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

[psychocabbage]

I have not read all the replies but...

If you are already breathing off someone elses reg, you two should not be able to easily seperate.. You should both be holding onto eachothers BC..

I think you are supposed to shut off the air incase you need the air later.. Say you get to the surface and find no boat..

 

[Doc Harry]

Per yourself you spent a "minute or two fiddling" with the regulator. Did you read what I said. I said to signal to your buddy and begin an IMMEDIATE ascent. From 70 feet, let's do the math, at 60 FPM thta is a 70 seconds. You said you fiddled for a minute or two, there was your error.

N

There's no error there, it's a philosophical difference. A regulator free flow is a common occurrence. Personally, I do not know of anyone (except you) who would not spend a minute or two trouble-shooting a regulator free flow. Yours is a more conservative approach and there's nothing wrong with that.

 

[Tigerman]

(If they are not my buddy, as one scenario described, then I'd signal my budddy to surface with us and we'd need to figure out who the "rescued" diver's buddy is and where they are. Hopefully this buddy would be coming to the surface having been attentive, or after 1 minute of a lost buddy! Remember if you have one diver... there should be a buddy to find out there somewhere.)

My $0.02

Then youll have a long wait in some cases considering theres more than a handful of divers who chose not to dive with a buddy..

 

[Dtaine]

I have not read all the replies but...

There's a good discussion you've been missing then.

If you are already breathing off someone elses reg, you two should not be able to easily seperate.. You should both be holding onto eachothers BC..

It depends on what procedures you're following. I dive with a 7' hose on my primary regulator and with a competent buddy I wouldn't consider holding onto his/her bcd to be absolutely necessary. With the short hose configuration it would probably be a good idea to hold on since there's not much room to work with. That said were someone I didn't know want to share air on ascent I would definitely have a hand on his/her bc/harness.

I think you are supposed to shut off the air incase you need the air later.. Say you get to the surface and find no boat..

I don't see what good the air will do you in that case - you can still inflate the bc.

Still, thanks for joining the discussion - this thread has given me a lot to think about.

 

[rawls]

This was a really good question and the responses have been very interesting.

A downstream valve is designed to, in the event of a freeflow, fail open and thus never cutting you off from your air source.

SB has many, many members with advanced knowledge and alot of experience, but in the grand scheme of things, i.e. compared to the total number of members of SB, they are the exception and not the rule.

In having said this, for what it is worth...probably not much to some of you...I have to go with the don't turn off the valve camp. One can easily breathe off of a free flowing reg. That is what is taught in most classes...Right or wrong, that is the reality of it. It may very well be ideal to do something different...feathering, valve off...whatever. but it simply isn't the way things are taught in most open water classes. And speaking of reality...How many recreational divers carry side gas String!!!! Good gracious!!!

IMHO one cannot look at the ideal in these cases. Until instructors incorporate...consistently so...these other methods, a diver is going to do what they are taught...breathe off of the freeflowing regulator and head to the surface. Sharing air is an alternative but as someone pointed out, you may be left with 2 divers OOA. Breathe off of the free flowing reg then share air if you run out.

Generally the average recreational diver is going to be within their NDL if this were to happen, so they can breathe off of the free flow and do a 60 ft/min ascent and generally get to the surface without injury. That is a pretty good clip for an ascent rate, so they will most likely be able to get to the surface pretty easily before running OOA. If they don't have enough air, then they stayed down longer than they should have....Bad diver...Without exception, every diver needs to have enough reserve in order to deal with emergency situations...

If however, whatever method a diver uses in a freeflow situation, he or she doesn't handle it as they should then they are a danger to themselves and possibly to others...Time to get out of the water...

 

[Peter Guy]

so they will most likely be able to get to the surface pretty easily before running OOA. If they don't have enough air, then they stayed down longer than they should have....Bad diver..

