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Old 10-06-2016, 11:02 AM   #1
City: Sturgeon Bay, WI
Country: USA
Join Date: Oct 2016
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Fuel Tank Dip Stick

I am sure this is not a new subject, but being new to the posts I am not finding it??

Anyone have information on the Dip Stick length and markings for a Grand Banks 36 (twin 120's if that matters) original 200 Gal tanks.



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Old 10-06-2016, 11:44 AM   #2
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Welcome aboard. Mr. LS. You should be able to figure that out quite readily. LxWxH=Volume. 1 gallon=231 cubic inches. So take your tank height and divide by gallons (or the other way around-('rithmatic ain't my strong suit) and that should give you how many gallons per inch.

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Old 10-06-2016, 01:49 PM   #3
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That formula will work on a square or rectangular tank that does not have a taper. Just sayin.
Easy way is to empty the tank and add 20 gallons, dip the stick and mark it 20, add another 20 and Mark it 40, continue until full. You could use 25 but you knew that. LOL
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Old 10-06-2016, 02:53 PM   #4
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Vessel Model: Grand Banks 46 Europa
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Fill your tanks. Lower a dowel into the tank and mark a full line on the dowel. The next time you are ready to fill up, drop the stick in again and mark the new lower level. Fill up and note the gallons. Measure the distance between the two marks on the stick and you can easily calculate how many gallons per inch. Then you can mark the stick in inches and you're all set.
Magic, 1996 Grand Banks Europa
Westport, CT and Stuart, FL
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Old 10-06-2016, 03:03 PM   #5
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Record the hours on your engines when you fill. Next time you think about filling, check the hour meters, note the addition of hours since the last fill, multiply by the consumption rate, gals/hr. Fill, record, calculate. Unless you consumption is wildly erratic, your average consumption per hour won't change. Record every time you fill, keep track, and never again have a concern about finding an accurate dipstick.
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Old 10-06-2016, 06:03 PM   #6
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If the tank isn't tapered vertically and you know the total gallons it contains...

Gallons divided by number of inches high equals number of gallons per inch of height.

Or height divided by 4 equals quarters. If the tank is 40 inches high that means each 10 inches is a quarter tank
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Old 10-06-2016, 06:32 PM   #7
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City: Cary, NC
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This doesn't totally solve your SPECIFIC problem, but here are tips on building a dipstick should your tank be a straight shot from the filler. Ours is... Over the past months, the dipstick I made has proved invaluable to learning what our GPH fuel burn is.

Good Dipstck Material

However, the best idea should your tank be a funky shape is to do what BigFish said. Just wait until you're empty and fill it slowly; recording the incremental points as you go.

Good luck.
2000 Navigator 4200 Classic
(NOT a trawler)
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Old 10-06-2016, 08:55 PM   #8
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If you really want to know ....

Pump the tank dry and put in the # of gallons in that you want to calibrate the stick for. Every time you add like 5 gallons of fuel dip the stick and mark it.

If you don't want to pump the tank dry you could start when it's about 25% full. Dip the tank and mark. Put in 5 gallons. Dip and mark. When you get fairly close to the top you can figure out by observing how many inches it takes for five gallons and how it changes with height. If the tank is tapered knowing the shape would be a big help.

My dip stick was marked by a previous owner. There are three black marks. Assumably they are 10 gallon marks as each tank is 50 gallons. I've never checked them. If I fill the tanks the marks give me a rough idea of about how much fuel it will take. Not very important. Perhaps a more useful use of the calibrated stick is observing roughly the difference of fuel level in each tank to help me decide when to switch the valves in the fuel manifold controlling what tank I'm drawing from. I always draw from one tank at a time.

I can't think of any time I've needed accuracy measuring fuel w my dip stick. My dip stick is not very accurate but for me I don't need greater accuracy at all. But knowing the approximate fuel level is indeed important.

North Western Washington State USA
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Old 10-07-2016, 08:05 AM   #9
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I kept it simple since my tanks are "basically" rectangular.
I measured the depth of the tank from the filler, and subtracted all the stuff above the top of the tank so I knew how deep the tank itself was.
Then I marked a 3/8 inch dia dowel in 1/4 tank increments.
Close enough without being anal.
Jay Leonard
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40 Albin
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Old 10-07-2016, 08:40 AM   #10
City: Carefree, Arizona
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As a step up from a measuring stick - A few years ago with the tanks empty I marked the sight tube every for known gallons as rhe ranks filled. Then I printed gallon labels on a piece of PVC pipe which was secured to the sight tubes. With non symmetric tanks built to the hull radius this technique works very well.

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