Clear, explosive, heavy, gaseous substances?

[Wardy]

My wife phoned me yesterday to say that the gas alarm was on!! (Shock horror)
Now from Guildford it's very hard to help her when she's on the boat in Ipswich, but... We don't think we've got a leak in the system, a friend has helped her look, we think that maybe it's a build up of gas in the bilges, accumulated over the four months of continual stove useage; getting to a height that the detector can now register.

What is the best way to remove this gas?

At present I have made her operate the manual bilge pump for a period of time, seemingly to pump nothing away but going on the theory that the gas is heavy and will act as water does, albeit invisibly.

Any advice would be most welcome and possibly crucial.

Steve

 

[salamicollie]

Dry pumping or dry bailing with a bucket is the best start - followed by Open all hatches and portlights, lift the cabin sole and let the wind blow....

Not much else you can do. Then get one of the portable detectors and sniff the bilges.

Then you need to get the system checked - in the first case a Gaslow regulator will give some indication or better still with a water manometer or bubble leak detector which will show the big leaks followed by an electronic tester (probably need a BSS gas man for this).

Then its trace the fault with soapy water

 

[MarkJohnson12345]

Not to be flippant, but often the problem lies with the detector.

But take no chances, get plenty of air flow through the boat, then check the detector.

Good luck

 

[alastair]

Pumping bilges has proved to be an unreliable method of avoiding gas buildup. The seals in bilge pumps are designed to seal water against air, not butane against air. Im sure its better to pump than not at all, just dont make this the primary method. Good practice is best ie shut off at the regulator when not in use.
To remove the gas, pump out with a pump designed for the job (sorry I cant be more specific), then retest by lowering the your gas detector head to the bottom of the bilge.

Good Luck

Alastair
www.javacharter.co.uk

 

[eyupdougdown]

Not to be flippant also but it may be preferable for the gas detector to be on - or it wouldn't be able to sound an alarm when sensing whatever gas it was designed for.

 

[Robin]

If you are REALLY REALLY sure there is no gas leak and have aired and dry pumped out the bilges then the detector may be at fault.

Another very possible scenario is that the detector IS detecting something but it isn't gas from the on board butane system. Most detectors will also go off for refrigerant gases (leaky seals in the fridge), lighter refuel cans leaking, aerosol spray propellants and contact adhesive solvents. I had ours go off and after a long fruitless search for a gas leak, realised it was the solvent from the contact adhesive I had used 45 minutes before to stick back a piece of lining in a locker in a stern cabin, it had taken that long for it to reach the sensor.

Check with your wife also what she had been doing up to an hour beforehand that might have caused it - hairspray perhaps?

Robin

 

[jerryat]

Hi,

I tend to agree with Mark Johnson. I posted on a similar thread a few weeks ago when I mentioned that we had the same problem that kept repeating itself. Extremely worrying even though there wasn't the slightest smell of gas AND the cylinders were shut of every time we left the boat.

Eventually we traced it to two things - the 'gas' was actually the strong smell from domestic cleaning stuff (bleach, surface cleaners etc) which we keep in a little locker under the cooker. One of the plastic bottles had leaked slightly which we'd sorted and cleaned up, BUT which had left such a strong smell, it was enough to set the alarm off. The sensor is immediately adjacent to this locker!

We could see no way of getting round this as, even with the tops tightly screwed down, the cleaners still emitted a slight smell. So, we contacted the alarm supplier (Canary) and they offered an adjustable sensor as an option. We bought one (not cheap IIRC) and installed it. Fantastic! We adjusted it using a gas cigarette lighter (unlit of course) until a few seconds with the lighter right next to the sensor set it off.

It's worked perfectly now for about 11 years, although at the start of each season, we do a similar test, just for peace of mind!! Did it two days ago as it happens!

So Wardy, it may well be worth you checking that you (or SWMBO!) haven't spilled some noxious fluid anywhere near the sensor, 'cos this MIGHT be the cause.

