Who here has done a real life CESA and what was your experience?

[Kevrumbo]

1. Why did it happen?
--Long Hose Reg: Afterward, found that adjustment knob on 2nd stage blew out causing unrecoverable catastrophic free-flow.

2. What depth?
--Doing an initial weight check at 6m/20'

3. What was your reaction?
--Ah! Simple free-flow . . .hey! I can't stop it!!!:shocked2:

4. What was your ascent rate?
-- around 15-20'/min (4-6m/min).

5. Did you have to go to the chamber?
--No, not for that incident !

6. General experience/thoughts/advice/anything else relevant
--Single Tank Dive. Switched to bungie necklaced back-up reg, instead of trying to "sip" air from the malfunctioning regulator. Had a moment to unclip the SPG and actually see that pointer quickly sweep from 2000 down to 800psi . . .reached behind and shut down tank valve and started CESA. Feathered/modulated tank valve on ascent to take breaths. Had enough gas for a 30sec safety stop at 3m/10'. Surfaced with barely enough tank pressure to inflate my wing (and one hand already undoing/about to ditch my weightbelt). . .

Feathering your tank valve is a skill that's not always taught in mainstream BOW classes; it's a vital technique to learn and practice, especially if your dive buddy is nowhere to be seen, or if you're diving solo. . .

 

[InTheDrink]

OK.

No-one's posted an incident where doing a CESA caused injury or trip to chamber, even those who did it from 100+ ft (although noted that some were proficient skin divers).

What does this actually say? It appears to say that you should rarely if ever need to drop your weights. I appears to say that, as opposed to the PADI doctrine where needing to do a CESA deeper that 9m (30ft) is major danger ground. It appears to say that it's do-able, at a safe ascent rate.

So why isn't it taught anymore? Is it purely insurance reasons?


John

 

[Thalassamania]

OK.

No-one's posted an incident where doing a CESA caused injury or trip to chamber, even those who did it from 100+ ft (although noted that some were proficient skin divers).

What does this actually say? It appears to say that you should rarely if ever need to drop your weights. I appears to say that, as opposed to the PADI doctrine where needing to do a CESA deeper that 9m (30ft) is major danger ground. It appears to say that it's do-able, at a safe ascent rate.

So why isn't it taught anymore? Is it purely insurance reasons?


John

Takes too much time out of a course that's already cut back so far.

 

[Wayward Son]

I did one once, from about 30 FFW. I lived, no injuries.

 

[TSandM]

What does this actually say? It appears to say that you should rarely if ever need to drop your weights. I appears to say that, as opposed to the PADI doctrine where needing to do a CESA deeper that 9m (30ft) is major danger ground. It appears to say that it's do-able, at a safe ascent rate.

So why isn't it taught anymore? Is it purely insurance reasons?

It isn't taught because, to get to the point where you have to do this, you have got to have messed up so many things . . . You've got to have had a catastrophic gas loss with no buddy in sight, or have two divers without enough gas to get to the surface, or one person out of gas and a buddy pair that can't execute an air-sharing ascent.

If you have a procedure which is high(er) risk, and is only going to be invoked in EXTREMELY rare circumstances IF the rest of your educational effort is successful, it seems reasonable not to stress it or practice it very much. When I finished OW, I knew a CESA was possible, and that it was not as scary as it sounded. But I'm perfectly happy that they left it there. I'd rather they taught buddy-breathing.

 

[Doubler]

TS&M is correct. IMO teaching it from 30 feet could be dangerous. My totally un-scientific demonstration showed me that the largest change in volume happened between 30 and 10 feet

My cave diving buddy was also a NAUI and NSSCDS instructor so I assisted him with classes and check out dives all the time. One of the demonstrations we did on check out dives, just before the CESA drills, was to bring a ballon down to 30 feet, Inflate it, tie it closed and let it go. Never ever made it past 10 feet without a rapid disassembly of parts. We would then bring the students to the surface and talk about what they just saw and how to prevent it.
During our cave diving safety practice weekends the two of us would do blow and go's any where from 80 to 100 feet. One weekend for the heck of it we brought a ballon down with us and started swimming up at our normal pace, watching the ballon. Really not much change in size between 80 and 60 feet. The ballon started to slowly expand after that and at about 20 feet started to rapidly expand until it burst at 12 feet. Not real scientific but did show old Boyle's knew what he was talking about.

 

[Thalassamania]

The greatest change is as you approach the the surface, almost as much from 10 to the surface as from 30 to 10. But as long as you keep the airway open ... which is exceedingly easy, it is no problem.

 

[InTheDrink]

TSandM - I'm new and would never challenge anyone who clearly has much more experience than me.

But in my limited experience, I have had a situation that made me understand just how useless the buddy system can be. Please correct me if you think I'm wrong: I'm here to learn.

In a raging current with critical kit malfunctioning (e.g. regulator) and your buddy downstream, what are your options? I've only 90 dives under my belt and this scenario, broadly, has already happened to me, so I wouldn't discount it happening again.

I think the buddy system is great and I really focus on it. But I think there are times when it cannot apply because you cannot get to your buddy. (because of environmental reasons: current, viz, etc.)

Ergo, understanding the possibilities and limitations of CESA are important to me.

Like I said, I'm new, so I'm shooting from the hip so if you can think of ways around the particular scenario (which can't be TOO uncommon) I indicated I'd be very grateful.

Thanks,
John

 

[Thalassamania]

What would I do ... for a start I'd never dive with that buddy again, our definition of where a buddy should be at all times is close enough to intervene on your behalf in case of an emergency.

 

[seaducer]

In a raging current with critical kit malfunctioning (e.g. regulator) and your buddy downstream, what are your options? I've only 90 dives under my belt and this scenario, broadly, has already happened to me, so I wouldn't discount it happening again.

In situations like this, the buddy system only works if you dedicate yourself to it. If you make a conscious effort to stay together, touching if need be, you won't have to worry about seperations. Buddies seperate because they aren't paying attention to each other.

I think the buddy system is great and I really focus on it. But I think there are times when it cannot apply because you cannot get to your buddy. (because of environmental reasons: current, viz, etc.)

There really is no reason why the buddy system has to fail, other than lack of attention. If you want to be able to rely on your buddy, the two of you need to dedicate yourselves to the effort. The DIR forum can really help you learn how best to achieve this mentality.