Is it time to sink the CESA?

[wetb4igetinthewater]

@boulderjohn

You've brought up some valid points. So if you were tasked with rewriting how CESA's are taught, how would you do it, taking also into account the health of the instructor?

 

[boulderjohn]

If you go to the post I made on problems with the horizontal CESA (which I would not eliminate), you will see a list of things that I would change. Here are some things I would do.

• I would amend the academic instruction, including the following information:
  • Why the regulator will be able to deliver air once the diver reaches shallower water.
  • Why the regulator will be harder to breathe before OOA, giving the diver time to seek a solution. Concurrently, I would junk the air depletion exercise, which is nominally supposed to teach this to the student, but does the opposite, because a shut off air supply stops giving air suddenly, falsely teaching the student that there will be no warning.
  • Why you do not need to have a full breath of air in order to do a real CESA, and why the Navy even recommends exhaling first.
  • Why it is so important to avoid a panicked, breath-holding ascent.
  • Why it is so important to keep the regulator in the mouth, including both prevention of inhaling/gagging and the ability to inhale if needed.
• I would include in the horizontal briefing the following:
  • A normal ascent rate is slower than a panicked ascent but faster than a truly normal, leisurely ascent. Covering the 30 feet in 18-20 seconds is just fine.
  • The air will not expand in the horizontal CESA the way it will with a vertical CESA, so it will be harder for you do make it all the way on one breath than it will be in a real CESA.
  • It is OK to inhale in the last few feet; in fact, it shows that you understand that you will get some air from the regulator if you do.
    • The idea that the student MUST be able to make it all the way on one breath is a false teaching, because it is different in a vertical ascent. Students learn that they need to exhale incredibly slowly to make it all the way, and that is not true in a real CESA.
• The actual procedures for the OW CESA follow the recommendations of the UHMS workshop, and changing those procedures is risky in terms of liability. That is why it is the only skill in the PADI program where the procedures are so carefully defined. The problem most people have with it, as is exemplified in many of the threads critical of it, is the difficulty for the instructor having to do it multiple times, not its benefit to the student. If it is a benefit to the student but a problem for the instructor, then we have to find a way to make it less of a problem for the instructor.
  • The biggest problem is the number of ascents required of the instructor. This depends, of course on the number of students in the class. With a class of 8 students, the instructor must do at least 8 CESA ascents, which may be distributed among dives 2, 3, and 4. On dive #2, the instructor must ascend with each buddy team on an OOA exercise. On all 4 dives, the students must ascend at the end of the dive--in addition to the CESA exercise, if it is done on that dive. Put it all together, and with a class of 8 students, the instructor must do at least 17 ascents and descents in the class, and that is not easy.
  • The CESAs can be distributed among dives 2, 3, and 4. That means there will only be one ascent on dive #1, so the remaining 16 dives are distributed among dives 2, 3, and 4. Dive #2 will have 4 OOA ascents, so doing CESAs on that dive as well is impractical, so they will probably be divided over dives #3 and #4. In a class of 8, the instructor will do at least 5 ascents and descents per dive.
  • With a class that large or even half that large, the instructor must have an assistant and probably 2. That is because of the requirement that a student cannot be left unattended. If the instructor goes to the surface for a CESA or an OOA ascent, someone has to stay down with the remaining students, or else the remaining students have to go up with the instructor and the ascending students. That latter choice is silly--tell me how an instructor supervising a CESA is going to be able to leave the CESA student to attend to an emergency with another student ascending at the same time. The fact that you really should have at least one assistant and probably 2 with more than a few students offers some possibilities.
    • A specially trained DM or AI can supervise OOA ascents and possibly even CESAs.
    • DMs and AIs should be able to supervise the final ascent of each dive.

 

[wetb4igetinthewater]

If you go to the post I made on problems with the horizontal CESA (which I would not eliminate), you will see a list of things that I would change. Here are some things I would do.

