On Fri, 04 Jul 2008 11:39:02 -0400, Gene Kearns
wrote:

GPH is pretty meaningless when one wants to determine fuel consumed
per distance traveled. Miles per gallon is really what we want to
know, since that is a better measure of fuel economy. (Least fuel
consumed, per mile, is my goal, anyway.)

Please take no offense, but that doesn't make any sense.

You have to have a base calculation which would be gallons per hour
(actually I've been told that the true base is per minute) because
it's the only true way to measure fuel usage.

Thus, you use X fuel over Y time.

So what can be the variable in the equation - RPM. At low RPM,
G(used)PH goes down and when RPM rises, G(used)PH goes up.

Thus, at A revolutions you use X Fuel over Y time.

That cannot change - it's the base calculation.

Now from there, you can make whatever calculation you want - furlongs
per fortnight or miles per gallon - it doesn't matter because it's all
based on GPH. It can't be any other way.

Feed distance, time, and gallons consumed into the computer and out
comes MPG.

That's fine, but it's still the same number as GPH. You have still
used a certain amount of Gallons Per Hour.

You asked a question in another post:

Heading upstream in a 10 MPH current at 8 MPH would give what
sort of MPG???? Sooner or later the fuel tank would overflow...!

That's exactly the point of GPH - you have a known figure.

If your not making headway, you are still using fuel - GPH again.

"Short Wave Sportfishing" wrote in message
...
On Fri, 04 Jul 2008 11:39:02 -0400, Gene Kearns
wrote:

GPH is pretty meaningless when one wants to determine fuel consumed
per distance traveled. Miles per gallon is really what we want to
know, since that is a better measure of fuel economy. (Least fuel
consumed, per mile, is my goal, anyway.)

Please take no offense, but that doesn't make any sense.

You have to have a base calculation which would be gallons per hour
(actually I've been told that the true base is per minute) because
it's the only true way to measure fuel usage.

Thus, you use X fuel over Y time.

So what can be the variable in the equation - RPM. At low RPM,
G(used)PH goes down and when RPM rises, G(used)PH goes up.

Thus, at A revolutions you use X Fuel over Y time.

That cannot change - it's the base calculation.

Now from there, you can make whatever calculation you want - furlongs
per fortnight or miles per gallon - it doesn't matter because it's all
based on GPH. It can't be any other way.

Feed distance, time, and gallons consumed into the computer and out
comes MPG.

That's fine, but it's still the same number as GPH. You have still
used a certain amount of Gallons Per Hour.

You asked a question in another post:

Heading upstream in a 10 MPH current at 8 MPH would give what
sort of MPG???? Sooner or later the fuel tank would overflow...!

That's exactly the point of GPH - you have a known figure.

If your not making headway, you are still using fuel - GPH again.

There are simply too many variables to calculate MPH over water. You can use
a GPS log of total miles traveled to calculate MPG of a particular trip.
That won't necessarily compare to the same trip on a different day. You can
collect data and come up with averages if you want. That might be useful.
You can reliably chart GPH at given throttle positions and then convert
throttle position to approximate MPH(over water, not land). You and I are on
the same page but the other folks don't buy into what we are saying. No big
deal.

On Fri, 4 Jul 2008 15:38:21 -0400, "Jim" wrote:


"Short Wave Sportfishing" wrote in message
.. .
On Fri, 04 Jul 2008 11:39:02 -0400, Gene Kearns
wrote:

GPH is pretty meaningless when one wants to determine fuel consumed
per distance traveled. Miles per gallon is really what we want to
know, since that is a better measure of fuel economy. (Least fuel
consumed, per mile, is my goal, anyway.)

Please take no offense, but that doesn't make any sense.

You have to have a base calculation which would be gallons per hour
(actually I've been told that the true base is per minute) because
it's the only true way to measure fuel usage.

Thus, you use X fuel over Y time.

So what can be the variable in the equation - RPM. At low RPM,
G(used)PH goes down and when RPM rises, G(used)PH goes up.

Thus, at A revolutions you use X Fuel over Y time.

That cannot change - it's the base calculation.

Now from there, you can make whatever calculation you want - furlongs
per fortnight or miles per gallon - it doesn't matter because it's all
based on GPH. It can't be any other way.

Feed distance, time, and gallons consumed into the computer and out
comes MPG.

