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What do I do about these propane tanks?

Started by Sailing_Photog, October 31, 2016, 02:45:03 PM

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I'm the new owner of Shayna, a 1979 Pearson 365.  It's been on the hard for many years, so despite a positive survey, I'm finding many things to fix.  I've had the v-drive rebuilt, bought a new windlass, and am now trying to figure out this propane locker.

The locker at the rear of the cockpit has two standard barbeque grill 20lb tanks in it laying on their sides.  I'm doubtful this is a correct installation?

What tanks fit in here?  The tray that holds the tanks is round at both ends, while marine horizontal tanks seem to have a flat flange to hold them upright, that I don't think would fit in here.

Anyone else with this style locker? What tanks do you use?



Dale Tanski


First off welcome to the group and congratulations on the purchase of the boat.  I think you will come to appreciate the boat over time despite its current short comings.  Be thankful that you have the ability to identify those issues such as the propane tanks and have the piece of mind to even ask the question... Huh???

I have never seen a propane installation such as yours.  It is well thought out, the plumbing seems to be neat and orderly and it fits nicely into the given space.  The utilization of the lifeline fittings as a quick release hold down is very well thought out.  If the aft compartment area has been completely sealed off from the rest of the boat and a gravity drain line has been installed to "drain" leaking or spilled propane over the side you are good to go.  I suspect that the sealed compartment aspect is not necessarily the case in hand.  When I use the term sealed, I mean the overhead bilge blower and the corrugated bilge ventilation hoses as well the recessed stern nav light. 

If one of the tube fittings ever leaked, even if the compartment was sealed from the rest of the boat a spark from the brushes in the bilge blower would be catastrophic.  In short, unless I'm wrong in my assumptions after looking at that image the whole thing needs to be removed NOW!  What is particularly disturbing is that the high side pressure is plumbed to the mounted pressure regulators in what appears to be rigid tubing. As the boat moves around and the liquid inside the tanks slosh back and forth the tanks have to move. And each time they do that rigid tubing work hardens with each movement.  Sooner or later, just like a metal paper clip that is bent back and forth too many times, that tubing becomes brittle and will break.  At the very least an armored hose should have been used.  The static pressure of propane runs anywhere between 100 and 200 PSI on the high side.  After the regulator the pressure is reduced to around 1/2 of a PSI. 

This sloshing thing brings up another potential problem.  Propane under pressure in a full tank is 90% liquid and perhaps 10% gas.  The pressure in the tank keeps the liquid form boiling off to the gas state.  As you use some of the gas the pressure drops and the liquid boils off into more gas.  The process repeats itself until you run out of liquid.  That's why you can tell how much fuel you have by shaking the container and feeling the liquid slosh around.  One of the things you must never do is let liquid escape because if it does the liquid abruptly expanse to the gaseous state and very bad things can happen if exposed to an ignition point in a much worse fashion than plain old gas at 1/2 PSI.   The way your system is laid out is if there was over half a bottle of liquid or if the boat rolled around and liquid was passed through the tanks discharge point your world could come to a very violent end. 

One last thing... I mentioned that propane high side tank pressure is around 100 to 200 PSI. This large variance in pressure is primarily due the temperature that surrounds the storage tank.  The higher the temperature the higher the tank pressure.  The tank and regulator system is equipped with a pressure relief that will vent the contents of the tank if the internal pressure becomes too high.  This possible venting of an overheated tank in a sun baked locker is yet another concern.

What ever you do, do not let your insurance company aboard.  I am surprised that your surveyor did not make this set up the top item on his list.

Dale Tanski
Maruska Hull #40 Cutter Ketch
Pearson 365 Cutter Ketch
1976 Hull #40
Buffalo, N.Y.

Della and Dave

Before you panic on the propane tanks, I think this may be a Pearson original setup.  Ours is very similar.   There are two possible orientations of propane tanks, Vertical which is more comon, and horizontal.  Ours are like yours, horizontal.   

