I had a debate with a friend this morning concerning miles vs gallons
per hour.

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

Later,

Tom

"Shortwave Sportfishing" wrote in message
...
I had a debate with a friend this morning concerning miles vs gallons
per hour.

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

Later,

Tom

Depends on the boat. Trawlers, etc gallons per hour, but performance boats
that run at difference speeds, average miles per gallon seems better.

"Shortwave Sportfishing" wrote in message
...
I had a debate with a friend this morning concerning miles vs gallons
per hour.

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

Later,

Tom

First of all, miles per hour is totally unrelated to fuel efficiency. It is
simply speed. A 19 foot ski boat and a 65 foot sports fisherman can both go
40 mph with vastly different efficiencies.

Gallons per hour is only indirectly related to efficiciency. You can sit
idling at the dock and use a certain number of gallons per hour - and your
efficiency is zero.

Efficiency is miles per gallon. If you know your speed then gallons per hour
can be converted to miles per gallon. Likewise if you know your gallons per
hour then speed can also be converted to miles per gallon.

Knowing how far a boat can go is related to miles per gallon and fuel tank
capacity.

Basically you were both wrong!

--
Peter Aitken

"Shortwave Sportfishing" wrote in message
...
I had a debate with a friend this morning concerning miles vs gallons
per hour.

These two items are different than the ones listed in the header. The text
above quotes MPH vs. GPH. The header quotes GPH vs. MPG. I'm sure you
realize the MPH and MPG are entirely different calculations, but perhaps
your end of the debate would be strengthened by consistency. Given the
discrepancy, I'm not sure if you are arguing GPH vs. MPH or GPH vs. MPG.
Either way, I'm not sure I understand the basis for the debate altogether,
as each tells a different thing, presumably to be used for different
purposes. GPH will tell you fuel consumption over a fixed period of time,
but as it has no accounting for speed, it has no direct accounting for
distance traveled in that period of time, so by itself is not reasonable
measurement of fuel consumption over distance traveled. MPH is simply a
measurement of speed, with no accounting for fuel consumption at all. MPG
is perhaps the more useful measurement of the three, because it calculates
fuel consumption for a given distance traveled, but may not be as relevant
as GPH for some.



I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?



Which of these is more appropriate for you will depend much on your boat and
the way you use it. For instance, if your boat is a trawler type, without a
great variation of speed, or if the majority of your engine hours are at
idle or trolling speeds, it may be that GPH is the most relevant measurement
of fuel consumption. for you. On the other hand, if your boat has
significant variations in speed, and is used to travel large distances, MPG
would more likely be the consumption measurement of choice.

My own case offers an interesting study. I have a 29' twin gas I/O cruiser,
with a top speed of 41 MPH, a typical cruise speed of 30 MPH, and I also
spend a significant amount of time gunkholing at idle and leisuring cruising
at about 8 MPH. Whenever I buy fuel, I always fill the tank completely, and
maintain a detailed fuel log with engine hours since last fill, gallons
used, and distance traveled. Distance traveled is generated from the GPS,
which has a resetable odometer function, which I reset at every fueling.
The boat never moves without the GPS being turned on and therefore recording
accumulated distance traveled.

Depending on how the boat was used for that particular tank of fuel, my GPH
will fluctuate dramatically. My fuel log (going back 5+ years) shows a GPH
high of 18 and a low of 3.6. Quite a range. I have two entries showing
18.0 GPH, with both of them being non-stop long distance cruises, using the
logged fuel in a matter of hours. One was a run of 133 miles using 109
gallons, and the other was a run of 67 miles using 49 gallons. I was at a
high speed cruise the entire time on both runs. At the other end of the
range, the 3.6 GPH entry logged 141 miles using 102 gallons, but over a four
month period of time. This was a period of time where the boat never really
went very far at any one period of time, and consisted of mixed usage at
high cruise speed and quite a bit of gunkholing at low speed cruising. I
also have many log entries with GPH readings anywhere between the 3.6 and
18.0 GPH readings. So for me, GPH isn't a very meaningful statistic by
itself.

