MPG chart.
- Thread starter tsubaki
- Start date
tsubaki
God
Those were simply range numbers if you had a fuel consumption gauge and was able to maintain a given speed while drawing a certain amount of fuel.
"IF" you could maintain sucking only 3gph at 37mph you would be getting 12.3mpg, multiply that by your available fuel then you would come up with your distance able to travel.
This is probably the thread that got me to do the graph or vice versa.
http://www.wellcraftv20.com/community/showthread.php?t=12543&highlight=numbers
"IF" you could maintain sucking only 3gph at 37mph you would be getting 12.3mpg, multiply that by your available fuel then you would come up with your distance able to travel.
This is probably the thread that got me to do the graph or vice versa.
http://www.wellcraftv20.com/community/showthread.php?t=12543&highlight=numbers
tsubaki
God
The actuality of it is, how it always was.
The faster you can go while consuming the least amount of fuel, the farther you can go.
The gph gauge was very important to me since I have only 2/20 gallon saddle tanks.
If I was fishing offshore and I was pressed for time to get back without running out of fuel I could calculate my available range by the gph/mph chart.
Our dock is 15 miles from the sound and around here we need to run another 6 miles to the first offshore reef which is in only 30' of water.
The next nearest reef is 10 miles offshore but it's in only 40' of water.
To get into some decent fish we need to be about 25 miles offshore and at that it's only 55' deep.
So you figure if I was wanting to fish 25 miles offshore and if I was able to maintain 30mph at 11.06gph (2.71mpg) I could go 108 miles on 40 gallons of fuel. The actual trip would be 80 miles and consume 30 gallons of fuel.
See why I was so worried about the fuel consumption?
The faster you can go while consuming the least amount of fuel, the farther you can go.
The gph gauge was very important to me since I have only 2/20 gallon saddle tanks.
If I was fishing offshore and I was pressed for time to get back without running out of fuel I could calculate my available range by the gph/mph chart.
Our dock is 15 miles from the sound and around here we need to run another 6 miles to the first offshore reef which is in only 30' of water.
The next nearest reef is 10 miles offshore but it's in only 40' of water.
To get into some decent fish we need to be about 25 miles offshore and at that it's only 55' deep.
So you figure if I was wanting to fish 25 miles offshore and if I was able to maintain 30mph at 11.06gph (2.71mpg) I could go 108 miles on 40 gallons of fuel. The actual trip would be 80 miles and consume 30 gallons of fuel.
See why I was so worried about the fuel consumption?
SkunkBoat
God
so MPH divided by GPH= the values in Miles per Gallon
IF you are travelling 1 mph @ 1gph you will travel 1 mile using 1 gallon in one hour
The chart doesn't do anything for you if you don't already know you gph rate at any given mph.
If you know your gph at a given speed you can use the chart to calculate range at a given speed.(if you accurately know how much gas you have)
If you accurately know your gph, you probably have a electronics telling you your range.
THEFERMANATOR
God
Just wished we had water that deep at those distances. 20 miles gets you 25 feet of depth, 40 miles gets you mid 50-55 feet deep. Gotta head out around 65+ to get around 100 feet.
SkunkBoat
God
tsubaki
God
so MPH divided by GPH= the values in Miles per Gallon
IF you are travelling 1 mph @ 1gph you will travel 1 mile using 1 gallon in one hour
The chart doesn't do anything for you if you don't already know you gph rate at any given mph.
If you know your gph at a given speed you can use the chart to calculate range at a given speed.(if you accurately know how much gas you have)
If you accurately know your gph, you probably have a electronics telling you your range.
Exactly!
I was lucky enough to be within a gallon of my actual fuel level as to what the gauge said.
Having the gph fuel consumption device and something like a gps for mph was the only way to get close. Doing the math does the rest.
tsubaki
God
There was no baseline, SkunkBoat pretty much covered it in post #8.
The chart is for at a glance as to your current mileage based on knowing your fuel consumption and speed.
Go back to my post #5, click on the link and see the pictures of my dash.
The device in the bottom center of pictures 5-7 is a Lowrance fuel flow device, the top right is a depth finder/gps. By knowing your speed and fuel consumption, math can do the rest.
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OK...missed the part about the flow meter...that's what i was looking for!
Thanks, this is good info.
So the flowscan shows ~3900 rpm is the most efficient cruise speed.
When u get over 4k efficiency drops off.
Speed/rpm/efficiency is not linear!
Makes the math a little tricky.
Tx, Bill
phatdaddy
God
I have never had any flow meter info until i got this new motor. It's included in the smart guage. It really lets u fine tune speed vs fuel consumption. Pretty accurate too. When i fill up i am usually within 2-3 gallons on a 45 gallon fill up. I wish i had trim tabs to even tweak it a little more.
Destroyer
God
So I was thinking - If high salinity increases buoyancy, does that improve fuel economy?...
I have no idea,
BUT...
Anything that will reduce the amount of friction between the hull and the water as the hull passes thru it will increase either the fuel economy or the speed (in the case of a sailboat) That's why sailboats (Especially racing ones) use special coatings on their hulls to reduce friction.
So that being said... if we postulate that higher salinity increases buoyancy then it should stand to reason that there would be a lessening amount of friction on the hull, which should result in better fuel economy. But since a hull's density is a lot different than human tissue (that is primarily water anyways) I question how much the effect of higher salinity on fuel economy would actually be.
Agreed. There is probably no practical difference or even anything that the typical boater could measure (though I bet NASA could measure it).
I'm guessing that the difference in efficiency would be most apparent in a displacement hull or at least when a planing hull is not on plane. The boat would sit higher in the water and therefore have less to push out of its way. Somewhat similar to decreasing the rolling resistance of a tire by inflating it more.
Still, a mitigating factor could be that the smaller volume of water that has to be pushed out of the way would also require more energy to move due to its added density. Who knows.
Truly a topic that I wouldn't give a second thought to if my boat wasn't stuck under a tarp...
I'm guessing that the difference in efficiency would be most apparent in a displacement hull or at least when a planing hull is not on plane. The boat would sit higher in the water and therefore have less to push out of its way. Somewhat similar to decreasing the rolling resistance of a tire by inflating it more.
Still, a mitigating factor could be that the smaller volume of water that has to be pushed out of the way would also require more energy to move due to its added density. Who knows.
Truly a topic that I wouldn't give a second thought to if my boat wasn't stuck under a tarp...
THEFERMANATOR
God
The added restriction from a quality flow sender is negligeable at the most. But if you have an etec, theres no reason you can't get a a nmea 2000 gateway connection, and read the calculated flow rate from the emm.
