Questions on CESA....

I’ve got about 30 dives so far and think of myself as safety concious. I read extensively, have a 19 cu ft pony that lives on the side of my main tank just in case, and am detail oriented. I am comfortable in clear water, becoming less uncomfortable in low vis as time goes on. I am thinking that one of the next things I should do to improve my safety skills, (apart from an upcoming AOW course and then eventually Rescue), would be to practice CESA. (Technically we did ONE, from about 15 feet during OWC but it’s barely a dim memory and didn’t seem real at the time if I recall.)

My question is what is the best way to do this? I ASSUME the best way is to do it near the start of the dive, and from around 25-30 feet. (This would be in a quarry with limited viz in the shallow areas on the weekends.) Since I know it means blowing off the 15 foot stop, does that mean it would not be ok to do it later in the dive after being down say 30 min between 30-70 feet? Also I assume the buddy should go up also, side by side, (breathing normally off her reg.), but should she blow through the stop also? Finally, as long as I exhale, how fast can I / should I go up? (Gotta know that in case I ever have to do a real CESA from deeper.)

Any advice is appreciated.

Interesting question... and well thought out. Yes, practicing a CESA at the begining of a dive wouldn't expose you to as much risk. When I teach I usually do them as the last skill in the last dive but your evaluation is correct and at the beginning would be fine. With PADI, we teach to look up (keeps your airway open) and say 'ahhhhh' the whole way up (has your expelling air) and go at a moderate speed. I wouldn't try from any deeper then say 25' although they should work from as deep as 60'.

Your buddy can either go along or watch from the mid point. Remember the safty stop isn't a required deco stop and from 25' isn't mandatory.

Hope that helps.

Be safe and have fun in the water! Bruce

No more than 60ft per min, preferably, 30ft per min. Do it from about 30ft. Keep in mind, CESA is not your best option, only for emergencies. Your best option is your buddy or your pony bottle. Personally I dont like practicing the CESA, becuase its unnecesarily risky. We do it in class becuase there is an instructor there to monitor your speed and make sure youre exhaling and stop you if you arent. I think prevention goes further in reality.

About a year ago I hired a DM to go with me to some shallow reefs of the Keys to practice navigating and CESA's. Cost me a few bucks but helped me out a lot. I eventually could do them from 25-30 feet. At first it was tough trying to get all the way to the suface without resorting to my reg but after a couple days it was a lot easier. It really gave my computer a headache though. You need to be careful about how many yo-yo trips you do.

jviehe:

No more than 60ft per min, preferably, 30ft per min. Do it from about 30ft. Keep in mind, CESA is not your best option, only for emergencies. Your best option is your buddy or your pony bottle. Personally I dont like practicing the CESA, becuase its unnecesarily risky. We do it in class becuase there is an instructor there to monitor your speed and make sure youre exhaling and stop you if you arent. I think prevention goes further in reality.

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I agree that prevention goes further and that is where most of my attention goes and will go. However, I'm not sure I want to try out the last resort under completely unexpected mulitple failures or issues that together could mandate a CESA. On a practical level, one reason I want to do some is at my level of experience I don't really know how much/fast to exhale when going up. If I need to do a real CESA I want to have a sense of how fast to exhale and still have enough air to make it to the surface. I know you end up with more than you think because you start out with compressed air, but I could easily imagine blowing it all our and still being 15 feet from the big air tank in the sky. Or for that matter if I don't practice and have a real emergency I could imagine, as a newer diver, getting freaked out and overwhelmed with whatever was going on and either forgetting to exhale or blowing it out too fast. I get the concept but am not sure about my ability to use it without a few practice runs. Do you think I should pay a DM or could I just cautiously do a few on my own?

Hi DC53,

Regarding practicing CESA: Since I didn't see it mentioned, another thing to consider practicing 1st is what I'd refer to as a "lateral" CESA. Essentially, you swim along the bottom, at the same controlled rate you would do a normal CESA, and perform a slow, continuous exhale. Regulator of course remains in the mouth.

