Gas Locker non return valve

[oldbilbo]

Here's a small problem which has emerged during the present Jester Atlantic Challenge and which others, including myself, may well have.

It seems that the gas locker in a stern quarter of one of the boats has a normal but simple drain hole through the hull, and that sailing for days in boisterous conditions has meant that hole has been submerged much of the time, and seawater gurgles in. Consequently, the inside of the gas locker has had several inches of seawater swilling about in there for much of the time. This has led to accelerated corrosion of the bases of the gas bottles, with consequent concern for their safety and integrity.

I'd like to find an economic solution, and perhaps one already exists, which would permit the draining overboard of any leaked gas and also any water that finds its way in there, but which would prevent the ingress of seawater.

Thinking caps on, please....!

 

[Tranona]

Don't think there is an answer, other than mounting the bottle higher and therefore the drain higher above the waterline. Just laws of physics - there is not enough height in many small boats to achieve that. one solution might be to use smaller bottles if the current bottle is too high. Or even more sensibly fit a Taylors cooker!

 

[prv]

If you don't have the height for a gravity drain to the sea, then I think the only option is some kind of fan (for gas only) or pump (for gas and water). Obviously this device needs to be safe for handling a potentially explosive medium, which is rare, and it won't meet any safety regs as these all insist on a gravity drain.

Pete

 

[Stemar]

When I was a kid I had a snorkel with a little cage and a ping-pong ball in it. If ever I get round to updating my gas drain, I reckoned a bit of pipe, and elbow so the pipe is vertical and a similar arrangement. When the pipe is submerged, the ball floats and blocks the drain then drops down to let the gas out when the wave goes by

 

[DownWest]

Plastic gas bottles, some even have translucent panels so one can see the level of liquid gas inside.

 

[Adamastor]

I would look at one of these: http://www.bgboats.co.za/products.php?sop=catselect&category=Transom+Scupper

 

[pvb]

There's a simple solution which is acceptable to the LPG police. Put the drain higher up in the compartment, and fill any spare space around the cylinder with LPG-resistant material up to the level of the drain. The aim is to prevent a situation where there's a significant build-up of a volume of gas in the bottom of the locker.

 

[VicMallows]

Surely, if the gas drain is EVER blocked by seawater its entire purpose is defeated?

Edit: referring to prior posts .. not pvb post above

 

[Rigger Mortice]

Simple answer is not to bother about it. Two or three weeks won't rust the bottle that much. Get into post, swap bottles for new ones. Problem gone.

 

[Rigger Mortice]

Surely, if the gas drain is EVER blocked by seawater its entire purpose is defeated?

It's only when the boat is heeled over. The rest of the time the drain works fine.
It happens on my boat when the boat heels hard over in bumpy water. Not ideal, but boats are full of compromises......that's why I don't understand why we call them 'she".

 

[sailorman]

lash the bottle to the stern rail, camping gaz always rust

 

[VicMallows]

Plastic gas bottles, some even have translucent panels so one can see the level of liquid gas inside.

Agree, these are excellent .....but how does this relate to the OP question?

 

[pvb]

Agree, these are excellent .....but how does this relate to the OP question?

After 3000+ posts, you're surely aware that posts are rarely (a) relevant, or (b) accurate!

 

[VicMallows]

After 3000+ posts!......

 

[nigelmercier]

My Campingaz bottles are in shallow plastic bowls; keeps them out of any deck wash and prevents any rust marking the locker.

Reminds me: must measure the cylinder base to get a new pair.

 

[Pye_End]

If there is one, put a loop in the drain hose (opposite way that would give you a water trap) so that the top is half way up the bottle. May just give enough head to resist water ingress, but should still provide reasonable ventilation of any gas.

 

[Tranona]

If there is one, put a loop in the drain hose (opposite way that would give you a water trap) so that the top is half way up the bottle. May just give enough head to resist water ingress, but should still provide reasonable ventilation of any gas.

Don't think it will. The whole point of the drain is that it should be at the bottom of the locker as gas is heavier than air. If it is halfway up then the area below the drain must be filled in as pvb suggested.

 

[VicS]

My Campingaz bottles are in shallow plastic bowls; keeps them out of any deck wash and prevents any rust marking the locker.

Reminds me: must measure the cylinder base to get a new pair.

8" or 203mm

 

[Pye_End]

Don't think it will. The whole point of the drain is that it should be at the bottom of the locker as gas is heavier than air. If it is halfway up then the area below the drain must be filled in as pvb suggested.

I accept the density argument, but with sufficient airflow, particularly at sea, I suspect that any escaped gasses will fairly easily be diluted and drain.

 

[Tranona]

I accept the density argument, but with sufficient airflow, particularly at sea, I suspect that any escaped gasses will fairly easily be diluted and drain.

Not sure where the airflow comes from. The locker is supposed to be gas tight apart from the drain at the bottom. With your proposal of a loop and the vent higher up there is no chance of any air flow. Any gas would accumulate in the locker below the level of your vent.