Fuel Gauge questions

[rikhall]

Hi all (and Happy New Year)

Background:

• new to us boat
• aluminum fuel tank (diesel)
• no gauge

Plan:

• buy a fuel gauge and sending unit
• install a fuel gauge and sending unit

OK - I know the theory - float is on an arm - as arm moves the wiper moves over a resistor and it changes the reading on the gauge (yes - very over simplified)

Questions:

1. With different depths of tanks how does one calibrate the gauge or the resistor in the sending unit?
2. What gauge do you recommenced (and if twenty of you read it when there is no football game on, I'll probably get ten different "best choices". Ya gotta love this group!

Many thanks!

[EO32]

From what I've seen, all the sensors are the same, something like 220 ohms empty to 33 ohms full.

You get a sensor who's length is equal to the depth of your tank.

[mdbee]

WM has some. They will say what depth tanks they fit. On the instructions they will tell you how to cut & adjust the float and float arm.

The last one I bought was a Tempo. I was not impressed by it's accuracy but that may be the norm. After following their directions, it still reads "too low."

I did see another brand at WM, I forgot the brand name but it has a square post running down, where the piviot arm attaches. It looks like it might be a better setup.

[CaptainForce]

Rik, When I installed new tanks in 2001, I constructed a chart that I keep in my log. Each of my tanks will hold 55 gallons of diesel, but when the fuel guage reads 1/2, I have 35 gallons in the tank. I started with an empty tank and recorded to amount of fuel added to the tank as the guage reached each calibrated mark. Although fuel guages don't tend to be very accurate except for the full and empty mark, at least they seem to be consistant in the error. 'take care and joy, Aythya crew

[rikhall]

Originally Posted by CaptainForce

Rik, When I installed new tanks in 2001, I constructed a chart that I keep in my log.

Exactly.

In my last boat, when I re-powered, a good friend gave me similar advice. I started with a completley empty tank and added five gallons at a time and marked the fuel gauge with a little blob of "white out" every five gallons. I always knew when I was down and how much I really had left.

Excellent advice!!!!

Thanks for reminding me.

[noelex77]

The Tank tender system is excellent, but reasonably expensive especially if you have only 1 tank to measure.
Advantages:
Easy to install
Very accurate
No electricity
No risk of stray current problems
Very reliable

The only drawback other than cost is you do not have a continual readout.

[SEMIJim]

Our "fuel gage" is a stick, marked at 1/2 and "FULL" , that came with the boat.

It has the advantage of being inexpensive and failure-proof. We don't go through enough fuel in a year to make anything more complicated or costly worth the trouble or expense.

If we ever start cruising seriously, I imagine I'll install a Tank Tender system, as the holding and water tanks will become important, too.

Jim

[BarryL]

Hey,

My last boat came with a gauge. It worked for the first year and then quit. I was going to replace it, but never got around to it. The engine was efficient and didn't use much fuel, and I didn't motor all that much. I figured I could motor for about 40 hours on a tank (I had a 2 0gal tank and burned about .5 gph). So I would fuel up every 20 hours (and would usually add about 10 gallons). That worked well enough for me.

My current boat has a working gauge. I still don't motor all that much and fill up at the end of big trip or mid way through the season.

Maybe you need a gauge, maybe you just want one, or maybe you can just continue without one.

Good luck
Barry

[sailingdog]

If you're going to put a gauge for the tank in... I'd second the TankTender system. It's pretty tough to beat and can be used for more than one tank... so you can use the same gauge for fuel, water, waste, etc.

[Rockter]

If the tank is of uniform vertical section (it does not taper vertically) and if the tank is installed on the level, then the relationship between the tank level and the quantity it holds is linear.
If the tank is not of uniform vertical section, then that linear relationship is lost, and the fuel guage will have to be calibrated.... marking the dial is one way.

If the tank sensor is if the "Tank Tender" type, then it works by measuring the pressure needed to blow bubbles down a wee tube into the tank, with the outlet for the bubbles near the bottom. Again, it will need a uniform vertical section or it too will need calibrated. It will need calibration anyway, methinks.

Personally, I use a dipstick, and read it off my calibration chart. It is reliable and simple, and costs next to nothing. The tank is not a uniform section, so I need the calibration chart.
.