MPG chart.
 

Put it on a chart to be able to see what the best range would be, all I got to do is remember to take it in the boat.

Hi tsubaki
I know this is an old thread...but it looks like you most efficient "cruising speed" is ~ 35-37 mph at 3 gph with the 150hp engine?

Did you prove this out? That is pretty efficient for a 2 st!

Thx, bill

That would translate to 12 mpg. Give the V20 a range of 600 miles. Sign me up.

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/communit...hlight=numbers

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?

Oh yes...i do understand. For those of us that fish offshore range (- gph) is critical!

I was wondering if you have had the chance to prove your extrapolations.

And what was your baseline?

Thanks, Bill

:head::head::head:

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.

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.

take a road trip to Pompano Beach. 15 miles>1000ft ... Boat a sword on a V20:sly:

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.

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.

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

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.

Warning - post hijack!..
 

http://i1253.photobucket.com/albums/...pslmlythyv.jpg

So I was thinking - If high salinity increases buoyancy, does that improve fuel economy?...

My Evinrude Master Tech advised me not to install a fuel flow gauge.....said it restricted flow.
So, in order to confirm mpg, got to do it the old way.....fill......run......re fill divide into miles.

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... :-)

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.

I have never had a working gas gauge!! Just filled up after every trip and never had a isue. When I had the 2 20 gal tanks I ewould run till the first was emoty then head back toward home.

Yep. My first V20 had that also. And that's exactly what I did. Same thing on my Cruisers, Inc. 19 footer. one 6 gal portable for emergencys, and the two saddle tanks.. one for going out, and the other for returning.

My gas gauge broke (it swung so wildly that the needle finally broke off!). Since then I have been happy just looking at the reading from the fuel flow meter and then just adding back in what it says I used. I mentioned this to someone and they said that's fine as long as no one steals your gas. Obviously a flow meter won't pick that up like a level gauge would so you might get stuck out there. My boat is stored next to my house so that's unlikely but it did give me pause.

On a related note. Is it common to have the gauges swing with the sloshing in the tank or was mine somehow missing a damping device, circuit or function? I have seen some that are smooth and some that bounce around like mine did. If I can be assured that a new one would be smooth I would probably replace it.

so many variables and inaccuarcies in fuel sending units/gauges..
Tank has a v bottom so the bottom holds less than the top..
If you are lucky, you get the sending unit to show full just as it spits. Usually it pegs full several gallons before it spits.(or it never pegs full)

fuel tank positioning... even when it spits full you don't really know exactly what you have.
If you are at a fuel dock by yourself, you are listing toward the filler. if you have a buddy standing on the bow with a line you are bow down...

estimates of gph

well, none of us are going to spend a day making precise 10 mile runs at 1000 rpm increments with precise measured fuel, charting out gph and mph and mpg...
and if it gets snotty, it won't mean a thing...

What you need is a fancy new 4 stroke with a computer readout to tell you gph and help you calculate out range at a given speed.
I ran a YamahaF250 this summer and it had a guage that did that....sweet:love:

I wish I could add a Flow Scan but I don't believe they will work on a fuel injected motor with a 2 stage -low and high pressure- fuel pump system.

I need to upgrade to a 2017 DF150 zuki with all the bells & whistles :sly:

Yes to all that.........and plus........if you have a working fuel gauge and know how many gallons the tank holds, refill when the gauge shows 1/2 full.

This way you'll know approx. how accurate it is.......if you have a 60 gal tank and it refills taking 30 gallons, well then your gauge is accurate.

Do it again when it shows 1/4 tank and see if it's still reading accurately.....and takes approx. 45 gallons to refill.

Most all the flow sensors will work with the efi outboards with 2 pumps except for some yamaha's. Some yamaha's don't run the low pressure all the time, but instead pulse it. The total fuel used will be correct, but the gph at any given time will be off. Just about ANY engine can have a fuel flow meter on it. I had one on my old 85 140 evinrude. Loved having that floscan, really changed how I ran the boat as what I thought was optimal speed wasn't. Found it liked to go alot faster than I'd guessed to get the best economy.

My offshore trolling trips cover an average of 110-130 miles. With a 200 hp 2-stroke I burn a very consistent 1.8 miles to the gallon. Given winds, current, and seas, there are so many variables to try and calculate from charts. I find the conditions are my speedometer more than anything else. Fuel consumption is easily forgotten when that massive thunder head pops up out of nowhere.