View Full Version : What does OOA feel like?
I recently suggested that as a freediver, in case of Out Of Air situation, I should be able to make a slow relatively safe ascent on my last breath. Someone however commented that I would only know there's no air left when trying to inhale, which means with empty lungs doing a slow ascent would be out of the question!
Why did I not think of that! Then I started wondering how does an OOA feel like? Does it cut off the air suddendly? Or does it feel harder and harder to inhale , giving you enough warning that something is wrong? Or are the changes so imperceptible that one would not notice until it was too late?
Has anyone experienced (and survived) a real OOA situation, and would care to give some insight?
Knowing about it can help us be better prepared for it, if it were ever to happen. The obvious action in this emergency situation is to turn to your buddy (or another diver nearby) for help. In case this was not possible though, what would you do? Here's what I would:
Suddendly no air when trying to inhale:
Start a swimming ascent
Remove BC and hold slightly below head level
Try to take a breath from air inside BC by pressing the purge button
If successful slow down ascent and attempt a safer swimming ascent
Remove weight belt and hold in one hand: in case of blackout on my way up, the belt would then drop, allowing my body to surface
If enough air in BC, can take more breath
Getting harder and harder to inhale
Start a normal safe ascent
Adapt breathing pattern to prevent ending up with empty lungs in case of sudden air cut off: exhale very slowly, stop exhaling at half lungs, inhale. There is a risk of blackout due to CO2 build up in the lungs, so safety stops should be avoided if possible
Remove weight belt and hold in hand, in case of blackout
In case of sudden air cut off, try a slow relatively safe swimming ascent on last breath, and switch to the previous procedure (ie: remove BC, try taking breath from it)
Please note that the above 2 procedures are only what I would do if there was no other diver around able to rescue me. I am not saying this is the right way to do it, maybe it is wrong, and I'll be glad if anyone corrects me. What would you do in such situations?
arman
You tend to be aware that you are running out of, it does depend a little on the regulator used. But, in my experience you feel the work of breathing increasing i.e. the regulator tightens up & you have to suck more!
Gareth
Kelvin Rutt
08-12-2006, 09:42
Suddenly out of air
1. Switch to pony/other bailout cyl.
2. Controlled Ascent
3. Figure out where buddy went. :(
Breathing becomes gradually harder
1. Switch to pony/other bailout cyl.
2. Controlled Ascent
3. Figure out where buddy went. :(
An easy way to practice OOA ( on dry land) is to breath from your reg and get someone to switch your air off. Then try your various remove BC antics (with empty lungs) without taking a breath. Trying this underwater will be MUCH more stressful and you will not be able to cope for as long.
I had a OOA "experience" when doing shutdown drills on my Twinset. Swapped back to my main reg without switching on the valve again. Breathed out to clear DV - breathed in - Nothing. It comes as a shock but I instinctively swapped to my backup.
Also had a similar experience when using club kit. The reg failed and just gave me water to breathe (diaphram problem). I was inside an aircraft cockpit at Gildenpit at the time. Didn't think to go for my Octopus but for some reason held down the purge button (it worked fine and got me coughing and spluttering to my buddy who was inevitably facing the other way). I invested in a pony shortly after.
But Both times I was able to extricate myself from the problem by having redundant air supply ( Twinset or pony) without bolting for the surface:eek: .
Nigel Hewitt
08-12-2006, 10:13
The only time I've done something similar I inhaled and got water. That is a panic situation as your body 'needs' to blow out the water and it can't. You have to work to stay in control of the situation developing within your own brain.
If you were to get some advanced notice and you could take a breath, even a small one, and hold it you could go for ages.
I've breathed deco stages down to the line and you don't get much notice on good regs. One minute they are flowing nicely and then, over one breath, they taper off and the next breath doesn't happen.
OTOH: I love spitting the reg when being used as a CBL demo dummy. I have breathed up, zenned out, have the octo discreetly in my hands and I know I can go for a couple of minutes but 20 seconds of looking at me, eyes closed, no reg and smiling gets to most 'rescuers'.
Suddendly no air when trying to inhale:
Start a swimming ascent
Remove BC and hold slightly below head level
Try to take a breath from air inside BC by pressing the purge button
If successful slow down ascent and attempt a safer swimming ascent
Remove weight belt and hold in one hand: in case of blackout on my way up, the belt would then drop, allowing my body to surface
If enough air in BC, can take more breath
Why over complicate it? The sh*t has hit the fan just go for the surface, as you go up the residual gas in your lungs will expand to help the feeling of needing to breath and the expansion of air in your BCD will make sure you keep going.
