A question from an 11 year old.

[Frosty]

Working through dive principles with the kids. We were discussing safety stops and out of air and emergency ascents.
Mr 11 pipes up and says --"Well dad if your tanks empty and you're out of aur why not take a breath off your BCD?"
danged if I can think of one single solitary reason why not. --I'm reluctant to use the donkeys backside analogy

 

[TSandM]

The interior of a BC bladder is likely to harbor an interesting set of microorganisms. That said, if that was the last bit of gas I had about my person, I'd breathe it. And at the surface, I'd beat my buddy senseless for not being there, and then commit seppuku for having been stupid enough to run out of gas.

 

[vladimir]

Eleven? That's the perfect age for him to watch Jessica Alba take an emergency breath from a lift bag in Into the Blue. In a year or two he won't be able to focus on the event itself.

 

[Simon-]

Going back some years (more than I care to admit), we actually did learn to breathe off of our ABLJ's (complete with little bottle).

I dread to think what was actually lurking inside them

 

[melanie.]

You could technically breathe the air in your BCD in and out (using the bladder and not letting air escape).
However:
1) You cannot analyze how much CO2 is building up, and eventually could pass out. Thinking you would get the nasty CO2 headache first though

2) If this is as a safety stop where you ran out of air, you probably wouldn't have any air in your BC if you were correctly weighted.

3) Microorganisms (as TSandM stated)

That being said... if I am OOA and in that bad of a situation, I wouldn't give a damn about future problems from germs and CO2. Deal with it later, would rather make it to the surface alive.
One of the guys mentioned that theoretically, if you are very low on air but still some left, you could breathe your BC for a while, dump then refill with air, breathe off that for a while, and so on until you run out. Should last longer then just breathing your tank

 

[DevonDiver]

As other have stated: you're chancing a nasty infection breathing from a (likely) very dirty environment. I'd do it if I had to, but would be going for a comprehensive check-up afterwards...

Another potential drawback is buoyancy. Suck to much air out of the BCD and you might find yourself sinking again. You'd need the presence of mind to prepare for this.

 

[ajduplessis]

Once out of air with no help around you will want to use the remaining air in your wing. I will however first use the last bit of air available in your primary/octo hoses. As you ascent the small amounts of air left in the 1stage & hoses will expand giving you at least one/two more breaths depending on depth and then go for my wing.

I would however not exhale back into to the wing due to CO2. More air will be available as you get shallower but there will only be 3-4 breaths of air if you are lucky. This should be enough to get you out from 100ft if you don't panic!!! How bent you are going to be is another story. Remember to exhale (CESA) on your way up!!!


In OOA with not help around you have 2 choices: Use whatever air you have in stage/hose & BC and bolt to the surface and deal with the consequences, or drown.

 

[cloudflint]

Ive tried breathing off the BC and found it worked quite well. If you add a wee "suicide" bottle to your BC you even have a totally redundant air supply! I would say however that i had to practice alot in the pool beforehand to get the knack down. Getting the timing right for breathing, pushing the button and managing the buoyancy is trickier than it appears so i wouldn't want to do it in an emergency having never done it before. With practice however i found I could set the suicide bottle to inject a constant rate of air so that my buoyancy didn't go up or down and I could get a few minutes at ten meters out of it. Also its important to note I washed my BC bladder out with Milton before trying this, though even this wont kill all the bacteria in the bladder.

Something I have wondered purely as a theoretical exersize, if you where to put some sofnolime or similar into your BC bladder and have a wee suicide bottle of nitrox I wonder if a BC rigged thusly could be used as an improvised constant flow semi-closed rebreather in an emergency. Obviously this would be incredibly dangerous for quite a few reasons but in theory i wonder if it could work?

 

[LouieLouie]

You can easily manage a 2 minute ascent without air supply. Do a slow CESA and you should be fine as long as you dive within the NDL. There is absolutely no reason to add extra risk by trying to force an extra breath out of your BCD.

 

[knowone]

1 W[SIZE=-2]ITCH. [/SIZE]Thrice the brinded cat hath mew'd.
2 W[SIZE=-2]ITCH. [/SIZE]Thrice and once, the hedge-pig whin'd.
3 W[SIZE=-2]ITCH. [/SIZE]Harpier cries:—'tis time! 'tis time!
1 W[SIZE=-2]ITCH. [/SIZE]Round about the caldron go;
In the poison'd entrails throw.—
Toad, that under cold stone,
Days and nights has thirty-one;
Swelter'd venom sleeping got,
Boil thou first i' the charmed pot!
A[SIZE=-2]LL. [/SIZE]Double, double toil and trouble;
Fire burn, and caldron bubble.
2 W[SIZE=-2]ITCH. [/SIZE]Fillet of a fenny snake,
In the caldron boil and bake;
Eye of newt, and toe of frog,
Wool of bat, and tongue of dog,
Adder's fork, and blind-worm's sting,
Lizard's leg, and owlet's wing,—
For a charm of powerful trouble,
Like a hell-broth boil and bubble.
A[SIZE=-2]LL. [/SIZE]Double, double toil and trouble;
Fire burn, and caldron bubble.
3 W[SIZE=-2]ITCH. [/SIZE]Scale of dragon; tooth of wolf;
Witches' mummy; maw and gulf
Of the ravin'd salt-sea shark;
Root of hemlock digg'd i the dark;
Liver of blaspheming Jew;
Gall of goat, and slips of yew
Sliver'd in the moon's eclipse;
Nose of Turk, and Tartar's lips;
Finger of birth-strangled babe
Ditch-deliver'd by a drab,—
Make the gruel thick and slab:
Add thereto a tiger's chaudron,
For the ingrediants of our caldron.
A[SIZE=-2]LL. [/SIZE]Double, double toil and trouble;
Fire burn, and caldron bubble.
2 W[SIZE=-2]ITCH. [/SIZE]Cool it with a baboon's blood,
Then the charm is firm and good.



So without further incantation there
are still less bugs inside a correctly
maintained bcd than on your home
remote

breathe it or not:Ripley