How many of you use an inline cutoff switch to your 2nd stage?

[Progen]

I have a Sherwood SR-1 and I just about will never dive in cold water since I live in the tropics but I was wondering whether it'd be useful to have an inline cutoff switch to my primary 2nd stage just in case I get a freeflow problem when I'm halfway through the tank and am still in 25 - 30 metres down.

What I was thinking of doing in such a situation would be to cut off the air to the primary 2nd stage, switch to my octopus and make a slow ascent with the usual 5 minutes at 5 metres stop instead of rushing up since I'd be pretty low on air by then.

 

[Doubler]

I would think that is just adding another point for failure.

 

[Progen]

I would think that is just adding another point for failure.

In that case, we might as well all dive hookah systems? With that switch, I can take my time to ascend rather than rush up. I do practice breathing from a freeflowing 2nd stage every now and then when I get bored of the usual exercises in the swimming pool so I don't think I'll panic should that happen to me although I'm sure it's another matter altogether in the open sea at deeper recreational depths which was why I thought it'd be good to be able to cut off air to that naughty 2nd stage and switch to the octopus.

 

[superspeed]

Most 2nd stage free flows are caused by something at the 1st stage. If your first stage goes than both 2nds are likely going to be useless and its best to just go with your buddy for the accent.

 

[Progen]

Most 2nd stage free flows are caused by something at the 1st stage. If your first stage goes than both 2nds are likely going to be useless and its best to just go with your buddy for the accent.

So what's happening is that something's busted at the 1st stage and sending too high a pressure to the 2nd stage and the diaphragm there opens up?

 

[DevonDiver]

IMHO, a pointless gimmick. As superspeed said, the vast majority of environmental free-flows are caused in the 1st stage. Shutting down the 2nd stage will just cause the AAS to flow instead. This potentially worsens your situation.

On balance with the dubious benefit of being able to shut-down a 2nd stage failure is the risk of accidental shut-down of the regulator you're breathing from. If the switch were to jam closed (hardly un-imaginable), then you're left OOA. Yes.. you could abort and transfer to your own AAS, but how many divers are trained to do that? Or seriously capable of problem-solving that solution when stressed from an air-depletion? In which case, you're racing off towards your buddy, eyes bulging for a life-saving air-share.

Comparing risk versus reward... these 'cut-offs' just don't make sense for recreational divers.

 

[vladimir]

IMHO, a pointless gimmick. As superspeed said, the vast majority of environmental free-flows are caused in the 1st stage. Shutting down the 2nd stage will just cause the AAS to flow instead. This potentially worsens your situation.

On balance with the dubious benefit of being able to shut-down a 2nd stage failure is the risk of accidental shut-down of the regulator you're breathing from. If the switch were to jam closed (hardly un-imaginable), then you're left OOA. Yes.. you could abort and transfer to your own AAS, but how many divers are trained to do that? Or seriously capable of problem-solving that solution when stressed from an air-depletion? In which case, you're racing off towards your buddy, eyes bulging for a life-saving air-share.

Comparing risk versus reward... these 'cut-offs' just don't make sense for recreational divers.

Especially in the tropics, I would think. In the hierarchy of risks, where do free-flowing regulators belong for warm-water divers?

 

[DevonDiver]

In the last 7 years, working full-time in the tropics, I've never seen a recreational diver experience an environmental free-flow. Overall, given the number of dives/divers I've been with, that's a pretty large sample size... but by no means a solid statistic. I've had a few 'trickles' and 'burps' caused by IP creep, that's all - not worth aborting a dive for and easily rectified with an hex key on the surface interval.

More risk evident on technical dives, but those participating have a far more reliable method of shutting down that a cut-off valve...

I did have a major free-flow in deep (36m), cold (4 celcius) water. A cut-off would have had absolutely zero benefit at that time. My pony cylinder, however, was invaluable. More education would have been better still... at the time (many years ago) I had no idea. It's far better to avoid cold-water free-flows than survive them

 

[Progen]

Ok, guys. Guess it's time to point the money arrow elsewhere then.

 

[cephasiii]

I did have a major free-flow in deep (36m), cold (4 celcius) water. A cut-off would have had absolutely zero benefit at that time. My pony cylinder, however, was invaluable. More education would have been better still... at the time (many years ago) I had no idea. It's far better to avoid cold-water free-flows than survive them

That about sums up the best answer to your question. Redundant system and training, and of course gear rated for the environment you will be diving in.



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