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Breathing the wrong gas at depth may be better than breathing no gas- the result will be the same, but you'll likely be unconsious when it happens.
Please continue to ask these questions- we learn when we play the "what if" game. In my early days of cave diving, that was one of the things that kept me alive.
protocol says to leave the backgas reg in your mouth and wait for the gas left in your tank to expand as you ascend. This shoud give you a few small breaths.
Absolutely.Quote:
Originally Posted by Tegg
Thanks all for the some of the useful comments.
Noting some of the comments regarding focussing on running out of gas, thanks for the pointers by the way, can I refer to the example I gave and this post followed on from my question regarding breathing inert gases in dire circumstances, that is to say a violent and sudden loss of back gas leaving gas that, under normal circumstances you would never ever dream of using in the emergency situation that I posed and some of you picked up on.
I am well aware that breathing inert gases is never ever advisable nor 100% O2 below 6m.
The thrust of the two posts was, in a really nasty situation you could be forced to take a decision to breathe inappropriate gases and I was trying to establish, whether ONE OR TWO BREATHS would be crtically bad or get you out of the situation....or as I asked.....is this an impossible question?
Thanks again.
kinetic
If I were at 100 feet with no gas except O2 & knew I could not make it to the surface without breathing something I would take a breath of it and go, quickly. If I needed 3 or 4 more I'd take them.Quote:
Originally Posted by kinetic
If its between breathing the O2 or just drown at depth, I'd breathe the O2.
Doesn't one of our basic scuba classes teach us certain physics & laws {Boyles} that relate to our decreases of gas while descending & the increase of gas volumn during ascents-? It seems to me, that if you are at 100' & you drain your tanks dry, would you not have an additional cf of gas by swimming up an atmosphere of 7'-? I have actually proved this very point from depth {60'} by breathing my tanks dry & then ascending to 50', thereby increasing a cf of gas {air} I didn't have at 60'-! While we are restricted in a cave at depth, the concern we should have is what we are all taught in the first place: 'One third in......two thirds out-! If you are 1500' back into Little River or some place similar, & you have breathed your tanks bare, unless you have a buddy bottle w\you, your 0-2 bottle isn't going to help-!
If you are in Eagles Nest with a straight ascent up, then just maybe you'll have some gas left in your tanks.
Just a opinion
J.E. 8)
Just to add what I'll admit is a hare-brained suggestion, if a person wanted to add a LP inflator hose to the pony bottle, it could be injected into the wing and rebreathed until the CO2 blackout took over.
As was suggested, it's best to plan on not running out by planning the dive, and planning for failures, contingencies, etc.
Mark
Human nature is to seek resolution to not having air by breathing. Having sucked the last out of a tank myself there are two things I can tell you. First you will breathe the first gas you can get no matter what it is and the second is that you may not even remember you have a tank of oxygen hanging on you. Hypoxia does weird stuff to your brain. Not that many dive with O2 hanging on them like your hypothetical problem but lets pretend...
You would then have a seizure and if no one is around you will drown. Will you have improved the situation? Not really. Will you be awake when you drown, most likely not. The people I have spoken to that have seizures tell me it's not all that bad until you come out of it. There is a reason the tender is in the chamber with you when you get bent. It's because if you have a seizure while on high oxygen you won't die and your family won't sue. Your tender is not on oxygen like you are.
Once you witness a few seizures you won't be quite so calm about causing one. I do have a video of a diver who did have a seizure in open water while on deco. He dropped another tank and went after it on high oxygen. He was lucky that there were well qualified people there to save his butt. It's not a pretty piece of video footage.
I'm not sure if there is a reason for these kind of 'what ifs'. I was taught that 'what if's' were a good exersize for training because they make you think. Ours were about what to do if we couldn't find the line, all our lights went out, we lost our buddy, we encountered a line arrow pointing the wrong direction, or got line trapped on the way out in zero viz. Basicly things that thinking can resolve and it gives you an idea how to configure gear, plan gas and pick buddies. This stuff of taking about how to die in a cave is just spooky to me and doesn't really have a meaningful purpose.
I am not tossing salt over my shoulder, but this whole deal gives me the shivers. Cindy :(
As 33' = 14.7 psi - 100' to 0' would provide less then 50 psi of availiable pressure in your tanks. Possiably less then the volume of a spare air canister.Quote:
Originally Posted by JE
One record deep diver diving to 1000' and carrying many huge tanks joined together did say his gas use durring ascent from 600'(?) up to his first real stops was met by the decrease in ambient pressure. So the idea is valid even if it takes an extreme situation to derive significant benefit.
Why were they wearing cumbersome gear instead of the usual fashionable cave diving attire?Quote:
Originally Posted by john
Reporters are so dramatic.
WJH