How Deep Can You Do An "Out Of Air Emergency Ascent" From?

[VTWarrenG]

NINman,

Reg starts free flowing at 100'. Gas goes from 2500psi to 0 in a matter or secs.

No. I'll quote my "SpareAir Myth #3" here:

3) The SpareAir will save me when my reg goes kaput and fails. Wrong -- there are paltry few situations where a reg can fail closed. Those situations, like ice diving, require real training and real equipment. The SpareAir has no place in such diving. If your HP SPG hose fails, you have a slow leak. If your tank O-ring bursts, or your first-stage HP seat fails, you will have a moderate leak. You will certainly have MUCH MORE than 3 breaths left in your primary, unless you were already run dry. Once again, anyone who lets himself go dry to begin with is waiting to kill himself. Anyone who worries about a HP seat failing after having already run dry really needs to think some more. The only conceivable way the gas supply could be completely interrupted would be to have a yoke reg literally popped completely off of the valve. This would require Herculean effort and inordinate stupidity to accomplish. It isn't a reasonable failure mode.

If your reg freeflows, and you're not already bone dry, you'll have plenty of air to make your ascent. (You should have practiced breathing from a free-flowing reg in your OW class.) The best first-stage scuba regulators made can only bleed an 80cf tank dry in about 80 seconds (IIRC). At depth, it will take even longer. A freeflowing reg does not constitute an emergency in open water.

While ascending you take a breath and then proceed to exhale as though you are doing an out of air accent. Take breaths as needed. This would allow your 3cf Spare Air to last much longer then having to breath in and out from the Spare Air reg.

Please explain to me how exhaling into the water and exhaling through the SpareAir reg are different. 3 cf is 3 cf, no matter how you breathe it.

I understand your points and if I had the money would opt for the pony bottle and reg setup.

As has already been pointed out, SpareAirs cost more than good pony setups. I don't like ponies much either, but they're radically superior to SpareAirs.

I have yet to buy the setup and may not.

Listen to the advice given here: they're a gimmicky waste of money.

- Warren

 

[VTWarrenG]

Hawk,

A pony is not a good option to try to travel with either.

I'm not sure I understand -- a SpareAir is a "tank," and thus will need to have its valve unscrewed for flying, just like a pony. If you're talking about size, you can buy little weenie 6 cf ponies that aren't much bigger than a SpareAir.

- Warren

 

[rcohn]

Scoobydoo,

That's not my understanding of the reflex, but you'll need to ask the docs for details.

From what I understand once you pass out, laryngospasm willl initially block the airway after contact with water, preventing water from entering the lungs. At some point this relaxes and you begin to inhale water. I don't think you can inhale water into the stomach.

Ralph

 

[FredT]

One involved pulling a vacuum on a tank at 138'. One of the more intense arguements above that didn't get much play is that in a true OOA it's OS time, not oops time. You'll only find out you're out when you try to inhale, by then it's too late to get the air you just exhaled back. In my case it was back in the early 70s (when the second low pressure port on the regulator was still labeled "tool") while trying to winkle a bug out of a hole. I was literally up to my armpit in his hole with fingers JUST touching the antenna knuckles of a big bull when I hit the bottom of that tank. Starting empty I made it out of the hole and up with no injury or DCS issues, although how I missed the second one is beyond me. There were two things that helped me make it. One as the husbanding of expanding air to allow it to "fill" the lungs a bit for the first 30' or so while maintianing an open airway. The second is the fact that the urge to breathe is translated by your body into "move air". The body doesn't care which way it is moved. When the throat starts to convulse just EXHALE a bit more. This buys another 10 to 15 seconds before it happens again. One thing though, at about 30' you start looking at fish and thinking "THEY are getting O2 out of this stuff around me, why can't I?" The correct response is to kick harder!

The second incident involved a large AJ, 800+' of water, a large bristle worm, partial paralysis of the body including the diaphram, and a ~160' VERY buoyant ascent. OOA because your BODY will not work enough to allow you to inhale is something I still havn't seen covered in ANY class. Surviving it did raise the OS bar for me quite a bit though.

The trick my instructor taught me that has stood me in good stead over the years is that when the world turns brown think the word "panic," and you won't. Just that thought reminds you that if you panic you die. It's almost always easier to relax and solve the problem, than to panic and drown.

FT

 

[NINman]

Please explain to me how exhaling into the water and exhaling through the SpareAir reg are different. 3 cf is 3 cf, no matter how you breathe it.

Well I think this was touched in the last post. Breathing out in the water is differnt in the case that it might stop you from doing an invalintary suck of air off of the "Spare Air". Thus allowing the compresed air to expand allowing you to use that before taking more air from the "Spare Air". I hope I am making sense, because if I am not then I ask those wonderful Regulators to remove my posts as I could endanger someone by giving them falus information.

