Propane drainage

[Jack Long]

I will try again.

Given the concern with propane sinking to the bottom of the cabin I would think any "safe" propane stove installation would require an above the waterline thru-hull drain from the cabin. Even if the propane tank is mounted outside with an over-the-side drain.

Is this true? (question 1)

I bet there are way more propane BBQ with outside mounted tank installations than internal installations. It seems unlikely that when these people add an internal stove that they would all also add the cabin drainage.

Is this true? (question 2)

If it is true, is it because the leak at the tank or fitting (which is hopefully inside the locker) is the far likelier point of failure? (question 3)

Actually, now that I think about it... There is a lot of cabin space that is below the waterline... How do you drain this?

Until I bought my oven my plan was to cook-out exclusively. Had I done this I would have used the same operating procedure with the BBQ on the boat as I did at home. Open the locker, open the tank valve, light a lighter by the burner, open the grill valve, see fire, turn on the next valve until all burners are lit. If for some reason the burner doesn't light I turn off the lighter, close the burner valve, close the tank valve, and wait a while. I am actually very conservative about this stuff.

I bought the stove so I would have an alternative in high wind or rainy conditions. Because I am not intending to use the stove regularly and I am stretching my dollars and running out of time I thought I could use a 12 foot hose and attach/remove it with each use. Other than the lack of a drain in the cabin I don't see how this has greater esplode-ability than solid copper tubing+solenoid+etc... (with the exception of the previously mentioned point of the solenoid being a closer shut off point if there is a leak while you are using the stove- but even that requires the leak be after the solenoid)

Is there something missing in the "remove hose after use" plan that introduces a danger I am not seeing? (question 4) Maybe the leftover propane in the hose leaking into the cabin and building up over time? (question 5) I would think that if I removed the tank end first there would be very little propane left in the line. Is that incorrect? (question 6)

[Ex-Calif]

Originally Posted by Jack Long

There are "righter" and "wronger" ways to do just about everything. Very few things, even on a boat, even with propane, have only one right way to do them.

Yes but there are also standards. Standards are there, primarily to make sure there is a minimum performance level for each system. If you Wallmart grill doesn't meet or exceed the standard you are on your own.

Originally Posted by Jack Long

I feel pretty good that I can avoid the robust/safest/permanent installation by removing the hose from the stove and cabin after each use.

No problem with you doing what you want. Airplanes are certified. Boats are not. However, don't be surprised or offended when it is pointed out that you are not complying with standards.

You ask for advoce and you get responses. Sometimes we get to "know" each other and we get an idea of the person's goals. Rightly or wrongly I read your goals as to challenge conventional wisdom and standards any time you can save money. That's a fine goal, if true, and I don't have a problem with it. Other's might and so be it - that's the internet.

Originally Posted by Pelagic

My 2 tanks are inside my cockpit locker seat which is vented on deck, plus if I ever have had a leak when changing tanks…you can smell it right away, but the pressure gauge is a much better way to monitor complete run…. so I will look to install.

One question….My propane tanks are in chocks laying on their side, rather than standing up. Is there any problem with that?

I don't have any experience with mounting the tanks horizontally so i wouldn't venture a guess.

Reading Casey's page carefully here is why a solenoid is helpful - Paraphrasing here.

"Hit the solenoid with the burner still lit. The burner will extinguish when the gas is depleted from the lines. Later if there is a leak at the stove the gas will not drain into the boat."

"Leave the burner off. Activate the solenoid. Go to the tank and close the manual valve. Monitor the pressure guage. If the pressure bleeds off you have a leak!"

Mounting tanks - He notes that he prefers the tanks mounted on decks in the open - then he describes how to make and vent a locker.

Originally Posted by Jack Long

Given the concern with propane sinking to the bottom of the cabin I would think any "safe" propane stove installation would require an above the waterline thru-hull drain from the cabin. Even if the propane tank is mounted outside with an over-the-side drain.

Sorry Jack, I lost track of the questions. The key to the cabin is to not let unburned propane in. The gas is never left on and the burners are purged by closing the tank valve or solenoid and letting the burners "flame-out"

If you left the tank on deck in a location where a leak in no wind conditions would preclude propane drifiting into the cabin, then you could do without a locker completely. Mount it on a stern rail for example.

