Composite Propane Tank

Good Morning ,Does anyone have any experience with composite propane tanks? Do you have a hard time getting them fill?

I have (2) 2 1/2 gallon composite propane tanks on my boat and I think they are much better than aluminum. They are lighter in weight and you can see the level of propane in them. I have never had a problem filling them in the US or Canada. Sorry, I can't remember the manufacturer.

Ron

We have a small composite tank on the cabin roof. I thought it was so ugly I covered it w a fender cover .. green. It almost immediately turned black ... presumably from UV rad.

They are newer and a tad high tech boasting several advantages but all of them are very small in my opinion. I rarely carry mine and can tell the fullness by lifting slightly. If I had it to do over I'd get aluminum.

ARRGH said:

Good Morning ,Does anyone have any experience with composite propane tanks? Do you have a hard time getting them fill?

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While composite propane tanks would seem to be an excellent idea, you might find yourself somewhere where you cannot get them refilled easily.

Standard steel propane tanks, on the otherhand, can be refilled or exchanged for full ones. In my area, home centers, Walmart, gas stations, and even grocery stores will exchange an empty tank for a full one for $17 or so. Places to get your own tank filled are few and far between.

While there are several ways to determine how much propane is left in a steel tank, I just weigh mine with a fish scale. The tank's empty weight should be stamped on the tank, anything more than that is propane.

For a dockside cottage they might be fine.

But the ability to simply exchange a steel cylinder at a gas station or 7-11 store is suprime for the traveling folks.

Do you want to pull in to a marina , locate a propane refill shop, call to see their fill hours , take a cab over and back?

Neither do most cruisers.

I bought one from West Marine a few years ago it came in fine but when I went to have it filled the guy told me they are illegal, to fill, in Louisiana. I thought he was B.Sing me so he called the D.O.T. Who confimed it. I asked why they said there had been issues of cracking that was in 2009. WM took back the composit on no problem and the DOT sent a guy to inform them of the law. I bought a Aluminum cylinder so haven't checked to see if it is still that way. the Composite, and aluminum, are larger in diameter than the steel cylinders if it will go in an existing locker be sure it will fit
I have 2 cylinders on board one a steel exchangeable the other mine which is to be refilled, I was planning to do a lot more cruising than has worked out, turns out I could probably get by fine with 1 lb canisters.
Steve W

We see more and more composite tanks and hear of no issues on filling them. Exchanging our tanks is not an option. Most countries very their tank size and valve configuration. I would buy a composite tank if we needed a replacement and not only because they are cheaper.

Steve said:

I bought one from West Marine a few years ago it came in fine but when I went to have it filled the guy told me they are illegal, to fill, in Louisiana. I thought he was B.Sing me so he called the D.O.T. Who confimed it. I asked why they said there had been issues of cracking that was in 2009. WM took back the composit on no problem and the DOT sent a guy to inform them of the law.Steve W

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So no one has paid the Edwin Edwards tax on that product yet?

Just kidding.

Not Edwin but if one looked close enough some politico probably has his hand in a steel tank business
Steve W

I haven't been able to find solid confirmation of this, but I think the fiberglass tanks require re-certification every 5 years, where the steel and aluminium tanks are good for an initial 12 years followed by 5 year re-certs. A friend bought one from WM and the guy who filled it told him that the certification was only good for another year.

Does anyone know more about this?

Point to note - they are great, but just beware of the construction used, and how it will be tested and how often.
I bought one here is Aussie about 10 yrs ago and loved it. So much lighter to haul up and install into the flybridge cupboard etc, and yes, one can see the level at a glance, so no unexpected running out. I had it filled only once in that time the 10kg of gas lasted so long. The last time I went to fill it, quite recently, I was told it had to be re-certified by pressure testing etc. Sadly, here in Aussie, it appears no-one has worked out a standard way of doing this specific for composite, so they stil do it like steel tanks, which means removal of the whole valve assembly. Unfortunately, the way mine was constructed, this was impossible without destroying the neck of the cylinder, as the valve and collar were fibreglassed in basically, so sadly it became a throwaway. Not because it was dangerous, but because we could not prove it wasn't, and the marina wanted a test/pass date. (New regulation, on top of insurance cover). So, I have had to go back to 4kg steel tank, and fill more often I guess, because there is no way I'm struggling up there and in with a full 9-10kg one. But I miss the easy level check. These magnetic so-called level gauges are pretty iffy in my view.

Peter B said:

.............. But I miss the easy level check. These magnetic so-called level gauges are pretty iffy in my view.

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From my post above:

"While there are several ways to determine how much propane is left in a steel tank, I just weigh mine with a fish scale. The tank's empty weight should be stamped on the tank, anything more than that is propane."

twistedtree said:

I haven't been able to find solid confirmation of this, but I think the fiberglass tanks require re-certification every 5 years, where the steel and aluminium tanks are good for an initial 12 years followed by 5 year re-certs. A friend bought one from WM and the guy who filled it told him that the certification was only good for another year.

Does anyone know more about this?

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No need to worry about recertification on steel tanks (or missing paint, rust, etc.). Just exchange it. Let the company worry about certification.

A few years back (when the Americans were invading Iraq), we had the US Army bring their composite air tanks for firefighting to us for filling. The valves were incompatible with any of our fill valves, so we had to machine some up. I'm not sure if valves on propane composite tanks are the same as those on steel or ali tanks, but I'm guessing they are if there have been so many people filling them no problems.

I have always received the impression that valves were more important than the tank composition for just this reason. I understand that European valves are different from Asian which are different from US, so our plan is to try and get hold of filling adapters for the different regions.

