What is the deepest you can do an OOA?

[Diver Dennis]

Please come up with a scenario where a dive resulting in a CESA was not the result of someone screwing up.

I don't think there is one unless you are diving solo and even then without a redundant air source.

 

[Scuba_Steve]

Please come up with a scenario where a dive resulting in a CESA was not the result of someone screwing up.

I think it's safe to say you're talking so far over his head, it's pretty well useless to go much further. He didn't understand a damn thing you said, and with that lack of scope he doesn't stand a chance in figuring it out any time soon.

 

[Diver Dennis]

Well ... either you are intentionally misquoting people or you have a great deal to learn about dive planning.

It isn't that sh_t never happens to them ... it's that they've considered what might happen, weighed alternatives, and planned for more appropriate responses.

CESA is your last option in an emergency ... not your first one.

Proper planning and monitoring of your gas supply will keep you from having a gas emergency in all but a tiny fraction of a percent of all the dives you will ever do.

Within that tiny fraction lie human error and equipment malfunctions ... the former a far greater risk than the latter, even within that tiny percentage margin you're already dealing with. Equipment malfunctions are very rare.

Blowing an O-ring or burst disk will still allow you to have breathable gas out of a tank for the time it takes for the gas to escape the tank ... sometimes that can be adequate to make a controlled ascent, assuming you keep your head and are able to ignore the tremendous noise and confusion such a failure entails.

Choosing an appropriate dive buddy will eliminate virtually any need for CESA. In the case of having to dive with a buddy of circumstance, alternatives would include either maintaining a conservative (shallow) dive profile or taking an alternate air source. If I were traveling alone in a case like that, I'd probably make arrangements to sling a pony and dive solo ... it'd reduce the risks.

In other words, there are way more options than the ones you're allowing for. Either through misrepresentation or ignorance you are ignoring the most viable ones ...

... Bob (Grateful Diver)

You put things more into perspective Bob. These situations are rare and there are a lot of viable options.

 

[Adobo]

Without getting sick by the way.
The thread on pony bottle has me wondering if someone can easily do an OOA from 120'. One of the divers there apparently can. I guess for some divers there's no need for redundancy when doing an open water dive. So what depth can most of you do it from safely. If you end up sick it doesn't count.

Seems an emergency swimming ascent would be a more like what I'm asking about.

I am absolutely mortified with the amount of time that has recently been spent agonizing over pony bottles, spare airs and swimming to the surface in OOG situations.

If a diver spends half as much energy setting himself up so that the OOG situation with no buddy in sight doesn't occur in the first place....

But hey, what do I know?

 

[Soggy]

If a diver spends half as much energy setting himself up so that the OOG situation with no buddy in sight doesn't occur in the first place....

This is exactly the point I've been trying to make.

 

[Gary D.]

Trying to understand the physiology:

So the instant you start exhaling the urge to breathe goes away? I always assumed there was some finite level of CO2 that caused the urge, and you'd have to exhale past it to "unpull" the trigger.

You don’t need to understand what triggers what. If you have ever done it you will know that even at the surface you will more than likely still exhale to get rid of the increased volume in your lungs.
That volume is increasing faster than most think.

Look at the gas laws and you may better understand what is going on. Boyle’s Law is a good start.

Here is just one of many sites.
http://www.aquaholic.com/gasses/boyle1.htm

Gary D.

 

[Blackwood]

If you have ever done it you will know that even at the surface you will more than likely still exhale to get rid of the increased volume in your lungs.
That volume is increasing faster than most think.

I thought it was buildup of CO2 in the body (or probably the brain), not the content of/volume in the lungs.

Look at the gas laws and you may better understand what is going on. Boyle’s Law is a good start.
Gary D.

My knowledge of basic gas phenomena is fine. It is the human body I'm trying to understand.

 

[airsix]

My knowledge of basic gas phenomena is fine. It is the human body I'm trying to understand.

It just works. There is no urge to inhale. You just keep slowly blowing, and blowing, and blowing, and blowing... and you think "will it ever stop?" and you blow some more, and then your head pops out of the water. Then you say to yourself "I'm so done with this thread." and you get on with life.

-Ben M. (done with this thread and getting on with life)

 

[gangrel441]

People who are OOA head for air. My nearest air will almost certainly, barring a complete disaster, be on my buddy's back. I think my time is much better spent practicing air-sharing procedures and good buddy awareness and positioning and underwater communication than practicing CESA.

Redundancy fails too. It is much, much less likely to fail than a non-redundant system, but from time to time, it does fail. If you roll the dice, one in 5 rolls will come up 7, and the vast majority of the time, the rolls will be between 3 and 11, but every once in a while, it does come up boxcars or snake eyes. Those are the situations where even a good diver with proper training and plenty of drill work will still need to do a CESA, because there just is no other choice.

 

[JeffG]

Those are the situations where even a good diver with proper training and plenty of drill work will still need to do a CESA, because there just is no other choice.

and they are?

Something other than these?

Solo diving with a simultaneous catastrophic failure on every breathing bottle they have or a brain fart.

One is highly unlikely, the other can be fixed by paying attention.