johndiver999
Contributor
If you were going to do this, you would exhale into the BC. You would be ascending vertically and presumably kicking. In the upright position, any water in the BC will fall to the bottom of the BC and inhalation off the inflator will release air - not water - the same as every other time you vent the BC in a vertical position.I just meant that as soon as you start re-breathing from a wing, you start a clock counting down with a matter of a few minutes to both hypercapnia and hypoxia. Hypercapnia leads to hyperventilation, panic, and then loss of consciousness, with increased rate of breathing happening pretty soon in the process. Hypoxia simply leads to loss of consciousness with little warning. Once consciousness is lost, drowning typically follows. If the diver ascends to the surface quickly enough, say at the same rate as in normal CESA, then there's probably not enough time for full hypercapnia/hypoxia to set in, so I concede that point, but what if the diver ascends a little more slowly because they now have the sensation of being able to breathe, taking two minutes to reach the surface? Anyway, if they black out, it's very very bad.
I forgot to mention another reason this procedure is a bad idea. It's pretty easy for some water to enter the inflator hose (and wing) during a dive. So if you are contemplating taking a breath from an inflator hose, you must remember to first purge the hose by somehow venting gas through it, or you risk inspiring water at the worst possible time. Coughing would be bad, at this point in the process. If you were running with the wing close to empty during the normal portion of the dive, there is likely water in the inflator mechanism, and at the same time not enough air to purge the hose completely. If there is water in the wing, then being slightly heads-down could bring that water forward and into the inflator hose. Starting to sound like a lot to keep track of, for someone who is calmly facing their own mortality?
I personally expect that if I were forced to make a real emergency ascent with no air source, I would drop everything (except a scooter if it were working) and just swim like my life depended on it. I'm not sure I would have the presence of mind to use the BC to recycle my exhalation. I never tried it as a drill.