Horizontal tanks are perfectly legal and safe if they have the new OPD valves.  If they don't, there may be an issue filling them and they are probably out of place nspection date anyway.  We had to get new tanks on Polaris because they came up on the survey.  Expensive for marine grade aluminum tanks, but available. West haw them as well as others.  RV stores sell non marine grade ones, but they rust over time.  Might still be cheaper though to go with cheaper tanks and just replace them more frequently.  Ours are Worthington aluminum tanks, but I had to cut off the support flange on the tank to fit in the cradle.  Fairly easy with a hack saw.  About ten minutes each. 

To Dale's point about rigid lines, our installation has flexible hoses from the tanks to the regulator, not hard copper.  If yours is hard lines, I would replace them with hose.  Hoses have to be replaced periodically as well.  Our propane locker is sealed and has an overboard low point drain in case of a propane leak, and a detector in the locker.  Chuck no the drain for clogs would be a good idea.  Just hosing down th locker will show you where the water leaves, for us it is out the transom. 

There is an old post on a similar topic with pics of our old installation, before new tanks.
Della and Dave
S/V Polaris


Thanks for the replies.  Yes, the locker is sealed and has drains plumbed in copper to overboard at the bottom.  The regulator is connected to the leak detector and solenoid with flexible hose, but the tank fittings are copper tubing. It's pretty old so I would like to replace it all anyway.

I thought the locker may have come from the factory from the way it was finished underneath - it's a nicely done installation.

Glad to hear you can modify new horizontal tanks to fit!


That is indeed a factory installation that Pearson had as an option.  You have 2 horizontal tanks.  It is vitally important the the valve threads face upwards when you install the tanks to keep liquid propane from entering your system. We still have one original tank and have had more luck getting it filled through our world cruising than the tank we got from West Marine which was a very expensive ($400+ USD)Worthington tank.  Worthington is the only manufacture that makes a tank that fits the locker.  We did NOT have to saw off the feet that keep the tank upright in its needed configuration.

The original tanks, though they look like a normal upright tank, have a stand pipe inside that adapts it to horizontal use.  Our second tank got broken because the guy who did the inspection on it broke it off, otherwise there was nothing wrong with it even after 30+ years of use.

You should have a flexible line to your solid copper lines.  That's ABYC and our system as designed by Pearson meets standards even in New Zealand where they are manic on boat propane systems.  I would get a book about propane onboats and see if your system meets specs.  I.E do you have a solenoid vale in your locker, are both the locker vents free and clear, is the designed copper line system still in good shape.

BTW, if you remove the 40 odd bolts from the floor of the locker you will find a quite large long term storage area.  Our spare mainsail is kept there.

Hope this helps!
Wayne is our cruising blog.


BTW, those 2 tanks are awesome when you are long distance cruising.  We can go more than 5 months without filling them.  Our hot water is an instant propane system and my wife cooks a good deal of meals.   Other people have taken out that system to gain back the large locker and installed 1 10lb tank in each corner of the aft cockpit in individual drop in propane lockers.

Everything is a compromise.... is our cruising blog.


Wayne, glad to hear the tanks are ok to use. I didn't see any markings on the steel propane tanks indicating they were for horizontal use.  Any idea how I could confirm?


Our old aluminum tanks aren't marked either. Nor did they have feet which is why they are not up to ABYC standards.  The only way to tell is to remove the venting vale first, then remove the fill valve and see if there is a stand pipe installed. I would then put a "this side up" sticker on your tank.

If there is not a standpipe, do not use that system.  Its very dangerous to have liquid propane leaving your tank and expanding in your lines.  You might be able to do your own pipe with silver solder and rigid tubing, but you won't find anyone to mod it for you.  Time to buy new tanks.  I don't like steel tanks on boats anyways, rust sucks.

A word on the Worthington horizontals.  They use a special fitting to fill.  Its the same fitting they use on LPG cars. You can't fill them through the valve you hook up your lines to like normal bottles, it has a check valve inside to make it exit only.  I add this info because we have found it near impossible to get it filled when out in the world cruising.  If you leave the country, make sure to have an adapter with you so your average 3rd world guy can actually hook up to it. is our cruising blog.