So you've discovered a gas leak

[ShipsWoofy]

So you\'ve discovered a gas leak

You arrive Friday night at the boat, open the door and get hit by the smell of gas.

What should you do?

What are the 'safe' options for ridding the gas in the bottom of the hull, opening the hatch and door will move some air, but it would take hours to clear the bottom.

Is it safe and actually worth anything to run the little bilge pump?

Serious question by the way, we all worry and take care of our gas installation. But I am not sure what I would do in the circumstance, prolly open hatches and vents and row back to shore. But this is not very fair to other boats close by on moorings unless I requested they all evacuated too.

 

[Rob_Webb]

Re: So you\'ve discovered a gas leak

Sounds like a Hamlet moment.

 

[webcraft]

Re: So you\'ve discovered a gas leak

Don't switch anything on. You might consider switching OFF the automatic bilge pump if you have one - but any switch operation is potentially dangerous, so best not unless you think it is likely to start up in the near future. Switching on the batterries is usually necessary to activate the gas alarm, so this may not be a good idea either.

Now use the hand bilge pump to clear the bilge. Amuse yourself as you pump by doing a quick volumetric calculation to work out how many strokes you need, then allow a very generous margin.

Another idea I read recently - can't remember where - is to open a seacock (eg take top off of engine rw inlet strainer) and flood the bilge. This will force all the gas out of those deep difficult to reach crannies and you can then open hatches and allow the gas to blow away and generally dissipate into a non-explosive mix (anything less than 2% according to the previous post). When the gas is clear (smell all gone should be sufficient with Calor) then you can fire up the bilge pump to remove the water.

OK, now the rest of you can tell me why I am totally wrong and would blow myself to bits . . .

- Nick

 

[Steve Clayton]

Re: So you\'ve discovered a gas leak

According to the "Blue Book" we are supposed to carry a "Gas Action Card". I'm surprised at how little information there is in the Blue Book on this matter. It seems comon sense to me to turn off the source, no naked lights or spark source and vent the boat.

My gas card details below - some detail taken from the Blue Book; (and I'm prepared to be shot down!)



GENERAL

Low Pressure Gas (LPG) is heavier than air and, if released, may travel some distance whilst seeking the lowest part of a space. It is therefore possible for gas to accumulate in relatively inaccessible areas, such as bilges, and diffuse to form an explosive mixture with air.

When a gas leakage is detected or suspected, all gas-consuming appliances should be shut off at the main supply, the vessel will be vented, and NO SMOKING will be permitted until it is safe to do so.

EMERGENCY ACTION

1. Turn all gas supplies and appliances off.

a. The gas bottles are located in the seat locker on the portside (left) helm position.
b. The saloon gas tap is in the cupboard under the sink.

2. Extinguish all naked flames.

3. Vent the bilges using the manual pump. (See picture below). A minimum of 50 strokes of the pump should be applied

... no picture here cos I'm not that clever......

- The manual pump is located by the starboard (right) helm position in the cockpit.

- The pump handle is located in the seat locker above the pump

IF AT BERTH IN A MARINA

In addition to the above:

a. Open all hatches
b. Remove the mains powerlead from it's socket on the pontoon.
c. All persons vacate the boat except for the skipper/person venting the bilges


NAKED LIGHTS SHOULD NEVER BE USED AS A MEANS OF LOCATING GAS LEAKS

 

[StephenSails]

Re: So you\'ve discovered a gas leak

If you are really worried a phone call to the fire brigade would seem prudent. If I was sure that there was no electrical stuff running or going to run, I would open every hatch, maybe set up a wind scoop arrangement to force air in to the boat, I would also get a large peice of cardboard and fan the bilges to try and get the gas moving out and in to the moving air blowing through the boat.

 

[claymore]

Re: So you\'ve discovered a gas leak

1 - Check insurance is ok
2 - Throw Bucket of water in bilges
3 - Manually pump
4 - Phone Corgi

 

[dralex]

Re: So you\'ve discovered a gas leak

Good thread- will a manual diaphragm bilge pump work for gases? I don't know the answer.

 

[Evadne]

Re: So you\'ve discovered a gas leak

Phone Corgi? /forums/images/graemlins/smile.gif

So why do you think a small metal replica of James Bond's Aston Martin will be of use? Or is that your friend at the palace?

I like the suggestion of flooding the bilges, although I'm not sure it would make any difference on our layout. Not having an electric bilge pump or fan at least I wouldn't be tempted to try it too early and lead to a Kaboom moment.

 

[TigaWave]

Re: So you\'ve discovered a gas leak

Interesting one, I was brought up with the belief that every time you light a gas appliance some gas will escape and fall into the bilges....
I always pump the bilges 100 times if the boats been left for a while or 50 times every moring just pumping fresh air, morning exercise routine..

