Twin Bladder Wing: Runaway Ascent

[tom]

OK, here's a simple one to start with. This was something that I saw happen to a buddy, rather than myself (I'll post some of my own screwups later ). Some aspects of the incident have been discussed on here before ( Missed stops protocols? ) but I'll post it again in the interest of getting things started.

My buddy (not on YD) and myself were ascending from a 35m dive. At around 20m he lost control of his buoyancy and shot to the surface (he was fortunately unharmed).

The cause of the incident was accidental inflation of the redundant bladder in a twin-bladder wing.

He was diving with the second inflator attached, routed under his arm I believe. At some point the inflator became wedged between his arm and body (probably as his arm was in 'holding the reel' position), the inflator button was pressed and some gas was added to the spare bladder.

He did not realise this, and spent the short trip to the surface desperately trying to dump gas from his suit and main bladder, not knowing it was the spare bladder that was the problem.

Lesson learned: if you dive with a twin bladder wing, it may not be a good idea to have the second inflator connected all the time. He normally did not, but had been wetsuit diving on holiday with it, and had simply forgotten to disconnect it.

[warmwaterdiver]

yes its a fine balance between :

having it connected for immediate use but with a fear of accidental inflation or
leaving it disconnected and wasting vital seconds connecting it when its to be used in an emergency

[tom]

Originally Posted by warmwaterdiver

leaving it disconnected and wasting vital seconds connecting it when its to be used in an emergency

... especially when stressed (likely) and potentially wearing thick gloves etc.

What is the likelihood of needing instant inflation though? Serious question.

[Harlequin]

[quote=tom]What is the likelihood of needing instant inflation though? Serious question.QUOTE]

I'd say only ever if you were at the surface with no air and thought "Fuck" I need to be positive, better dump the weight belt. But there are twinset guys that use no weight at all.

[warmwaterdiver]

Originally Posted by tom

What is the likelihood of needing instant inflation though? Serious question.

generally gas heavy at the start of a dive
you hadn't planned a seabed dive but maybe 10-15m above on "deck level", maybe 60 instead of 75m
burst bladder (which you were using for buoyancy)
your now seriously negative

I used to keep mine permanently connected (for well over 100 dives), was told of the risks and disconnected it. Then I needed to use it on a training exercise and realised how slow I was and what trouble I could be in if it was a serious dive. In hindsight you need to practice the connection/disconnection regularly, but I now dive with it connected again

I believe Mark Chase posted not all that long ago about an inline switchblock you could integrate between the inflater hose/inflater, meaning it could be permanently connected but "switched off"

[Sakara Drinker]

Originally Posted by tom

What is the likelihood of needing instant inflation though? Serious question.

Don't know the overall likelihood but it happened to me this summer. I was solo diving under the arch at the blue hole when I heard a sudden noise of air escaping. I realised something was amiss but wasn't sure what. I pressed the inflate as I was sinking now. The air shot past my left ear. I then used my connected second bladder to arrest this and made my way out. On the surface I de kitted and found the corrugated hose had come off the fitting at the top of the wing. I always dive with both connected now if in a wetsuit. If in a drysuit I move the hose to the other side and use it as my dry suit feed. I have now fitted my hoses on using glue and at least 2 cable ties to stop it happening again. I have no idea why it came off though.

[rustuk]

In which case, inflate it orally?
(Oooh err missis!!)

[quote=Harlequin]

Originally Posted by tom

What is the likelihood of needing instant inflation though? Serious question.QUOTE]

I'd say only ever if you were at the surface with no air and thought "Fuck" I need to be positive, better dump the weight belt. But there are twinset guys that use no weight at all.

[ardhill]

I know of a diver where this same thing happened. His redundant wing was attached, got stuck, and started to inflate. As the wing expanded, the inflator got more jammed due to the position it had gotten caught in.

This happened at around 70m. He couldn't get it sorted and hit the surface with a full wing.

The diver didn't need a visit to the chamber, but is sorely missed by his friends and family.