Hope this helps,

Cheers Jerry

 

[joss]

Anybody have a recommendation for a good gas detector?

Jo

 

[snowleopard]

Gas alarms can certainly be activated by things other than LPG. Contact adhesive has done it for me, a little more sinister is CO in high concentrations. A lot of aerosols are now powered by Butane since CFC propellants were banned and of course there's methane from decomposing things. Even a well-placed fart will do it!

A reliable way of clearing the bilges of gas is to lift the floor and use a windsail over the forehatch to drive air through the boat. if you can shut the internal doors so the draught has to pass through the bilges so much the better.

 

[snowleopard]

Forgive me for hijacking this thread...

But as we've got all this gas detector expertise gathered together, what is a good choice of twin-head detector? I got a Plastimo that worked fine until a few drips from the galley sink killed one of the heads and the whole thing is now kaput.

 

[StugeronSteve]

Re: Forgive me for hijacking this thread...

I have one detector head below the cooker and I've never even considered the possibility of fat fall out knackering it. Must check that it is ok. I have noticed that the vapour from a disposable flash wiper has set it off in the past.

 

[snowleopard]

Re: Forgive me for hijacking this thread...

These were drops of water. An expensive device designed to detect gas in the bilge of a boat - totally disabled by a few drops of fresh water!!

 

[Anonymous]

Re: Forgive me for hijacking this thread...

This might answer a lot of questions.......

Flammable gas detector information

 

[Bergman]

If it IS a leak and your bilges really are full of gas then open a sea cock and fill bilges with water. That will drive gas into boat. Then open all hatches and vents and get off the thing and keep everyone else away.

You would be best getting a second opinion with another detector first if possible.

Whatever you do don't touch enything electrical. If its turned on leave it on.

Take heart though - probably false alarm.

 

[Bergman]

Re: PS

Dont forget to close the sea cock!!!!!!!!

 

[pappaecho]

Re: Forgive me for hijacking this thread...

Dont be fooled by false alarms. Last summer we had the same problem whilst cruising - did all the right things - switch off the gas - ventilated the cabins etc, to no avail. Then we looked at the voltage of the service battery, which was down to 9 volts, due to the beer cooler (fridge). Switched off the fridge and magically the alarm stopped. I have the instructions for the alarm, and nowhere does it say there is a built in alarm which alerts for low battery voltage.
In Newport in October, a similar alarm went off on a another yacht, and sure enough it was low voltage causing the problem.
Many forumites do not believe in the value of a voltmeter, but
I now alway check the service battery voltages... I even thought of having an alarm system which triggers at 9.5 volts, to warn me that the gas alarm was about to go off. But then again I moved the gas bottle to the pushpit, in free air, and only switch on the gas when cooking... but I am getting my own back on the alarm - i haven't told it!

 

[eyupdougdown]

It's a boat not a house. Francis Drake never had a gas stove and he went round the world. Maybe an idea to get rid of the gas appliance and all its modern attributes and get yourself a nice barbeque that is mounted on the rails. Any bother just chuck it over the side. Or a nice coal burner with hotplate. Lovely. Get some soul back into sailing.

 

[Wardy]

Thank you all for your most informative replies. Julie has now baled out the bilges, allowed a free flow of air to help push any remnants away and the detector has remained silent since.
In a way, I feel better knowing that the detector operated; hopefully it'll do it next time we get a problem even though we never found a leak.
Thoughts of a new style impromtu underfloor heating are now at the back of my mind.

Cheers

Steve

 

[eyupdougdown]

Maybe it was guff gas? Just a thought.

 

[PeterBell]

Why not get your gas system tested by a marine corgi registered gas engineer. Like all gas equipment, it is recommended to have it tested annually, this also helps satisfy the insurance company. Good contact within your area: rp.projects@tiscali.co.uk /forums/images/graemlins/mad.gif