Diesel fuel level sight gauge?

[Rohorn]

Hi....My stainless fuel tank has a plastic tube on the end where one can see (almost) the fuel level. Behind the tube is a tape measure. Very simple, and I bet that's what many folk have got.
Question. If I can replace the plastic tube with glass tube, will that stay pristine and transparent, rather than rapidly deteriorate to a turgid brown colour through which one has to shine a torch?
Another question. Can one get a tank made up in plastic which will resist diesel?
Thanks in advance for any comments....cheers...R

 

[Freebee]

there are comercially manufactured glass tubes but they tend to be quite expensive because they have threaded fittings and a metal tubular guard to protect the glass from being broken also a tap top and bottom so you can turn off the fuel and remove the glass for periodic cleaning. The commercial sight glasses are made by seetru. one other interesting feature of these glasses is they are made to read from top to the very bottom of the tank and they have a paint stripe down the back. If your tank gets water in it, it rises up the glass and by the differing refractive index the stripe changes width in the presence of water hence easy to spot. you could also modify the bottom fitting to become a water drain.

 

[tomg]

Good question. I replace my plastic tube about once every 18 months and am just about to install a black floating ball into the tube(rather like the electric kettle system) - having reduced the very ends of the tube with inserts of a smaller size- to see if that helps. Presumably the problem worsens when/if red diesel becomes clear diesel! I worry slightly about a glass tube but I may be being over-cautious.

 

[Freebee]

Ive tried the floating ball, it needs to be significantly smaller in diameter than the tube because there seems to be a stiction effect with the walls of tube, also it goes without saying a plastic that floats nicely on fuel surface and not affected by fuel also at the top and bottom there must be no possibility of the float blocking the tube fitting or passing through it if the tank empties or gets topped right up.

 

[sailorman]

plastic tube + shut-off valve @ the bottom. /forums/images/graemlins/grin.gif
stops fuel comming out if tube fails /forums/images/graemlins/mad.gif

 

[Talbot]

I bought a custom tank from Tek Tanks. It is white plastic and you can see fuel level through the plastic. Thoroughly recommend them

Sight level glasses should not be glass on a boat as it is easy to break the glass and end up with a bilge full of fuel.

 

[AndrewB]

Good idea!

We replace the plastic every couple of years which is fine, but adding a little float is a clever idea. A little piece of bunched up wire at either end will prevent the float escaping.

I certainly wouldn't want glass either. But a plastic sight tube is regarded as a fire hazard, even though ours has a shut-off cock at either end. It won't, I believe, pass BWB certification.

Is there a heat-resistant version?

 

[scottnewcombe]

Re: Good idea!

You should really have the valves at the tank normally closed. Just open them when you want to see the fuel level and shut them off when done. That way plastic or glass if they fail you only get a small amount of spillage, not the whole tank (or to the level where it breaks at least). I realise this can be akward especially if access to the valves is hard but if access is hard how are going to turn them off in an emergency??

I did also read on this forum somewhere that red and white diagonal stripes painted like a barbers pole behing the tube give the best view of the fuel level.

Scott

 

[jerryat]

Yeh, I put a red plastic golf tee in my tanks plastic sight tube a few years ago for the same reason. Works a treat and cheap too!!

Cheers
Jerry

 

[dickh]

Another source of plastic tanks is Plastimo but in a limited range compared to Tek Tanks but much cheaper(and probably from the same factory). In red plastic so more difficult to see the level but they have a cheap mechanical fuel gauge which sits in the top. Even with the gauge is still cheaper than Tek Tanks for the same size. Plastimo also do a small tank(about 25litres) which is translucent plastic with all moulded in Inlets, and Outlets.

 

[Rohorn]

Hi people, ...Thanks for all that. I also worried about a glass tube breaking but came to the conclusion that if I mounted it within a piece of aluminium channel it would be as acceptable as the unprotected plastic tube I've got at present. Also thought about a float indicator, but couldn't decide what material to use...didn't want it to disolve slowly.
My question really was, would the glass also discolour, like the plastic? I guess it will slowly, by staining, but not due chemical reaction like plastic.
Replacing the existing 300 litre pitted and seeping stainless with a Tec-tank see-through sounds neat....would it have a life limitation.....and would it affect my insurance I wonder? I'll make a few discrete enquiries and report back
Cheers....R