Riddle Me This? Propane Safety?

[Matt Johnson]

Originally Posted by hellosailor

"Doesn't every boat have engine ventilation? "
Ah, but is that blower on an explosion-proof switch? Or just a cheap breaker? Or plain switch and fuse?

I know someone who set a printing press on fire, by slopping too much of the wrong solvent on it before hitting the $1.19 regular light switch they used as a poser switch on it. After the fire the repairman installed the same kind of switch...instead of using a proper BOM *Bureau of Mines) certified explosion-proof switch, which would have prevented the fire in the first case. But, hey, it saved him more than twenty bucks. (sigh)

Good point! And I'm guessing mine is not. It's a simple Cole Hersee push-pull switch. Wheres the "kaboom" smiley?

[SimonV]

I would Check to see if the fridge is running if running open fridge to keep it running. If not turn it off. Turn on bilge blower after turning off the propane. Then slap the monkey back on the beach.

Sent from my GT-N7105T using Cruisers Sailing Forum mobile app

[Cavalier]

Originally Posted by boatman61

Whale manual bilge pumps work very well..
And next time you head ashore.. don't leave Salty alone on the boat.. and check your bottles turned off..

+1

The Lower Explosive Limit (too much oxygen) and Upper Explosive Limit (too much fuel) for propane/air is 2.1% and 9.5% consecutively. You have to be in the range in between (flammability range) to be flammable to open flame or spark.

Typically, the rotten-egg/dead-animal smell of propane is detectable in the lower end of the flammability range.

Propane is heavier than air, but due to RMS velocity of the gas molecules a volume will mix readily with air in an enclosed volume. The warmer the environmental temperature, the higher the RMS velocity of the gas molecules, the quicker the dissipation.

Due to the spread of gas mixture, the "slower"/cooler molecules will tend to remain in the bottom of the boat down in the bilges. Opening hatches etc will get rid of most of the gas but not the bilge-trapped pockets.



The Emergency authorities would ask you, when smelling gas, to:

1) Leave immediately;

2). Shut off power at the dock;

3). Call emergency services.

....or some version of that.



However, I would personally:

1). Evacuate anyone on board:

2) Shut off power at dock;

3). Shut off gas tank regulator;

4). Tell neighbors;

5). Wait a short while for air to circulate down from companion way, then go down and open hatches;

6). Invite Salty down from the mast and go for a drink or two;

7). Come back and pump manual bilge rigorously for 20 minutes to help with calories from cocktails consumed.

8). Go down and locate source of leak.

[Wotname]

Originally Posted by Delancey

After a nice afternoon at the beach, you return to your boat find to the heavy scent of propane belowdecks and a monkey up your mast starring down grinning at you. A quick check of your propane locker reveals an empty cylinder. Now what?

Obviously, getting as far away as possible from the boat is probably your best first move. Calling the fire department the second. But what if you are far away and there is no fire department to rescue you?

Grab a bucket and start bailing? Chunk of hose and siphon? Sleep on the beach and come back the next day? What?

Deal with each issue in a priority order; I suggest the following:

If the monkey is part of the crew, assume he/she is upset about being left on board as anchor watch detail. Deal with this first, read the riot act to him/her and set appropriate punishment - assuming there is no active RSPCA or local equivalent in the vicinity.

If monkey is an uninvited visitor (pirate monkey?), then chuck him/her overboard and prevent further boarding - RSPCA be dammed.

Now deal with gas issue - plenty of suitable advice already given.

Next, locate new gas supply to ready galley for a nice hot dinner - monkey brains perhaps!

[BandB]

Originally Posted by BandB

What in the world would you be doing with propane below deck?

Apologize for repeating myself but still waiting to hear the OP's answer to this question. Seems to me the monkey isn't the only part of the scene that's absurd. Would any of you store propane below deck? I sure hope not. We don't carry it period but if we did it wouldn't be there.