And be aware that the big danger in this scenario is not build up of CO2 (which you would probably be aware of) but falling ppO2 which you would not
Why over complicate it? The sh*t has hit the fan just go for the surface, as you go up the residual gas in your lungs will expand to help the feeling of needing to breath and the expansion of air in your BCD will make sure you keep going.
And be aware that the big danger in this scenario is not build up of CO2 (which you would probably be aware of) but falling ppO2 which you would not
Why over complicate it: To avoid shooting up to the surface. I am trying to minimize the risk of injury by doing a slow swimming ascent. Shooting up to the surface is a last resort, and would happen should I black out and lose my grip on the weight belt.
If there was absolutely no air source, then I would have no option but go straight up. However, as long as there was some air available somewhere, it would be foolish not to use it to avoid getting bent.
If there was absolutely no air source, then I would have no option but go straight up. However, as long as there was some air available somewhere, it would be foolish not to use it to avoid getting bent.
Bent is fixable, dead is not. Plus if you are within no stop time and depth limits the chances of getting bent is not that high as the tables and computers we use have a reasonable amount of padding in them.
The more complications you add the more chance of something not working
To be fair i would have thought this be a last resort? Especially with no AAS and no buddy? I am sure the only thing going through my mind would be to get to the surface, not how to minimise injury as this is irrelevent if you never make the surface in the first place.
But i guess this all depends on the depth this happens and how calm you manage to stay.
Please note that the above 2 procedures are only what I would do if there was no other diver around able to rescue me. I am not saying this is the right way to do it, maybe it is wrong, and I'll be glad if anyone corrects me. What would you do in such situations?
Personally, I'd pay no more attention to it than "what would I do it a submarine hit me underwater"
I dive with a buddy (unless my snorkelling depth)
I use an independant cylinder (or I stay with my buddy abroad and limit cave/wreck penetration)
I watch my air, look after my own kit.
I have done many swimming ascents from 20m (examining the french training scheme) and they are not fun, I practiced them while examining by not letting myself breathe in. If you accidently breated out first, then 20m was a long way away.
My philosophy is to manage the situation before it occurs so the likely hood is so small as to not worry about it (know my kit, look after my kit, stay close to my buddy)
Equipment failure is very rare, and cylinders take time to empty themselves (even a dislodged a clamp) plenty of time to get to a buddy - or even the surface.
I would not suggest inhaling from the BC, I was trained to do it, but the loss in buoyancy (and time) make the ascent even harder.
In the same way I do not have an emergency parachute/anchor on my car in case all the brakes fail going down a hill.
Tony
Ed Howarth
08-12-2006, 14:32
Why on earth would anyone want to make a free ascent where the possible result is death or dci (not all dci result in an inconvenient rash, some put you in a wheelchair or worse) when your buddy with AAS is only 5 seconds away?
What do you mean, your buddy is not 5 seconds away? I bet your instructor was on all your training dives. That should tell you something.
I try and get all my trainees to breathe a cylinder down during training so they feel what it's like.
Ed
What do you mean, your buddy is not 5 seconds away?
Calm down :-)
The aim of this discussion is to explorer the "what if" scenario, and think lateraly. Most people, myself included, would do whatever necessary before and during the dive to avoid ending up in this situation; this means diving with a buddy and staying close to them, carrying an extra tank or pony bottle, etc...
However, no matter how well prepared, accidents do happen. If I were ever to find myself in that unlikely situation, I would rather have thought it through before hand to avoid making a bad decision in a panic situation. Part of my job involves risk analysis, and then explore the different scenarios to avoid it or minimize the impact; maybe I got a bit carried away :rolleyes:
jim oldham
08-12-2006, 16:54
Calm down :-)
If I were ever to find myself in that unlikely situation, I would rather have thought it through before hand to avoid making a bad decision in a panic situation. Part of my job involves risk analysis, and then explore the different scenarios to avoid it or minimize the impact; maybe I got a bit carried away :rolleyes:
Opening this up for discussion seems to be a very sensible thing do. The "where is your Buddy" question assumes that you should be tied to them. Buddies do get separarted and that is a fact. Building that factor into a risk reduction exercise/discussion is not getting carried away.
Jim.
Hi.
How would you be without air, is it a calamitous equipment failure like a blown O ring, or HP pipe which usually blows at the beginning of the dive when there is most pressure in your tank, and theoretically enough air to surface safely, or just bad diving practice not monitoring your air.
You should no your SAC and no before you go in how long you expect your tank to last at whatever depth you are in, so hopefully you will not run out of air.
Whatever happens you should ALWAYS have an alternative air source and regulator that is easily at hand, and if you are doing any deco diving an alternative air source that will allow you enough gas to complete any deco obligations.
