personally I think that what is required is training the students to control panic, control breathing, and control their emotions, so that they take proper action staying underwater instead of speeding towards the surface.
I agree.
My more thorough analysis of what is wrong with the way we teach scuba is not so much that it fails to teach divers not to panic in that situation;
rather it helps induce panic in that situation.
The horizontal CESA done in the pool requires the student to swim
at a normal ascent rate for 30 feet while exhaling the entire time. What is a normal ascent rate? When I started, it was 60 FPM, meaning that a diver would need to exhale for 30 seconds to complete the exercise. Today 30 FPM is the norm, so a diver would have to exhale for a full minute to complete that exercise. Exhaling for 30 seconds is really hard for new students; exhaling for 60 would be about impossible. That is because in the CESA, there is no expanding air to help the process. When it is done in a swimming pool starting at the deep end, there is some expanding air benefit, but not a lot--the student is really only ascending about 7-8 feet.
The student then does it vertically in the open water portion of the class, but often only from 20 feet or so. this does nothing to overcome the overriding learning experience from the pool session--
this is really hard! I probably would never make it in real life!
When I did my IE, the examiner told us all to interpret the word "normal" liberally. The standard was 30 feet, and no time range was mentioned. When I assisted classes before becoming an instructor, though, the norm was to get the students to as close to 30 seconds as possible He looked at his watch the whole way. If the student took only 27 seconds, he might let it go, but anything quicker than that was a failure. We did one CESA repeat after another after another before getting the whole class through the exercise.
In my 18+ years on ScubaBoard, I have seen countless threads on the CESA, and the overwhelming sense of posts is "I could only do one from very shallow depths. Deeper than that, I am toast." You even see people with some level of expert status offering the nonsensical advice to practice freediving to increase the depth from which they can ascend, as if your ability to hold your breath has any relationship to exhaling expanding air. With this representing what people think of the CESA, it is no wonder people panic in that situation.
When I teach horintal CESA, I do everything I can to do away with that fear:
- I flat out explain why the horizontal CESA is not realistic.
- I explain that they will very likely get a warning as their breathing gets harder.
- I emphasize that they can do it easily from most depths.
- I remind them that holding the breath is the worst mistake they can make.
- I tell them they will be able to get air as they ascend, so keep that regulator in the mouth!
- I don't care if they take less than 30 seconds, although no outright sprinting is allowed.
- If they inhale briefly at the end, I won't notice