Petcocks for sight gauge on fuel tanks

JDCAVE · Dec 30, 2015

The PO replaced the two back iron tanks with (700 gallons total), with 4 aluminum tanks (760 gallons total). The two forward most tanks are 200 gallons each and the two aft tanks are 180 gallons each. Each tank has a sight gauge with a petcock, top and bottom.

The petcocks are kept in the closed orientation. However, sometimes one forgets to close them. I have found that two of the bottom petcocks "weep" a bit only when they are in the open orientation. Clearly these should be replaced and I am looking for a supplier, if anyone can provide.

On purchase, my surveyor identified these sight gauges as a cause for concern and suggested that I replace them with tank tenders of some sort. He felt they were a fire hazard. I suggested that they could be enclosed in a protective chamber (suggestions please), and he still felt they could fail and be a hazard.

So here are the options as I see it:

1) replace the Petcocks at the very least.

2) 1) above and also put some sort of shield around them.

3) Other low cost alternative? (i.e. put permanent plugs in).

Note: I cannot get a dip stick to the bottom of these tanks.

Thought please.

Jim

FF · Dec 30, 2015

You might just cycle the valve a hundred times or so to see if the tiny leak is from gunk.

Sit with a brew and hope for the seal to clear as you move it.

Larry M · Dec 30, 2015

I'd stay with the sight tubes. Just make sure you close the valves.

Did your surveyor site any specific regulations regarding them? (and please no offense) or was it just his personal opinion? I though sight tubes were an industry accepted practice as long as you had valves similar to what you have so you can shut the flow off from the tank?

psneeld · Dec 30, 2015

Sight gauges are only a fire hazard if left open...I hope he told you that or it is yet another time that we discuss why there is a problem with run of the mill opinions...from anyone.

There are spring loaded valves that auto shut...yes it involves getting right up to them to activate them...but that is one safety factor against what the surveyor was saying.

Even then...unless you have remote shutoffs to bottom takeoff engine supply lines...what's the difference?

Anyone have the spring loaded valves or know of a supplier?

The Azimuts I used to run had them.

JDCAVE · Dec 30, 2015

Thanks guys. Of course no offense taken! Harsher words have been said on this forum, for sure.

I distinctly remember the surveyor mentioning his concerns on inspection but he did not identify them on his written survey for insurance. Also, I have another survey from a previous failed purchaser. There was no mention of concern in this regard.

Those petcocks are a bit of a concern. The weeping is slight but over time can be significant and eventually it can get into the bilge. As I mentioned, neither petcock weeps when shut but these can be bumped. We go to the boat at least once a week for inspection and I always check these.

Does anyone know of a better petcock design? I do not know the manufacturer.

CPseudonym · Dec 30, 2015

Granger and pretty much all the other normal suspects carry spring loaded ball valves as well. Spendy little things but will keep you out of the running for the Darwin Award.

I still see nothing wrong with the op running things as is. Even the leak in the open position is no big deal in the grand scheme of things IMO.

JDCAVE · Dec 30, 2015

Hmmm! These fittings might be aluminum. I had thought they were SS. Better if they were aluminum it seems.

Replacing A Fuel Tank Photo Gallery by Compass Marine How To at pbase.com

Jim

obthomas · Dec 30, 2015

Some excerps

NFPA 302 Fire Protection Standard for Pleasure and Commercial Motor Craft

7.3.12 The use of gauge glasses shall be restricted to day tanks and service tanks of diesel fuel systems.
7.5.1.7.1 Plastic pipe and plastic fittings shall not be used in fuel distribution lines, vent lines, and fill lines unless permitted by 7.5.1.7.2 or 7.5.1.7.3.
7.5.1.7.2 Components of deck fill fittings, vent fillings, carburetor fittings, fuel pump fittings, and fuel filter fittings shall be permitted to be of plastic.
7.5.1.7.3 Engineering-grade plastics, such as glass-reinforced nylons, shall be permitted to be used in fuel distribution lines, vent lines, and fill lines.

koliver · Dec 30, 2015

I use my log book.
I record engine hours when I refuel, and knowing my /hr consumption, I know when to refuel.
This wouldn't work if I lost both my log book and my memory of my last fill, so there is some redundancy.

Wxx3 · Dec 30, 2015

Larry M said:
I'd stay with the sight tubes. Just make sure you close the valves.

Did your surveyor site any specific regulations regarding them? (and please no offense) or was it just his personal opinion? I though sight tubes were an industry accepted practice as long as you had valves similar to what you have so you can shut the flow off from the tank?

also, you may consider just exercising the petcocks as already mentioned, or leave alone.

Unless they feed from the absolute bottom of the tank, not sure I see the point.

