It a little unusual, Larry, but there is a very serious side to it. :11:
As our diving gets deeper, a risk of isobaric counterdiffusion induced middle ear bends rises, and hits occur in-water at a gas switch at decompression. The symptom is mostly severe vertigo and remits after enough inert gas has been unloaded.
To name a few who have written of such hits on scubaboard or the Internet are Bennett, Elyatt and recently Don Shirley while attempting to rescue David Shaw, who died in January 2005 in Boesmansgat. Granted, these were very deep dives.
There is also a vertigo that occurs with severe drops in visibility, which can happen in dives with unusual events, such if a dive team in front of us panics inside a silty wreck or cave.
When I first contemplated doing it to myself I first asked, what would I do if I ever got vertigo in open water, in the middle of the ocean, inside a cave or wreck? How long can one endure it, maintain buoyancy and orientation? Can it be done?
In cold quarries, caloric vertigo is reverseable and done in controlled conditions. I now know it is endurable, manageable and likely survivable. I do these types of 'training' at least once a year during winter quarry diving, it doesn't take much to induce it, pulling your hood open enough to let 40F water in on one side kicks it in.
I wouldn't advise anyone to try it and not take it deadly seriously. As winter is upon us, I had just finished one such exercise several weeks ago.
As for vomiting underwater, I have done it several times mainly due to sea sickness, and I leave a technique for that for another day