We had a simple card near the cooker for the MCA coding thingy
Saying
DO...
Turn off gas at cooker
Turn off gas at bottle
Extinguish all naked flames
Ventilate boat
Pump bilges with manual pump in cockpit
Inform skipper

Dont...
Operate any switches
Light matches
Connect any electrical items
Disconnect any electrical items

I think that was all, but I havn't looked at it for a while.

 

[Aeolus_IV]

Re: So you\'ve discovered a gas leak

Both my manual bilge pumps self prime, and so must by definition actually be quite good at pumping air!

It occurs to me that if the gas leak has significantly filled the bilges to above floor board level, then some lockers them selves will contain gas .. these will take longer to empty/drain into the bilge, so it may be prudent to go round all of the lockers and vent them individually.

Regards, Jeff.

 

[Achillesheel]

Re: So you\'ve discovered a gas leak

I like the Coarse Yachting story of the crew who, on discovering gas in the boat, decided that as it was heavier than air they would bail it out with saucepans. Passers by were treated to the sight of the crew appearing to pour out nothing over the side!

Seriously though, don't switch anything on, leave all ports/hatches open, rig a wind scoop, leave it for an hour, go back and see if you can find what is causing it, and pump out the bilge thoroughly.

 

[IanPoole2]

Re: So you\'ve discovered a gas leak

[ QUOTE ]
Phone Corgi? /forums/images/graemlins/smile.gif

So why do you think a small metal replica of James Bond's Aston Martin will be of use? Or is that your friend at the palace?



[/ QUOTE ]

You've got confused with a dinky?

 

[Rowana]

Re: So you\'ve discovered a gas leak

[ QUOTE ]


You've got confused with a dinky?

[/ QUOTE ]

You've been reading my mail again, haven't you??

/forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif

 

[Sans Bateau]

Re: So you\'ve discovered a gas leak

I believe that switching electrics OFF causes the spark that would ignite the gas, however best practice is to switch nothing on or off.

The best 'tool' on the boat for getting rid of the gas is the inflatable pump. Use it in the cockpit with an extended length of hose, draw the mixture out of the cabin into the cockpit to drain over the side. Once the air is fairly clear down below the hose can then be used in the lockers and bilges to get rid of the last bits.

Two points though, firstly, you should never get into this situation if you always turn the gas off as you leave the boat. Secondly, with the question being "what do you do if you open the hatch to be met by a strong smell of gas", let me ask the question of the smokers on the forum, do you open the hatch with a lit ciggy in your mouth? Think about it!

 

[JKay]

Re: So you\'ve discovered a gas leak

ask the wife to put the kettle? (while you go to the pub) /forums/images/graemlins/laugh.gif

cheers Joe

 

[mithril]

Re: So you\'ve discovered a gas leak - or have you?

I often wonder whether smelling gas means that the gas levels are at danger level. I know janet often smells gas on our boat and its only because I've just lit the gas ring for a cuppa and a small(?) amount of gas has escaped before the first spark from the auto igniter.

Also, if the alarm is not beeping is it OK to carry on smoking, switching electrics on/off etc etc.

Doubt I'll ever know!

 

[Evadne]

Re: So you\'ve discovered a gas leak - or have you?

If you've ever walked downwind of a balanced flue outlet for a gas-fired central heating boiler you will realise that the "smell" doesn't burn with the rest of the gas so smelling it is quite normal, but not necessarily healthy as it may indicate the presence of the combustion products, CO2 and H2O. Fortunately it would appear that a little smell goes a long way (like another gaseous emission that springs to mind). Our old cooker used to make my eyes sting but the new one burns much cleaner.

 

[TrueBlue]

Re: So you\'ve discovered a gas leak - or have you?

Agree - Always turn off the gas at the supply bottle

Agree - A little gas marker goes a long way

Suggestion - IF CO2 is heavier than propane / Butane; how's about carrying a CO2 extinguisher and flus the bilges with that - CO2 displaces the gas which can be vented through open doors / windows.

Just a thought - might even be a practical suggestion.

BTW ASFAIK there haven't been (m)any on-board explosions due to gas flooding. Most reported fires / explosions that I know about have been due to petrol fumes ignited by a spark or absorption fridge pilot etc.

Comments anyone??

 

[peterb]

Densities

[ QUOTE ]
Suggestion - IF CO2 is heavier than propane / Butane; how's about carrying a CO2 extinguisher and flus the bilges with that - CO2 displaces the gas which can be vented through open doors / windows.

Just a thought - might even be a practical suggestion. Comments anyone??

[/ QUOTE ]

Butane (C4H10) has a molecular weight of 58, carbon dioxide has an MW of 44. So butane is heavier than CO2.

 

[peterb]

Re: So you\'ve discovered a gas leak - or have you?

[ QUOTE ]

Also, if the alarm is not beeping is it OK to carry on smoking, switching electrics on/off etc etc.

[/ QUOTE ]

Careful. Some gas alarms go out of the alarm state once the concentration (at the sensor) goes far enough above the explosive level. Where you are smoking the concentration may be lower and explosive.