Gas Stove Installation

[ANDY_W]

I am putting this before the honorable members of this forum as a reality check.

For the last 18 years, my two ring gas stove has been one of those with a Camping
Gaz bottle screwed directly under the stove.

The whole thing is mounted firmly, not gimballed, in an open topped box in the galley area.
The bottle rests on the bottom of the box and the stove is secured with latches to the box.

A gas alarm sensor is fitted at the bottom of the box.

In an emergency, the box can be dismounted, without disturbing the stove, and thrown over the side.

Anytime I mention this arrangement, especially to surveyors, I am greeted with expressions of horror, as if the whole thing was the work of the devil, and I am left with the impression that they honestly believe that I am playing with fire.

The attraction of such a system to me is that it is very simple and uncomplicated. There is only one seal ( stove to cylinder ). Provided I ensure that the seal is in good condition ( I inspect it every time I change the bottle ) no other maintenance is required.

Compare this with the requirements for a modern gas system:

6 or 7 joints minimum from bottle to stove
Gas pipe passing through bulkheads and locker sides
Flexible connection from tap to stove.
Gas tight locker sealed from the rest of the boat and draining over the side.

Each joint and every point at which the pipe passes through a bulkhead is a potential failure point, requiring frequent inspection for safety, even if, as is often the case, the system is wholly or partially buried behind interior fittings.

I wonder how many people religiously inspect their entire gas system every month or so, as I do when I change bottles.

I also wonder how many gas explosions on boats have been due to un-noticed failure
of systems installed to modern requirements. That on Lord Trenchard, a training ship, springs to mind.

Am I a lucky so and so to have survived so long, or is my approach valid?

I would really appreciate your views just in case I need to re-think.

Andy

 

[Topcat47]

I think your approach is valid, however, I'm not so sure I'd advocate it. Apart from anything else, I'm no great fan of those wee camping gas bottles. Mind you I notice Calor have plastic ones these days, although you won't find one on "Snark".

I'll be sticking to my old fashioned "conventional" system in which the Pipework is fixed to the hull, the system checked out once a year and the flexible hoses changed every five (whether they need it or not).

 

[VicS]

Those types of stoves are mentioned in the Boat Safety Scheme

http://www.boatsafetyscheme.com/downloads/BSS_Guide_chap7.pdf

See section 7.1

I am not so sure that the installation on The Lord Trenchard was to modern standards!
Non gas-tightness of the ready-use gas locker allowing LPG to migrate into the hull of the vessel was one of the contributing factors.

 

[Dockhead]

Those types of stoves are mentioned in the Boat Safety Scheme

http://www.boatsafetyscheme.com/downloads/BSS_Guide_chap7.pdf

See section 7.1

I am not so sure that the installation on The Lord Trenchard was to modern standards!
Non gas-tightness of the ready-use gas locker allowing LPG to migrate into the hull of the vessel was one of the contributing factors.

It seems to me that the basic design of the gas installation of the Lord Trenchard was indeed up to modern standards. There was a gas locker which was supposed to be gas-tight, and the vessel had a gas alarm. The report makes scary reading:

http://www.maib.gov.uk/cms_resources.cfm?file=/lord trenchard.pdf

As in "there but for the grace of God go I".

By the way, I puzzled over this in the report:

"Bilge pumping procedures
While at sea, standard operational procedure for this class of vessel require that all
bilges be pumped every hour. Once all water has been pumped out, procedures require
that the bilge pump be given thirty more strokes to remove any gas which might have
accumulated.
Similar procedures are required to be followed in port; once first thing in the morning
and once more during the day."

Never heard of this "standard operating procedure". Does any of you pump your bilges like this as a precaution against gas accumulation?

 

[snowleopard]

I wouldn't be happy about your arrangement. Gas alarms are unreliable and can be killed with a tiny amount of stray water. A gas cylinder inside the boat could potentially leak its whole contents into the boat and a stray spark could ignite it.

Forget throwing it overboard. If there was a serious gas fire you couldn't get near enough to pick it up. It then becomes a bomb.

A 'best practice' gas installation will have the cylinders in a self-draining locker, a pressure-operated Gaslow valve to shut off the supply in the event of a pipe rupture, A bubbler to allow you to check for pinhole leaks and a remote solenoid valve to turn off the supply in the locker when you aren't cooking.

 

[Ubergeekian]

For the last 18 years, my two ring gas stove has been one of those with a Camping
Gaz bottle screwed directly under the stove.

Standard fitment in all the smaller Westerlies, and probably many others too. I have one of these on the Jouster (no reasonable offer refused) and it works just fine. While it's all very well to have solenoid valves (oo-er - electricity right next to a potential leak point), bubblers and all the works, such systems have many, many more points of failure.

 

[Dockhead]

While it's all very well to have solenoid valves (oo-er - electricity right next to a potential leak point)

This whole discussion is very, very relevant to me at this moment. Weekend before last my solenoid valve, which lives in the gas locker, failed. It failed by somehow (!) shorting out and melting down before the breaker tripped. If there had been any stray gas about, my boat would have gone boom.

 

[Searush]

"safety is no accident"


18 years without an accident seems pretty safe to me. I wouldn't worry too much about the fear mongers, it's not their boat is it?

