Average fuel economy- anyone tracking this?

Toolate

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Its been said that fuel consumption and engine hours should be recorded every refill but does anyone ever look back at this at the end of the year to see how they actually did?

I would be curious to see some answers if anyone has. Like this kind of answer- 28' BHM, 600hrs, 2400gals diesel/gas, cruise around 11kts usually and idle all day while fishing, average = 4gph. Something like this anyway plus any info you think is relevant.

Curious what the real world results are. I have never done this for the record but planning to.
 
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plowin

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I have never tracked my average fuel burn over the course of the year.I have always made sure that the burn is roughly the same for two similar trips, just to be sure everything is running the same but ultimately the amount burned=dollars per hour and I care not to know! I have to be where the fish are so ultimately fuel burn doesn't matter. What does matter is that fish,lobsters,squid,slime eels,scallops or whatever pays the bills and keeps the boat going ends up on the deck.
I concede that if my operation were solely for recreation I may focus on it a bit more.
 

backman

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I have assiduously tracked hours run, hours trolled and total gallons burned for close to 15 years on 3 separate boats and have as a result good real world data on how each performs in a variety of conditions.

It's really easy at the end of a trip to jot down those 3 numbers and then pretty easily solve the equation to give you hard data on cruise burn and troll burn...
 

petrel

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You are so right, Backman. It's pretty easy; that's why I never really thought about a "Flo Scan" for my old school diesels. The key to it is you just have to run the boat a bit. Most of the time you can tell by the sound of the engine when the fuel burn is picking up considerably and that is usually borne out by reading the manufacturer's spec sheets.
 

BillD

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Yes I have tracked the 6BTA 370s in my Blackfin from hour #1
Average only.

I do know that a 45 mile round trip (90 total) running @ 23 knots,trolling for 6 hours on one engine burns around 135 gallons.

OK back to totals.

600 hrs., average fuel burn 4.5 gals. per hour per engine = 9 gals per hour to run the boat.
9X600= 5,400 gals. over 6 years = (@$3.75/gal) = $20,250

or $3,375 per year for fuel ONLY to have what I consider some fun !! :D
 

Keelboater

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Its been said that fuel consumption and engine hours should be recorded every refill but does anyone ever look back at this at the end of the year to see how they actually did?

I would be curious to see some answers if anyone has. Like this kind of answer- 28' BHM, 2400hrs, 600gals diesel/gas, cruise around 11kts usually and idle all day while fishing, average = 4gph. Something like this anyway plus any info you think is relevant.

Curious what the real world results are. I have never done this for the record but planning to.

I always keep a running log for every boat that I have owned. Sometimes I think I do it to remind myself of how much money I have spent. Other times I think I do it to remind myself of how much money I still have to spend! :D I always track destinations, fuel fills, oil changes, motor hours, maintenance items, weather conditions, etc. .........even pump outs! Back in the day, I also let the kids enter their 2 cents worth after each trip which makes it fun to look back and read years later. It will be a new deal for the Bertram in 2014. New power, new props, and a nice new Floscan unit to make things interesting. Sorry but my past numbers won't help you guestimate seasonal fuel burn on your boat...........besides, do you really want to know that BEFORE you finish your project? :D
 

petrel

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Yes I have tracked the 6BTA 370s in my Blackfin from hour #1
Average only.

I do know that a 45 mile round trip (90 total) running @ 23 knots,trolling for 6 hours on one engine burns around 135 gallons.

OK back to totals.

600 hrs., average fuel burn 4.5 gals. per hour per engine = 9 gals per hour to run the boat.
9X600= 5,400 gals. over 6 years = (@$3.75/gal) = $20,250

or $3,375 per year for fuel ONLY to have what I consider some fun !! :D

How much fuel would she burn if you throttled back to 20 knots? I'm guessing a fair bit less.
 

Toolate

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You need another cup of coffee, Did you mean 600hrs, 2400 gallons?

I have been sick in bed for almost 4 days haha. I edited the OP. THanks!
 

Toolate

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I am certainly not going to look at that number now Keelboater- thanks for the numbers on your boat too. I have all my chips in so it is what it is but I would like to track it somewhat carefully even if its just on an annual basis. For those of you in business you have write that number on your tax info anyway so its really just a matter of looking at the hour meter and one calculation from there.

The floscan is what got me thinking really. Fuel economy is a big deal as hours go up and there is so much focus on it- every magazine article, new boat listed here etc. has gph at cruise but the average over a long period based on real life use is really what matters, not what she will do at cruise. Dont get me wrong I see the point of the floscan and tailoring your cruise to the most efficient rpm.

My boat spends much of its life idling while fishing or booze -'err- leisure cruising so I suspect use will average out well and I will track it more carefully on long trips to see what it cruises at (no floscan planned). Seems like a quick bit of math would yield an interesting number to think about.
 

Duke

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Sailorgp

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Sisu 26 - 1991 Chevy 5.7 liter carburetor engine 260hp. Cruise 2800rpm 11-12knots burning 5 gph
 

fortier256

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GPH this year.

It was a short year for me this year. I only ran for 58 hours. Mostly cruise speed (14 knots 2600 RPM) with normal in and out of harbor at 5 knots. I don't fish so no trolling or lengthily slow speed runs. 159 gallons / 58 hrs = 2.74 GPH.

Fortier 26 with Yanmar 4LHDTE. Not a speed boat but comfortable, reliable, and economical.
 

backman

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To follow up w/ facts:

Northern Bay 36/QSM 11-670. I put ~460 hours on the engine this year and burned 3000 gallons. I don't track annual burn but I assiduously track offshore runs as I mentioned earlier. 2 trips to Welkers Canyon/125 nmiles each way/troll 10-12 hours - ~240 gallons each trip. Likewise - 2 trips to Hydro - ~110 nmiles each way - ~220 gallons, 2 trips to Veatch ~100 nmiles and troll the same 10-12 hours - ~200 gallons.

I can also state I burn 17.5 GPH at 1850 RPM and make 19.5 to 20 knots; drop down to 1750 RPM and I'm burning 16 GPH and making 18+ knots. Bmp up to 1900 and I burn 18+ GPH and make 20 + GPH. All of the above are in 2-3' seas, winds 10-15 knots; add a foot of sea and I drop close to knot and gain 1/2 GPH. Likewise going out full I'll lose 1/2 knot an gain that same 1/2 GPH.


FWIW - this is w/ a 26 X 25 prop; when I was running a 26 X 26 prop I was 1 to 1.5 GPH higher across the RPM curve.

I troll at 2 GPH/7 knots at 820 RPM, go up to 860 and I'm burning 2.7 GPH to go 8 knots.

Thats the type of tracking that I do that seems meaningful to me.
 

plowin

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Very accurate tracking, I can see how that would be useful.
 

petrel

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What's your reduction Backman? Not much prop f/ that hp.
 

dthompson004

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Not a lot of data as I bought the boat late August. 34 hours, 220 gallons, 30 foot SISU, 383 Crusdaer, 2.57 ratio. I haven't bothered to track idle/troll/cruise as each trip has some of all. I've got a log book and started a file. I'm also not convinced the engine is running as well as possible, just feels starved for air. Offseason project.
 

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petrel

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Impressive, but wonder what it would be w/ a 2 to 1 and more diameter. That's a tiny wheel, but maybe there's not room for more? My 31' BHM is probably 15 knots at 10 gp. Don't know the weight, but not much in her. 26 square, med. cup, could probably stand at least another inch of pitch.
 
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