• I would amend the academic instruction, including the following information:
  • Why the regulator will be able to deliver air once the diver reaches shallower water.
  • Why the regulator will be harder to breathe before OOA, giving the diver time to seek a solution. Concurrently, I would junk the air depletion exercise, which is nominally supposed to teach this to the student, but does the opposite, because a shut off air supply stops giving air suddenly, falsely teaching the student that there will be no warning.
  • Why you do not need to have a full breath of air in order to do a real CESA, and why the Navy even recommends exhaling first.
  • Why it is so important to avoid a panicked, breath-holding ascent.
  • Why it is so important to keep the regulator in the mouth, including both prevention of inhaling/gagging and the ability to inhale if needed.
• I would include in the horizontal briefing the following:
  • A normal ascent rate is slower than a panicked ascent but faster than a truly normal, leisurely ascent. Covering the 30 feet in 18-20 seconds is just fine.
  • The air will not expand in the horizontal CESA the way it will with a vertical CESA, so it will be harder for you do make it all the way on one breath than it will be in a real CESA.
  • It is OK to inhale in the last few feet; in fact, it shows that you understand that you will get some air from the regulator if you do.
    • The idea that the student MUST be able to make it all the way on one breath is a false teaching, because it is different in a vertical ascent. Students learn that they need to exhale incredibly slowly to make it all the way, and that is not true in a real CESA.
• The actual procedures for the OW CESA follow the recommendations of the UHMS workshop, and changing those procedures is risky in terms of liability. That is why it is the only skill in the PADI program where the procedures are so carefully defined. The problem most people have with it, as is exemplified in many of the threads critical of it, is the difficulty for the instructor having to do it multiple times, not its benefit to the student. If it is a benefit to the student but a problem for the instructor, then we have to find a way to make it less of a problem for the instructor.
  • The biggest problem is the number of ascents required of the instructor. This depends, of course on the number of students in the class. With a class of 8 students, the instructor must do at least 8 CESA ascents, which may be distributed among the 4 dives. On dive #2, the instructor must ascend with each buddy team on an OOA exercise. On all 4 dives, the students must ascend at the end of the dive--in addition to the CESA exercise, if it is done on that dive. Put it all together, and with a class of 8 students, the instructor must do at least 17 ascents and descents in the class, and that is not easy.
  • The CESAs can be distributed among dives 2, 3, and 4, so the best ratio is 2, 3, and 3. That means there will only be one ascent on dive #1, so the remaining 16 dives are distributed among dives 2, 3, and 4. Dive #2 will have 4 OOA ascents, so doing CESAs on that dive as well is impractical, so they will probably be divided over dives #3 and #4. In a class of 8, the instructor will do at least 5 ascents and descents per dive.
  • With a class that large or even half that large, the instructor must have an assistant and probably 2. That is because of the requirement that a student cannot be left unattended. If the instructor goes to the surface for a CESA or an OOA ascent, someone has to stay down with the remaining students, or else the remaining students have to go up with the instructor and the ascending students. That latter choice is silly--tell me how an instructor supervising a CESA is going to be able to leave the CESA student to attend to an emergency with another student ascending at the same time. The fact that you really should have at least one assistant and probably 2 with more than a few students offers some possibilities.
    • A specially trained DM or AI can supervise OOA ascents and possibly even CESAs.
    • DMs and AIs should be able to supervise the final ascent of each dive.

Going to steal this, but give credit to the source. Need to mull it over. I want to at least share this information with future students. While I am hesitant to add too much to courses (that whole theory of interference I learned from you), I think this should at least be a discussion on dive safety and handling emergencies.

 

[TMHeimer]

In 30 years of open water diving I've never truly run out of air and had to do a CESA. I've been low on air and had to surface to keep from running out but never run out or had to make a mad dash to the surface. Then I use an AI computer and frequently check my air supply. I guess there's a minute chance of a catastrophic supply failure combined with buddy separation, but aside from that there is no excuse for running out of air.

It may not just be running out of air. I was doing a shore dive once with my pony bottle and tried to check to make sure the air was on. It was, but the pony reg wasn't delivering it. Yes, I guess that was the 1% of the time that happens as opposed to a free flow. What if this freak thing that happened to my pony reg happens to my regular reg at depth. Or as you say, some other rare catastrophic thing happens--say you are near the end of the dive with not lot a lot of gas left and a hose breaks (I've had that happen, fortunately on land). And you're diving solo, as many do. Hence, knowledge of doing a CESA may come in handy. I guess I'm just referring to that minute chance as you posted.

 

[apenland01]

I remember doing a CESA in my OW dives for my open water diving certification. We were hanging out in 25' of water at Blue Hole Santa Rosa and there were maybe 4 of us on that dive because we were taking turns on our skills dives. My instructor grabbed each one of us by the BCD strap and held on to us and shook us to make sure we were secure. We had to do a CESA to the surface following him, as he held on to us. We held up our BCD tubes and If we started to go faster than him, we slowly let out air to match his pace all the way to the surface. It was a pretty quick pace, but we didn't dare beat him to the surface. We had a lot of practice on that in the pool, so it wasn't out of line. After doing that, I had a feel for how fast I should be going during a CESA. If I remember right, before taking off on this skill, we took a full breath, started humming and counted to 3 with our hands, then started up. Once we were at about 5 or so feet from the surface, we started to yell until we popped up.

