Venting a locker

[PabloPicasso]

How should a gas locker be vented overboard?

 

[Boo2]

How should a gas locker be vented overboard?

Mine has what seems to be a length of copper pipe glassed into the locker near the base and running to pass through the hull where it is also glassed in. It's below the heeled waterline but above the unheeled waterline.

Boo2

 

[VicS]

How should a gas locker be vented overboard?

There should a drain from the bottom or from close to the bottom. It must exit the hull above the waterline to be effective

The minimum diameter depends on the total capacities of the gas cylinders.

The Boat Safety Scheme rather curiously only requires the locker to be gas tight up to above the high pressure connections and components but logic suggests it should be totally gas tight with a vent as well as the drain.


Best look at all the details in the Boat Safety Scheme, Chapter 7.

There is a new edition in the pipeline but the complete BSS 2005 edition is archived at http://www.boatsafetyscheme.org/media/180428/bss guide 2005 complete web.pdf

 

[sarabande]

VicS

I wonder if the reason for the restricted height gas tightness, is to do with a potential gas-filled enclosed compartment. If that fired off, it would be worse than a locker partially open. Perhaps ?

 

[sutton sailor]

I have never heard of a gas leak that was anyting other than a very gradual leak, and as butane gas is very much heavier than air it will always sink to the bottom of any enclosure and flow out of the bottom like water. The sugestion that the exit end of the drain should be above the waterline at all times is significant. One way to achieve this is to have it exit the boat on the centreline of the stern when it should not be afected by heeling. The only problem could be when motoring hard and the stern will squat down.

 

[PabloPicasso]

I have never heard of a gas leak that was anyting other than a very gradual leak, and as butane gas is very much heavier than air it will always sink to the bottom of any enclosure and flow out of the bottom like water. The sugestion that the exit end of the drain should be above the waterline at all times is significant. One way to achieve this is to have it exit the boat on the centreline of the stern when it should not be afected by heeling. The only problem could be when motoring hard and the stern will squat down.

So a gas vent should be;
lower than the floor of the gas locker
exit through the stern above likely waterline
Exit position should be inboard of the gas locker as far towards the centre line as practical
Be 3/4"inch diameter minimum
Be made of gas and saltwater resistant materials

Anything else?

 

[TimBennet]

Anything else?

Yes the vent tube should fall continuously between the gas locker and the exit, so that any water that may enter the line drains away. If the water accumulates in any dips it will block the gas's escape.

 

[PabloPicasso]

Ah yes. So not made of flexible tubing. What should the vent pipe be made of?

 

[Woodlouse]

VicS

I wonder if the reason for the restricted height gas tightness, is to do with a potential gas-filled enclosed compartment. If that fired off, it would be worse than a locker partially open. Perhaps ?

Probably because if the locker is gas tight with just a drain then the gas would be impeded from flowing overboard due to air not being able to get in and equalising the pressure. Any locker would ether need a non gas tight lid or a vent at the top which roughly equals making the locker gas tight up to the high pressure fittings.

 

[Scotty_Tradewind]

Why are you asking?
What type of vessel is it?