Discovering a Bomb on the boat....

[2divers]

A question from the Admiral.

Ok, lets say that for what ever reason, in a momentary and temporary lapse of sanity, one has some how allowed the propane stove to leak, maybe the fitting's leaked, the solenoid never got turned off, etc. filling the boat with propane that has now sunk into the bilge and otherwise filled the boat to over flowing. And one discovers this with out blowing one's self to kingdom come, some how.

Besides having to replace one's drawers in very short order, EXACTLY how does one go about removing the propane from the boat and TESTING, dare I say that word, that is gone?

2divers

[delmarrey]

One could use one of those plastic foot or hand pumps for pumping up inflatable boats.

Some have a port for putting a suction tube for pumping out water. One could put a tube in the suction hole and run that into the lower bilge, then pump out the gas.

For testing one can use a gas detector or your nose which ever is available.

The hand pump I carry for my dinghy will pump 1 gal. per stroke.

The important thing to remember is to put the pump up on deck in fresh air with an exit tube running over the side. Some plastics will create a static charge so a ground wire from the pump to the ground of the boat maybe necessary.

But the smartest thing to do is install a gas detector in a low area near the stove for safety sake.

Personally, I only use the small Colman bottles for our stove and store them in an outside locker with the 20#er. It seems expensive but one can buy the fitting for refilling them from a 20#er, as I do. They only get about half full but that's OK too. Less to leak out. And no long line of fittings to check on. One half full bottle will last 2-4 meals.

Using a spay bottle, squarting soapy water on your fittings and bottle valves, it's EZ to keep them all in check..........................................._/)

[Alan Wheeler]

Ummm, I hope your not wanting the answer to your question because of a current situation:-(
Sucking the air/gas out is about the only solution. Blowing fresh air in helps but can't really get rid of gas that has fallen to the furthest depths.
I suppose you could tip the boat over.;-)

[GordMay]

Although propane is non-toxic, it can displace the air required to breathe. Inhaling propane vapors can cause dizziness, anesthesia, and respiratory arrest.
Propane is combustible at ratios of between 2.15% and 9.60% (Percent of Vapor in Air/Gas Mixture).
Most of us will have no way to determine if explosive levels of propane are present, nor the proper ventilation equipment* required to exhaust the gas from the boat.

* delmarrey was trying to address this with his manual air pump

In the event of an accidental release of propane in a confined area, such as inside a boat:
DO
1. evacuate all personnel
2. remove all sources of ignition, if practical
3. shut off source of gas, if practical (expanding propane can present a frost-bite hazard)
4. seek professional assistance (fire dept, propane distributer)
5. Professionals will ventilate with explosion-proof* equipment

Do NOT
4. do not reenter area without self-contained breathing apparatus (propane can be a simple asphyxiant)
5. do not turn on (or off) electric switches
6. do not use light sources such as flashlights, matches, candles, etc.
7. do not smoke

*Explosion-Proof Class I - Division I - Group D:
Areas in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures are Class I.
Group A, B, C & D - Defines the type of combustible gases in the Class I location atmosphere.
Class I Area Groups:
Division 1 and 2
A (acetylene)
B (hydrogen)
C (ethylene)
D (propane)


Most jurisdictions prohibit filling one propane tank from another portable tank.

[Talbot]

I have manual bilge pumps which I use frequently to ensure that there is no build up of gas cause they will pump gas just as well as air.

Dont try this with an electric one

[2divers]

Originally Posted by Alan Wheeler

Ummm, I hope your not wanting the answer to your question because of a current situation:-(.... I suppose you could tip the boat over.;-)

No Alan, Thankfully this is not a problem in my current location!

I could think of several ways to get the bulk of the propane out of the boat, but the admiral was wondering about this one and I didn't know if there was an established proceedure for doing so. I've read and heard of lots of ways of preventing it from occurring to begin with, but never how to solve the problem once it has occured.

Once again, Thanks Gord for being an excellent source of information!!!!

So, along with the good and true answers I'm open to all the ones not to do for entertainment sake.

Ways not to empty the boat of propane!
1) Drill another through hull to let it flow out!
2) Start the engine!
3) Use an Electric Fan
4) Light a Match

[S/V Elusive]

Originally Posted by GordMay

Most jurisdictions prohibit filling one propane tank from another portable tank.

Del and I do the same thing. They make and sell a nice little adaptor for using your large tank to fill the small 1 pounders. Common sense has to prevail. I fill my little bottles on an outboard deck (no where for fumes to go but overboard). Since I don't smoke, no open flames, and no ignition sources. I use an aligator to aligator clip to ensure that both bottles have the same electrical potentials.

As Del said, they only fill 1/2 full (unless you want to mess with the venting schreider [sp?} valve). 1/2 works for me.

[Pura Vida]

Just for grins let's say that this has happened in a far off anchorage. There is no outside help. Turn off all of the electricity including emergency bilge pumps. Move the engine room air vent hose as low in the bilge as possible. Fill the bilge with seawater to displace any propane below the mouth of the vent. Close the boat as tightly as possible with the exception a forward hatch. Now only the engine room fresh air exhaust and the hatch alow air into and out of the boat. Put out another anchor. Set up a windscoop using a small sail to force as much air into the hatch as possible. Dingy to the nearest beach with valuable beverages and foodstuffs. Have a picnic and wait a couple of hours. It may not work but it beats sailing around with a bilge full of propane.