I have no idea how this relates to modern day training, but I remember doing that to this day and will never forget. The last damn thing I would do is hold my breath.

When the instructor got to the top, we would exit and he would bring down the next diver to the 25' area and put them in line to do the skill. He would grab the next diver in line. Wash, rinse, repeat until everyone had done it...

 

[boulderjohn]

I have no idea how this relates to modern day training,

With PADI, the rules for doing the CESA in open water have not changed for decades. There are specific things that must be done a certain way, but the instructor has some latitude on the rest. Some of the things you mention in your description, such as how the instructor held you and how you began the ascent, are done differently by different instructors, but other than that, your experience sounds like it was by the book.

 

[The Chairman]

It's time to ditch the CESA. It's not healthy for instructors and it really doesn't teach what we want them to know. The biggest problem is that you should really try to take a breath on the way up. If they do, they get failed. When I first started diving in 1969, I had the worst instructor anyone could ever have. He gave all of his instruction pool side and never even got in the water with the two of us. Back then, I didn't have an SPG, I had a j-valve. Oh, there were SPGs available, but he said we didn't need them. When you breathed it down to your last, you simply reached by your left butt and pulled the rod. Well, that's if the rod wasn't already down. if you were really, really out of gas, swimming to the surface was pretty intuitive. You never had a full breath, and you tried to breath a few time as you made your way up. The bad part was when you reached the surface. We dove without BCs back then, so there was no inflating or floating. We had to swim back to the shore in such a manner that we could breathe. It was incredibly important to be as neutral as possible so you wouldn't drown after.

Caveat: since I started diving with an SPG, I have yet to run out of air. It's my belief that a lack of sufficient neutral buoyancy results in a distraught diver who is so distracted that they can easily run out of air. Most standards don't address being neutral near enough, nor do they address gas management near enough. The best way to do a CESA is never to have to do a CESA. I've done more than enough of them to know I don't ever want my students to have to do them.

 

[TMHeimer]

It's time to ditch the CESA. It's not healthy for instructors and it really doesn't teach what we want them to know. The biggest problem is that you should really try to take a breath on the way up. If they do, they get failed. When I first started diving in 1969, I had the worst instructor anyone could ever have. He gave all of his instruction pool side and never even got in the water with the two of us. Back then, I didn't have an SPG, I had a j-valve. Oh, there were SPGs available, but he said we didn't need them. When you breathed it down to your last, you simply reached by your left butt and pulled the rod. Well, that's if the rod wasn't already down. if you were really, really out of gas, swimming to the surface was pretty intuitive. You never had a full breath, and you tried to breath a few time as you made your way up. The bad part was when you reached the surface. We dove without BCs back then, so there was no inflating or floating. We had to swim back to the shore in such a manner that we could breathe. It was incredibly important to be as neutral as possible so you wouldn't drown after.

Caveat: since I started diving with an SPG, I have yet to run out of air. It's my belief that a lack of sufficient neutral buoyancy results in a distraught diver who is so distracted that they can easily run out of air. Most standards don't address being neutral near enough, nor do they address gas management near enough. The best way to do a CESA is never to have to do a CESA. I've done more than enough of them to know I don't ever want my students to have to do them.

OK, I see what you say and agree with it all except the first sentence. I think we all agree something should be done to eliminate the problems it may cause for instructors. Perhaps something along the lines of what John outlined.
But, regarding from the students' aspect-- Again, I agree with what you say about in reality you should try to take a breath on the way up. But in an OW course, you will too easily get that breath since you have air in the tank. So, that's not really a good test. As well, you have to consider that rare catasprophic reg (or other) failure where you aren't getting any air and won't get any if you try on the way up. Thus I favor keeping the CESA.

 

[wetb4igetinthewater]

It's time to ditch the CESA. It's not healthy for instructors and it really doesn't teach what we want them to know. The biggest problem is that you should really try to take a breath on the way up. If they do, they get failed. When I first started diving in 1969, I had the worst instructor anyone could ever have. He gave all of his instruction pool side and never even got in the water with the two of us. Back then, I didn't have an SPG, I had a j-valve. Oh, there were SPGs available, but he said we didn't need them. When you breathed it down to your last, you simply reached by your left butt and pulled the rod. Well, that's if the rod wasn't already down. if you were really, really out of gas, swimming to the surface was pretty intuitive. You never had a full breath, and you tried to breath a few time as you made your way up. The bad part was when you reached the surface. We dove without BCs back then, so there was no inflating or floating. We had to swim back to the shore in such a manner that we could breathe. It was incredibly important to be as neutral as possible so you wouldn't drown after.

