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

[wrecNcaver]

One of the great things about this board is that for all level of divers, these types of questions make you think. As fairly new to this board I find the interaction very interesting and hope that those new to scuba use these discussions to increase their education. Fortunately my emergency at 110 feet was handled by having redundant air source, (not spare air). Not sure I want to try from that depth to ascend OOA but as many have said, you do what needs to be done to survive. I hope many read this discussion just to keep these things in mind when planning their dive.

 

[Rick Murchison]

Originally posted by VTWarrenG
Rick,

Au contraire. I understand exactly how it works. I'll quote myself:



- Warren

Ahhh... mea culpa... missed that somehow.. sorry 'bout that.
Bottom line - from both of us - rebreathing the BC is a bad idea.
Rick

 

[VTWarrenG]

Rick,

Yay!

- Warren

 

[Blargh]

Originally posted by Rick Murchison
Bottom line - from both of us - rebreathing the BC is a bad idea.

Sounds like a dangerous precedent, that.... (the implicit agreement, that is)

:whoa:

 

[ScubyDoo]

Originally posted by rcohn


The major broblem is that there is water in the inflator. If there is no air in your lungs you can't exhale to clear it. Attempt to inhale the water and you'll choke.

Isnt it true though that reflex action will cause you to swallow the water instead of aspirating?

In most drowning cases, divers panic as the Co2 levels rise in thier lungs, which triggers the reflex to inhale. Upon inhaling water, a defensive reflex action will divert the water into the stomach instead of the lungs. By this time the diver is already unconscious. This process will continue (even though the diver is unconscious) until the stomach is full of water, creating excessive negative buoyancy. After the stomach is full, water is aspirated into the lungs, which begins robbing the brain of oxygen. As the stomach and lungs are both full of water, positive buoancy is lost and the individual sinks to the bottom (assuming there are no flotation devices).

This why so many individuals can be saved after being under for considerable amounts of time. It can take several minutes before oxygen deprivation begins occuring due to the "stalling" effect of swallowing water.

I didnt mean to go off on a tangent there, but my main point is that even though the BC inflator may have water in it which cannot be cleared, isnt it still possible to ingest the water, and then proceed to inhale the BC air?

 

[NINman]

I have heard a lot of negativity about the use of the "Spare Air" product, but I feel that it could in fact work well. Think about it. Reg starts free flowing at 100'. Gas goes from 2500psi to 0 in a matter or secs. You grab the Spare Air and begin your ascent. 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. I understand your points and if I had the money would opt for the pony bottle and reg setup. I don't and the Spare Air idea would be perfect for me. I have yet to buy the setup and may not. Just like some of the others .. 3cf is better then 0cf. Now I am a newbie and will be one for some time as I only have 18 dives under my belt.

 

[SpyderTek]

The main point in your arguement for why you personaly would chose Spare Air over a Pony setup is price? Am I wrong?

The problem with that arguement is that Spare Air is nearly double the cost it would take to set yourself up with a 13CuFt pony setup.

I know cause Money is the main factor for most of my choices as well.

But beyond the "false sense of security" issue associated with Spare Air I am inclined to agree with the assessment that 3 breaths of air are still better than no breaths of air. Especially if your OOA situation is "detected" on the exhale so there is no inhale breath left in your tank. Then you are trying for the surface with no air in your lungs to ehale onthe way up.

SpyderTek

 

[NINman]

I guess I was wrong in saying the money was a factor, as it is not. Which is why I also stated that I would most like do with out either for now. I also stated that I was a newbie and I have not done much research on the costs of a pony setup as aposed to "Spear Air". SO my leason learned has been to do the research before giving an COST opion in this board .. which is a good thing.

Thank you for understanding my other point which is what I was getting at to begin with. Just should have left the cost portion out ... haha .. oh well.

 

[MikeFerrara]

A number of people have mentioned ditching weights. If you are weighted correctly, from any reasonable depth you shouldn't need to ditch weights. Ditching weights is only done when there is no other way. A rapid ascent is very likely to cause injury. A controlled emergency swimming ascent is controled and can be done without injury. A buoyant ascent is a bad thing only to be used in really bad times. All that said, I intend to never run out of air.

 

[Hawk]

NINMan, please don't take what I said earlier as a sparkling, great endorsement for Spare Air. If you will use it, a pony is a better way to go. Some people get a pony and then don't like packing it around. If it is not with you it does no good. A lot of this comes from one of the threads that Warren had links to earlier. A pony is not a good option to try to travel with either. If you need a little bit of air and not the ammount needed for a normal ascent, then it will give you some. I have one, and will definately agree that for what you get that it is way overpriced. It is however a good option for me for certain situations. If most of your diving is local the pony is definately a better setup. I just don't like people saying it is useless when it is not. My guess is that most people who say this have never even tried it in the water.




Later, Hawk.


Ps. This has brought up some good discussions which have led to other areas than just what it started as, which is what I hoped it would.