Out of Air! Could you...

[DBailey]

Completely hypothetical situation:

You are neutrally buoyant at about 40' (i.e. there is some air in your BC). Then you take the last breath off your tank and your buddy is nowhere to be found. So you now have to make it to the surface.

Couldn't you, in theory, suck some air from your BC during your ascent? You have to deflate as the air expands anyway on the way up, why not breathe some of that air?

Granted, through good buddies and air management, you should never encounter this, so it is more food for thought.

 

[ShakaZulu]

If you do a CESA you will be at the surface before you even need to breath again.

 

[opiniongirl]

In theory, yes you could.

But the difficulties would be:

1. Calculating the amount of air to take in without making yourself negatively buoyant.

2. A rapid ascent could lead to an air expansion injury

3. Organisms inside the bladder from poor rinsing could be inhaled, nasty...

4. the deflator deflates quite forcefully, which could lead to a lung overexpansion injury.

Generally, it would likely end up in a massive mess. Ditto with Shaku, easier to do a cesa, but in theory....

 

[Walter]

At 40 ft I wouldn't worry about it, I'd make an ESA. From 100+ feet, I'd consider it. BTW, yes, it has been done.

 

[Ontario Diver]

If you've just taken your last breath, you have a full set of lungs, No need to play with the BC, CESA.....

 

[Damselfish]

The theory is there could be nasty things living in your BC and that air may not be the best thing to breath. On the other hand, it's better than not breathing. It would depend how desparate you are.
Once you start to ascend, you may be able to get another breath off your tank.

 

[MXGratefulDiver]

If you've just taken your last breath, you have a full set of lungs, No need to play with the BC, CESA.....

There is no guarantee that the last breath on an empty cylinder will provide you with a full set of lungs ... in fact, I'd suggest that the odds are against it ...

... Bob (Grateful Diver)

 

[scubadoguk]

Completely hypothetical situation:

You are neutrally buoyant at about 40' (i.e. there is some air in your BC). Then you take the last breath off your tank and your buddy is nowhere to be found. So you now have to make it to the surface.

Couldn't you, in theory, suck some air from your BC during your ascent? You have to deflate as the air expands anyway on the way up, why not breathe some of that air?

Granted, through good buddies and air management, you should never encounter this, so it is more food for thought.

AP valves in the UK used to make a BCD inlet outlet that you could breath from, the bag also used to have a bottle like the spare air that could inflate the bcd or air in and breath from it.
Tasted funky! I know it was "skill" we used to have to do in the pool it was more a ABLJ skill from days of yore but was a nice way to fool around on a saturday night at the dive club. I would also use a regular inflator/deflator to practice as well just to say you could, some how I doubt I would think about it at 40 ft though you will be up before you know it, cesa would take care of it.

 

[PlanoDvr1]

Ummm....excuse me....ESA...Emergency Swimming Ascent????? What's the C?

 

[Dryglove]

Ummm....excuse me....ESA...Emergency Swimming Ascent????? What's the C?

Controlled emergency swimming ascent, same difference fancier term