Breathing from BCD

[boulderjohn]

Thanks doc. Good stories and I appreciate your safety focus.

Can you describe the reason for needing a redundant air supply if diving solo in less than ten metres (about 30 ft) of water with no risk of entanglement and overhead structure?

I think that is a question you will have to ask in the solo divers forum rather than here.

Most agencies and (I assume) most divers will not condone solo diving with or without a redundant air supply. Those that do have their own protocols, and the best way to get your answers is by asking that particular group directly.

 

[Foxfish]

Some have mentioned doing an emergency ascent. In a recent discussion, I was told you need a redundant air supply if diving solo. I asked why when diving shallow and they said it may be that you have just exhaled when you ran out of air. I agree this does seem unlikely and you could normally just do an emergency ascent. My next question then is why do you need a redundant air supply if diving in water less than ten metres on your own.

 

[The Chairman]

Thanks doc. Good stories and I appreciate your safety focus.

Can you describe the reason for needing a redundant air supply if diving solo in less than ten metres (about 30 ft) of water with no risk of entanglement and overhead structure?

Two things:

• If you are in the water, there is ALWAYS a chance of entanglement.
• If you have a redundant supply and DO run out of air, then you can ascend gently and on your schedule. I often ascend as slowly as 15 fpm after long shallow dives. Other than a somewhat increased task loading, I don't see any reason to NOT dive with redundant air if you are diving solo.

 

[Foxfish]

I think that is a question you will have to ask in the solo divers forum rather than here.

Most agencies and (I assume) most divers will not condone solo diving with or without a redundant air supply. Those that do have their own protocols, and the best way to get your answers is by asking that particular group directly.

Bit of a ghost town in the solo divers forum, or should that be a cemetery. .

 

[Foxfish]

Two things:

• If you are in the water, there is ALWAYS a chance of entanglement.
• If you have a redundant supply and DO run out of air, then you can ascend gently and on your schedule. I often ascend as slowly as 15 fpm after long shallow dives. Other than a somewhat increased task loading, I don't see any reason to NOT dive with redundant air if you are diving solo.

Thanks Netdoc, your advice is appreciated.
As a matter of interest, why the extra slow ascent rate on shallow dives?

 

[The Chairman]

Thanks Netdoc, your advice is appreciated.
As a matter of interest, why the extra slow ascent rate on shallow dives?

When I dive shallow, like Venice Beach Fl, on a 130, I can accumulate 3 hours of bottom time. There are a lot of tissue groups that have been saturated and so I take it slow to the surface as a precaution.

In fact, if you find yourself feeling overly tired after a dive, you're probably ascending too quickly. I always do a full five minute safety stop and add a two minute half stop if I descend below 80fsw. Where most on the boat accrue only 3 minutes I often spend 7 minutes getting rid of N₂ at my safety stops. Why? Saturation of blood and cerebral fluid is a problem and especially the latter. Some put the half time for cerebral fluid between 2 and three minutes. If that is the case, I have reduced my cerebral fluid saturation significantly more with this protocol. Why is this important? A non-commercial diver is far more likely to suffer Type II DCS than Type I (per DAN). As a non-commercial diver, I want to stack the deck in my favor and get rid of as much N₂ from my cerebral fluid as possible. Result? I never feel tired after a dive anymore.

 

[Kilili]

Beats drowning, but clearly an action of last resort.

 

[fjpatrum]

That will never happen. First, I am OCD about checking my air... maybe because I'm new and still don't really know how fast I breath at various depths. Second, I am religious about staying close to my buddy. Even when they are behind me I turn around and put eyes on them every minute or so. If at any point my buddy is "nowhere to be found" I'm calling my dive after a very quick search around.

Now, that said, if somehow I ever did find myself OOA and w/o buddy, I probably still wouldn't be able to breath off my BC because I almost never have air in it. If I did have air in it, I'd start my ascent and get as far as I could before breathing off my BC, "cooties" be damned. Anyone that worries about mildew/bugs/whatever on the inside of their BC more than getting to the surface has their priorities mixed up, in my opinion.

 

[rk288]

I heard a story about a group of people trapped in a submarine in more than 300 ft of water. There was a diver with them who instructed them about the cesa telling them not to pass their own bubbles on the way up. They all made it...good illustration for never holding your breath huh?

 

[falcon125]

Thank you foxfish for asking the question.
Someone in my pool class recently asked the same question and the instructor had no answer.