I don't understand this statement. If I recall correctly, students use close to 1000 psi doing about 30 seconds of freeflow with an HP 72. I could certainly envision someone diving conservatively in 60 FSW and just deciding to start up at 1000 psi when a free flow hits. I'm quite sure someone wouldn't immediately start up, but, to the contrary, take at least a few seconds to figure out what's happened (especially if they did the smart thing of changing regs to their non-free flowing reg, assuming it existed), signal their buddy, etc. -- even if they were well versed at breathing off a free flowing reg or taking emergency procedures. In all of the tech (type) classes I've taken, it is assumed you'd take up to a minute after an emergency to get everything together to go up. In any event, even with a 60 feet/minute ascent rate, from 60 feet, I could certainly anticipate someone going OOA on the way up just because they don't start with a full tank.

That is one of the prime reasons why I believe it is a better strategy to use the time to get air from a buddy and THEN ascend rather than trying to ascend on a tank that you know is about to be empty.

 

[TSandM]

IMHO one cannot look at the ideal in these cases. Until instructors incorporate...consistently so...these other methods, a diver is going to do what they are taught...breathe off of the freeflowing regulator and head to the surface.

Rawls, you appear to be acknowledging that another method of dealing with the situation is ideal, but suggesting that there is no point in anyone trying to learn it? I think that's what threads like this are good for -- opening people's eyes to the idea that there are other ways of handling situations than the one they were taught, and allowing them to think about what the advantages and disadvantages of different approaches might be.

 

[rawls]

students use close to 1000 psi doing about 30 seconds of freeflow with an HP 72

God yes they use a load of air but we do not take them that deep, there is an instructor with each student and they have 1000psi when we get to the ascent line, or exit point, but I was referring to certified divers.

take at least a few seconds to figure out what's happened

I agree...It could only be a purge valve that is stuck open...

In all of the tech (type) classes I've taken, it is assumed you'd take up to a minute after an emergency to get everything together to go up.

But most recreational divers do not have that advanced training.

Rawls, you appear to be acknowledging that another method of dealing with the situation is ideal, but suggesting that there is no point in anyone trying to learn it? I think that's what threads like this are good for -- opening people's eyes to the idea that there are other ways of handling situations than the one they were taught, and allowing them to think about what the advantages and disadvantages of different approaches might be.

Above that statement I said...may very well be...And I think that you missed my point...which I am not going to repeat. You are one of the very advanced divers I spoke of, however most divers do not have the training you do...

I have no problem with opening ones eyes to alternative methods. I don't know how you interpreted that statement as me saying they shouldn't. But IMHO...You also need to look at the reality of what is being taught...

And I would appreciate your not trying to tell me what a thread is for...

 

[TSandM]

I agree that most divers don't have my training. But what I got from your post was that we should simply accept that divers are taught to do one thing, and that's what they'll do. I'm just saying I think divers are more plastic than that, and that people reading threads on the internet may experiment with other solutions and practice skills they otherwise might not, so there is a point to talking about these things.

BTW, my husband and I both agree that we were taught to BREATHE off a freeflowing regulator in our OW class, but no mention was made of what one did after that -- Go to buddy? Go to surface? -- and I do not recall any discussion of how long you have to make that decision, although my husband says the classes he's DM'd, they DO talk about how fast the gas escapes.

 

[Peter Guy]

Re the assumption of planning up to a minute to "figure out" what's going on before ascending as part of my "tech type" training. This has nothing to do with being an advanced diver or having more training -- it has to do with how people react in the real world.

I find it difficult, or impossible, to believe that your "average recreational diver" who is faced with a sudden free flow will immediately (if not calmly!) tilt her head, pull the reg part way out of her mouth and start a controlled ascent while sipping the free flowing air -- nor would I want her to do that! I'd hope the diver would first go "***!!!!!" and then look around to find the buddy who is supposed to be "right there" -- all the time breathing some of the air that is flowing into/out of her mouth (and bouncing on her mask, etc.). Honestly, I can't imagine that it would take less than 15 seconds for anyone to actually start up -- and in those 15 seconds you've lost a lot of air (and of course it could be a lot more than 15 seconds).

But what do I know -- I'm not a highly trained professional who has been through this scenario numerous times. I'm just your average techreational diver who tries to think about things now and then.