On the other hand, and I've always found this somewhat fascinating, even
with GPH readings all over the place, my MPG readings are remarkably
consistent. MY MPG high and low readings are 1.41 and 1.22, with the vast
majority of them hugging around 1.3 MPG. For instance, the 18.0 GPH
readings resulted in 1.22 and 1.38 MPG readings. The 3.6 GPH reading
resulted in a 1.39 MPG reading. What this tells me is that my boat gets
about 1.30 MPG whether I'm cruising at 3500 RPM and 30 MPH or at 1700 RPM
and 8 MPH. Obviously the former has a much higher GPH reading than the
latter, but the MPG readings seem to equalize. I would have never guessed
that both those speed would offer the same MPG, but it has been offered up
way to many times to be denied.

So for me, GPH is pretty much irrelevant, while MPG is highly relevant. If
my MPG readings started to consistently show less than 1.2, I would start to
suspect something amiss with one of the engines. GPH readings would give me
no such clue. So I guess that puts me on the other guy's side of the
debate. But, as they say, your mileage may vary.

RG

On Wed, 11 May 2005 11:45:11 -0700, "RG" wrote:


"Shortwave Sportfishing" wrote in message
.. .
I had a debate with a friend this morning concerning miles vs gallons
per hour.

These two items are different than the ones listed in the header. The text
above quotes MPH vs. GPH. The header quotes GPH vs. MPG. I'm sure you
realize the MPH and MPG are entirely different calculations, but perhaps
your end of the debate would be strengthened by consistency. Given the
discrepancy, I'm not sure if you are arguing GPH vs. MPH or GPH vs. MPG.
Either way, I'm not sure I understand the basis for the debate altogether,
as each tells a different thing, presumably to be used for different
purposes. GPH will tell you fuel consumption over a fixed period of time,
but as it has no accounting for speed, it has no direct accounting for
distance traveled in that period of time, so by itself is not reasonable
measurement of fuel consumption over distance traveled. MPH is simply a
measurement of speed, with no accounting for fuel consumption at all. MPG
is perhaps the more useful measurement of the three, because it calculates
fuel consumption for a given distance traveled, but may not be as relevant
as GPH for some.

So I take it you have never made a typo in your entire life?

Damn, it must hard to be so perfect. :)

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

~~ mucho snippage ~~

So for me, GPH is pretty much irrelevant, while MPG is highly relevant. If
my MPG readings started to consistently show less than 1.2, I would start to
suspect something amiss with one of the engines. GPH readings would give me
no such clue. So I guess that puts me on the other guy's side of the
debate. But, as they say, your mileage may vary.

Thanks for your input.

Later,

Tom

In article ,
says...
I had a debate with a friend this morning concerning miles vs gallons
per hour.

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

Later,

Tom


Actually, as stated I'd have to opine the gallons per hour was almost
right or rather only part of that side of the argument.

I'd would think gallons per hour at X rpm is much more accurate for a
boat. With all the variable forces acting on a boat in motion, hull and
upper works design, wind, or current, for example

A boat at, say, 3500 RPM isn't going to cover the same distance with a
head wind and cross current as a boat with a tail wind and following sea
or one in a dead calm and glass smooth surface. The only constant you
can really use to figure your range at any specific time is the is the
fuel consumption at that RPM rate.

Let's say your favorite fishing grounds is, under ideal conditions, a
two hour run at the boats ideal cursing speed/RPM. That makes things
easy but how often are you going to find ideal conditions that will
allow you to run at your best cruising speed/RPM with no external
variables to figure in. Once you get past the break water the whole
thing is a crap shoot till you get your RPM's up to where you are
getting the best ride. That may or may not be at your ideal cruising
speed, may or may not be covering distance over the ground at the same
speed as you would in ideal conditions. Again, the constant, RPM.

Hell you can't accurately tell what one automobile will really give you
in miles per gallon. It all depends on how much of a lead foot the
driver is, traffic and weather conditions. You take an EPA rating on a
new car and some people are going to be able to better it some not even
get close. That's why they call them estimates and your mileage may
vary.

--
Mike G.
Heirloom Woods

www.heirloom-woods.net

On Wed, 11 May 2005 15:01:56 -0400, Mike G
wrote:

In article ,
says...
I had a debate with a friend this morning concerning miles vs gallons
per hour.

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

Actually, as stated I'd have to opine the gallons per hour was almost
right or rather only part of that side of the argument.

I'd would think gallons per hour at X rpm is much more accurate for a
boat. With all the variable forces acting on a boat in motion, hull and
upper works design, wind, or current, for example

A boat at, say, 3500 RPM isn't going to cover the same distance with a
head wind and cross current as a boat with a tail wind and following sea
or one in a dead calm and glass smooth surface. The only constant you
can really use to figure your range at any specific time is the is the
fuel consumption at that RPM rate.

