Tubular fuel level.

Sean Carter

Sean Carter

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Hello All

I have a plastic tubular fuel level indicator on my sailing yacht diesel tank and it is not in a very easy place to view and even with a torch it is not that easy to see the level when close to it, if the boat is moving it is easier to see. I am thinking of installing a switchable LED light near the tube to see better and maybe a coloured light as well. A dipstick is not an option because of length and bends. Has anyone else had this problem and found an easy solution as I would really like to be easily able to see fuel level at any time.

Sean
 
Hello

A simple removal of the top hose and insert one of thoseand replace, with the addition of a switchable LED in the correct position would work perfectly, I love low tech solutions to problems thank you very much.

Sean
 
Mine is extended to the front of the engine space. Unfortunately the old plastic tube had become so dark as to be totally impossible to see the level.
I changed the tube with a thick-walled one of glass (from a laboratory). Even though it is unlikely to be broken, it helps to install a shut-off cock, visible at the bottom of the picture; that way only what is in the sight-glass is lost.

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I am certain I have read that most marinas will ban your yacht entry to their marina if you have a glass fuel sight glass (plastic would be even more dangerous?) but I can't find anything just now.

This article talks about a tap to stop the flow of fuel into the sight glass
http://www.yscsurveys.co.uk/blogpost/?blog=5&title=Fuel-tank-sight-gauges

Another forum (gCaptain.com)

[I said:
tugboatchief;141646]According to my local ABS rep. The sight tubes have to be glass and have valves attached at both ends.
Click to expand...

And those valves have to CLOSE Automatically if a Tube Breaks. With that type of valve you have to be very careful when using them while fueling (Not that anyone would ever do that) as sometimes they will close all by themselves.[/I]

An alternative measuring technique is a transparent sight glass spanning top to bottom whose fuel level reflects that of the main tank. This clear plastic/glass tube is more vulnerable to fire and impact than the main steel tank, so survey regulations specify that a self closing valve be fitted in case of rupture. Under no circumstances must these valves be left open. A recent variation is a non ferrous sight gauge containing a steel float whose height (and tank volume) can be determined by magnetic sensors.(splashmarine)

Clive
 
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A cheapo LED (head) torch strapped to the bottom of the sight tube will, by total internal reflection, make the level clear.
 
coopec said:
I am certain I have read that most marinas will ban your yacht entry to their marina if you have a glass fuel sight glass (plastic would be even more dangerous?) but I can't find anything just now.

This article talks about a tap to stop the flow of fuel into the sight glass
http://www.yscsurveys.co.uk/blogpost/?blog=5&title=Fuel-tank-sight-gauges

Another forum (gCaptain.com)



And those valves have to CLOSE Automatically if a Tube Breaks. With that type of valve you have to be very careful when using them while fueling (Not that anyone would ever do that) as sometimes they will close all by themselves.[/I]

An alternative measuring technique is a transparent sight glass spanning top to bottom whose fuel level reflects that of the main tank. This clear plastic/glass tube is more vulnerable to fire and impact than the main steel tank, so survey regulations specify that a self closing valve be fitted in case of rupture. Under no circumstances must these valves be left open. A recent variation is a non ferrous sight gauge containing a steel float whose height (and tank volume) can be determined by magnetic sensors.(splashmarine)

Clive
Click to expand...

Agree our club Fire and safety inspection document lists fuel level sight gauges as not acceptable unless made of fireproof tubing or have 2 shut off vaves always kept closed. ol'will
 
William_H said:
Agree our club Fire and safety inspection document lists fuel level sight gauges as not acceptable unless made of fireproof tubing or have 2 shut off vaves always kept closed. ol'will
Click to expand...

Why two? If there's one at the bottom and the sight glass is open at the top, surely that would be enough; it's not a boiler. Opening the bottom valve and then closing it after use traps just the diesel that is contained within the tube. Work out the volume a 4mm bore and a column of, say, 200mm (assuming that that would be typical on a 12-metre sailing boat).
 
"Why two? If there's one at the bottom and the sight glass is open at the top, surely that would be enough; it's not a boiler."

That bewilders me too. Of course if the fuel was petrol I'd want one at the top of the tube as well. I can't think of any other reason for having two.......

Clive
 
"To correctly install a sight glass it should be fitted with a self closing valve at the bottom and top so that in the event of the tube breaking - or melting - the fuel will not empty from the tank. The self closing valve in the bottom picture was reasonable cost from Aquafax and simple to install. The sight glass is protected by a metal cover and still clear after 3 years in use".
http://www.yscsurveys.co.uk/blogpost/?blog=5&title=Fuel-tank-sight-gauges

That doesn't solve it............still bewildered.
 
Sean Carter said:
Hello All

I have a plastic tubular fuel level indicator on my sailing yacht diesel tank and it is not in a very easy place to view and even with a torch it is not that easy to see the level when close to it, if the boat is moving it is easier to see. I am thinking of installing a switchable LED light near the tube to see better and maybe a coloured light as well. A dipstick is not an option because of length and bends. Has anyone else had this problem and found an easy solution as I would really like to be easily able to see fuel level at any time.

Sean
Click to expand...

Have you ever thought of a "ships" torch
 
The real trick to make the level easy to see is shown in the photo earlier in this thread, though the poster did not refer to it.
Diagonal stripes behind the sighting tube are distorted behind fuel, acting as a lens in the tube.
 
guernseyman said:
The real trick to make the level easy to see is shown in the photo earlier in this thread, though the poster did not refer to it.
Diagonal stripes behind the sighting tube are distorted behind fuel, acting as a lens in the tube.
Click to expand...

Thanks. I thought that it would be obvious for someone who has ever seen a proper sight glass and that it would be therefore unnecessary to explain further.
 
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