Performing a CESA After Exhale

[decompression]

You know this is the Solo forum, no?
Agree completely on focusing on situational awareness. Doesn't mean knowing how to do a CESA is pointless. You just may slip up someday--we are all capable of that. I read that the most likely candidates for accidents are new divers and very experienced ones (due to becoming complacent). You can have great situational awareness and still have CESA in your tool box. What can it hurt?

Totally forgot it’s in the solo forum....... Yes, the confidence that you can ascend on zero breathe does have a positive. I see the value in that....
But back in solo mode, the awareness of gas remaining in every tank you carry....solo should always have a redundant gas supply.....should enable you to switch on a no-breath situation. No tank should be breathed empty, so No CESA required.

 

[Akimbo]

But back in solo mode, the awareness of gas remaining in every tank you carry....solo should always have a redundant gas supply.....should enable you to switch on a no-breath situation.

Even when you are doing macro photography in 20' of water? How about less than 10'. "Always" might be a OK for training new students but understanding individual limitations is THE most important skill of a solo diver. IMO, knowing the conditions you can survive when all your gear fails is an important skill.

Unfortunately, learning to perform free ascents, which I prefer over CESAs, is a labor intensive skill to teach. It also requires watermanship skills well beyond current minimum standards for recreational Scuba training.

 

[TMHeimer]

Totally forgot it’s in the solo forum....... Yes, the confidence that you can ascend on zero breathe does have a positive. I see the value in that....
But back in solo mode, the awareness of gas remaining in every tank you carry....solo should always have a redundant gas supply.....should enable you to switch on a no-breath situation. No tank should be breathed empty, so No CESA required.

Agree. Except I am usually one of the exceptions Akimbo mentions in that 98% of my dives are in the 20-30' range. So, on those dives my pony bottle stays home since my redundant supply is the surface (thus the CESA practicing I do on occasion). For deeper dives than that I will seek a buddy. For below 80' I will have a buddy and possibly the pony as well. Just my own particular rules for risk tolerance. Of course, I always stay way clear of entanglement possibilities (even tall seagrass), but in a pinch I suppose I could ditch my whole unit and make it up from the shallows.
I'm deviating now, but have to mention that I bungee my primary in my mouth in case I ever should go unconscious for any reason. If I were to go solo on deeper dives I would spend the big bucks on a FFM.

 

[Subcooled]

When people discuss emergency ascent, be it swimming or buoyant or hauled, controlled or not, it is often forgot that running out of air is not a sudden event but a process. Once you notice the inhalation resistance growing, you can still get a few breaths. As you ascend and the ambient pressure drops, even more gas is freed from the cylinder. I have breathed a number of cylinders empty in a pool, at there is some time to think and act.

It is quite important to ensure positive (or neutral) buoyancy though. Sitting on the bottom with no gas and noticing that one is negatively buoyant is no fun experience. Not even in a pool. Yes. I tried.

 

[TMHeimer]

When people discuss emergency ascent, be it swimming or buoyant or hauled, controlled or not, it is often forgot that running out of air is not a sudden event but a process. Once you notice the inhalation resistance growing, you can still get a few breaths. As you ascend and the ambient pressure drops, even more gas is freed from the cylinder. I have breathed a number of cylinders empty in a pool, at there is some time to think and act.

It is quite important to ensure positive (or neutral) buoyancy though. Sitting on the bottom with no gas and noticing that one is negatively buoyant is no fun experience. Not even in a pool. Yes. I tried.

I agree, though I have not experimented with breathing my own tanks down to see what it feels like. Of course I assisted in classes where we turned the air off on students, but that is a different thing. As I mentioned, I would tell students that the instructor tells them to take a deep breath before starting up in order to make it as safe as possible and avoid any panic.
Of course if you are able to take a full breath, as you say you can probably just start up on a normal ascent and be OK as the ambient pressure allows you to get more air.
Perhaps what you say sort of eliminates the need to practice a CESA, but for whatever reason, I still do.

 

[drbill]

Years ago my tank stopped delivering gas at about 80 fsw 3 1/2 minutes into a dive. I had just exhaled and when I tried to inhale nothing came out of the reg. As soon as I sensed that, I began my slow ascent. As stated above, the gas in my lungs began expanding and I kept my air passage free. It was not a fun ordeal but I made it. Turns out a particle had entered my debris tube and stopped airflow.

 

[TMHeimer]

Years ago my tank stopped delivering gas at about 80 fsw 3 1/2 minutes into a dive. I had just exhaled and when I tried to inhale nothing came out of the reg. As soon as I sensed that, I began my slow ascent. As stated above, the gas in my lungs began expanding and I kept my air passage free. It was not a fun ordeal but I made it. Turns out a particle had entered my debris tube and stopped airflow.

Thanks. I guess that is a good justification for practicing CESA. Wow- 80'. I've heard it can be done from those depths, though I'm not gunna try it. I assume you made an ascent no more than a foot a second (or even 1/2 foot)? Were you keeping track on your gauge/DC?

 

[hedonist222]

Grab a lungful of whatever's left in your BCD.

I'm disappointed in myself that this magnificent solution never occurred to me.

Thanks for sharing!

 

[wetb4igetinthewater]

I just realized we are in the solo forum.

What is a solo diver doing without a redundant air source? That is violating one of the most important rules for solo diving.

 

[Dan]

Perhaps this will ultimately be a silly thought, but it has crossed my mind enough to ask around. There are certainly scenarios for a solo diver -- or any diver really -- where a CESA is the only answer. I have always wondered however, what if the failure occurs at the very end of an exhale? Are you simply totally screwed with regard to needing to exhale throughout the accent? Am I missing something regarding the physics? Thanks.

David

You’ll know when you would be running out of air, as it will be getting harder to draw air out of your regulator. So, you would be warned by the regulator that you would be running out gas in the next few breath. Therefore it’s time to get the hell up and inhale your last breath before before you do CESA. May be you won’t be OOA since the ambient pressure would decrease as you ascend and the regulator would be continue supplying enough gas to you. You may not have enough gas to complete your safety stop or any DECO obligation and ended up locking out your dive computer, but you at least be alive and may be not getting DCI as you ascent at 30cft/min or slower. The key is to keep calm & slow ascent.

I’ve been in such situation, during DECO, the inhaling got harder, looked at my SPG and noticed it was down to 100 psig. So I pulled out my Spare Air, ready to switch to it when the gas in the tank became completely out. At DECO ceiling of 10 ft depth I can breathe my 3cft Spare Air for 6 minutes, enough time to clear my DECO obligation and keeping my SUUNTO D4 from locking out. Now I have Shearwater Teric, it’ll be ever better than D4. Those who own Teric, you know what I mean.