Gas leak detected and fixed, should I make efforts to clear gas out?

[Chris Green]

I have just detected a (small) gas leak on my boat using the Alde bubble leak detecter I installed a while ago. I have fixed the leak, just a compression fitting on a tap needed a tweak.

It was a very small leak, just a bubble a second or so or even a bit less. It's LPG (propane) though and is thus heavier than air and will sink into the bilge. The leak has been there for a few days (probably three or four days) since the gas was turned on, I only just got some propylene glycol to replenish the bubble detector. Presumably the gas will eventually diffuse but should I do something to clear any gas that may still be sitting down there and, if so, what?

The boat has a diesel engine (sitting immediately above the bilges) which sucks air in from the outside and (presumably) blows it out of the exhaust. The engine was running for several hours yesterday and Saturday so that would, I guess, have cleared things a bit. So the accumulation is probably only over the last 24 hours since yesterday.

My feeling is to let sleeping dogs lie and leave it to diffuse, there's no source of combustion down there anyway.

[Scott]

I would suggest maximum ventilation. Surely you should not be running a diesel engine in the vicinty of a suspected gas leak?

[paul.mccann]

You need to clear it out as it will have gathered in the bilges. Get a small bucket and scoop up the air gas mixture and throw it over the side. You might think you look stupid doing it but not half as stupid if a spark sets it off

[paul.mccann]

A further point. Do you not have a bilge fan ? These are spark proof so safe to use. As a precaution we always run the bilge fan for a minute or so before starting the engine. Better safe than sorry

[Harry Bloomfield]

Chris Green expressed precisely :

If I were worried, I would be inclined to rig up a fan to blow air into the lower reaches of the boat to forcefully stir it up and out. It would be wrong to put the fan in the bilge, where it might ignite the collected gas.

More effective, would be something like a vacuum cleaner hose, which you could drop to the bottom and suck the gas out - except for the fact that the gas would then pass through the vacs motor. LPG leaks in boats are a deadly combination, due to it being heavier than air.

[Jethro_uk]

Er, isn't LPG prohibited on boats for the very reason you state ?

[Scott]

Surely not? Electrical equipment in the vicinity of a gas leak. Why do you think mobile phones are banned at petrol pumps?

[Andy Burns]

Not banned, testing is part of the BSS ("boat mot")

[Chris Green]

It's something I've had in mind for a while but I don't have one yet. It is only a small boat (10 metres or so), not the sort of boat where bilge fans are standard.

Thanks for the other ideas folks, I'll be scooping out soon! :-)

[Chris Green]

Yes, I though blowing down the engine's air intake ventilators might be the way to go.

Exactly! That's why doing nothing for a while before doing anything rash seemed a good idea to me.

[Harry Bloomfield]

on 03/04/2018, Scott supposed :

They are mostly banned because they distract the pump operator, there has never been a recorded incident of a phone causing ignition, but plenty of myths.

I did say 'More effective, would be something like a vacuum cleaner hose, which you could drop to the bottom and suck the gas out - except for the fact that the gas would then pass through the vacs motor.' In other words, not something to try.

[Harry Bloomfield]

Jethro_uk has brought this to us :

[Scott]

You have added the owrds 'not something to try' later. This was not clear from your original post. You obviously don't take safety warnings very seriously.

[Thomas Prufer]

I'd like to encourage you to do that, but April 1st is over...

If you can't smell the gas, don't worry.

The odorants are added in concentrations so that gas becomes noticeable well before dangerous concentrations are reached.

Otherwise: remove all you clothes so as to avoid any chance of static buildup and sparks. Take two fans, dance on the deck of the boat, while fanning air into the bilge of the boat. Extra points for singing!

Thomas Prufer

[dennis]

That's a good question but the answer isn't simple. Mobiles transmit even when they re not being used so it isn't because they are transmitters or you would have to turn them off before you got to the petrol station for them to be safe.

[dennis]

If the OP has a compressor then using the air directed up the vacuum hose would remove the vapour.

[Jethro_uk]

That's my fact for the day then :)

[Mark Carver]

....and in some cases mobile phone base stations are situated inside the illuminated forecourt signage. I drove past a filling station last week, that had three mobile masts all within the perimeter of the premises.

[Harry Bloomfield]

dennis@home formulated on Tuesday :

Good solution, using a vortex effect and no risk involved!

[Harry Bloomfield]

dennis@home presented the following explanation :

Is the correct answer. The rule is mainly about being distracted by the actual use of a phone, whilst handling fuel.