CESA from 40ft

[TSandM]

Moerby, I tried the experiment you're talking about, but not with a CESA. I got my husband and me as far as apart as he seemed to like to dive, and then I exhaled, pretended I had no gas, and swam to him. It was harder than I thought, because of course, I was negative as well as distant, so I had to swim UP as well as across the 25 or 30 feet of space. I got to him, tapped him on the shoulder (he was, of course, head and camera in a hole), got him to turn around, signaled OOG, and got a reg from him. By the time he gave it to me, I was very glad to have it, but I hadn't reached the point of considering breathing water yet.

Going to the surface is easier, of course, because buoyancy gives you a boost, so you don't have to swim as hard as I was doing. You may not feel much urge to exhale, and again, so long as you keep your glottis open, it is not really necessary to vent a lot of gas. I remember from my CESA in my OW class that I was quite surprised that the air kept coming and coming as I went up, and how easy the drill was to do, compared with doing it across the pool. I suspect you'd be surprised that you could find some gas to let out, even if you thought your lungs were empty (which they never actually ARE, when you have finished exhaling). And as boulderjohn observes, there is nothing wrong with sucking on your regulator a bit -- you may be surprised and get quite a bit of a breath.

But, although I know I sound like a broken record here, this whole scenario of being at 100 feet and out of gas and all alone is one you only reach after so many failures that you should never, ever be there. If you plan your gas, monitor your gas, and stay with your buddy, you simply aren't going to face the "out of gas and alone" issue. I just keep feeling as though you are spending a lot of time and energy and thought on the last link in a nasty chain that needs to be broken much closer to the beginning. Please just acknowledge that you have read the references I gave you, and I'll stop bothering you about it.

 

[Thalassamania]

...
5. Your blood has enough O2 in it to keep you conscious for about a minute to a minute and a half, so even if you had absolutely nothing to start with you should make it to the surface.

I believe that you have enough oxygen in your bloodstream to maintain consciousness of four minutes or so.

Moerby, I tried the experiment you're talking about, but not with a CESA. I got my husband and me as far as apart as he seemed to like to dive, and then I exhaled, pretended I had no gas, and swam to him. It was harder than I thought, because of course, I was negative as well as distant, so I had to swim UP as well as across the 25 or 30 feet of space. I got to him, tapped him on the shoulder (he was, of course, head and camera in a hole), got him to turn around, signaled OOG, and got a reg from him. By the time he gave it to me, I was very glad to have it, but I hadn't reached the point of considering breathing water yet.

Going to the surface is easier, of course, because buoyancy gives you a boost, so you don't have to swim as hard as I was doing. You may not feel much urge to exhale, and again, so long as you keep your glottis open, it is not really necessary to vent a lot of gas. I remember from my CESA in my OW class that I was quite surprised that the air kept coming and coming as I went up, and how easy the drill was to do, compared with doing it across the pool. I suspect you'd be surprised that you could find some gas to let out, even if you thought your lungs were empty (which they never actually ARE, when you have finished exhaling). And as boulderjohn observes, there is nothing wrong with sucking on your regulator a bit -- you may be surprised and get quite a bit of a breath.

But, although I know I sound like a broken record here, this whole scenario of being at 100 feet and out of gas and all alone is one you only reach after so many failures that you should never, ever be there. If you plan your gas, monitor your gas, and stay with your buddy, you simply aren't going to face the "out of gas and alone" issue. I just keep feeling as though you are spending a lot of time and energy and thought on the last link in a nasty chain that needs to be broken much closer to the beginning. Please just acknowledge that you have read the references I gave you, and I'll stop bothering you about it.

Yes, today that is surely the case, buy the time you're OOA at 100 ft a lot has gone wrong. I guess I have trouble understanding why it is so upsetting to people because we used to have that happen all the time, as I said, that was how we used to know that it was time to come up. Since it did not upset me, it never upset my students either, because I taught them how to handle it from the get-go.

 

[boulderjohn]

How ridiculous! Not under any circumstances???? What if it is the typical over weight, out of shape American scuba diver whose heart is absolutely pounding and they have been struggling at depth BEFORE starting the CESA.......

How long can you stop breathing for in the middle of a jog?


I can do 20 seconds, but I loose color vision and I am dizzy and the legs become very weak. Serioulsy, what can you do?

So if you are jogging and try to hold your breath you go into convulsions? The term "convulsions" is pretty extreme. Are you sure that's what you mean?

