SailNet Community banner
1 - 20 of 21 Posts

·
old guy :)
Joined
·
1,061 Posts
Discussion Starter · #1 ·
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!
 

·
Registered
Joined
·
165 Posts
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.
 

·
Large Member
Joined
·
1,000 Posts
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.
 

·
Registered
Joined
·
1,720 Posts
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
 

·
old guy :)
Joined
·
1,061 Posts
Discussion Starter · #5 ·
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.
 

·
Registered
Joined
·
510 Posts
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.
 

·
Registered
Joined
·
2,706 Posts
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
 

·
Registered
Joined
·
2,483 Posts
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
 

·
Telstar 28
Joined
·
993 Posts
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.
 

·
Registered
Joined
·
2,509 Posts
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.
.
 

·
old guy :)
Joined
·
1,061 Posts
Discussion Starter · #11 ·
As usual, great replies.

More background from us:

  • we live in eastern Canada and cruise the coast of ME and points south - I think we need a gauge
  • the tank is not really easy to access - I am not sure the "stick" would be the best
  • the water tank has a really, really good gauge - a vertical clear tube running up the side of the tank - easy to read, easy to calibrate
  • the holding tank is very easy to see and although not transparent (there's an ugly thought) it is translucent - so, easy to see the level

I think I will probably do a simple mechanical sender with a normal cockpit mounted gauge.

Thanks for so many good ideas and posts.
 

·
Registered
Joined
·
1,720 Posts
Rik, Rockter states quite reasonable advice about the symmetry of the tanks and the deduction that this would make the readings accurate; however, without an explanation, I observe the non-uniform fall in my guage related to the remaining volume of fuel within my vertically symmetrical tanks. The error is consistant and identical with both tanks and their corresponding guages. 'take care and joy, Aythya crew
 

·
Telstar 28
Joined
·
993 Posts
Rik—

This is called a sight glass IIRC.

the water tank has a really, really good gauge - a vertical clear tube running up the side of the tank - easy to read, easy to calibrate
 

·
Registered
Joined
·
2,509 Posts
Captain :

The non-linearity is possibly due to the throw of the float sensor, if it is the ball-**** type.
That angular sweep, is not linear with the level in the tank. I guess the rheostat could be altered to compensate for that, but it would not be too easy.
I am wary of the ball-**** types, as the boat is constantly rolling and pitching, and they get wobbled around a fair bit.
 

·
Registered
Joined
·
5,198 Posts
The electrical fuel level gauge on my Cal has been trouble free in almost 20 years of ownership. The tank is rectangular but the sensor is located on the port side of the tank, so readings change depending on what tack you are on. When not healed, it is pretty accurate. I would have no trouble recommending a similar system. Cost for sensor and gauge is under $100. As was noted, all the gauges use the standard resistance sensors so any gauge will work with any sensor.
 

·
Registered
Joined
·
2,509 Posts
Guys...

"Ball-c**k" is a legal term in the UK. Plumbers use it all the time.... you know, it's that level control in a water tank, normally in the attic of a house. The second word is also the term for a male hen.

It's nothing to do with what Americans call a "Johnson, or a "John Thomas".

When joined to "sea" it seems legal everywhere, even here.

Do I have to say "ballcock" as one word? Was the hyphenation the mistake?

I try to be polite, most of the time.
.
 

·
Registered
Joined
·
2,706 Posts
Guys...

"Ball-c**k" is a legal term in the UK. Plumbers use it all the time....
*sigh* It's a "legal" term here, as well. In fact: The Merriam-Webster on-line dictionary shows it as two words: "ball c*ck," non-hyphenated. Furthermore: The second word is a legitimate word for:
  • An adult male chicken
  • A device for controlling the flow of water
  • Positioning the hammer or striker of a firearm for firing
  • Tilting ones head to the side, as if in enquiry
  • And, with an "s" appended, apparently as a surname
Hey, at least we can use "seacock" here, without it being "*"ed-out, now :rolleyes:

The word is also frequently used in place of less-acceptable words, in polite company, as in "c*cked-up" and "don't c*ck it up" and is not one of the "seven words you can't say on television." "C*ck-eyed," which is hyphenated in M-W, I believe is even found in family entertainment, in phrases such as "c*ck-eyed opimist."

I don't know what "inspired" Sailnet ownership to put that word censor in, but it's clueless, childish and annoying, IMO.

Jim
 

·
Registered
Joined
·
2,509 Posts
Oh Semjim, it was the hyphen that did it, was it?

We'll survive.

I thought I had been intercepted for being uncouth, or something, when in reality it was the inclusion of a humble hyphen.

I got trapped by Sailnet's "anti-American spelling" division.... AAS?

"Ballcock" is legal, and "ball-****" is not.

You live and learn.


Best wishes....

Rockter.
 

·
Registered
Joined
·
285 Posts
1 - 20 of 21 Posts
Top