Coal Gas Buildup In Bilges?

[CaptainBob]

I understand that coal gives off a small amount of gas and wondered if storing quite a lot of it aboard might be a bad idea if the storage space doesn't vent over the side like a gas locker.

Or are the amounts given off too small to concern ourselves with?

Ideally I would like to load up as much as possible when we next refloat to save having to restock by dinghy.

 

[Mistroma]

The "coal gas" of old was made by putting a lot of energy into coal to break down the tars into hydrogen, methane and carbon monoxide. You won't get that from coal that's just lying around. I suppose that it is possible for small amounts of gas to be entrained in coal (e.g. methane), perhaps someone else can comment on that aspect with some authority.

I'd be surprised if it was a problem and assume you will store the coal in a bag, so you could always put it into double plastic bags. It isn't like a gas cylinder filled with LPG. You could only get small pockets of methane (assuming there's any at all) at close to atmospheric pressure so the volume of gas must be small. Methane is the most likely gas to be present air and wouldn't pool in the bilges anyway as it is less dense than air. So my own "guess" is that it won't be a problem during storage.

 

[alant]

I understand that coal gives off a small amount of gas and wondered if storing quite a lot of it aboard might be a bad idea if the storage space doesn't vent over the side like a gas locker.

Or are the amounts given off too small to concern ourselves with?

Ideally I would like to load up as much as possible when we next refloat to save having to restock by dinghy.

Red hot 'coal' + water, can produce a readily combustible gas.
As well as obvious 'water gas/producer gas' systems, I witnessed an explosion caused by such gas percolating into a hollow metal beam - gas produced from rainwater getting onto red hot coke.

 

[NormanS]

My previous boat had a coal bunker, holding about 6cwt. It was normally kept full, and never gave any cause for concern.

 

[CaptainBob]

Phew

 

[Mistroma]

Red hot 'coal' + water, can produce a readily combustible gas.
As well as obvious 'water gas/producer gas' systems, I witnessed an explosion caused by such gas percolating into a hollow metal beam - gas produced from rainwater getting onto red hot coke.

So OP mustn't light his coal in order to be completely safe

Actually, the explosive gas in "water gas" is hydrogen and that should just escape through the hatch. However, even if the OP seals the hatch and sits spraying water on the red hot coal the carbon monoxide will probably kill him before the LEL for hydrogen is reached.

 

[alant]

So OP mustn't light his coal in order to be completely safe

Actually, the explosive gas in "water gas" is hydrogen and that should just escape through the hatch. However, even if the OP seals the hatch and sits spraying water on the red hot coal the carbon monoxide will probably kill him before the LEL for hydrogen is reached.

Water gas, is a mixture, which contains Hydrogen 45 -51%, Methane 0.1-0.5%, carbon monoxide 40-45%, with a specific gravity of about 0.55 (air=1), so stop peeing on the coal, should do the trick.

 

[Mistroma]

Water gas, is a mixture, which contains Hydrogen 45 -51%, Methane 0.1-0.5%, carbon monoxide 40-45%, with a specific gravity of about 0.55 (air=1), so stop peeing on the coal, should do the trick.

Always good to see someone agreeing so completely.