This can be done at any depth, is safe, and gives you a feel for keeping your airway open and exhaling. Remember that in a "real" CESA the air will be expanding in your lungs as you ascend, so you'll have a near-constant source of air to exhale (in other words, it is much easier to do a continuous exhale ascending than swimming laterally). So the lateral CESA practice does not "feel" at all like the real thing, it simply gives you a little practice in exhaling slowly. And it gives a feel for how far you can comfortably swim without taking a breath (which for most folks will instantly reinforce why you need to stay close to your buddy ).

One of the problems (in my opinion) with the traditional "Ahhhhhh" style exhalation as you ascend is that most folks are exhaling much too quickly, and WILL run out before hitting the surface, which may then cause them to hold their breath and bolt the last 20 feet or so, and embolize. Not good. The key is to keep the airway open. Saying "Ahhhh" is a good way to remember not to hold your breath... but it is pretty easy to blow out too quickly unless you practice. Think more along the lines of blowing through a straw, or whistling... sit in your living room, take a deep breath, and exhale saying "ahhh", then try the same thing through pursed lips to see the difference.

CESA's are not taught as thoroughly as they were 30 years ago, and it seems that depths differ depending in the location of the class. I was taught from 60' in my OW class in the 1976. My kids (including my son who was 11 at the time) were taught from 30' in 2007. If you did 15' in class, 30' should not feel significantly harder, and 60' should be reasonable in a true emergency.

Best wishes.

DC53:

....Finally, as long as I exhale, how fast can I / should I go up? (Gotta know that in case I ever have to do a real CESA from deeper.)

Any advice is appreciated.

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Hi again DC53,

Just one more comment on CESA's.

Practicing is one thing, the "real deal" is another.

CESA's (or ESA's) have been performed from up to and beyond the edge of recreational depths (130 feet or more) and the divers survived unharmed. However, I would bet one or more of my favorite appendages that their ascent rates were well above 60 feet per minute.

In a true catastrophic OOA emegency at depth, you are going to need to weigh the risk of DCS vs the risk of black out and drowning.... my own "strategy" would be to ascend quite rapidly until hitting maybe 30', then slow down to a more normal rate once convinced I was going to "make it" without blacking out.

Note: Remember that any air in your BC is also going to be expanding on the way up, especially in the final 30', and will be accelerating your ascent, but again I'm trying to get to the surface quickly so I would probably just ignore it and "flare" in the final 30 if needed.... This is just the way I've thought it through, I've never had to do it "for real". And I have learned how to "flare" to control the speed of an overly-buoyant ascent....

Disclaimer: Please don't take this as a recommendation to view CESA as a good alternative to gas planning, good buddy skills, etc. It is a last ditch, final resort, but I think it is valuable to know you can survive situations that you may not have considered survivable, and to think about how you would do it. Knowing that others have done it might make the difference between panic and drowning or staying focused and surviving.

Best wishes.

I remember practicing CESA from 60ft, but stopping at 15ft - the idea was to avoid the last meters where the pressure gradient is the highest.

But it's a distant memory... I haven't practiced it in years. I'm not sure the risk of accident during the exercise is worth it.

ptyx:

I remember practicing CESA from 60ft, but stopping at 15ft - the idea was to avoid the last meters where the pressure gradient is the highest.

But it's a distant memory... I haven't practiced it in years. I'm not sure the risk of accident during the exercise is worth it.

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That is sort of how I feel now.

I do still practice CESA (since I solo somewhat frequently), but from maybe 30 feet, not 60. From 30 feet it is just a normal controlled 60'/min ascent, minus a safety stop.

When I started diving, not everyone had spg's, and J-valves were pretty common (I still have an older tank that has a J-valve). We were trained how to CESA. While I've never gone OOA, I do think it is a good skill to have in your "tool bag", just one that hopefully will never be used... and one that needs to be practiced, but VERY carefully.

Best wishes.

The problem with laterals and deep to shallows is that a critical part of the skill, the end of the ascent, when air is expanding at its fastest and control is most critical is missed.

Practicing a CESE has hazards associated with it, that's the price that must be paid to be prepared. Be careful.