[GordMay]

Good try Pura Vida, you’re on the right track ~ but ”... Turn off all of the electricity including emergency bilge pumps ...” is not universally safe advice. Turning off a running pump may cause a spark and propane gas ignition (BOOM).

Accept it folks, most of us are somewhat “limited” (ie: I won’t do unassisted brain surgery under any conceivable circumstances), and must accept a certain level of “helplessness”.

Please note that I didn’t comment on the typical prohibition against filling portable tanks from each other - I just noted the law.

[rsn48]

I've had something like your scenario while at a marina. I got one of those small industrial vacums that can also act as a blower, and used the blower to move out the gas. I first stuck the blower tube into the V birth area, then through the forward hatch, then after doing this for about 20 minutes I walked in towards the V birth with the companion way open and blew out the rest through there. I spent about an hour doing the entire boat.

[delmarrey]

I'm glad you're still with us

Using any kind of of electrical device in an enclosed area with flamable gas could be catastrophic. Even tuning off the switch to the batteries can cause an arc.

MY SUGGESTION IS; if you're NOT trained to handle flamable gasses, Get the HELL outa there and call the fire department!!!!!!!!!!!!!!!

Part of my job is maintaining CNG compressors at 4000 psi. CNG is a lot safer then Propane. It dissipates upwards (lighter then air) which allows for a safer interior storage.

Where as, you'll notice that the Propane industry keeps their large tanks in a wide open area. CNG can be stored inside vehicles (trunks and truck beds), one reason you never saw propane cars, no place to put a propane tank, only PU trucks, travel trailers, forlifts and manlifts with the tanks attached on the outside.

The only reason I use propane in my boat is because I'm TRAINED to deal with flamable gasses. I'd prefer CNG but it's not available everywhere like propane.

Hummmmmm! Maybe I should start a CNG business selling small CNG canisters like Colman does with the propane. The only problem is it takes a high pressure system with CNG to get the same amount of gas in the same size of bottle as the propane. More expensive equipment too with all the specialized fittings.

I tried an alcohol stove for a while but had problems with it too. The containers they come in can get holes and it's a lot harder to get out then gas when it satuates the wood. One should store the extra in an outside compartment also. And you have to preheat the burners to get it to burn properly, not good with a low overhead. I know a Cal 39 that sold cheap because of that.

Enough of the rant.............................................. ......................._/)

[Alan Wheeler]

When I was a boy, (not sooo long ago) my Dad lost three of his friends with a vapour explosion in a confined space. They had been painting a solvent based paint on a floor in a work room. Someone started a Vacum cleaner and the resulting explosion killed them all.

There are specific extractor fans sold for evacuating the hull of a boat befor starting the engine. With the above advice, is this suggesting that they should not be used??? I have one in my engine room and the on/off switch is someway away in a seperate area. Infact, this is my layout.
I have two 9Kg tanks out oon the aft deck. On those tanks are electric valves. These both feed into regulators and into a common gas line. In the Galley, is a Gas detector with two sensors. One imediatly below the oven and the other much further down in the bilge in the engine room. I have an A/B switch for the tanks and can remotely turn on and off each tank. If a detection occurs, the detector closes the electric valves on the tanks firstly and It switches on a the extractor fan to evacuate the bilge. Once the detector resets the fan turns off till the detector senses gas again. This makes the system auto for at night when we are asleep or if we are not onboard. It saves us having to go do anything manual. It means if the detector goes off, we exit the boat for our own safety first and let the system take care of itself till the detector stops sounding. Then I know it is safe or afer to go and inspect the problem.

Hey I reckon this is another proponent to the need of drilling a hole in the bottom of the boat. It not only will let water out if it comes in, but it can let gas out as well. Plus on really cold days, you can fish fromthe comfort of inside the boat. Just like ice fishing;-) :-)

[Boracay]

I'll second the advice to evacuate and call the fire department.
Defusing bombs is a job for experts.

[2divers]

Exactly HOW dense is propane? Will it mix with other air like CO2 will allowing it to be vented with a sufficent air flow? Or is it much more dense requiring a concentrated flow. Personally if it happened away from dock... I like Pura Vida's idea. It follows the KISS Principle.

The only question is how do you test to be sure that you got rid of all of it?

[Rick]

Too many of us view the real natural world as black and white. Someone told us that propane settles to the bottom of a container and we imagine that there is a definitive line separating the propane from the air. This is NOT the case.

Yes, propane TENDS to stratify yet if there is ANY disturbance at all including temperature variations around the container there will be mixing. Eventually a space open to the outside will cause mixing until it is safe....how long? Well that depends upon the amount of air exchange, naturally.

I like the idea of using the air scoop through a hatch. Yeah, if you are really conservative and can at least open up the boat and wait for five or ten hours you would at least be able to compare any propane smell coming out of the boat (as you check for which way the flow is moving to place your nose downwind of an exit). If you don't smoke the nose is a pretty good detector (at least where your nose is). IF you no longer smell any propane leaving the boat and wait longer then the risk is much lower.