Actually it is neither in this particular case.
If I am so stupid as to head out on a lake/river that I don't know without a
chart or gps and I did not fill up my gas tank before leaving but I kept up
w/ my time at various rpms then GPH at each of these rpms would mean
something.
On the other hand, assuming I at least filled the gas tank, as long as I
have over 1/2 tank left (not what the needle says but actually 1/2 tank) I
should be able to get back as long as I don't run any harder than I did
getting to where I am.
I use MPG as an overall average but GPH as an overall average works out to
be the same thing.
MPG I know I can run for 2.5 miles per gallon of fuel on average (averaging
40 miles per hour). This of course changes if I run wide open for long
periods of time or idle along.
GPH I know I can run one hour on 16 gallons of fuel on average (averaging 40
miles per hour). This of course changes if I run wide open for long periods
of time or idle along.
Both work just as good.
--
Tony
my boats and cars at
http://t.thomas.home.mchsi.com
-
"Shortwave Sportfishing" wrote in message
...
On 11 May 2005 12:56:41 -0700, "Camilo" wrote:
~~ snippage ~~
My only reason to have a flow meter on my boat (GPH) is to ultimately -
through a mental calculation- determine the most efficient speed, in
other words, the speed that maximizes MPG.
Nowadays, it becoming more common have the flowmeter GPH input to the
GPS's MPH measurement to give you an MPG reading on your GPS screen.
If I could afford a new unit, I would definitely get that feature -
because again, that's the only reason to measure GPH in the first place.
I mean no offense here. Don't get upset - just follow me through
this.
To do a MPG calculation you basically need to know how many miles you
have traveled. Which means that you either need to know that by
experience or stop to use a chart or take a measurement with a GPS.
Now, you already know how many gallons you are using per hour. So all
you need to do is know how much gas is in your boat and how many hours
you have been traveling.
That seems a hell of a lot easier than doing arithmetical calculations
on the fly.
And just to add a complication, let's say that your GPS is kaput for
some reason. You have no idea how many miles you have traveled, but
you have a good idea of how many gallons you have left and how much
time it takes to return. That's a GPH calculation, yes?
Later,
Tom