Flow Meters

[Freeebird]

5 GPH is roughly $13 an hour these days so if you even save just that then 350/400 hours will make the $5000 costs.

Seriously?

Everything you said above that pretty much voids this comment. Not just trying to argue, but the reality is, especially with a motor yacht, you run either hull speed (or maybe a little less), or you put it up on plane. Running in between where you know would burn more fuel won't happen unless sea conditions dictate you do so. Even then, it will take TONS of total running hours to make up the $5,000 you spent.

Funny, I used to think that buying Flowscans and rigging them on a portable setup, like the magazine, boat test folks do, could present a good business opportunity. You could spend a few hours setting it up, making a number of runs throughout the RPM range, and recording the results. You could pin down the sweet spot for both displacement and planing speeds, and make yourself a few bucks while saving the owner thousands.

Seems to me a cheaper alternative would be just to plumb in gauges that would show GPH usage. I can do a lot of math for the difference in savings, and seeing a big increase for no particular reason would let you know you have a problem.

 

[Westfield 11]

Isn’t the fuel flow data already in the computer of the new electronic engines? I thought all you needed to do in that case was to get the numbers up on a display. Fo instance, the display on my tender shows gph and mpg for the f.i. Yamaha.

 

[Freeebird]

Isn’t the fuel flow data already in the computer of the new electronic engines? I thought all you needed to do in that case was to get the numbers up on a display. Fo instance, the display on my tender shows gph and mpg for the f.i. Yamaha.

How dare you even mention computers and electronic engines on this forum!

Seriously, I did a quick Google search to find some fuel burn numbers for the 8V92TA and came up with references to this and other forums. There have to be some numbers from Detroit out there somewhere. Find that, and it's a matter of doing simple math and making a few runs.

It's pretty much a given that planing speed on this boat in question is going to be 1,900-2,100 RPM. Find the GPH number from Detroit, watch your GPS, and do the math to find your optimal spot. Do that while playing with the tabs and watching your GPS to find your sweet spot for them too. Anything you can do to pick up speed at the same RPM will increase your MPG's. I do this with I/O's and outboards to find the sweet spot where trim angles are concerned. Run it up to the RPM you want, then play with the trim until you get your best speed.

 

[racclarkson@gmail.com]

How much fuel would you have to save over the fill/run/measure/repeat method to break even with that $5K investment to let a computer do it for you?

My Hatt came with one Flo Scan on the port motor. It does help even at hull speed getting the absolute max knots before plowing. Also very useful determining best high cruise RPM v knots v trim v burn. My math is simpler than Freebird’s. I just multiply X 2. I’m just a simple man; sometimes I need a pencil and paper.

 

[Freeebird]

My Hatt came with one Flo Scan on the port motor. It does help even at hull speed getting the absolute max knots before plowing. Also very useful determining best high cruise RPM v knots v trim v burn. My math is simpler than Freebird’s. I just multiply X 2. I’m just a simple man; sometimes I need a pencil and paper.

Well there you go! Just spend $2,500 on one Flowscan and multiply x 2... and be a simple, kind of man (Skynyrd).

Maybe it's time for me to post this for the 237th time to let you see how relatively small these variations are. Yes, these are 71's, and the 92's will burn more fuel, but the percentages will still be the same. Look at page 5.

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://www.hatterasowners.com/Brochures/53ED/53EDA-0083.htm[/FONT]

 

[Pascal]

Yes seriously. . There are many people that do not know how badly fuel flow goes up as you reach hull speed. I ve seen so many boats running at a knot or so above hull speed pushing a huge wake the owner oblivious to the waste of fuel. Easy to waste as much as 5 GPH

Even water depth will affect your NMPG. Depending on LWL you may loose a knot or more at hull speed in water below 10/12 feet. On plane you may actullay go a little faster. So many factors

 

[Pascal]

Isn’t the fuel flow data already in the computer of the new electronic engines? I thought all you needed to do in that case was to get the numbers up on a display. Fo instance, the display on my tender shows gph and mpg for the f.i. Yamaha.

Yes electronic engines have flow meters and totalizers. I keep a fuel log day by day using the totalizer and estimating genset use. A simple spreadsheet on my phone with formulas already set to calculate fuel used, fuel remaining, NMPG etc. very useful. I just pumped 1100 gallons and my numbers where within 3% which was likely generator burn

 

[Westfield 11]

How much was the fuel with tax?

 

[Westfield 11]

Sorry, I just saw your post on the oil thread.

 

[Freeebird]

Yes seriously. . There are many people that do not know how badly fuel flow goes up as you reach hull speed.

Yes, but we're talking about Sadey who knows these things... along with most who are members of this forum.

Does your 53 have Flowscans from its DD days?

Had you not repowered, would you spend $5K of YOUR dollars to install them?

I think that's the primary issue here. My answer for my part is obviously, no, but to each their own. I don't think I'll ever reach the point where I won't find a better way to spend $5K on a boat.

 

[oscarvan]

Is there anything wrong with installing one of these? It doesn't give you real time data at the helm, but it does give you an accurate count of what came out of the tank. Guess you need one on the return too. You can do an hour at various power settings and do the math, make a table, and you can get good averages over time. Not to mention knowing how much to put in a tank...... Lot less than 5K and no wires!

https://www.massflow-online.com/about/news/intelligent-robust-fuel-flow-meters-readout-units/

 

[Photolomy]

Is there anything wrong with installing one of these? It doesn't give you real time data at the helm, but it does give you an accurate count of what came out of the tank. Guess you need one on the return too. You can do an hour at various power settings and do the math, make a table, and you can get good averages over time. Not to mention knowing how much to put in a tank...... Lot less than 5K and no wires!

https://www.massflow-online.com/about/news/intelligent-robust-fuel-flow-meters-readout-units/

It would be difficult to read both meters at the same time depending on where they are positioned.