Let's say your favorite fishing grounds is, under ideal conditions, a
two hour run at the boats ideal cursing speed/RPM. That makes things
easy but how often are you going to find ideal conditions that will
allow you to run at your best cruising speed/RPM with no external
variables to figure in. Once you get past the break water the whole
thing is a crap shoot till you get your RPM's up to where you are
getting the best ride. That may or may not be at your ideal cruising
speed, may or may not be covering distance over the ground at the same
speed as you would in ideal conditions. Again, the constant, RPM.

Hell you can't accurately tell what one automobile will really give you
in miles per gallon. It all depends on how much of a lead foot the
driver is, traffic and weather conditions. You take an EPA rating on a
new car and some people are going to be able to better it some not even
get close. That's why they call them estimates and your mileage may
vary.

I agree with you, but for a different reason.

My argument is that GPH is a more reliable measure of efficiency
because it covers the spectrum from sitting at the dock warming up to
running full throttle. For example, my Ranger with the 200 FICHT
averages 5 to 6 gallons per hour considering everything. At cruise,
which is about 35 mph, it's about 8 GPH and that seems to be pretty
consistent in most sea conditions. The base is 8 GPH and from there I
can figure MPG - believe this or not, I just typo'd MPH :). So the
way I look at it, GPH is essential to determining MPG and thus the
more relevant factor in determining efficiency.

We argued this for a freakin' hour this morning. :)

Of course, he's a physicist - dumbass. :)

Later,

Tom

Around 5/11/2005 5:20 PM, Shortwave Sportfishing wrote:

On Wed, 11 May 2005 15:01:56 -0400, Mike G
wrote:

I'd would think gallons per hour at X rpm is much more accurate for a
boat. With all the variable forces acting on a boat in motion, hull and
upper works design, wind, or current, for example
snip

I agree with you, but for a different reason.

My argument is that GPH is a more reliable measure of efficiency
because it covers the spectrum from sitting at the dock warming up to
running full throttle.
snip


I like GPH just because I know that after about two hours of cruising,
it's time to switch to the other tank. MPG (as measured with a GPS)
isn't nearly as consistent.



--
~/Garth - 1966 Glastron V-142 Skiflite: "Blue-Boat"
"There is nothing - absolutely nothing - half so much worth doing
as simply messing about in boats."
-Kenneth Grahame, The Wind in the Willows

On Wed, 11 May 2005 16:50:28 GMT, Shortwave Sportfishing
wrote:

I had a debate with a friend this morning concerning miles vs gallons
per hour.

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

Later,

Tom

If they're both accurate, then they're both reliable. Most of my boating is
cruising to get to the fishing area and then trolling for however long I'm going
to do it, and then cruising back. I figure 8gph cruising and 2 gph trolling.
This morning I cruised about an hour, total, and trolled for about an hour.
(Took that long to catch a 38"er and a 36"er.) So, I figured I burned about 10
gallons, or $25 worth of gas. We split the gas amount.

I'd say the most reliable way is to use a flow meter, but I haven't put mine in
yet.
--
John H

"All decisions are the result of binary thinking."

On Wed, 11 May 2005 15:07:02 -0400, John H
wrote:

On Wed, 11 May 2005 16:50:28 GMT, Shortwave Sportfishing
wrote:

I had a debate with a friend this morning concerning miles vs gallons
per hour.

I contend that gallons per hour is a more reliable method of
determining how far and fast a boat can/should go. Obviously, my
friend took the opposite viewpoint.

What is the collective wisdom concerning these measure of fuel
efficiency?

Later,

Tom

If they're both accurate, then they're both reliable. Most of my boating is
cruising to get to the fishing area and then trolling for however long I'm going
to do it, and then cruising back. I figure 8gph cruising and 2 gph trolling.
This morning I cruised about an hour, total, and trolled for about an hour.
(Took that long to catch a 38"er and a 36"er.) So, I figured I burned about 10
gallons, or $25 worth of gas. We split the gas amount.

I'd say the most reliable way is to use a flow meter, but I haven't put mine in
yet.

I don't have one on the Ranger, but I do on the Contender. Of course,
I have no idea what the GPH figure is on the Contender BECAUSE THEY
HAVEN'T FINISHED INSTALLING THE FREAKIN' THRU-HULL AND OR PAINTED THE
BOTTOM!!!!

AARRRGGGHHHH!!!!

Later,

Tom