On the other hand, if bottom feed, then they are useful.

rwidman · Dec 30, 2015

JDCAVE said:
The PO replaced the two back iron tanks with (700 gallons total), with 4 aluminum tanks (760 gallons total). The two forward most tanks are 200 gallons each and the two aft tanks are 180 gallons each. Each tank has a sight gauge with a petcock, top and bottom.

The petcocks are kept in the closed orientation. However, sometimes one forgets to close them. I have found that two of the bottom petcocks "weep" a bit only when they are in the open orientation. Clearly these should be replaced and I am looking for a supplier, if anyone can provide.

On purchase, my surveyor identified these sight gauges as a cause for concern and suggested that I replace them with tank tenders of some sort. He felt they were a fire hazard. I suggested that they could be enclosed in a protective chamber (suggestions please), and he still felt they could fail and be a hazard.

So here are the options as I see it:

1) replace the Petcocks at the very least.

2) 1) above and also put some sort of shield around them.

3) Other low cost alternative? (i.e. put permanent plugs in).

Note: I cannot get a dip stick to the bottom of these tanks.

Thought please.

Jim

1) They are not a fire hazard unless you have a fire.

2) Any safety standard that requires humans to remember to do something isn't worth the paper it's written on.

Are the sight tubes plastic or high temperature glass made for the purpose? Plastic would melt in a fire and dump fuel onto the fire. If you forgot to close the petcocks, you would have a steady source of fuel for a very long time. Glass, of course could break and do the same thing.

It's up to you to decide the risk, but in any case, I would replace the petcocks with self closing ones and make sure the tubes were not plastic, but glass designed for the purpose and I would put a metal guard (screen so you could see through it) around them.

twistedtree · Dec 30, 2015

Our site gauges are recessed into an aluminum channel for physical protection. On CE certified boats, my understanding is that the spring loaded valves previously mentioned are required. That way if a glass does break, the fuel loss is limited to the contents of the glass. That seems like the best belt and suspenders approach.

Xsbank · Dec 30, 2015

Mine are always off, I open them to check the level, shut off. If you think you can accidentally open them, rotate the valve so the handle is harder to get to. No worries.

kulas44 · Dec 30, 2015

Most of the sight tubes used in the oil industry are protected by a housing. Looks like aluminum with oval "holes" the length of it. I dont have a clue where to get them.

C lectric · Dec 31, 2015

Those valves look like cheapies.

There are good quality miniature ball valves that will not leak. 600psi WOG. You may need to use a SS 316 nipple for isolation from the tank to the valve as many valves are brass. The SS will isolate the alum tank from the brass valve.

Check out:
Fairview Fittings, 1st ave., Burnaby

They may also have spring loaded valves but don't know.

As far as guarding the valve and the tube itself it looks like with some thought you could use an aluminum angle secured to the stringer just below the tank and to the overhead. Stand it off a bit so it does not contact the tank.

Marin · Dec 31, 2015

Our boat has sight tubes on the four saddle tanks. The tubes are PVC flexible tubing. There are other types of flexible tubing that are more resistant to discoloration from the dye in the fuel. Glass can be a poor choice because it can be broken or shattered accidentally.

Ideally there should be a shutoff valve at the top and bottom of the tube. Our sight gauges have shutoff valves only at the bottoms of the tubes but so far in 17+ years no surveyor has commented on them or written them up. We keep the valves closed at all times and only open them momentarily to get a level reading.

FF · Dec 31, 2015

"neither petcock weeps when shut but these can be bumped."

Drill hole 1/16 inch in petcock handle , install safety wire .

DONE

folivier · Dec 31, 2015

Easy solution to bumping the handles open. Remove the handles and keep them tied nearby. You'll only need them to check the levels anyway.

sunchaser · Dec 31, 2015

C lectric said:
Those valves look like cheapies.

There are good quality miniature ball valves that will not leak. .

Marine grade ball valves, I have eight of them on my tanks and ten on the fuel manifold

rwidman · Dec 31, 2015

Marin said:
Our boat has sight tubes on the four saddle tanks. The tubes are PVC flexible tubing. There are other types of flexible tubing that are more resistant to discoloration from the dye in the fuel. Glass can be a poor choice because it can be broken or shattered accidentally.QUOTE]

PVC will melt if there's a fire.

stubones99 · Dec 31, 2015

Get a machine shop to build a channel for the tubing. ABYC has two fears. One is fire, and two is something falling against the tubing, pulling it off the hose barbs and filling the bilge with fuel.

The commercial sight gauges have a milled aluminum channel that protects the tube from impacts. It also slows the heat from fire from cracking / melting the site tube. If they use glass, they use borosilicate sight glass, to better tolerate temperature. They often have banjo bolts mounting the whole rig at the top and bottom and valves at the top and bottom.

If you have a vented / open pipe, you don't need two valves, just one at the bottom.

