Breathing from BC

[Orlando Eric]

WoW bunch of testy My way is the right way and everyone else is going to hell hooligans we have here.

Not nearly as "Task loading, death defying dangerous" as many claim.

Nor is it practical either, however-- on that WAY WAY WAY

outside chance.

You are not near a buddy. Both second stages are not giving air but the first stage is still working fine.

Then yes you could indeed blow air into your bladder with the auto inflator and pull air out of the manual oral inflator.

As to nasty bateria in the bladder I rinse mine and use the walmart brand mouthwash every time my BC has a nice Citrus smell and taste.

IS this a skill to put high on the list? Nope. But I have practiced drawing my sidearm from the ground, on my back, stomach, side with my left hand. I never intend to get into that position without the use of my right hand... BUT-- I have done it before should I end up there someday.

 

[Crowley]

agree with boulderjohn

- You will probably get a breath or two from your regulator as you ascend.
- Breathing from your BCD is a viable option, not to be recommended but a throat infection is a whole lot better than drowning
- Many agencies teach - or at least dicuss - (but again still don't encourage) the emergency buoyant ascent: drop weights, inflate BCD, breath out... the theory being that Decompression Sickness (being bent) is fixable, drowning is most generally not.
- Many people don't agree with the CESA - but I do. If it teaches you nothing else, it's to not hold your breath on the way up
- the question is somewhat moot anyway because trust me, if a person ever runs out of air underwater they will more than likely panic. I've seen it happen several times in a swimming pool... with experienced divers (instructor trainees!)
- Check your gauges, don't lie about your air consumption if you're embarrased about it, try not to get into this situation in the first place!

Dive safe

C.

 

[InTheDrink]

But you do have another means of getting air as you ascend--your tank.

Your tank is not out of air. It is just so low on air that your regulator cannot supply it at the pressure you need. Air mut come to you at approximately the same pressure around you. As you ascend and the pressure decreases, your regular will be able to give you some air.

You are taught to keep your regulator in your mouth during a CESA. This is one good reason for it.

Good point, well made. Really. In fact it was the reason I thought actually doing this in real life wouldn't make sense but somehow forgot. Reg in mouth if doing CESA is probably most important thing.

That said, I still don't regret the drill. Even if just for confidence levels.

thx,
J

 

[InTheDrink]

- the question is somewhat moot anyway because trust me, if a person ever runs out of air underwater they will more than likely panic. I've seen it happen several times in a swimming pool... with experienced divers (instructor trainees!)

Thanks for your response and I agree with your points. But the one I've quoted above is of most interest to me: do you really think that most people if they go OOA will panic? This is my primary driver with my OOA drills, it's so that I don't panic and can survey my options. I think that part is maybe more important than whichever particular skill or drill you're practising. It's not freaking out if you're not getting air delivered.

The Instructor Trainees you refer to - do you think they were adequately comfortable? Seems surprising to me that someone at *level* would panic in a pool.

J

 

[Crowley]

Okay to qualify my post a little:

I work in the industry so I've seen a lot - and yes - unfortunately I've seen it happen. I have dived with thousands of people, and I have seen an out-of-air situation happen three times. Two of these were in a swimming pool and one was in a confined water enviroment at sea. I also have talked to to or three people who have had or witnessed similar experiences. The three thay I witnessed personally were all experienced divers, and they all went into panic mode. One of them really did rip the reg out of his buddy's mouth. And this is in 1.5 metres of swimming pool!. On the other hand, a good friend of mine CESA'd from about 26 metres due to an equipment malfunction and did it so slowly and correctly that the hospital cleared him from DCS symptons in minutes. At the time he was open water diver with maybe 15 dives or so?

It's not something you can predict, I think.

Check your gauges!

C.

 

[InTheDrink]

Consider my guages checked I usually finish a dive with a little shy of half a tank so my gas management isn't too bad.

Again, interesting that you've had thousands of dives and only seen 3 OOA situations. I had my first at around 60 so I extrapolated on that basis, hence perhaps my over keen-ess on the topic.

In any event, it can't hurt being prepared. Worst thing that can happen underwater is run of of air (ok boats, jetskis and any number of aggressive fish aside) so being able to react sensibly if that does occur must be a good thing. No panicing.

And even if you die, at least you'll have looked a bit more stylish as you go...

 

[Doubler]

JClynes,
I can see your point about using the BC as a emergency source of air and not exhaling back into the BC. This however is exactly what we were doing back in the late 70’s. Trying to extend our time by re-breathing back into the BC. We only actually tried it in the pool at the deep end. We would swim back and forth getting our SAC up and then go on to the BC. Got maybe 3 good breaths and then the amount of CO2 you were taking in almost made you hyperventilate. We decided that at 60 ft in a cave , swimming hard for the entrance you were better off keeping your regulator in your mouth and hoping for residual gas as you went up. I can tell you from experience a BC is not a Rebreather. I still think a CESA with the regulator in your mouth is the safest way to go. Just my opinion.

 

[Slonda828]

I think we need to be clear about what we are talking about. Where I come from, when someone uses the phrase "breathing from their BC/BCD" they are typically referring to holding down both buttons on the low pressure inflator so that the inlet side of the inflator provides IP air to the diver while simultaneously exhausting all the extra gas from the bladder into the water. If we are talking about "rebreathing" BC air, then that's different, and IMO no where near worth practicing.

I was taught the technique of breathing off of a power inflator a few years ago in case your primary second stage fails while you are providing your buddy with gas from your alternate second stage. Did I ever have to actually use this? Nope, not once. However it can be done as long as you hold both buttons down, and if you aren't panicked your buoyancy shouldn't change provided you are not massively overweighted.

IIRC the GUE also had something about using your LPI in this way as well, or at least they did at one point.

 

[Soggy_Diver]

Thanks for all of these responses.

To provide a little more info, yes, I carried some extra weight so I could try this out on a pool dive. I tried breathing from the BC on the pool bottom a couple of times with a break in between. To reduce the risk of blacking out, I only did it for a short time--less than a minute each round. Then later I tried doing a slow ascent (15 feet). It was easy to control the ascent speed by either exhaling through my nose to slow down, or exhaling into the BC to speed up. But that was wearing a thin shorty, which made buoyancy control easy.

The whole time, I depressed the deflate button completely, but air continued to leak out around it. Herman's post answers my questions about that:

If I understand you correctly, air was coming from between the deflate button stem and inflator housing. That really does not surprize me considering the manual inflate stem on all the BCs that I recall do not seal that stem. No real need to, usually there is water on both sides of it or you are dumping air and any small leakage when orally inflating is not worth trying to save.
.

Thanks for the background on BC breathing and the pros and (mostly) cons with this. One thing that I learned from this exercise was that in a real OOA ascent, breathing from my BC, air would leak around the deflate button the whole time, which would complicate things. To me, breathing from the BC is one of those skills like buddy breathing--something I would probably not use in real life, but really interesting to learn, and it adds to my intuitive feeling for how gear and skills work. In a real OOA, as a last resort, I think that a CESA with reg in would have the same advantage of providing a few breaths on the way up without the extra task loading.