How deep can you do a CESA and survive?

[MaconBubbles]

There's been a couple of comments about CESA lately and I had a question about it. I know that it's the very last option in an out-of-air situation, but I was wondering how deep you could be, use the CESA, and likely survive? Because whatever air you had left in your lungs is expanding as you ascend, would it make you feel like you had more air to exhale as you rise? Would you be able to blow out longer, say, than me sitting in my chair right now slowly blowing out a full breath? Just wondering.

 

[fisherdvm]

I've heard of people doing CESA with a regulator in their mouth and breathing a few more breath of air out of their tank.

I also wonder, how many have done CESA with a flooded reg, or without a regulator in their mouth, and from what depth.

 

[Brandon]

One of the four lettered training organizations says that CESA should be used for emergency ascents of 40 feet or less.

Practice it several times and you'll be able to do it from deeper depths.

And it's not the very last option - the very last option is to blast your inflator and hope for the best (the positive buoyancy emergency ascent) It'll get you to the surface, but it isn't going to be pretty.

I remember reading somewhere that "they have chambers to fix the bends... but they don't have a chamber to fix drowning"

-B.

 

[fppf]

I saw someone do an uncontroled ascent from 120 feet.
Lucky the boat was not over the person because they breached the water like a whale.

They where uninjured and did not get bent, happened just as they hit the bottom.

 

[MaconBubbles]

And it's not the very last option - the very last option is to blast your inflator and hope for the best (the positive buoyancy emergency ascent) It'll get you to the surface, but it isn't going to be pretty.
-B.

Thanks Brandon, but I was assuming I had NO air left, and my main question is if you had that one last breath, how long could you use it to exhale, assuming the air in your lungs is expanding as you rise. Seems like it would make it last longer. It's just a question I've always wondered about but keep forgetting to ask.

 

[drbill]

I did one from just over 70 ft when I exhaled and then couldn't draw another breath because the tank valve's debris tube clogged. There was nothing coming out to fill the BCD (which I had already deflated, getting ready to film on the bottom). It took 70 seconds to get to the surface and I didn't ditch my weights.

I wouldn't want to do one deeper than that, but am sure I could do 80-90 ft IF I had just taken a lungful of air.

 

[Charlie99]

I did a controlled ascent, taking almost 2 minutes to go from 90' to 15' in a practice CESA, and could have gone much slower than the 40fpm of that ascent. It was very strange to end the ascent with more air in my lungs than I had started with.

The trick was to NOT to actively exhale or hum or aaaaah, but instead KEEP MY AIRWAY OPEN and let the excess air just kind of bubble out on its own.

The certifying agencies are taking a shortcut by teaching people to hum or aaaaaahhhhh all the way up, rather than teaching that what is important is an open airway, and then teaching people what that means.

Report of very slow 100' submarine escape training tower ascent


Charlie Allen

 

[Brandon]

my main question is if you had that one last breath, how long could you use it to exhale, assuming the air in your lungs is expanding as you rise. Seems like it would make it last longer. It's just a question I've always wondered about but keep forgetting to ask.

It should last longer, as it will be expanding as you ascend. You should also be able to get another breath or two out of your regulator as you come up, so keep it in your mouth.

-B

 

[SteveC]

In theory you are right, you will have more air to exale, but I've have never wanted to test the theory

 

[jimdiverman]

I saw someone do an uncontroled ascent from 120 feet.
Lucky the boat was not over the person because they breached the water like a whale.

They where uninjured and did not get bent, happened just as they hit the bottom.

I think it has a lot to do with how much time you have been underwater, and therefore, how much nitrogen you have built up. I have heard stories of people diving air making runs to deep depths, and coming right back up... such as to retrieve a weight belt or other dropped item. I have only heard of this, and not seen it personally.