 

[axxel57]

I did once a CESA from 27m (90"feet) just to see how that practically works. I had plenty of air and started a normal ascent ( with my 2nd in my mouth), only that after a big breath I just kept my airways open. I almost held my breath, but definitely didn't. Ascending, two, three times my computer gave me an ascent rate warning, so I slowed down immediately. After half the way to the surface when I had the feeling there should be no more air to exhale it kept on and on coming. I stopped at 15'feet to descent again to finish my dive ( I had done this just in the beginning), but the last 15'feet wouldn't have been any problem. IMO the ascent rate I dove was much slower than I could have done ( for example using the PADI table) with little risk.
I'm an expeienced diver, the situation was a controlled one, but that showed me that when done right, probably relying on yourself might be the better option in normal dive profiles than trying to reach your buddy, who might be some stretch away.
In my experience with my students the bigger problem usually doing the CESA is inflating the BCD on the surface orally ( especially in rough coditions). So that is a point I'm stressing in my courses.
Of course rule number one is forsight and good preparation before a dive, but there is no problem to try a CESA in depht for some feet to get a feeling and some confidence, because what could be the problem to do a normal ascent , just exhaling for a while?

 

[Moerby]

I did once a CESA from 27m (90"feet) just to see how that practically works. I had plenty of air and started a normal ascent ( with my 2nd in my mouth), only that after a big breath I just kept my airways open. I almost held my breath, but definitely didn't. Ascending, two, three times my computer gave me an ascent rate warning, so I slowed down immediately. After half the way to the surface when I had the feeling there should be no more air to exhale it kept on and on coming. I stopped at 15'feet to descent again to finish my dive ( I had done this just in the beginning), but the last 15'feet wouldn't have been any problem. IMO the ascent rate I dove was much slower than I could have done ( for example using the PADI table) with little risk.
I'm an expeienced diver, the situation was a controlled one, but that showed me that when done right, probably relying on yourself might be the better option in normal dive profiles than trying to reach your buddy, who might be some stretch away.
In my experience with my students the bigger problem usually doing the CESA is inflating the BCD on the surface orally ( especially in rough coditions). So that is a point I'm stressing in my courses.
Of course rule number one is forsight and good preparation before a dive, but there is no problem to try a CESA in depht for some feet to get a feeling and some confidence, because what could be the problem to do a normal ascent , just exhaling for a while?

Thank you very much for that info. Very useful.

 

[Osric]

In my experience with my students the bigger problem usually doing the CESA is inflating the BCD on the surface orally ( especially in rough coditions). So that is a point I'm stressing in my courses.

Based on dive accident statistics, I would have thought it was more important to stress that your students should dump their weights and keep trying their inflator which is more likely to deliver gas at the surface even if they were OOA at depth. Am I mistaken / is oral inflation an important skill?

I honestly want to know because so far as I can recall I have never done a drill where I've practiced oral inflation. If it's important, I want to practice it.

Osric

 

[Moerby]

Based on dive accident statistics, I would have thought it was more important to stress that your students should dump their weights and keep trying their inflator which is more likely to deliver gas at the surface even if they were OOA at depth. Am I mistaken / is oral inflation an important skill?

I honestly want to know because so far as I can recall I have never done a drill where I've practiced oral inflation. If it's important, I want to practice it.

Osric

We practiced it a LOT in our pool sessions. I think the key is that OOA can happen due to equipment failure too so you may not be able to use your LP hose to inflate the BCD. Our instructor also stressed the need to save the air for breathing as much as possible when you're at the surface, which makes sense.

 

[Moerby]

[Double post]

 

[dumpsterDiver]

So if you are jogging and try to hold your breath you go into convulsions? The term "convulsions" is pretty extreme. Are you sure that's what you mean?

Nope not yet. I feel close to passing out though. Divers with too little oxygen may become unconsious, but often they first have visual distrurbances (tunnel vision) and possibly later loss of motor control and/or tembling or freedivers call it samba, where the body is moving in an uncontrolled or spastic manner and then unconsiousness can occur.

It does not always occur in that order and people can easily just go out.

Now how about an answer for my question: How long can YOU continue to jog without breathing? I figure that is relatively analogous to a diver who is stressed out, breathing hard and looses all air.

 

[Akimbo]

... I think the key is that OOA can happen due to equipment failure too so you may not be able to use your LP hose to inflate the BCD….

Dropping weight is pretty darn reliable (if it comes to that) and doesn’t consume any air that you may be able to breath.

... Our instructor also stressed the need to save the air for breathing as much as possible when you're at the surface, which makes sense.

Not sure I understand the “when you're at the surface” part. Did you mean something like “for the trip to the surface”??? I couldn't care less if there is any air left after reaching the surface.