Removal of life raft gas bottle?

[FL390]

Could anyone please help identify how to remove this bottle from the head so I can check the weight ? Don’t really want a cylinder through the wall!

Lots of threads about pro’s and cons of DIY liferaft servicing. Please don’t let this be another one! I am happy to update this thread for others learning if requested.

 

[LadyInBed]

Two spanners, one on each nut on the right of the picture and unscrew.
PS Bob wrote this SEAGO 4 man Offshore Liferaft - Self Service : Monty Mariner

 

[duncan99210]

I think that the nut nearest the cylinder is a valve: the paint mark on the Allen screw head set into the nut shows it’s open position. If that is the case, then turning it through 90 degrees will “probably“ shut it. Then use the two spanners to unscrew. If you find ANY significant resistance to unscrewing, then you still have high pressure gas in the set up and you should stop and return things to how they were. However, I don’t recommend doing this as I’m by no means certain that there is a valve and messing about with high pressure gas isn’t a good idea.... Remember that the gas system is set up so that you can’t turn the gas off under normal circumstances, as that defeats the object of the system.
That said, the cylinder should be marked with an empty weight and the weight of the gas it contains. IIRC the gas will weigh somewhere in the hundreds of grams for a life raft and it will be obvious when weighing the cylinder if it has gas in it or not. The gas is unlikely to have leaked to any great extent if the trigger is intact, so you can weigh the cylinder plus trigger to confirm that it has not been set off and replaced empty.

 

[pvb]

Surely this is the blind leading the blind?

 

[duncan99210]

Not quite. Spent a good few years working on diving gas cylinders: any undue resistance to valve being undone = cylinder not drained properly.

 

[pvb]

Not quite. Spent a good few years working on diving gas cylinders: any undue resistance to valve being undone = cylinder not drained properly.

Your post 3 contained a lot of uncertain comments.

 

[Jmc1764]

Surely this is the blind leading the blind?

It will be if he gets it wrong...BANG wooshhhh

 

[FL390]

It will be if he gets it wrong...BANG wooshhhh

Haha - I would rather avoid that scenario.

 

[LadyInBed]

The make of the raft might help.
I was probably a bit rash saying unscrew the nuts!
Looking closely, it looks like the manifold branches into the two tubes. Does the manifold have a release mechanism to separate it from the tubes?

 

[FL390]

The make of the raft might help.

Plastimo manufactured in 2013. Came with the boat. I must say it is in mint condition, quite amazing.

 

[Graham376]

Watch this at 6 minutes - (70) Self Servicing a Plastimo Offshore life raft - YouTube

 

[William_H]

It will be if he gets it wrong...BANG wooshhhh

Well that is a bit alarmist. I remember when SCUBA diving asked a friend to cehck my valve was open. It was. He loosened the clamp of the first stage regulator. Venting full bottle pressure to the water/air. Very noisy. But not really a danger. Yes I am aware off stories of valve breaking off a gas cylinder venting a lot of air at once. The bottle becomes a rocket. Very dangerous. Just go slow and be careful. ol'will

 

[duncan99210]

Your post 3 contained a lot of uncertain comments.

Indeed it did. My last paragraph told the op that he could weigh the cylinder plus trigger to confirm it the cylinder contained gas or not, which is the easiest and safest option. Hence the qualifications in the first bit of the post.

 

[FL390]

Thanks for the input and help. The primary objective was to check the raft to my satisfaction, remove the flares, and it won’t be being passed on. So to that end I weighed the bottle with the trigger, as Duncan suggested. This also removed the risk of me reassembling with an unknown leak. (It weighed 0.6kg more than without the trigger.) Given the mint condition I am satisfied.

What did I learn?
It’s perfectly possible to service your own raft and indeed fun getting to know the inside. I would have liked to have done a proper job with the cylinder. For my purposes content with self-service. Further offshore, (or if needing to repack in a canister) a pro job might be time and money well spent, but I would insist of being present and inspecting / upgrading the contents.

The raft is a Plastimo Coastal 4 seemingly purchased in 2013. It had not been inspected since. It was in mint condition except for a minor breach of the vacuum bag (see cable tie below) It survived 24 hours in my living room and did not smell at all.

There is enough how-to info elsewhere I will post a couple of photos of the contents and time expired kit should it help.

What I found disappointing was the attention to detail. I cut my finger as soon as I put my hand in the grab bag! There was a burr left on one of the plastic oars that was a razor sharp point. On a similar note couple of lines, painter etc,
had been spliced and a cable tie used to secure. Again where the tie had been trimmed it was very sharp. I filed these down. - Perhaps something to check for if you are attending the service centre as both had potential to destroy the raft over time.

HTH

 

[ithet]

Plastimo manufactured in 2013.

I was told (and I think it's on my certificate) that the Plastimo cylinders only need testing every ten years. So you don't need to touch the cylinder until 2023.