CESA theory

[Blackcrusader]

Sorry. I forgot to mention that I was not expecting out of context answers like buddy, pony bottle, doubles or whatever. The question is clear. Let’s assume that there is no other solution than CESA. Thank you.

One should not assume there is no other solution than a CESA from 30m or deeper

If you are OOA and alone or cannot get to a buddy there is another solution. Some may consider it risky as you could get a lung infection if you do not clean your BCD bladders. I would prefer a curable lung infection over death. The solution comes with something you wear on your dives. I was taught this by my BSAC instructor who was also a commercial diving instructor. Also I see many divers who suck their BCD bladders dry for traveling and also when they empty them at the end of dives. People do actually suck air out of BCD's on a regular basis and never get lung infections or die. Only one diver who had a freak death died from doing this by sucking from moldy bladders when not on a dive. I have done this procedure myself and lived without any lung infection. Self reliant rescue is really a good thing.

Emergency Breathing from Your BCD: Undercurrent 06/2011

 

[Blackcrusader]

and the buddy is.....

My BCD

 

[boulderjohn]

Do a Google search to find videos of emergency ascent procedures as practiced by the navy for submarine escapes. They now use special suits, but when first practiced they used nothing more than a simple vest like a BCD. They are taught to exhale completely BEFORE they begin the ascent. When you think you are exhaling completely, you actually still have lots of air, and it expands rapidly, so after exhaling "completely," you still need to exhale all the way to the surface.

They are doing what is called a buoyant ascent, not a controlled ascent. If you are very deep, then head on up quickly. You can do it from any scuba depth. The navy has done buoyant ascents like this from 300 feet.

 

[rhwestfall]

My BCD

Again, another tool in the toolbox!

 

[Blackcrusader]

Have you missed the part in your training on how gasses respond to changes in pressure? Do you understand why you don't hold your breath? You are asking questions that are basic principals...

You list your credentials as a DM....

Dody is DM certified and he should have learned about these things. There is no issue in asking again as it is not like people practice for a CESA. Perhaps they should do so so they do not panic in case they need to. My own post is sure to get some blow back but in an OAA with no buddy to assist I would rather risk a wee infection than a drowning. Not a lot of people survive drowning.

 

[Dody]

One should not assume there is no other solution than a CESA from 30m or deeper

If you are OOA and alone or cannot get to a buddy there is another solution. Some may consider it risky as you could get a lung infection if you do not clean your BCD bladders. I would prefer a curable lung infection over death. The solution comes with something you wear on your dives. I was taught this by my BSAC instructor who was also a commercial diving instructor. Also I see many divers who suck their BCD bladders dry for traveling and also when they empty them at the end of dives. People do actually suck air out of BCD's on a regular basis and never get lung infections or die. Only one diver who had a freak death died from doing this by sucking from moldy bladders when not on a dive. I have done this procedure myself and lived without any lung infection.

Emergency Breathing from Your BCD: Undercurrent 06/2011

So, you consider that the risk of death is higher in a CESA from 30 m than breathing out of BCD? So all those stories about CESA from 30 m are just from exceptional i dividuals?

 

[BoltSnap]

Here's the deal. If you are out of gas at 30 meters you have two choices. Stay there and die or head for the surface. All of your questions are irrelevant if you're 30 meters deep and out of gas.

Bottom line is keep your airway open on the way up. If you end up bent so be it. Rather be bent on the surface than dead on the bottom.

At least one gets a proper burial not end up as fish food with crabs nibbling on your eyes and shrimp crawling up your nostrils (ouch).

 

[Dody]

Have you missed the part in your training on how gasses respond to changes in pressure? Do you understand why you don't hold your breath? You are asking questions that are basic principals...

You list your credentials as a DM....

You are thick, aren’t you? For your guidance, I am graduated in physics so all you know about gas from diving lessons, I have learnt earlier and deeper. Who talked about holding breath? I asked how long can you exhale. And is there data about gas inflation and exhalation from 30 m to surface.
Try to understand the question before playing the expert… that you are not.

 

[Blackcrusader]

So, you consider that the risk of death is higher in a CESA from 30 m than breathing out of BCD? So all those stories about CESA from 30 m are just from exceptional i dividuals?

Dody as a diver one must know your own limitations. Let's put it this way, a CESA from 30m requires a lot of effort and must be done correctly. Are you going to ditch weights and scream as you ascend? It's one way not the only way. Using a BCD you can rebreathe the air as when you exhale you have 15% 02 put back. You can ascend at a fast speed and as the air does expand you get some extra lift. For me far less stressful than a CESA and more controllable.

I have posted many times I do use extra weights on my dives as this means at depth I use a little more air in my BCD. I do this as many vacation divers are underweighted when they are low on air and have uncontrolled ascents. You know what it is like to be underweighted on dives yourself from your other threads. You should in your training have already been shown how to clear water from your inflator hose using your mouth. I do not think I would make it from 30m doing a CESA and I'm not about to try anytime soon lol So I could also rebreathe from my BCD to get to another diver as well if there was some separation between us and also that diver can get to me. There can be residual air in the secondary you can suck out and exhale into your BCD as well. A first stage failure is not always so sudden you do not have time to get some air into your BCD either.

Try this at home, get a large plastic bag and put it over your head and do slow breathing and feel the effect. You are not going to die from a little CO2 buildup.

 

[BoltSnap]

I am graduated in physics so all you know about gas from diving lessons, I have learnt earlier and deeper.

I asked how long can you exhale. And is there data about gas inflation and exhalation from 30 m to surface.

You are Einstein, yet you ask this question??? You should be the expert to answer the question. Perhaps you were out sick with a hangover when they discussed this in your physics course??