Posted by Karl S. on July 29, 2003 at 14:45:46:
In Reply to: open water student OK posted by Chris on July 28, 2003 at 20:54:52:
The first batch of open water skills typically includes the mask clearing drill, among others, such as reg clearing underwater, reg retrieval, air sharing, etc.
I have seen more students bolt during the mask clearing drill than any other exercise, when I was a D/M.
I checked NAUI standards, and the minimum depth at which this exercise must be accomplished is 15 ft.
Since 15/33 + 1 = 1.45 ATAs, this means in a worst case scenario, from a depth of 15 ft, a lung expansion of 45 percent could still occur, which is more than enough to cause an embolism.
This drill can be dangerous at any depth, 15 fsw, 30 fsw, etc. The shallower, the better, of course.
With a beach diving class, you can help the divers get used to cold water on their faces by first doing a "skin dive" out to the kelp bed, then spashing around there by taking their masks off. But it does not always help.
Mask clearing is my lease favorite exercise to teach. I justify it with the words "NAUI requires this." You have to hype it, and act enthusiastic about it, but that does not always help either. Poor students. :(