If you wanted a temporary connection to your stove, that is one way to go. I think wear and tear on the stove fittings would be a problem and I would not trust a "quick disconnects" long term for the wear and tear reason.

If you wanted to be as simple as possible?

Rail mount the bottle
Use a pressure guage in the system
Permanent mount fittings to the stove
"Flame-out" the burners by closing the gas at the tank valve at the end of cooking
Pressure bleed check the lines as frequently as you think necessary


I don't think there are many that would disagree that this is the most important thing to get right on the boat. Don't mess this up. Don't overdo it but don't scrimp on the quality of the equipment.

[Jack Long]

I am not sure I've ever been out to "save a buck" in my life. I just don't have much money left and there are a lot of things that still require it.

I have a plan for the locker that I think will look better and be a little nicer/safer than just mounting the tank on the rail. I will post pics when it is done and you can laugh at me.

Actually, thinking through this more. I think I would leave the stove end of the hose hooked up and remove it from the tank side.

Anyway, thanks for the discussion. It sounds like even in the super-safe-standard-compliant installations you could still be in trouble if you develop a leak at the stove end. I thought perhaps I was missing some element of all this that prevented that.

I will, at the very least, do a little looking into the copper tubing route.

[Trekka]

My boat has 2 propane sensors - sniffers - inside the cabin and bilge. After I have manually opened the tank valves the solenoid keeps flow shut off until the sensor panel is turned on, powers up and self tests, then sniffs for propane. If none is detected then I can push a button and the solenoid opens. If propane is detected at any time after that the sensor alarms go off, and ( I will have to read the manual to verify, but I believe) it also cuts off the flow by closing the solenoid.

[Liberty28]

Just a quick comment. We have incorporated a timer into our solenoid switch circuit. When we want to use the stove, we turn on the timer which activates the solenoid and turns on a little red LED warning light in the galley. After a set amount of time, the timer shuts off the solenoid and the gas flow stops. We can also manually shut off the gas by simply turning the timer to zero. The advantage is that we can never forget to turn off the solenoid and, hence, create an unsafe condition.

The odor-producing gas (a sulfide-containing gas) dissipates faster than does the propane. If an intermittent leak is occurring, it's possible to have free-propane gas lingering in the boat with no odor from the sulfide present, ie. just because you can't "smell" a leak doesn't mean you don't have one. The gas monitor we have on board checks for carbon monoxide as well as propane gas.

I will now return control of the forum back to you all.

Cheers,
Steve

[john connell]

Hi Jack Long,

For what it's worth.
I have held an advanced LPG gasfitters licence here in Australia for around 35 years.I've also lost a very close friend in an LPG ( Propane ) explosion and another was lucky to survive his horror story he endured.

Their are standards to comply with and they are there for a reason.Wherever we can shave corners ( and save a few bucks ) in the yachting fraternity on whatever we are doing it is well worth it but never should it be considered where it comes to LPG and installations concerning this type fuel.It is entirely deadly and gives no quarter.

Please listen closely to what advice is given here as it just may save your life and those around you.It's good to question some things and common sense should always be the winner but where life is at risk I sincerely question taking shortcuts.

Solenoids have a place as do sniffer units.Not sure what is available over there but here in Australia we have what they call a "gas fuse ".Just like a RCD ( residual current device ) that shuts down electricity when there is an earth leakage.Basically it mechanically ( not electrically ) senses a drop in pipe pressure and shuts down the supply.

Whatever you do please reconsider the doing up/undoing the gas union /pipe or connection as you say each time.Each time you undo/do it you will risk lowering the integrity of the connection till one day your concentration will also lapse, a leak will develop at the union or other fitting and you will forget about the time -BOOM.
A 12 ft stainless steel flex easy hooker lpg hose would also be fairly expensive too so maybe better to hard pipe it anyway ?Here the longest s/steel flex pipe we can fit is restricted to 4ft so are you using joiners also ?? Whoa !!! dangerous.
If you do choose to continue this practice-carry some washing up detergent with you at all times and mix a small amount in a bowl with water ( or have a ready mix in a spray bottle for this purpose ) and use the soapy water / bubbles to test the joints.Any leaks however small will instantly show up as larger air bubbles.