You could put a solenoid valve at the bottom of each sight gauge and trip them all at once. Use a momentary contact switch for that so they stay shut with no power applied.

Marin · Dec 31, 2015

WesK said:
Marin said:

The tubes are PVC flexible tubing.

Click to expand...

PVC will melt if there's a fire.

So will the boat.

Marin · Dec 31, 2015

stubones99 said:
... is something falling against the tubing, pulling it off the hose barbs and filling the bilge with fuel.

Our small diameter sight tubes hold about a quarter cup of fuel if that. With the valves properly closed, pulling one off a hose barb will not "fill the bilge with fuel."

Xsbank · Dec 31, 2015

I think this is being over-thought. With them closed, minimal/minor fire hazard, maybe a teacup full of fuel at most in the lines. If the valves leak, replace them. If they don't and you forget lots then bungee the handles. Shock cord is available everywhere. Somebody mentioned lock wire (which I use lots) but it will drive you mad redoing that every time you need to look at the quantity, even with good lock wire pliers.

JDCAVE · Dec 31, 2015

Thanks to all for your contributions. WesK: your comments essentially mirrored those of my surveyor. When I asked him about ABYC standards, he said he didn't care what those were. He considered the NFPA as the authority on the subject. There was a to-and-fro with between the PO and the surveyor on this issue. PO thought everything was to specifications. Surveyor pointed to the fact that even the fuel in the tubes represented a hazard, in the event of a fire. Note that another highly regarded surveyor from the PNW didn't identify an issue with the site tubes at all.

Here are the steps I want to take:

1) get the Doug the welder, who knows a thing or two about marine fuel tanks, to assess the materials that have been used for the fittings, whether there is an issue with possible corrosion in the future and then decide if other fittings need to be replaced as well. I need to first determine if I have available free capacity in the other tanks in order to change the valves.

2) at the very least replace the bottom valves on all four tanks with something that is self closing.

3) look into enclosures for the site tubes.

While two of the valves currently "weep" only when open, a more complete failure at a later time might be a much bigger issue. Best to nip it in the bud before it becomes more serious. I've been trying to contact the PO for some history without success.

Thanks Clectric for the local source for valves. I'll see what additional actions Doug suggests and proceed from that point.

Jim

rwidman · Dec 31, 2015

JDCAVE said:
Thanks to all for your contributions. WesK: your comments essentially mirrored those of my surveyor. When I asked him about ABYC standards, he said he didn't care what those were. He considered the NFPA as the authority on the subject. There was a to-and-fro with between the PO and the surveyor on this issue. PO thought everything was to specifications. Surveyor pointed to the fact that even the fuel in the tubes represented a hazard, in the event of a fire. Note that another highly regarded surveyor from the PNW didn't identify an issue with the site tubes at all.

Here are the steps I want to take:

1) get the Doug the welder, who knows a thing or two about marine fuel tanks, to assess the materials that have been used for the fittings, whether there is an issue with possible corrosion in the future and then decide if other fittings need to be replaced as well. I need to first determine if I have available free capacity in the other tanks in order to change the valves.

2) at the very least replace the bottom valves on all four tanks with something that is self closing.

3) look into enclosures for the site tubes.

While two of the valves currently "weep" only when open, a more complete failure at a later time might be a much bigger issue. Best to nip it in the bud before it becomes more serious. I've been trying to contact the PO for some history without success.

Thanks Clectric for the local source for valves. I'll see what additional actions Doug suggests and proceed from that point.

Jim

I think you will be safe with those modifications. Also, if you get everything ready ahead of time you could change the valves without too much spillage. Have a container and rags to catch the fuel and dispose of it safely.

Most folks recommend pipe dope, not Teflon tape on fuel fittings. Get everything assembled and doped up then remove the old and quickly install the new. You could even block the tank vent to slow leakage.

Insequent · Dec 31, 2015

Mine are from Ballard Hardware (Seattle)

They have a ball inside which stops high flow in the event of a breakage. Also note the brass rods that run down to lower valve either side of the tube. The sound insulation effectively makes a recess for the tubes to lie in.

kulas44 · Dec 31, 2015

I guess I just dont get it. Install industry standard sight tubes and stop worrying. Maybe they just cost to much $$$.

JDCAVE · Dec 31, 2015

kulas44 said:
I guess I just dont get it. Install industry standard sight tubes and stop worrying. Maybe they just cost to much $$$.

Provide more details please. For example I saw some fancy magnetic setup on a Selene last summer that cost about $7,000. Outa my range I think.

Jim
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Capt.Bill11 · Jan 1, 2016

JDCAVE said:
Provide more details please. For example I saw some fancy magnetic setup on a Selene last summer that cost about $7,000. Outa my range I think.

Jim
Sent from my iPad using Trawler Forum

Exactly. What industry and what standard?

Petcocks for sight gauge on fuel tanks

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