I'll quote my "SpareAir Myth #3" here:

3) The SpareAir will save me when my reg goes kaput and fails. Wrong -- there are paltry few situations where a reg can fail closed. Those situations, like ice diving, require real training and real equipment. The SpareAir has no place in such diving. If your HP SPG hose fails, you have a slow leak. If your tank O-ring bursts, or your first-stage HP seat fails, you will have a moderate leak. You will certainly have MUCH MORE than 3 breaths left in your primary, unless you were already run dry. Once again, anyone who lets himself go dry to begin with is waiting to kill himself. Anyone who worries about a HP seat failing after having already run dry really needs to think some more. The only conceivable way the gas supply could be completely interrupted would be to have a yoke reg literally popped completely off of the valve. This would require Herculean effort and inordinate stupidity to accomplish. It isn't a reasonable failure mode.

If your reg freeflows, and you're not already bone dry, you'll have plenty of air to make your ascent. (You should have practiced breathing from a free-flowing reg in your OW class.) The best first-stage scuba regulators made can only bleed an 80cf tank dry in about 80 seconds (IIRC). At depth, it will take even longer. A freeflowing reg does not constitute an emergency in open water.

I was just using the free flow as an example. Thanks for making that clear.

I thought I would jump in on this discussing and now I am sorry I did. Next time I will keep my mouth quite and just let the discussion go on with out me.

 

[budgy]

I have never tried an out of air ascent. I hope I never have to. I don't dive with a redundant air supply but I have been giving it some thought. A 2.5 litre pony with 200 bar would give me more than enough air to return to the surface from 50 metres with a short safety stop, so provided I was diving within no stop times, I can see no problem with a pony. They look clumbersome and there is the cost of the cylinder and extra reg and the service cost. I see in practice many divers leave their pony behind, I also see that a medium size reasonably fit lady can manage a 15litre and a pony out of the water, so with a twelve and a pony I should have no problem. I dived with a club last week where all their divers carry a redundant supply, I think it is right way to go. Regarding travel arrangements and being unable to transport the weight on aircraft, I am told that golfers get extra baggage allowance for their clubs, because their sporting associations have spoken to the airlines, isn't it about time we did the same?

 

[VTWarrenG]

budgy,

In general, when one decides it's necessary to have truly redundant gas systems, the right answer is doubles and isolation manifold. Ponies are better than nothing, but they can't hold a candle to a good set of doubles.

NINman,

Please don't just "be quiet and let the discussion go on." There's no better way to learn things than asking questions. There's no shame in being wrong, so long as you're willing to learn what's right.

- Warren

 

[SpyderTek]

Originally posted by NINman



I thought I would jump in on this discussing and now I am sorry I did. Next time I will keep my mouth quite and just let the discussion go on with out me.

Oh no! You don't get away THAT easy NIN!

Even when things get heated here I can tell you from first hand experience that this board, and the people in it, would rather have you post a contraversial opinion or an incorrect assesment of fact than to not post at all. It is the best way to learn and keep open discussion flowing.

So keep throwing your two cents in the fountain along with the rest of us...later we're planning a group dive down to collect all the change!

SpyderTek

 

[SpyderTek]

Originally posted by VTWarrenG

Please explain to me how exhaling into the water and exhaling through the SpareAir reg are different. 3 cf is 3 cf, no matter how you breathe it.
- Warren

Thats an easy one to explain...it happened to me. With a regulator in your mouth your mouth is being held much wider open than without. In the checkout dives when we did the free ascent simulation from 10 meters the first time I had a regulator in my mouth. Breathing out through the regulator I had exhausted my lungs air supply after 15 or 20 feet. My lungs were bone dry. I could have gotten to the surface no problem but my instructor couldnt see any bubbles comming out so he grabbed my leg and stopped my ascent.

However, take your breath, take the regulator out and pucker your lips like you are whistling you exhale your breath in a much more controlled manner and you can exhale all the way to the surface.

Also, as NIN pointed out, having the reg / spare air in your mouth gives you an involuntary reaction to "sneak a breath" as he put it before you might actually have to.

So I see this point of his as valid.

SpyderTek

 

[Uncle Pug]

I can't take it no more....

I know that this thread is supposed to be about totally OOA without a redundant source and buddy... and how deep can you go before you can't make it back with that one last breath of air that you no longer have because you just let it out.

I just have to speak up...

Please indulge me...

I realized some time ago that trying to prepare for an emergency OOA ascent with spare air was irrational and it wasn't long after that I came to the same conclusion in regards to the pony.

The way to prepare for an emergency OOA ascent was two fold:

1. Take steps to prevent such an occurance with appropriate training & equipment.

2. Plan the dive (depth, buddy, gas management) to insure that should the *umpossible* happen it could be handled no matter what the depth and no matter what the deco obligation without undue stress much less injury.

Anything less is worse than nothing as it lulls the diver into thinking that meaningful precautions have been taken when they have not. Better you should stay within 60' of the surface and constantly monitor your SPG than to dive with a spare air or pony. When I see someone with a spare air or pony I figure that they are divers who have no clue about proper gas management and dive planning & execution. I may be mistaken in my judgement in a small percentage of the cases... but if you are honest about it you will acknowledge that most of you diving with spare airs and ponies are *Laissez Faire* divers... who's sole approach to dive planning is "Hey, let's go diving!" And that is why you are worried about OOA in the first place.... and why a question such as the original one was even asked!

And my original answer is the correct one... and if it isn't yours is should be!

But Uncle Pug still loves you... just a little more worried about you is all