Max Depth for CESA

[DaleC]

For me, the acceptable CESA depth is a personnel number based on what one feels comfortable ascending from, which in turn should be based on some sort of experiential evidence and not someone else's values. For me this is about 50' and, as a result, that is the depth that I will solo dive (hard bottom) without a redundant airsource.

I base my number on being able to very comfortably free dive to 30' (which means a return trip of 60'). I also like to apnea swim in the pool and can do 25m (75') without fins horizontally (again without undue stress). Considering, as DD points out, that a real CESA probably won't occur on a full breath, but also considering the lift that increased buoyancy will provide, I like 50' as a fair compromise.

As Lynne points out, a CESA in a buddy situation means two failures have already occurred and those should be addressed before/instead of working on alternate solutions to them; but for a solo diver, or someone who wants to be well rounded and just have more tools in the box, it doesn't hurt to have a working number to base dive/contingency plans on.

Better than just imagining one can do a CESA from some theoretically generated number.

 

[Diver0001]

A CESA is actually not terribly difficult from 40 feet or so, although the way we set them up in class is very artificial, because the students can hyperventilate before starting

You allow your students to do that? You're a lot more forgiving than I am. I don't brief that at all. We just get neutral on the line and when I'm set up I give them a thumbs-up and they can proceed with the CESA as soon as they're ready.

R..

 

[TSandM]

No, we don't brief that they can -- but as you said, you give the signal, and they can go when they're ready, and nothing prevents them from taking a couple of extra-deep breaths in preparation.

 

[Diver0001]

I see.

Well you're right about one thing. The exercise lacks a sense of reality.

R..

 

[Mr Carcharodon]

The "C" in CESA stands for "controlled"...

With LA County doing a few thousand CESAs uneventfully from 100 fsw its pretty clear the max depth to CESA is beyond that. We can throw in cautions about how that was a somewhat contrived excise and it is not recommended to be routine. Still it seems to more directly amswer the original posters question.

 

[Akimbo]

…If I drop the 20 lbs of lead I wear around my waist in Puget Sound, I seriously doubt I'll be able to control my ascent, once I get into the shallows. I would be surprised to learn I can swim down 20 lbs of buoyancy.

I suppose it all depends on your definition of a controlled ascent. I have dropped a 10 Kg/22 Lb belt from 60'+ in a wetsuit at least a dozen times in training and testing and had very little difficulty controlling ascent. Descending when 20 Lbs buoyant is, IMHO, very difficult but possible for strong freedivers. I did it 30 years ago, but probably not today.

I was trained when free ascents were the norm in recreational diving and the Navy repeated and expanded that training 8 years later. I have made free ascents from 180' in open sea for practice. The deepest free ascent I am aware of was made by Captain/Doctor George F. Bond (father of saturation diving) and Chief Cyril Tuckfield in 1959 from 302' from the submarine USS Archerfish, without Stanky Hoods.

I feel that being skilled in free ascents is the single most valuable training to avert panic in recreational divers. It is a shame that training agencies are too lazy to teach it and agency lawyers make it largely impossible.

A lot of new divers get their underwear in a twist at the mention of free ascents. What about DCS!!? Well, DCS is not a certainty and is highly treatable. Blacking out before reaching the surface… not so much.

 

[DaleC]

I feel that being skilled in free ascents is the single most valuable training to avert panic in recreational divers. It is a shame that training agencies are too lazy to teach it and agency lawyers make it largely impossible.

I agree with you on this sentiment. The value of understanding my own CESA capabilities is not that I can use it as a first resort or that it allows me to be lax in dive safety, but rather, that I know it is there if all else fails. I know where the exit is and I know I can get to it. That delays the impulse to a reflexive fight or flight response and allows one to work through problems in a more controlled fashion.

 

[Peter_C]

I feel that being skilled in free ascents is the single most valuable training to avert panic in recreational divers. It is a shame that training agencies are too lazy to teach it and agency lawyers make it largely impossible.

Maybe what should be trained is freediving? There is nothing like having your lungs burning as you ascend to the surface. A lot can be learned doing so. I know NAUI requires it at least a little freediving.

Then again I would guess a little comfort in the water would alleviate a lot of the panic situations. I am lucky that I grew up with a swimming pool and tried everything possible to drown and failed...at least so far.

 

[TSandM]

Still it seems to more directly amswer the original posters question.

In my first post in this thread, I did say that there are documented CESAs from 100 feet, which I believe WAS responsive to the OP's question. But he also asked whether this was a skill he should practice, and in my opinion, it is not.

 

[Bob DBF]

I feel that being skilled in free ascents is the single most valuable training to avert panic in recreational divers. It is a shame that training agencies are too lazy to teach it and agency lawyers make it largely impossible.

And for those who don't like this idea, the second would be to become a decent freediver. Both is better. When you have a reasonable idea how much time you actually have to deal with a problem, a more reasoned solution is likely to emerge and if it dosn't, you know your escape route.

When I was in submarines, the escape was done from 50 and 100' by kids with no SCUBA training, and went well for most. I believe the most problems occurred on the pressurization to depth as it was fast and equalization was difficult. Divers in the tower took care of any problems in the water on the way up.



Bob
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I may be old, but I'm not dead yet.

HoHoHoHoHo...........