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...just don't call me "technical"
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Discussion Starter · #1 ·
An interesting incident last week.

On the boat, preparing for the dive, one of our party was filling the crack bottle on her DSMB.

Suddenly, there was the most terrific bang, and a short sound of the cylinder emptying. Everyone jumped, especially the one holding the DSMB.

The valve had sheared off the cylinder. The cylinder flew 10m over the side of the boat, and the valve remained in the diver’s hand. She suffered bad bruising on her left wrist, and speckled bloodspots on her right forearm. She was wearing her undersuit. We were not sure whether the bloodspots were tiny fragments of metal entering her arm, or a result of the high pressure gas suddenly hitting her arm.

The crack bottle and DSMB had been given to her several years ago. They have never been tested.

We were all a bit shocked, especially when we started talking about what could have happened!:eek:mg:

I would post pictures, if I could figure out how to do that!

Annie
 

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Well Balanced - Bitter and Twisted !!
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1,987 Posts
Glad no one was badly hurt but Not surprised, I had two looked over by my cylinder tester, and they were both fails around the neck was corroded, and they were looked after only 2 years old.
 

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Making God laugh...
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3,112 Posts
Or you could unscrew the valve, check inside, or you could get the bottle tested...

Glad no one was hurt but it is worth remembering this is a very rare occurrence...
Indeed, but considering the number of dives I do and the amount of launches that this entails, I'll just buy new.
 

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Squidgey Member
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2,151 Posts
This is one of the reasons when i fill i open the main cylender slightley so as the fill is slow and i stand well back and hope to hell nowt happens when i handle it.
 

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aka Chimp 1 or Mavis...
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10,108 Posts
Which is why bottle testing is in place and should prevent this sort of thing happening with big cylinders if all the servicing centres did their thing properly.

Glad it all worked out ok but could have been much worse if pointing the other way into the boat.

Regards
 

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Registered
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16,363 Posts
AP also have a replacement cylinder service that should help - though my experience of the pricing was that it would be almost as cheap to buy a new DSMBCi.

What I found useful with DSMBCis, based on that, was to "retire" my crack bottle jobbie by fitting a blanking plate over the bottle hole as soon as it was well used and then buy a new one. The blanked one goes into the bag or pocket as a spare, and if you have a bag fail on a trip you can swap the bottles over, or fire it manually.

Digs.
 

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PMs are being edited
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9,612 Posts
Which is why bottle testing is in place and should prevent this sort of thing happening with big cylinders if all the servicing centres did their thing properly.

Glad it all worked out ok but could have been much worse if pointing the other way into the boat.

Regards
IIRC under 0.5 litres does not need testing, under the pressure vessel regs.
 

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Registered
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64 Posts
Having made yourself negativly buoyant, or secured the DSMB. A possible solution is to open the bottle slightly. Allow the bag to fill slowly and to close the bottle prior to releasing the DSMB. Close bottle with one hand whilst reel release is controlled with the other. Thus allowing pressure to reamain in bottle and preventing water entering.
I dismantled my crack bottle and was horrified what I saw inside.
 

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aka Chimp 1 or Mavis...
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10,108 Posts
IIRC under 0.5 litres does not need testing, under the pressure vessel regs.
If that is the case, that is fine. However, there probably needs to be a little more awareness of this risks to ensure that divers keep the bottle pressurised on the surface (as explained one post above) so make sure you don't trash them while holding them...entirely user preventable...

Regards
 

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Registered
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..entirely user preventable...
Indeed, leaving them rolled up and damp does nothing to help either, they need to be unravelled and allowed to dry as soon as is practical....

This advice is brought to you by my bottle tester, I close the valve prior to release, never drain the bottle completely and dry it properly, never had any sign of internal corrosion....
 

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Conscientious Objector
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1,269 Posts
It needs testing but not to 1968 which iirc only covers from 1 to 15L
Legally, you don't need to have them tested... but frankly, if you think I'd fill one if it wasn't in date, you've got another think coming! Further, the bit about closing the valve is also of paramount importance, as is the bit about rinsing and drying.

I've seen 3 of these let go - one while filling, two while testing. All were at the neck threads.

I hate to say it, but if you can't / won't use a "normal" DSMB, then I agree with Woz. CO2 is a LOT safer.
 

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Registered
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54 Posts
AP also have a replacement cylinder service that should help - though my experience of the pricing was that it would be almost as cheap to buy a new DSMBCi.

What I found useful with DSMBCis, based on that, was to "retire" my crack bottle jobbie by fitting a blanking plate over the bottle hole as soon as it was well used and then buy a new one. The blanked one goes into the bag or pocket as a spare, and if you have a bag fail on a trip you can swap the bottles over, or fire it manually.

Digs.
I replaced my cylinder a couple of years ago (when I found I was squinting and holding my breath while filling the shabby old one!) - I think it was about £40 from Stoney Cove shop. Just the cylinder mind - I cleaned up and re-used the original valve.

Mike
 
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