That's fine, but it's still the same number as GPH. You have still
used a certain amount of Gallons Per Hour.

You asked a question in another post:

Heading upstream in a 10 MPH current at 8 MPH would give what
sort of MPG???? Sooner or later the fuel tank would overflow...!

That's exactly the point of GPH - you have a known figure.

If your not making headway, you are still using fuel - GPH again.

There are simply too many variables to calculate MPH over water. You can use
a GPS log of total miles traveled to calculate MPG of a particular trip.
That won't necessarily compare to the same trip on a different day. You can
collect data and come up with averages if you want. That might be useful.
You can reliably chart GPH at given throttle positions and then convert
throttle position to approximate MPH(over water, not land). You and I are on
the same page but the other folks don't buy into what we are saying. No big
deal.

You've wrapped it up much more clearly that I did. :)

It's actually a tomato/TOMAHTOE thing - I'm comfortable with GPH and
others are comfortable with MPG.

No worries.

"Tom The Prophet" wrote in message
...
On Fri, 4 Jul 2008 15:38:21 -0400, "Jim" wrote:


"Short Wave Sportfishing" wrote in message
. ..
On Fri, 04 Jul 2008 11:39:02 -0400, Gene Kearns
wrote:

GPH is pretty meaningless when one wants to determine fuel consumed
per distance traveled. Miles per gallon is really what we want to
know, since that is a better measure of fuel economy. (Least fuel
consumed, per mile, is my goal, anyway.)

Please take no offense, but that doesn't make any sense.

You have to have a base calculation which would be gallons per hour
(actually I've been told that the true base is per minute) because
it's the only true way to measure fuel usage.

Thus, you use X fuel over Y time.

So what can be the variable in the equation - RPM. At low RPM,
G(used)PH goes down and when RPM rises, G(used)PH goes up.

Thus, at A revolutions you use X Fuel over Y time.

That cannot change - it's the base calculation.

Now from there, you can make whatever calculation you want - furlongs
per fortnight or miles per gallon - it doesn't matter because it's all
based on GPH. It can't be any other way.

Feed distance, time, and gallons consumed into the computer and out
comes MPG.

That's fine, but it's still the same number as GPH. You have still
used a certain amount of Gallons Per Hour.

You asked a question in another post:

Heading upstream in a 10 MPH current at 8 MPH would give what
sort of MPG???? Sooner or later the fuel tank would overflow...!

That's exactly the point of GPH - you have a known figure.

If your not making headway, you are still using fuel - GPH again.

There are simply too many variables to calculate MPH over water. You can
use
a GPS log of total miles traveled to calculate MPG of a particular trip.
That won't necessarily compare to the same trip on a different day. You
can
collect data and come up with averages if you want. That might be useful.
You can reliably chart GPH at given throttle positions and then convert
throttle position to approximate MPH(over water, not land). You and I are
on
the same page but the other folks don't buy into what we are saying. No
big
deal.

You've wrapped it up much more clearly that I did. :)

It's actually a tomato/TOMAHTOE thing - I'm comfortable with GPH and
others are comfortable with MPG.

No worries.

I need an average MPG, as if you are running to an upriver or offshore
point, it would be nice to know if you have enough fuel capacity. I could
slow down and get a little better mileage, or go faster for fun.

On Fri, 04 Jul 2008 15:26:45 -0400, Gene Kearns
wrote:

Wouldn't it be nice to be able to figure out the most efficient RPM
for covering a given distance? Say, I want to head 30 miles offshore
and use the least amount of that $4.759 liquid gold?

My boat specs, per the Grady site:

2000 RPM 8.5 MPH 3.8 GPH 2.22 MPG
3500 RPM 20.3 MPH 10.9 GPH 1.87 MPG
4000 RPM 27.5 MPH 12.8 GPH 2.16 MPG
4300 RPM 30.7 MPH 14.5 GPH 2.12 MPG
4500 RPM 33.1 MPH 15.7 GPH 2.12 MPG
5000 RPM 37.5 MPH 19.2 GPH 1.96 MPG

Well, I think we've entered tomato/TOMAHTOE stage. :)

I understand your points - they just don't make any sense to me.

Then again, I'm not exactly normal.

Check out that helicopter POH.... same thing there, too.....

Speaking of which, I solo next week and get my "official" license.

WHOO HOO!!!