Caveat: since I started diving with an SPG, I have yet to run out of air. It's my belief that a lack of sufficient neutral buoyancy results in a distraught diver who is so distracted that they can easily run out of air. Most standards don't address being neutral near enough, nor do they address gas management near enough. The best way to do a CESA is never to have to do a CESA. I've done more than enough of them to know I don't ever want my students to have to do them.

Pete,

Given the data that @boulderjohn has presented, I think more data is required to consider. I'll insert some comments with in his statement:

Actually, something changed, although it has not had an impact on that training.

A few years after this thread ended, PADI and DAN did a study to determine the most common reasons for dive accidents, other than health issues, and see how training could be adjusted accordingly. The number one factor in diver deaths, it turned out, was an air embolism following a diver reaching the surface after a panicked ascent in which the diver likely held his or her breath. This usually followed an OOA event.

In other words, the most likely cause of death was an improperly performed emergency ascent.

Now we are all familiar with Boyle's Law (and I learned what it stands for from you Pete). And we all know that the norm in open water courses is that students are on their knees and overweighted. And we know that extra amount of gas required in a BCD (and/or drysuit) is going to contribute to the ascent rate if not dumped appropriately. So the overweighting is likely. I don't have the data to back this though, just an (un)educated guess. We do know however that the 2016 DAN report found here: https://www.diversalertnetwork.org/medical/report/AnnualDivingReport-2016Edition.pdf, calls for improved buoyancy control and proper weighting.

I still hear crickets from ALL mainstream agencies (though I could be wrong about a couple agencies) not addressing this, which honestly drives me crazy. We all know that a diver is properly weighted when at the safety stop with a nearly empty cylinder, empty BCD/dry suit, they neither sink nor rise, except with their breath. AND the weight they have is distributed so that they are comfortably (i.e., no sculling) in the horizontal position.

Why this is not explicitly stated in every agencies' open water student manual/materials is beyond me. Why agencies don't require instructors to do weight checks at the end of dives as well, draining cylinders down at the end of the safety stop, and making appropriate adjustments, is also beyond me.

Ladies and gentlemen, we are not quantum physicists. We are not brain surgeons. This isn't complicated stuff. Is it laziness? Incompetence? Rectal-cranial inversion? Why cannot we move forward and not have "get off my lawn" types like me ranting about this?

Following that, PADI training did change in that they made a significantly greater emphasis in training on using the buddy system and especially frequent checking of air supplies. It left the CESA in the course.

Years ago, a thread on ScubaBoard that argued for the elimination of CESA included the fact that BSAC no longer taught CESA. I wrote to BSAC's leadership, and in our email exchange, I was told that their training emphasized making sure that the diver never needs to do a CESA by making sure they cannot run out of air. OK, I said, but what does a diver do if that happens anyway? What does a diver do if they are out of air with no nearby alternate air source? The reply was that they will have to do a CESA--they just will not have been trained on how to do it.

I'd want to see the data from the yearly BSAC report to see if they have the same issue in the incidents in the UK. Obviously BSAC doesn't have 100% of the market there, but I'd gather it is rather sizeable. If they don't have air embolisms at the same rate as the rest of the world, that's a possible red flag for the training conducted in the rest of the world relative to what BSAC provides.

I'm mulling all the statements over, but I don't feel enough data is available.

 

[The Chairman]

We'll just have to agree to disagree. Here's a few more reasons:

1) I've met a dozen or so instructors who can not teach anymore and it's obvious to me that this happened due to a bad CESA. Why do you think we have so much instructor burn out? It's wrong to require instructors to put themselves at risk.
2) Monkey see: monkey do! It's simply a horrible example for the students. They see their instructor doing bounce dive after bounce dive. Hey, if the instructor does it time after time, it can't be that bad, can it? Every dive should have one descent, and one ascent with a safety stop. There should never be a time you say "Dive as I say, not as I dive!" Your students want to dive JUST LIKE YOU, so set the example on every dive. Be the example on every dive.
3) I alluded to this earlier, but if you spend more time teaching how to be neutral, buddy awareness and gas management, they simply won't run out of gas and if they do, they'll have redundant air in the form of a buddy. An ounce of prevention is worth 500 psi.
4) Divers are still getting hurt. Obviously, what we're doing ain't working. None of them wouldn't have gotten hurt if they had never run out of gas. Again, an ounce of prevention is worth 500psi.​