Question Practicing Out Of Air ascent: good idea, or bad idea ?

[TMHeimer]

There's two kinds of OW divers: those who know they can swim 40 metres on a single breath, and those who don't.

Don't know if I could or not-- not gunna try.
There are two kinds of divers: Those who can (surface) swim 200 yards and those who can gut out 200 yards with any old "stroke" without succumbing to heart attack and pass a PADI swim test.

 

[GiraffeMarineSalvage]

There's two kinds of OW divers: those who know they can swim 40 metres on a single breath, and those who don't.

You raise an interesting point in terms of "No tanks, I'ld rather freedive..." ;-)
Even though there's plenty of banter between different types of divers, holding ones breath for a minute would actually in many ways be a reasonable and far safer OW requirement than practicing out of air ascents...
(And to anyone thinking "there's no way I could hold my breath for a minute!" the reality is with a little training/practice and no major medical issues, the reality is YES, you, yes you, can almost certainly hold your breath for well over a minute if you prebreathe correctly and stay relaxed... )

P.S. Obviously never hold your breath while scuba diving, especially on any ascent, and being able to hold your breath over a minute after a proper in breathup while relaxed is entirely different than when under an unexpected highly stressful situation... My above point is more about ways to reduce panicked responses from beginner OW students when they experience something unexpected in favor of #1 pause #2 problem solve...

 

[dmaziuk]

Here's another such division: those who understand that the ability to hold your breath has nothing to do with an out of air ascent and those who don't.

Yes, well, the other thing I know is what happens if you're forcefully exhaling on the way up, like they teach you in OW because "I wanna see bubbles".

Spoiler

You find out the hard way that the surface is much farther away than it looks.

(It's not that hard to hold one's breath and keep one's airway open, it just takes practice.)

 

[boulderjohn]

I m still not clear on the benefit of being able to hold your breath for an extended period of time while on scuba, especially when talking about an emergency ascent. In submarine escape training, navy divers are taught to exhale before beginning the ascent and then continue to exhale throughout the ascent. If Diver A has great breathholding ability and Diver B has terrible breathholding ability, they should both have the same experience on an emergency ascent.

BTW, I have no idea how far I can swim while holding my breath because I never saw any reason I would need to know this.

 

[CT-Rich]

I believe they stopped teaching it as a skill because some students were getting injured/killed practicing it. I think redundant air and realizing a free flowing regulator will probably get you all the way to the surface from recreational depths. I believe the record from a submarine escape trunk was several hundred feet, but only one survived. Most gear failures will not prevent you from a quick ascent while still being able to drawn from your regulator.

Being comfortable diving will help you keep from panicking and bolting to the surface. Diver die because the exceed their training, get over confident, Dunning-Krueger, etc... Practicing CESA is needlessly risky and tough on your ears. I've never needed to do it and hope that if I ever do, I will not panic and think through the problem and do it correctly. The not panicking part is probably the most important.

 

[johndiver999]

Being comfortable with a regulator out of your mouth (or one that is not functioning) is going to be a benefit to the diver should an emergency occur which brings about this condition. A person who is an accomplished freediver and who had quite literally swam 100 feet with no air supply THOUSANDS of times and has learned to be completely comfortable doing that, is most likely going to be calmer when this sort of situation occurs.

The amount (rate really) of oxygen consumption is going to be dependent on exertion level, physical condition, acclimation to exertion with high carbon dioxide loads, ability to stay calm and NOT overexert themselves and swim efficiently. These are ALL traits that are essential for a freediver. If these traits/skills are well developed, it is hard for me to imagine why they would not be advantageous in a OOA emergency, all things being equal.

 

[GiraffeMarineSalvage]

I m still not clear on the benefit of being able to hold your breath for an extended period of time while on scuba, especially when talking about an emergency ascent. In submarine escape training, navy divers are taught to exhale before beginning the ascent and then continue to exhale throughout the ascent. If Diver A has great breathholding ability and Diver B has terrible breathholding ability, they should both have the same experience on an emergency ascent.

BTW, I have no idea how far I can swim while holding my breath because I never saw any reason I would need to know this.

Substantial value in my mind is comfort/confidence in the water (which was one of justifications given to practice out of air ascents...). Other than that, my being able to freedive over 100' deep in warm water hasn't improved my scuba diving at all (even to point I was kinda surprised my freediving didn't even improve my SAC rate, which actually got worse when I spent much more time freediving than scuba diving..).
There's a lot to be said for "Slow is smooth. Smooth is fast..." and in a stressful underwater situation it sure is nice to know I have a few moments to calm myself with a brief pause and think of how to best solve a problem. Simply knowing my immediate urge to breath is CO2 driven as opposed to an urgent need for O2 gives considerable confidence to simply slow down a moment, which without training runs entirely contrary to human instincts...

 

[EFX]

I m still not clear on the benefit of being able to hold your breath for an extended period of time while on scuba, ...........
BTW, I have no idea how far I can swim while holding my breath because I never saw any reason I would need to know this.

The only reason I see to holding your breath is when you run out of gas and you need to swim to your buddy and get their attention to share gas. It would be better to swim closer to your buddy and practice buddy awareness. This awareness includes paying more attention to your buddy and to the surrounding environment, and properly positioning oneself to eliminate long swims, or long periods of time to get or give gas in an emergency.

 

[happy-diver]

What about holding your breath when your buddy has already run our of air, is breathing from your octopus
and you are clearing out your reg as a completely unforseen circumstance has occurred and it is full of fishes

 

[CT-Rich]

Substantial value in my mind is comfort/confidence in the water (which was one of justifications given to practice out of air ascents...). Other than that, my being able to freedive over 100' deep in warm water hasn't improved my scuba diving at all (even to point I was kinda surprised my freediving didn't even improve my SAC rate, which actually got worse when I spent much more time freediving than scuba diving..).
There's a lot to be said for "Slow is smooth. Smooth is fast..." and in a stressful underwater situation it sure is nice to know I have a few moments to calm myself with a brief pause and think of how to best solve a problem. Simply knowing my immediate urge to breath is CO2 driven as opposed to an urgent need for O2 gives considerable confidence to simply slow down a moment, which without training runs entirely contrary to human instincts...

I have not practiced CESA in a long time because of the danger. Your SAC, I think, has more to do with your body size and how you breath. in 99.9% of your existenc it reall doesn’t matter because you have unlimited access to air. Underwater it does because you have a limited supply and you only get to use it once (on OC). I have seen smokers with great SAC, why? Maybe scarring in their lungs and a high tolerance for CO2. During a CESA, that is all pretty irrelevant because the gas is expanding.

As free diver you are trying to maximize exchanging gas at the surface, pretty much the exact opposite for scuba.