Max Depth for CESA

[DCBC]

What is the maximum depth that one can do a CESA?

Bill, this depends upon the individual, the amount/type of training and the time they've dedicated to practice. I usually do a a 50' CESA (vertical) in OW and 100' in Advanced. Personally, I usually do a CESA to my decompression stop as a matter of routine. I figure I have to ascend anyway, so why not benefit from the drill?

We should all be diving within our 'safety envelope.' When you start, it's prudent to not dive deeper than a depth in-which you can reach the surface in an emergency, keeping in-mind that CESA is a last resort (that's one of the reasons why you dive with a Buddy).

 

[Divenomad]

In 2001, I, personally, did one from 100 feet.It was not a drill. It is my opinion that it can be done from much deeper if the diver keeps their head together.

 

[billt4sf]

Personally, I usually do a CESA to my decompression stop as a matter of routine. I figure I have to ascend anyway, so why not benefit from the drill?

Oh, this sounds like a nice drill to practice. Would it be safe for buddies of moderate scuba skills (50 dives) to practice going from, say, 70 feet to 35 feet with the reg in but slowly breathing out continuously? 50 feet to 25 feet? I think it would be good for us to have some confidence in our ability to do this, if only for peace of mind. We do try to practice our other buddy skills, e.g. sharing air.

 

[Peter_C]

Anyone complaining about fatigue after diving needs to do the slowest ascents possible, and especially AFTER the safety stop on the way to the surface. Plus part of the reason for deep stops is to control buoyancy. As most know it is fairly easy to loose control of buoyancy in a drysuit when ascending too fast.

 

[TSandM]

Bill, I suspect you may not have a lot of opportunities to do this, if you intend to continue with local diving. Unless you go out on the boats, you will be swimming upslope, rather than doing direct ascents.

I still think, very strongly, that your time and energy is better spent on working on good situational awareness and buddy skills, gas planning, gas monitoring, and occasionally practicing gas sharing (which you are doing) rather than practicing a rather dubious approach to dealing with an out of gas situation. Remember -- the things that are going to land you underwater and out of gas are OVERWHELMINGLY things that are within your control. And of the few that aren't, most will give you time to get to your buddy and establish an air-share, assuming you have stayed within a reasonable distance of one another. (Or they will have given you time to ascend to the surface before you are completely out of gas.) There are very few failure modes that will put you instantly and completely out of gas when there is still gas in your tank. Going head down and having a dip tube block is one, and there are VERY rare 1st stage failure modes that apparently can. But the likelihood is that, if you plan your gas and monitor your gas, you will likely NEVER have to deal with an out-of-gas situation. Between me, my husband, my mentor, and my two best SoCal diving friends, we have almost 10,000 dives. None of us has been instantly out of gas. None of us, past the very beginner phase, has run out of gas. I have had one freeflow which resulted in an air-share and routine ascent.

Don't worry about CESAs. Worry about being a thoughtful, prepared, and competent buddy pair.

 

[letterboy]

Here's why

Think twice before breathing off a bag - Divernet

not really that much more meaningful ;-)

 

[Rhone Man]

I hadn't heard the Bret Gilliam story, but I have heard a pretty well sourced story about a CESA (although probably more of an ESA...) from the Andrea Doria when a J-valve accidentally got tripped. That is a good solid 180' plus. Not recommended.

 

[BDSC]

In my OW class, we practiced CESA in the pool, and maybe in the ocean as well -- I don't recall. Never practiced it since -- should I?

- Bill

I was certified back in 91. We did a CESA in our OW class from about 25 to 30 ft. or so. I was thinking at the time it was going to be really hard to do this but in the end it wasn't bad at all. Since then I have practiced it maybe 4 or 5 times. The last being in Bonaire about two years ago when I was doing a solo dive at about 40 ft and just decided since I hadn't tried it in a few years, I'd give it a shot and again no real problem. Of course I'm not sure how realistic that really was since I was not in a panicked state and had plenty of gas but still it was practice.

So to answer your question, I do think it's a good idea to practice it now and then. Perhaps I should practice it more than I have. I think the way DCBC does it is an excellent idea.

 

[DCBC]

Oh, this sounds like a nice drill to practice. Would it be safe for buddies of moderate scuba skills (50 dives) to practice going from, say, 70 feet to 35 feet with the reg in but slowly breathing out continuously? 50 feet to 25 feet? I think it would be good for us to have some confidence in our ability to do this, if only for peace of mind. We do try to practice our other buddy skills, e.g. sharing air.

Absolutely. Today there seems to be way too much dependence on equipment. Training standards have (and continually are being) lowered because of available technology. It is however only a matter of time before any piece of equipment fails. The hard drive on your computer has a specified MTBF (Mean Time Between Failure) estimated in hours of operation. It's failure is expected. Even though this is known, not everyone backs-up their information as regularly as may be required...

Good skills on the part of the diver can make the difference between not reaching the surface, or simply dealing with an unfortunate situation. Many divers haven't experienced equipment failure and because they dive 'just for fun,' failure isn't something that's seriously planned for. Although maintenance is a recognized factor, the risk is never eliminated. We each have to prepare for the eventuality of equipment failure to whatever level we feel comfortable with. For me, efficient emergency swimming ascent skills are as much a part of my dive plan as my gas source.

 

[elmer fudd]

If you really want to experience a CESA, breathe your tank dry sometime. Bring along a pony and keep your depths and nitrogen levels reasonable of course, but after you get down to 1000 PSI or so just don't check your air. Let it catch you by surprise, the way it will if if TSHTF. Using a balanced regulator, I found I just went from breathing easily to nothing in one breath and like Dumpster Diver mentioned in a previous post, I did not have full lungs when the air ran out. I was able to inhale a little, (not much), on the 25' or so I had to ascend to reach the surface and from that shallow depth, with the CESA being something I was expecting, I did not find it difficult.

What I did find shocking was how suddenly I ran out of air. I was really expecting to be sucking my last few breaths out of the tank and instead it was like someone had just turned off the hose.