Most important in any LPG install in a boat caravan or RV as has already been stated is a continous run with no internal joints in the copper pipe.
In regards to venting it is imperative that any closed cabinet used for LPG storage is itself "gastight" and cannot leak via the door or opening if it does leak.Another readily forgotten point is that LPG valves sometimes completely " drop their guts" and self vent. Ventilation in the bottom of the cabinet and /or lower sides should be able to self drain all the gas in the bottle if required at a nominal rate.Drains as stated should be free flowing and no kinks in them.
Never use an unvented LPG cabinet for any reason.

Hope this may be ofr some help to you.

Regards
John.

[GordMay]

Here’s an “old” (circa 2000) version of ABYC Standard A-1 (LPG Gas Systems):
http://www.abycinc.org/committees/A-01.pdf

[Lodesman]

Originally Posted by Jack Long

I will try again.

Given the concern with propane sinking to the bottom of the cabin I would think any "safe" propane stove installation would require an above the waterline thru-hull drain from the cabin. Even if the propane tank is mounted outside with an over-the-side drain.

Is this true? (question 1)

Ultimately the propane will sink to the lowest part of the boat so in most cases it's impractical to have a drain in the bilge. Having a drain in the cabin above the waterline may be safer, but wouldn't alleviate the problem entirely - and in small boats would likely allow water to slosh into the cabin.

I bet there are way more propane BBQ with outside mounted tank installations than internal installations. It seems unlikely that when these people add an internal stove that they would all also add the cabin drainage.

Is this true? (question 2)

Another reason a cabin drain would be impractical. A safer alternative might be to add an alcohol stove inside. That doesn't imply that you should forego the convenience of propane inside, just that it is inherently riskier - but the risk can be managed.

If it is true, is it because the leak at the tank or fitting (which is hopefully inside the locker) is the far likelier point of failure? (question 3)

Leaks can occur anywhere in the system, hence the reasoning for the pressure guage, locker drain etc. Regularly inspections are necessary and I would personally mount a propane detector low in the cabin in the vicinity of the stove.

Is there something missing in the "remove hose after use" plan that introduces a danger I am not seeing? (question 4) Maybe the leftover propane in the hose leaking into the cabin and building up over time? (question 5) I would think that if I removed the tank end first there would be very little propane left in the line. Is that incorrect? (question 6)

Removing the hose regularly, IMO increases the likelihood that you will introduce a leak - doing and undoing the connections will wear the gaskets. Kinking and unkinking the hose can do the same. Will you do a leak check with soapy water every time you hook up? The West Marine website has a tips section with an abridged version of the ABYC requirements:

ABYC Requirements for Onboard LPG Systems

• Propane Lockers: isolated, vapor-tight and above the waterline with ventilation directly overboard
• Tanks: made of corrosion-resistant materials with overfill protection devices (OPDs)
• Pressure Gauges: installed in-line to detect system leaks
• Solenoid Valves: required for remote shut-off if the tank valve is not within reach of the appliance
• Supply Hoses: corrosion-resistant flexible tubing must provide a continuous connection to the appliance
• Dedicated Vent: located at the bottom of the locker with a minimum 1/2" dia.
• Warning Sign: with safety instructions located in the immediate vicinity of the cylinder

To me, these seem like sensible requirements without being overkill. The solenoid just allows remote shut-off at source (the tank) - a manual shut-off is also safe; they suggest that it should be within reach though - obviously if you had a fire while cooking, it would be safest to shut-off the fuel without leaving the scene.

I wonder why natural gas hasn't supplanted propane on boats, since it is so much safer. But I accept that propane seems to be what is commonly used, so it comes down to managing the risk. I don't profess to being an expert on flammable gasses, but suggest you look at the ABYC 'suggestions' and if you have any questions on any of those tips, we can probably try to address each of them separately. Hope this helps.

Kevin