The Maretron stuff is not much more expensive than that and gives you realtime data at the helm, assuming you have a NMEA-2000 compatible chart plotter. The flow meters are $400 each and the NMEA interface (for two sensors) is $400. So each engine is $1200. The NMEA interface does all the math.

(much) Higher on my list would be reasonably accurate electronic tank gauges that I can read at the helm. I have been looking at the ultrasonic types, but don't know how accurate they are. I might try one on my water tank first. They are relatively inexpensive compared to the fuel flow setup.

 

[Photolomy]

I agree with a lot of points here. Fuel flow rate was high on my list when I first thought about it, but now after having used the boat a bit, just watching RPM and how much fuel you put in your tanks is enough for me. Plus, I don't use enough fuel each year to warrant this kind of expense. But, it still would be nice to know. I am not sure that it would change my driving habits though. I already have a feel for when I am being economical or not, and when I am not it is because I am in shallow water or there is a current, or we left late, and I have to make the next stop before dark. So a fuel flow sensor telling me what I already know isn't going to make me slow down.

 

[Fanfare]

I have had FloScans for years. Very helpful. But best of all you get digital electronic tachs to replace the inaccurate mechanical ones. Engine hour meters too.

My understanding is that (at least on early common-rail diesels) the reported fuel usage is not actually measured at the engine as with FloScan but comes from a pre-calculated hourly burn at various rpms set by manufacturer. Don't know if this is still true.

 

[Pascal]

Yes, but we're talking about Sadey who knows these things... along with most who are members of this forum.

Does your 53 have Flowscans from its DD days?

Had you not repowered, would you spend $5K of YOUR dollars to install them?

I think that's the primary issue here. My answer for my part is obviously, no, but to each their own. I don't think I'll ever reach the point where I won't find a better way to spend $5K on a boat.

I had installed flowscans years ago on my previous boat. Paid for themselves on a couple of years. Never did on the 53 because it could only run at HS. At some point I will probably add Maretrons to the cummins I have now, right now I just don’t use the boat enough to make it worth it

 

[Freeebird]

I had installed flowscans years ago on my previous boat. Paid for themselves on a couple of years. Never did on the 53 because it could only run at HS. At some point I will probably add Maretrons to the cummins I have now, right now I just don’t use the boat enough to make it worth it

Which previous boat was that? Just curious.

Again, I’m not just breaking your balls (this time), but there is just no way you can convince me that you or anyone else can save $5,000 in fuel in a couple of years. First, if you do have them, you’ll find out PDQ where NOT to run the engines. Now if you just ignore that information and run in no man’s land, you won’t save a dime... quite the opposite. What am I missing, and where will these magical savings come from?

All that being said, I did install a fuel management system on a Sea Ray I had many years ago. It was relatively inexpensive, and it was gas stern drives. Sure, it gave me a better idea of exactly how far I could go, but in reality it just gave me a digital readout of what I already knew. I could see subtle differences when I played with the trim and tabs, but certainly not enough to make any huge difference. That was a full planing hull, not a semi-planing barge that will rarely be run on plane.

 

[Pascal]

It was a new Maxum 37 with gas vee drives. I put a lot of hours on it in the 5 years I kept it before the hatt.

It s not just fuel savings but it s also the ability to track fuel usage and fuel remaining. On many boats you can’t stick the tank because of where the tanks are located. It’s easy to keep a fuel log with a boat run at hull speed but with a planning boat since you may run at different speeds, it gets more difficult to accurately know what s in your tanks without flow meters with totalizers

For instance the Lazzara 84 i run can cruise anywhere between 18kts (65 GPH) and 26 kts (110gph). Add 10 to 15% depending on sea state. Accurately knowing what we re burning is a big help and has often allowed me to come back from the Exumas without making a refueling stop at twice the fuel price...

As I ve said before flow meters are probably not worth the $$ for a boat mostly run at HS by an experienced owner. But when the boat often runs on plane and various speed, it really helps and he’s saves money.

It certainly makes more sense than spending 3 times that on advanced top of the line electronic packages most owners don’t need ... or barely know how to use

 

[Freeebird]

Strike three, yer outta here!

 

[oscarvan]

has often allowed me to come back from the Exumas without making a refueling stop at twice the fuel price

For sure. If you play the "stretch the fuel to get to the cheap gas" game good data is a MUST. Every time I get a new vehicle, including motorhomes, I have some fuel in a can with me and run the gauge down to where it says EMPTY. Then I fill it and see how much it takes....Gotta be able to trust the data if you play the game. Some people I know stop for fuel when the tank reads half.... and don't care what they're paying. To each his/her own.

It's always fun to explain to people that, no we don't fill up the airplane for every flight. Carrying fuel costs fuel. We put on enough to get there and then some more subject to weather, airport conditions etc etc. Ideally we land with no more than strictly legally required at that point. We have a whole department full of MIT whizz kids doing fuel burn models" based on historical data etc etc etc......They assign percentages and recommended add fuel and so on and so forth... We save millions this way.

 

[Pascal]

In a car it doesn’t matter. In a boat heavily used in the Bahamas where fuel docks aren’t always open and with often short weather windows... you have to. Having to stop in New Prov to refuel the next morning instead of continuing thru the night can result in a 4 day delay... knowing exactly what you’re burning and adjusting accordingly helps.

Years ago i had flow meters installed in our Piper Aztec. Great tool too