Shutting off a single tank diver's air supply in a free-flow?

[Peter Guy]

One of the things that continues to amaze me here is how many believe that breathing off the free flowing reg is preferable to breathing off your buddy's secondary. I only know the PADI OW program and OW students get one experience, in shallow water, of breathing off a free flowing reg. OTOH, they get numerous experiences of going to a buddy and doing an air share and air sharing ascent.

WHY do you believe breathing off the free flowing reg is preferable to a normal air sharing ascent?

 

[caseybird]

WHY do you believe breathing off the free flowing reg is preferable to a normal air sharing ascent?

Gotta go with Pete on this one, get him on the octo, get the bubbles out of the way, latch onto that BC strap like a pit bull. Exchange ok's, go to the surface in a controlled manner. Not hard, all within BOW training.

 

[String]

I never said you can prevent all failures. Those are your words. However you can prevent a cold water freeflow by using a regulator that's built for the conditions you're diving in.

Terry

You can REDUCE the chance of it happening but not eliminate. No regulator is immune.

 

[rawls]

taking a redundant air source makes sense.

String...

It may make sense but is it truly needed? I see very, very few free flows happen. They may be more frequent in other places, but where I dive, witnessing a freeflow is extremely rare. I do not use one myself on NDL dives, but that's just me. What feels ok with me is something that other divers will be uncomfortable with and not agree with....And...That's ok too...Whatever floats your boat....

WHY do you believe breathing off the free flowing reg is preferable to a normal air sharing ascent?

Peter....

Assuming someone ascends breathing free flowing gas as opposed to some other method that has been discussed I feel that since the cylinder still has gas then why not use it. If it empties before one gets to the surface then share air. There is always a chance that two buddies sharing air will end up being 2 buddies who are OOA. If the diver carries out the proper procedure for this method of ascent and follows the recommendation of 1000psi at the beginning of ascent there should be no need to even share air. Whatever method one uses is ultimately up to them but any method should be incorporated into the dive plan. On the other hand, if the diver with the freeflow begins to get a case of the panics, then he or she is in a heap of trouble any way you look at it. I am simply of the opinion that if you have it then use it. You disagree and I totally respect that.

 

[ArcticDiver]

Interesting assessment, food for thought.

When I was initially certified I was taught to always be a Thinking Diver. This fit nicely with my background. The key to being a Thinking Diver, or a Thinking Anything is to ask the question:Why?

In the case posited by the OP it is clear the Fix the Underwater Problem Underwater techique is not applicable. Promptly go to the surface. Promptly doesn't mean a panic ascent. It means a controlled, safe ascent as has been taught.

It is interesting to read the differing opinions on what to breathe on the way to the surface. But, that is essentially a thread hijack to a related but different topic.

On that topic: I don't know many people who are trained and have practiced the skill of breathing off a free flowing regulator. I wasn't trained on that skill but I have tried it and, frankly, for a person who doesn't practice the technique it is difficult and would be even more difficult under a lot of circumstances. It is maybe better than nothing under a last ditch condition.

 

[TSandM]

Assuming someone ascends breathing free flowing gas as opposed to some other method that has been discussed I feel that since the cylinder still has gas then why not use it. If it empties before one gets to the surface then share air.

I have had a freeflowing regulator, when I was a fairly novice diver. It was freaky and stressful. I wasn't panicky -- far from it -- because I had two buddies sitting RIGHT in front of me with their regulators in hand to donate (the freeflow occurred at the end of an air-sharing drill). Ascending in a loud cloud of bubbles that essentially reduced the viz to zero (I couldn't see the instructor whose gas I was sharing) was hard. I simply cannot imagine trying to get organized to initiate an air-share from the middle of that mess, if I had run out of gas halfway to the surface. I CAN imagine that being the last straw to put an end to what composure I was maintaining, and having me just bolt. It didn't happen, obviously, but as a result of that experience, I would say that, whether you turn the valve off or not, the diver with the freeflow should ascend on someone else's gas.

Initiating an air-share in midwater, under stress, is to me far harder and fraught with far more hazard than initiating the same air-share with visual reference to the bottom, and ascending together. If you want to ascend vertical and hanging onto one another, that beats the dickens out of trying to find somebody's octopus at 50 feet in 5 feet of viz, surrounded by din and unable to see.

 

[drdaddy]

Turning off the (still working) tank on a single reg diver means that an air-share is now mandatory and unless the buddy is really good or the OOA diver remembers oral inflation and/or weight ditching from class, there's a good chance of a drowning once he reaches the surface and can't inflate his BC.

Also, unless the donor has a non-freezable first stage, you'll end up with one tank off (OOA) and two divers breathing a freeflow from a single tank.

There's just no reason to turn an annoyance into a potential double fatality just to stop some bubbles.

Terry

I've written a number of times about this issue mentioned by Terry. In an OOA situation, you cannot inflate your BCD. I would not recommend turning off a freeflowing tank for the reason mentioned above. Even a pony does not take care of this situation as it does not connect to your BCD. In order to be prepared for an OOA emergency, one should practice orally inflating your BCD, and if necessary, be prepared to ditch your weights.

drdaddy

 

[divingmoose]

A pair of new OW divers needs to be following training. They haven't even worked out how to handle an emergency using the skills they've been taught. Now is not the time to be playing with valves underwater.
The cost of a couple of air fills isn't worth even the smallest risk of a single or double injury or death.
Terry

I've had 4 frozen second stage free flows 2 were solved by bending the hose and squeezing off the air to my reg and breathing off my own octo and doing a controlled buddy assent as per training. (I inquired about the burst hose senario but I got not response other than "I should not sqeeze the hose")after the first two with air blowing out clouding my vision and Scaring the hell out of me"They were at the beginning of my dive training". I thought about it(I work with lp air hoses all the time "air tools" and have sqeezed off a few).The next time I figured at 90 ft. I'd give it a try so my buddy and I would have enough air to surface The last time we weren't as deep and I wanted to keep diving, my reg thawed out at about 55 ft.and I switched back and for a short while continued the dive.
I have since changed my regs and hopefully no more of that.
One thing ? Other then Tec and advanced specialty trained divers I dont know any two tank divers. some of us carry ponys but as far as I know we all have octo setups, the divers in Canada central and Eastcoast area that I've met anyway!