CESA Training

[Dody]

Yes. But from really shallow waters. I think that the idea was to get familiar with dropping the weights and the position. There was absolutely no risk in my point of view as I exhaled all the way up and I had my regulator with a full tank.

This was a rescue course for advanced divers, not an OW.

 

[Dody]

You should never practice a buoyant ascent. I assume you had very little weight and not a thick wetsuit, so your ascent, particularly from 4 meters wasn't fast enough to be of major concern. I assume you were in a pool and not outside in The Netherlands in Feb.
Buoyant ascent can be very dangerous for the bends, and is the last resort when you run out of other options.

For the CESA, you may have been exhaling too much air at once. 5 meters should be a breeze at a safe speed-- shouldn't run out of air, but I guess you were just too slow. I like the idea of staring with lungs maybe half full and have mentioned that to students after they did it with a big full breath in the OW course. I figure if you can get a full breath from the tank you can at least start out with a normal ascent.

I had a 5mm wetsuit with 5 kg of lead. Not in the Netherlands but in Cape Verde but this is currently the bad season and water temperatures are low. So instead of doing it in the 17 degrees pool, we did it in the 20 degrees ocean (I will buy myself a semi-dry suit. Even 20 degrees water is cold for me, I was in bad shape at the end of the dive, shivering), 10 meters from the shore.
I hope and I am pretty sure that I will never be in an OOA situation but I think it was good to do those exercises. And once again, it was not an OW or new diver course, it was a Rescue course for AOW divers.
From such shallow depths, as long as you exhale, you should be fine. I think that the real risk is not so much bends or DCS but lung overexpansion.

 

[Edward3c]

...
From such shallow depths, as long as you exhale, you should be fine. I think that the real risk is not so much bends or DCS but lung overexpansion.

When I learned to dive in the 1970s, the instructor took us out with snorkel kit plus ABLJs with 0.5Lt crack bottles. We duck dived to 3-4m then opened the bottles to simulate a buoyant assent. The reason we were snorkelling was so as not to burst a lung, the practise was stopped a year later as one student had breathed off the ABLJ on the way up and died.

Don’t think for a minute 3 or 4m is safe to just come up from. The shallows are more dangerous than deeper water as the change in pressure/volume is so dramatic.

 

[BoltSnap]

Yes. But from really shallow waters. I think that the idea was to get familiar with dropping the weights and the position. There was absolutely no risk in my point of view as I exhaled all the way up and I had my regulator with a full tank.

The shallower, the worse it will be in terms of "rate" of pressure change and chances of getting serious lung injury. You can get lung over-expansion injury in the deep end of a 3 meter pool or even shallower. I am not sure about your agency but I don't think that this exercise is within agency standards. You may have lucked out and exhaled all the way out but what about another student who didn't or what if something went wrong and you got hurt? If I had to teach it, I'd have done it free diving and not have to worry about lung injuries. Buoyant ESA is really a last option and done in real condition when everything else fails and you want to float up to the surface knowing that there is a much higher chance of injury but it is better than being stuck for eternity on the bottom. We talk about it in class as a last resort option that is extremely dangerous but we don't practice it in the pool or openwater at all.

 

[Dody]

When I learned to dive in the 1970s, the instructor took us out with snorkel kit plus ABLJs with 0.5Lt crack bottles. We duck dived to 3-4m then opened the bottles to simulate a buoyant assent. The reason we were snorkelling was so as not to burst a lung, the practise was stopped a year later as one student had breathed off the ABLJ on the way up and died.

Don’t think for a minute 3 or 4m is safe to just come up from. The shallows are more dangerous than deeper water as the change in pressure/volume is so dramatic.

From 3/4 meters, we talk about a max 30/ 40% risk of overexpansion. However, if you keep on exhaling, I don’t see where the risk is. There was no Nitrogen (DCS) issue as we did not exceed 5 meters and stayed underwater for 30 minutes at the most.

 

[Dody]

I do understand your comments but we need to train for those situations, right?

 

[Dody]

the practise was stopped a year later as one student had breathed off the ABLJ on the way up and died.

I don’t understand. What id ABLJ?

 

[Edward3c]

From 3/4 meters, we talk about a max 30/ 40% risk of overexpansion. However, if you keep on exhaling, I don’t see where the risk is. There was no Nitrogen (DCS) issue as we did not exceed 5 meters and stayed underwater for 30 minutes at the most.

We had a fatality in the 1980s where a trainee died from holding their breath after breathing off an aqualung from 1.5m in a swimming pool.

The danger of buoyant assents is burst lungs. You damage them both your dead.

I don’t understand. What id ABLJ?

ABLJ = Adjustable Buoyancy Life Jacket, a form of Buoyancy Device. Here is a later model as its got a power inflator

 

[johndiver999]

I actually tested CESA and buoyant ascent today but it was not what I expected. What I did not know is that it is part of the Stress and Rescue course that I started today. First, the CESA is done at maybe 5 meters. I wanted to make it as realistic as possible so I did not fully inhale at start-up. I was ascending too slow and I screwed up. Before reaching the surface, I had to stop exhaling and breath in through my regulator :-( . Then came the buoyant ascent. It was from 4 meters. I ditched my weights, put myself on my back but I ascended way slower than I expected. No feeling of not being in control. So apart from the fact that I can't sustain a breath out longer than 30 seconds ( I will probably die if I have to do a CESA from 10 meters ), I did not learn much.

You were able to perform a CESA for a distance of only one meter and then ran out of "breath" and consequently had to ditch lead, and then breathe from the regulator and perform a buoyant ascent for the remainder of the ascent (from a depth of 4 meters to the surface)??

 

[Dody]

You were able to perform a CESA for a distance of only one meter and then ran out of "breath" and consequently had to ditch lead, and then breathe from the regulator and perform a buoyant ascent for the remainder of the ascent (from a depth of 4 meters to the surface)??

I think that you did not read correctly