 

[Martin_J]

Dockhead....

Yes - in the (not so distant past) it was standard to pump out the bilges using a manual pump before switching on anything electrical. It was always more than 30 strokes though. Seems like these days electrics are left on and gas is switched off between uses.

 

[vyv_cox]

For the last 18 years, my two ring gas stove has been one of those with a Camping
Gaz bottle screwed directly under the stove.

The whole thing is mounted firmly, not gimballed, in an open topped box in the galley area.

My first boat, French, had the same system but was additionally gimballed, the bottle swinging in a large recess beneath the stove. The bottle was the largest one, a 907, so the space taken up by this arrangement was considerable. I believe that many French boats built in the 1970s and 80s were similar. The boat was built in around 1976 and I had the opportunity to go aboard again about two years ago when she was up for sale. The same gas system was still used.

We never had a problem with it and, having survived some 35 years, it would seem to have proved itself. Some care is needed when changing the bottle and as already said the washer needs to be good, but OK in all respects.

 

[Adonnante]

"safety is no accident"


18 years without an accident seems pretty safe to me. I wouldn't worry too much about the fear mongers, it's not their boat is it?

As much as I agree with these sentiments I would suggest that all systems on our boats come with a degree of risk. So far I've avoided being blown up by about 2 minutes after being invited on board a RN vessel for a cup of tea and purchased a Gaz bottle that had been locally over filled. The latter experience resulted in our correctly connected system supplying liquid gas to the cooker that had flames at all valves including the ones that were off. Access to to an external shut of valve on top of the bottle is the priority on my boat.

Peter.

 

[Dockhead]

"safety is no accident"


18 years without an accident seems pretty safe to me. I wouldn't worry too much about the fear mongers, it's not their boat is it?

Well, I know people who have smoked cigarettes for 18 years and still don't have cancer. Just because it hasn't happened to you yet doesn't mean it's safe. That is a logical fallacy.

Of course every system on board brings a certain amount of risk, and the sport of sailing brings with it various risks in and of itself. Life is inherently risky and none of us will get out of it alive!

Everyone has to decide for himself what is reasonably safe or not, but keeping a bottle of liquified petroleum gas inside the cabin of my boat in contravention of all sensible safety rules requiring gas bottles to be kept where leakage can disperse overboard, does not make it onto my own personal list of risks which are sensible or reasonable to take. Call me a "fear monger" if you like. I don't mind going out in a storm, and I do it regularly. But gas bottles in side the cabin -- nein danke.

People do get blown up by gas leaks on boats. It happens every year and probably every month during the season. It would seem to be an unpleasant way to lose a limb or indeed your life. And/or to have your boat blown to bits.

If you Google "boat gas explosion" you get literally thousands of hits.

http://www.guardian.bz/all-crime/1062-gas-explosion-shreds-boat-to-bits

http://news.bbc.co.uk/2/hi/uk_news/england/devon/8157515.stm

http://au.news.yahoo.com/thewest/a/-/breaking/8787503/gas-blast-sinks-boat-at-rotto/

http://www.thisissouthwales.co.uk/news/Boat-wrecked-gas-blast/article-264351-detail/article.html

 

[Searush]

Have any of them been "direct Stove on Bottle" systems or are they all the more common traditional "Bottle in external locker" ones?

Everything has "a risk", everyone should assess the risks they want to take, but give over trying to impose your personal risk assessment one everyone else please.

 

[daveyw]

6 or 7 joints minimum from bottle to stove

Not sure why you need so many joints. 1 in the gas locker and one in the galley. Providing the installation is done correctly there should be no leaks.

 

[Ubergeekian]

Not sure why you need so many joints. 1 in the gas locker and one in the galley. Providing the installation is done correctly there should be no leaks.

Two at least in the galley - one at each end of the hose.

Giving bottle to regulator (1), regulator to hose (2), hose to tail (3), tail to cutoff valve (4), cutoff valve to pipe (5), pipe to hose (6), hose to cooker (7). Add another two if you want a valve by the cooker.

 

[Topcat47]

That sounds like mine, right enough.

BTW, I always pump 20 to 30 strokes on "empty" when clearing bilge water. I thought everyone did.

 

[Ubergeekian]

BTW, I always pump 20 to 30 strokes on "empty" when clearing bilge water. I thought everyone did.

I'd be astonished if the average bilge pump was any good at all at pumping gases.

 

[VicS]

I'd be astonished if the average bilge pump was any good at all at pumping gases.

Absolutely.

Not only will an ordinary hand bilge pump perform very poorly when it comes to pumping gases but you must remember that gases diffuse to occupy the whole space available.

Leaking LPG may well tend to fall to the bottom of the bilge initially but it wont stay there in a little puddle like a liquid does. It will slowly diffuse until the concentration is equal throughout the space.

To be effective then you must pump at least a volume equal to the volume of the bilge. If the extent of the leak puts the concentration well above the LEL you may have to pump several if not many times the volume in order to return to a safe situation.

It just is not practical.

You just get an aching arm, waste half the morning and wear out the pump.

 

[goboatingnow]

direct gas to stove systems are not now valid under CE rules for gas installations in boats. I have such a system , but the canister beside the stove is contained in a gas tight container with a drain tube to a skin fitting.