What is the deepest you can do an OOA?

[miketsp]

For me it would depend a lot on what I was doing just prior to the OOA.
If I'd been exerting myself swimming hard into a strong current I doubt if I'd be able to go for 1 minute without requiring a new breath. OTOH if I'd just been pottering around a reef drifting around I might be able to go for up to 4 minutes.

The other issue is if you found yourself OOA just after a deep exhale.
At least when we trained CESAs we always took a full breath before starting up. In practice you'd probably have to do one after an exhale.

So the question is how far can you swim vertically in 1 to 4 minutes?

 

[HowardE]

I posted a thread last year about people sharing their CESA stories. I remember Rick Inman posted his. If you search I bet you can find it

 

[String]

130ft is about 40m

Using a sensible ascent rate of 10m/min you'd need to be able to hold your breath, begin to swim vertically and maintain that for around 4 minutes. Im sure a very small % of people can do that but i seriously doubt many can maintaining a normal ascent rate therefore reducing the chances of a bend.

Then add in (i) stress of the situation and (ii) the fact you're likely to have less than half full lungs at the time and its something very few people are going to be able to complete safely.

Id be amazed if it can be done safely by most people from even 1/3 of that depth maintaining a sensible ascent rate.

 

[cerich]

Well, then were talking a controlled swimming emergency ascent and that shouldnt be done from more than 60 feet..

why? It's easy enough to do from any recreational no deco obligation depth (130')

 

[WesTexDiver]

Did you get a full breath off the tank and then notice OOA, or was a half sucking breath that was labored. From 100' on a full relaxed breath would be no problem. From 50' with half a breath and a paniced feeling like someone grabbed you around the throat in the middle of the breath would be worrysome.

 

[drbill]

I did an emergency ascent (solo) from 70+ feet when my tank valve clogged and no air was being delivered. Based on that, I could do 80' but not sure I could manage anything beyond that and do it safely (max 1 ft per sec ascent rate).

 

[gangrel441]

130ft is about 40m

Using a sensible ascent rate of 10m/min you'd need to be able to hold your breath, begin to swim vertically and maintain that for around 4 minutes. Im sure a very small % of people can do that but i seriously doubt many can maintaining a normal ascent rate therefore reducing the chances of a bend.

Then add in (i) stress of the situation and (ii) the fact you're likely to have less than half full lungs at the time and its something very few people are going to be able to complete safely.

Id be amazed if it can be done safely by most people from even 1/3 of that depth maintaining a sensible ascent rate.

On a full breath at the start, if you hold your breath, you're gonna' get hurt. Theory is if you vent your lungs on the way up, the expanding air in your lungs will give you sufficient breath to make the trip. Also, doing a CESA, you shouldn't target 10m (30 ft)/minute. You should really aim for 20 m (60 ft)/minute, or no faster than your slowest bubbles. The E in CESA does, after all, stand for "Emergency".

The other factor is that you keep your reg in your mouth, because the deeper you are, the more the air in the hoses will expand on the way up. Sip it from time to time to see if you can get any more air.

Still, all that said, I wouldn't want to test any of this from deeper than 60 ft. Better to have a buddy, a redundant supply, or both.

 

[HowardE]

at any depth, it would be worrysome. even being bent is better than being dead

 

[Divin'Papaw]

at any depth, it would be worrysome. even being bent is better than being dead

Unless of course you end up so bent it kills you. Highly unlikely given the senario mentioned ... recreational depths (<=130) and no deco obligation. The bigger concern would be AGE or other lung overexpansion injuries. I'd hate to try it from 130, but I believe it is theoretically possible based upon what the training agencies teach.

 

[String]

On a full breath at the start, if you hold your breath, you're gonna' get hurt. Theory is if you vent your lungs on the way up, the expanding air in your lungs will give you sufficient breath to make the trip. Also, doing a CESA, you shouldn't target 10m (30 ft)/minute. You should really aim for 20 m (60 ft)/minute, or no faster than your slowest bubbles. The E in CESA does, after all, stand for "Emergency".

Even with expanding air managing to not breathe for several minutes with a half empty lung and stressful situation is beyond most people. As is slowing down to keep the ascent rate safe.

I dont class 20m/min ascent rate as safe. Emergency maybe but its the wrong option to take. If you have to risk rapid ascent rates like that and increase the chances of a bend, take some equipment with you which eliminates the need to play roulette like that.

The other factor is that you keep your reg in your mouth, because the deeper you are, the more the air in the hoses will expand on the way up. Sip it from time to time to see if you can get any more air.

Depends on the nature of the OOA. If its simply breathing tank down due to stupidity fair enough, if a tank o-ring or first stage has gone it wont work.