[colemj]

While the thought problem may be interesting, one should never find themselves in this situation. A propane locker should be external to the boat, sealed and/or situated so propane cannot get into the boat and drained overboard. There should be a solenoid that cuts off the gas supply remotely when not in use. The stove/oven should have temperature sensors that cut the propane supply if a burner goes out. Best practice for using propane is to shut it off at the tank when not in use.

So, unless that monkey turned on the propane at the tank, turned on the solenoid, and chewed through the line between the solenoid and the stove, then the hypothetical situation should not occur.

BTW, we just had a regulator fail between using and shutting off the propane at the tank. 20lbs of propane was safely dumped overboard with no issue. Didn't discover the problem until we went to use it again and found the newly filled tank empty and the replacement tank shooting propane out the old regulator.

Mark

[StuM]

Originally Posted by BandB

Apologize for repeating myself but still waiting to hear the OP's answer to this question. Seems to me the monkey isn't the only part of the scene that's absurd. Would any of you store propane below deck? I sure hope not. We don't carry it period but if we did it wouldn't be there.

Monkey got on board and fiddled with the gas bottle and gas cooker resulting in a gas leak below decks.

Solution: Lock monkey below decks with a cigarette lighter. Come back later with insurance loss adjuster and dine on roast monkey.

[cheoah]

Assuming this is all hypothetical? Essentially whaddya do when your boat fills up with LP....

If someone left their solenoid on, and mono turned the knob of the old force 10, that would do it, no?

[atoll]

don't use a candle to search for the leak...........

[colemj]

Originally Posted by cheoah

If someone left their solenoid on, and mono turned the knob of the old force 10, that would do it, no?

No, the Force 10 won't allow gas flow unless it is lit.

Mark

[cheoah]

That's what I thought, but impossible, or just designed not to flow?

Originally Posted by colemj

No, the Force 10 won't allow gas flow unless it is lit.

Mark

[BandB]

Originally Posted by cheoah

Assuming this is all hypothetical? Essentially whaddya do when your boat fills up with LP....

If someone left their solenoid on, and mono turned the knob of the old force 10, that would do it, no?

Run like all heck. That's what you do. Then you call professionals in. You do not attempt to do it yourself unless you're trained.

But you shouldn't ever put it at risk of this happening. If you're going to have propane have it stored and connected properly.

[Cavalier]

You could always fill the boat with gasoline - that'd surely displace the propane!

[Red Sky]

Originally Posted by cheoah

That's what I thought, but impossible, or just designed not to flow?

As far as I know, impossible. A thermocouple has two ends, one called the hot junction, the other is called the cold junction. When the burner is first lit, it exposes the hot junction to the flame, raising its temperature. That's why you hold down the knob for a few seconds when you first light it, that will manually hold the valve open. The temperature differential between the now warm hot junction and the still cool cold junction creates a small amount of voltage, measured in millivolts. That voltage opens the solenoid on the gas valve that supplies the burner, allowing the gas to flow. If the flame goes out somehow, the thermocouple cools rapidly, stopping the voltage and closing the valve.

I guess if somehow the knob on the stove was pushed in and became stuck in that position, without the corresponding burner being lit, that could create a problem.

[Delancey]

Originally Posted by Cavalier

Propane is heavier than air, but due to RMS velocity of the gas molecules a volume will mix readily with air in an enclosed volume. The warmer the environmental temperature, the higher the RMS velocity of the gas molecules, the quicker the dissipation.

Due to the spread of gas mixture, the "slower"/cooler molecules will tend to remain in the bottom of the boat down in the bilges. Opening hatches etc will get rid of most of the gas but not the bilge-trapped pockets.

This is great. RMS took me to Maxwell-Boltzmann Distribution which is what I was really looking for, to understand the mechanism by which gases dissipate. Any idea how long it would take a given quantity of propane to clear from a boat?

Also, for your heavier-than-air viewing pleasure-

http://m.youtube.com/watch?v=KReTvW7BTHQ