SaucySailoress said:

... I understand that European valves are different from Asian which are different from US, so our plan is to try and get hold of filling adapters for the different regions...

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If the adaptors are easy to get it may help but I wouldn't to worry much about having them. The only countries where we could not fill our North American tanks have been Madagascar and Panama. In both counties we rented a local tank (deposit for the tank), filled our cylinders from them back on the boat, then returned the cylinders and received our deposit back, only paying for the gas. I don't know about Europe but here in Trinidad, the Caribbean, Central and South America, MX, FP, OZ, NZ, RSA, the gas plants can fill most international cylinders with the exception of the type where the regulator is part of the adapter.

I got the best price on line on the U-Haul site of all places. I got the 10 pound tank and use it just for the grill. I love the size/weight and the plastic encasement is gentle on the boat surfaces.

I just saw a composite propane cylinder at the Seattle boat show. It was a 20lb size and was certified for either 12 or 15 years with no option for re-certification.

In the PNW propane is available at or near many fuel docks and marinas. The propane exchange stations at supermarkets, etc., cost about twice as much as getting your own tank refilled.

I just did some research on composite propane tanks and they are all now certified to DOT for USA and also are certified for Canada, and Europe.

Trident Marine has a nice tank they sell, the plastic outer case looks very durable.

The fiberglass tanks are better in a fire, as they are not subject to exploding like a grenade as a steel tank can.

Not to mention the exchanges don't fill the tanks completely. They provide less propane than an actual fill to keep their costs down.

"Not to mention the exchanges don't fill the tanks completely. They provide less propane than an actual fill to keep their costs down."

Sadly our nany state required the new valve style on ALL fill valves, so the worker just fills till the fill stops. Done.

Unless you have an old style tank with a new style valve handle (to fool the filler) the tanks will all only fill to the same amount.

rwidman said:

From my post above:

"While there are several ways to determine how much propane is left in a steel tank, I just weigh mine with a fish scale. The tank's empty weight should be stamped on the tank, anything more than that is propane."

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Well aware of the weight thing for checking Ron, but where my tank is fixed in place it is totally impractical to weigh it, and a major hassle to detach and remove it do do so. Most of the gauges that measure the level pick up the temp difference, and require one to pour hot water down them to indicate, (briefly), where the level is. Also not really feasible in my case. But I have heard of one magnetic strip one which does not require hot water poured on, so am investigating that.

Maybe I'm missing something but if the question is "how much propane is in the tank" I've been using this for years, without a hitch.

"Gas Watch"

SeaHorse II said:

Maybe I'm missing something but if the question is "how much propane is in the tank" I've been using this for years, without a hitch.

"Gas Watch"

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That won't fit in my propane locker.

SeaHorse II said:

Maybe I'm missing something but if the question is "how much propane is in the tank" I've been using this for years, without a hitch.

"Gas Watch"

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Any secrets? Most people I know and my own experience is they are wildly inaccurate.

It's...gas...gas...gas...no gas or about 10 minutes worth....

They are good for checking leaks though..

psneeld said:

Any secrets? Most people I know and my own experience is they are wildly inaccurate.

It's...gas...gas...gas...no gas or about 10 minutes worth....

They are good for checking leaks though..

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It's just a pressure gauge and makes no measurement of the liquid left in your tank. As long as you have liquid you will have pressure. No liquid and the pressure goes away quickly.
You are correct about checking for leaks. Pressurize the system, shut the tank off and you should maintain pressure indefinitely.

For checking the amount of fuel in a metal tank just spray some water on the outside. It will freeze to the level of the fuel inside. Spray bottle with water works good.

OFB said:

For checking the amount of fuel in a metal tank just spray some water on the outside. It will freeze to the level of the fuel inside. Spray bottle with water works good.

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Say what? You might want to re-think that.

Greetings,
Mr. OFB. Thanks, good tip. Can you still see that effect if the tank is not in use? Say it's been sitting, properly positioned and secured of course, on an open deck unused for a period of time. Wouldn't the gas inside the tank be the same temperature as the surrounding air?

RT Firefly said:

Greetings,
Mr. OFB. Thanks, good tip. Can you still see that effect if the tank is not in use? Say it's been sitting, properly positioned and secured of course, on an open deck unused for a period of time. Wouldn't the gas inside the tank be the same temperature as the surrounding air?

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That about sums up the issues with measuring what liquid gas is still there. The gauge Walt showed only starts to warn you once all the liquid has turned to gas, so warns only when there is just minutes or at best a couple of hours of gas left.
The temp difference thing is what most of the other gauges use, and the water sprayed on has to be hot, so the difference between the level of liquid gas (colder), will show up on a special magnetised, (to stick to the side of the bottle), strip with a special agent which changes colour with the hot/cold difference marking the level. You won't see ordinary water freeze just sprayed on tho in my experience, they are not that cold to start with, even over the liquid gas portion.
That's why the composites where you can see the level are soooo good. Damn, I wish I'd kept mine anyway. I could have probably convinced someone to fill it for me if I wasn't so law abiding. There was nothing wrong with it. And no corrosion issues is the other huge plus.

Greetings,
Well, my point is I don't think there will be a temperature differential if the tank has been static for any length of time. Once the gaseous propane reaches an equilibrium with the liquid propane, I think everything inside, outside and the tank itself will be at the same temperature. It's only when the gas is being drawn off (used) that the liquid propane cools due to evaporation thus creating a temperature differential. Do I understand the situation properly?