hypothetical question:using BCD manual inflator as spare alternate

[CT-Rich]

To get into this situation, you really are coming in from the shallow end of the gene pool. But lets play pretend. If you try to use the LP inflator, you are going to end up pinned to the ceiling. I wouldn't worry about the lung infection you'll be dead anyway.

Assuming the tank has air, you should unsling it hold it in front, ditch the regulator and breath directly off the tank by cupping your hand over the valve and cracking it slightly to release a steady trickle of air. This is actually a skill taught when I was certified. We did for fun at the end of a class and is really pretty useless, but if you are having your ticket punched anyway this will actually work.

I am always impressed by the ability of people to come up with a Rube Goldberg solution to make sure they are properly dead.

 

[dumpsterDiver]

There used to be a TV show called "Little House on the Prairie". I never watched it, but apparently in every episode, one thing after another would go wrong . . . My good friend Mo2vation refers to scenarios like the one the OP posited as "LHOP" scenarios -- the things that are simply never going to happen.

When you do your dive planning, you can get hysterical trying to set yourself up to avoid or cope with every conceivable malfunction or mishap. The group I dive with plans for ONE major error or malfunction, with the idea that an appropriate response to that will keep you from sliding down into the incident pit, where things start to snowball.

Yes, you can breath from an inflator. You can rebreathe into it, although you will quickly become short of breath and anxious, and develop a severe headache. It might well get you out of that wreck to do so. But you have already pointed out so many preferable methods of handling the situation, including not getting into it in the first place, that I think it should be clear that this is an intellectual curiosity and not a useful strategy.

When the alternative is drowning, you do whatever you can or have to do.

I think the inflator breathing "trick" is a fun thing to do. You get to practice airway control. It might be useful. Seeing underwater with no mask by making bubble goggles with air trapped by your fingers might be useful too, in some weird situations..Fun trick to learn in the water..

If you think about it,,, breathing from an inflator might not be THAT impossibly unlikely. What if you end up paired with a diver who has no octopus and you need to share air and he does not want to give up his single second stage? It might be "beneficial" to be able to snatch a few breaths off his inflator before you ditch him and make a swim for the surface. (of course i would remember to kick him in the mask on the way out for refusing to share his only second stage with me.)

 

[DivemasterDennis]

The simple answer to the op's question is yes. In most bcd's that have a low pressure inflator WITHOUT the alternate air source as a part of it, holding the vent button in while holding the inflator button down will exhaust air through the "mouthpiece," and you breath off of it much like a free flow regulator that you can turn on and off, thus "wasting" less air. This is a tricky little skill, but a good one to know. You can use the same method to inflate a lift bag or smb, if you care to try it.
Divemaster Dennis

 

[LeadTurn_SD]

.... i searched a bit here, & while there is mention of taking a last breath from the BCD before CESA, i didnt find this idea discussed. i didnt want to verify this by actually trying it topside as BCDs can culture nasties inside, but maybe people here familiar with how it works mechanically inside might comment on if the idea might work in a desperate situation.

thx

Nothing wrong with thinking "hypothetically", as long as you realize it is just that, and not a planned OOA strategy.

1. Yes, you can use the inflator as a poor-man's regulator. Try it on the surface for safety.

2. Yes, during a CESA you might be able to get a breath (or two) out of the BC on the way up, as any air in it expands. But I probably wouldn't try unless I was certain I was not going to make it before blacking out. If you got a mouth full of water (and most BC's do take on a little water during the dive from venting them), you could choke, and that would almost certainly push you right over the edge into full panic, you would reflexively hold your breath, and kick like hell for the surface.... and embolize.

You can CESA (if you are fairly fit and don't panic) from almost any "recreational" depth and survive... but you may bend the crap out of yourself in the process... but that is better than drowning.

Best wishes

 

[Centrals]

If you think about it,,, breathing from an inflator might not be THAT impossibly unlikely. What if you end up paired with a diver who has no octopus and you need to share air and he does not want to give up his single second stage?

I refuse to buddy with anyone who does not has alternative air-source.
In the unlikely event, just purge the 2nd stage.

 

[Tigerman]

I've heard that suggestion before. I suspect that there would be a minimum of oxygen and an overdose of methane in that exchange. We'll need to run some tests.

Sounds like a job for Mythbusters if you ask me...

 

[Dsix36]

I have always stated that I would suck a fart from a donkeys butt if I needed to breathe bad enough. A breath from an inflator is not only easier but also tastes a whole lot better.

It is still a very short lived breathing ability and you better be headed up quickly.

 

[fbk]

an alternate method would be to cut the bad reg off and sip the free flow, but you would have to hold the cut end shut with your hand

If you've torn the diaphragm in your 2nd stage just hit the purge button when you want to breath...

 

[ballastbelly]

Psh, I'll breath the fart out of a donkey's ass if it means not drowning.

aparrently a similar 'enriched blend' was actually tested in WWII, as it was found successful to avoid getting narced:

The Swedes, and Arne Zetterström in particular, were interested in hydrogen diving during World War II for a simple reason; they wanted to dive deep, without the effects of nitrogen narcosis, but did not have access to helium. Most helium comes from gas wells in the United States and Russia. So, looking for another diluent gas other than helium, Zetterström briefly considered two constituents of intestinal gas (flatus), namely methane and hydrogen.Eventually, hydrogen was chosen for the Swedish dives simply because hydrogen was less dense than methane.

Diving with Hydrogen ? It?s a Gas John Clarke Online

 

[DaleC]

Attain neutral buoyancy using only your drysuit (or proper weighting if wetsuit diving) with no air in the wing.
Go heads up, depress the vent button and keep it depressed.
Press the inflate when you want a breath. Put your tongue in the front of the mouth to detect water coming in.
Sip rather than suck (stop it).
Keep your mouth on the inflator; excess air and your exhalation will vent out the inflator.
It's a party trick.