift, tide,
wind effects excluded, your choice of units..

Calculated against dollers per hour time on vacations aboard (what
price freedom?)

I calculate time at 10 bucks an hour for me, shopping for bargains,
whatever. The guests can do as they please.

Terry K

Terry K wrote:
The only measure that makes sense is miles per gallon, drift, tide,
wind effects excluded, your choice of units..

Calculated against dollers per hour time on vacations aboard (what
price freedom?)

I calculate time at 10 bucks an hour for me, shopping for bargains,
whatever. The guests can do as they please.

Terry K


Someone receintly said that as long as gas cost less than designer
water nobody was ging to worry about it.

Now there's a place in NYC selling water for over $50 a quart.
And people are buying it!!!

Richard