CESA Question

[Boarderguy]

Instead of learning CESA, you can learn to dive in a team and plan your gas.

Does that mentality also include no dives below 100 without helium or doubles only for dives requiring redundant air?

 

[Eric Sedletzky]

Instead of learning CESA, you can learn to dive in a team and plan your gas.

You should learn both.

 

[boulderjohn]

A simpler and more generic way of saying what has been said in the last few posts is that there is no reason to learn emergency skills. Just don't make any mistakes. That philosophy would apply to most pursuits in life.

 

[Nosmosis]

Does that mentality also include no dives below 100 without helium or doubles only for dives requiring redundant air?

no, I‘m just surprised that there is so much emphasis on this skill and nothing usually taught significantly on gas management until later levels. Just „be on the boat with 500 psi.“ Seems backwards to me that’s all.

 

[dmaziuk]

no, I‘m just surprised that there is so much emphasis on this skill and nothing usually taught significantly on gas management until later levels. Just „be on the boat with 500 psi.“ Seems backwards to me that’s all.

Maybe you should go to your OW instructor and demand your money back.

I distinctly remember mine explaining this thing about SPG and all

 

[Boarderguy]

no, I‘m just surprised that there is so much emphasis on this skill and nothing usually taught significantly on gas management until later levels. Just „be on the boat with 500 psi.“ Seems backwards to me that’s all.

In my wife's OW course in April '22 the CESA was discussed, but never demonstrated at any appreciable depth. Blow bubbles, ascend at normal rate, breathe fresh air once up top. Gas planning and turn pressures were talked about and executed during check dives. Gas management has almost nothing to do with a cesa unless you don't follow your plan...

 

[gordonscuba]

Others on here will question what I am going to say next. If I was in a no alternate air source situation I would ascend breathing a little using my inflator hose as a counterlung.

Yup, there's a reason other divers will question it.

(1) Actual counterlungs, as found on rebreathers, are disinfected with steramine at the end of every diving day, whereas most BCs are not; so either (a) the rebreather community is wasting tons of steramine every day, or more likely (b) any random diver's wing may have bacteria growing inside that are not present in actual counterlungs.

(2) Why is this CESA + additional task-loading believed to be safer than a standard CESA (especially given that in deeper CESA the diver feels less starved for air than one would think, due to gas expansion)? Is there just a small chance that while breathing from your inflator in a flustered state, you forget to keep an eye on your ascent rate?

(3) If you are using the wing as a "counterlung" implying exhaling into it, then after a certain number of breaths the mix inside will become hypoxic. Actual rebreathers monitor ppO2, which this "counterlung" doesn't.

 

[johndiver999]

Yup, there's a reason other divers will question it.

(1) Actual counterlungs, as found on rebreathers, are disinfected with steramine at the end of every diving day, whereas most BCs are not; so either (a) the rebreather community is wasting tons of steramine every day, or more likely (b) any random diver's wing may have bacteria growing inside that are not present in actual counterlungs.

(2) Why is this CESA + additional task-loading believed to be safer than a standard CESA (especially given that in deeper CESA the diver feels less starved for air than one would think, due to gas expansion)? Is there just a small chance that while breathing from your inflator in a flustered state, you forget to keep an eye on your ascent rate?

(3) If you are using the wing as a "counterlung" implying exhaling into it, then after a certain number of breaths the mix inside will become hypoxic. Actual rebreathers monitor ppO2, which this "counterlung" doesn't.

So you think that the hypoxic mixture in the BC bladder it more problematic than the hypoxic mixture in the lungs? Not sure I understand the logic of this statement.

 

[gordonscuba]

So you think that the hypoxic mixture in the BC bladder it more problematic than the hypoxic mixture in the lungs? Not sure I understand the logic of this statement.

I just meant that as soon as you start re-breathing from a wing, you start a clock counting down with a matter of a few minutes to both hypercapnia and hypoxia. Hypercapnia leads to hyperventilation, panic, and then loss of consciousness, with increased rate of breathing happening pretty soon in the process. Hypoxia simply leads to loss of consciousness with little warning. Once consciousness is lost, drowning typically follows. If the diver ascends to the surface quickly enough, say at the same rate as in normal CESA, then there's probably not enough time for full hypercapnia/hypoxia to set in, so I concede that point, but what if the diver ascends a little more slowly because they now have the sensation of being able to breathe, taking two minutes to reach the surface? Anyway, if they black out, it's very very bad.

I forgot to mention another reason this procedure is a bad idea. It's pretty easy for some water to enter the inflator hose (and wing) during a dive. So if you are contemplating taking a breath from an inflator hose, you must remember to first purge the hose by somehow venting gas through it, or you risk inspiring water at the worst possible time. Coughing would be bad, at this point in the process. If you were running with the wing close to empty during the normal portion of the dive, there is likely water in the inflator mechanism, and at the same time not enough air to purge the hose completely. If there is water in the wing, then being slightly heads-down could bring that water forward and into the inflator hose. Starting to sound like a lot to keep track of, for someone who is calmly facing their own mortality?

 

[MidOH]

Yup, there's a reason other divers will question it.

(1) Actual counterlungs, as found on rebreathers, are disinfected with steramine at the end of every diving day, whereas most BCs are not; so either (a) the rebreather community is wasting tons of steramine every day, or more likely (b) any random diver's wing may have bacteria growing inside that are not present in actual counterlungs.

(2) Why is this CESA + additional task-loading believed to be safer than a standard CESA (especially given that in deeper CESA the diver feels less starved for air than one would think, due to gas expansion)? Is there just a small chance that while breathing from your inflator in a flustered state, you forget to keep an eye on your ascent rate?

(3) If you are using the wing as a "counterlung" implying exhaling into it, then after a certain number of breaths the mix inside will become hypoxic. Actual rebreathers monitor ppO2, which this "counterlung" doesn't.

I cleaned my wings when I quit scuba in 2019.

Maybe we should consider doing this.

I manually inflate before dives, and am manually inflating and filling with water in my hotel, to clean the wing, inflator, and OPV. Ain't a stretch to assume there's risk of a bacteria whatever.