Student fatality - Kreidesee, Germany

[Twiny]

Which of course is exactly the wrong thing to teach because you have to forcefully exhale to make the sound and if by some miracle you can stick to 9m/m ascent rate, there is no way you can keep it on for the full minute it takes to come up from 9 metres. You can only hope your student won't be dumb enough to do that from any real depth.

Like Jim said: an incredibly stupid exercise.

Here at time 1:30, the nice lady explains that making a sound will even make your exhalation last longer. I do not have any proof of that and it seems to me that Padi never communicated about that. However one thing is sure is that if a student stops making a sound during the (vertical) OW CESA, the instructor has to stop his ascent immediately.

 

[Celt]

you’d have to wonder would the ability and confidence to make a CESA have saved the lady in question?

 

[Twiny]

The good habit of making a sound in case of any emergency ascent would have avoided many lung injuries / deaths among scuba divers, for sure. Beginners when super scared all have the tendency to hold their breath (common reflex) while doing a fast ascent ...

 

[Twiny]

Moreover, the CESA in open water is not only about making a permanent sound on the way up while deflating one's BCD, it also gives the students the opportunity to practice again the bobbing method to orally inflate the BCD and the skill emergency weight drop.
Those last 2 skills are also essentials