If I have learned anything in over thirty years of diving it is do not rely on anybody to get you out of a situation, that is for a last resort. Be like a boxer protect yourself at all times, you will live longer.
Ed Howarth
08-12-2006, 17:19
Calm down :-)
Calm.....:o
Yup, if you've lost your buddy by shear bad luck *and* you're suddenly in an OOA situation, you would have no option other than to head up to the surface accepting all the risks that that entails, probably undoing your weightbelt on the way up and dropping it as your head breaks the surface. Easy decision to make. Just take care not to practice it so many times in your head that it then becomes automatic even though a perfectly good AAS exists closeby. Bit like the old buddy breathing training.
But I see so many people who think that the process of leading a dive is to have their buddy 3 or 4 metres behind them and finning like there's no tomorrow. If the guy at the back has a problem, his first reaction is to stop finning, maybe only for a second or two, but that puts his buddy's AAS way out of reach, and that's when he has to bolt to the surface.
Buddies should swim level with each other, or at least be within touching distance if one is slightly behind the other. An OOA situation should then be little more than an inconvenience that cuts short the dive.
Om
Ed
But I see so many people who think that the process of leading a dive is to have their buddy 3 or 4 metres behind them and finning like there's no tomorrow.
That made me laugh! Thanks. I know exactly the kind of person you are talking about, and have a few examples in mind. I am just the opposite, going very slowly, mainly using my fins for direction, and probably infuriating those "mad finners" :D
Nigel Hewitt
08-12-2006, 18:50
But I see so many people who think that the process of leading a dive is to have their buddy 3 or 4 metres behind them and finning like there's no tomorrow. If the guy at the back has a problem, his first reaction is to stop finning, maybe only for a second or two, but that puts his buddy's AAS way out of reach, and that's when he has to bolt to the surface.Yes.
We have a couple like that...
I try to make the point that I am equipped to manage my own problems so if you swim off and leave me it ain't anything like such a problem for me as for you but...
these are only my humble opinions, they are probably not the gold standard or may even be downright daft! So should you choose to adopt them you do so at your own risk.
Next time before you take your reg. of your cylindar in stead of venting the air breath the reg empty.
That is probably a good approximation to what your last breaths feels like if you are out of air under water?
I get like half a breath after I notice incread resistance.
You may get another half breath out of it while you ascend and the air in the hoses expands/cylindar pressure will rise slightly above abient again???????
As for breathing from your BC.
I was told that CMAS stopped training this skill due to the risk of fungla lung infection contracted from your BC bladder. Not that that would worry me in an embergency, but what would worry me is that i have never done it.
So i would not risk it going wrong and losing valuable time in an emergency. e.g. there will be a rest of water in the mouth piece and I'm not sure how I would clear that effectively to avoid a coughing fit.
More importantly I have absolutely no air in my BC when diving in a dry suit.
My main worry during a free ascent would actually be a burst lung!
It really takes a while for me to pass out. I have never managed to hold my breath long enough to pass out yet (i.e. 4 min. but this was at rest and during fitter times in my life).
If i'm deep enough that I worry about passing out on the way, I'd have a completely redundant air source with me.
I can't see myself running out of air without warning, unless i am/my buddy is in deep **** already for some other reason and I forgot all about monitoring my air over that incident.
If i run out of air/get an unexpected gob full of water and the Octo is no use, plus my buddy really appears to have vanished, i'd start camly but destinctly finning up making sure I breath out all the way up. Once the boyancy of my suit takes over i would dump some air trying to keep the ascend fast but controled if i'm not too despreate for air at that stage (as if?) try to slow down on appoaching the surface.
The rate i would go by feel say 0.5m/sec-2m/sec, i.e. as slow as I think i can get away with without risking getting anywhere near fainting towards the end.
If i just got half a lung full of water and have an uncontrolable coughing fit so i cant even think about getting an Octo. or even my buddies Octo in my mouth within a couple of seconds.
Bolt for the surface, keep breathing out hard, try to dump the weight belt on the way unless i go like a rocket anyway due to increasing boyancy in my suit.
Paul Fivian
08-12-2006, 23:40
i'd start camly but destinctly finning up making sure I breath out all the way up. Once the boyancy of my suit takes over i would dump some air trying to keep the ascend fast but controled if i'm not too despreate for air at that stage (as if?) try to slow down on appoaching the surface.
Look. In a REAL OOA (and this should never happen if you observe any sort of "normal" protocol) if you're at more than 15 or 20m (at less than this you should know you can make the surface - especially if you're a freediver) then panic will grab you and you will ascend like your life depends on it. Within seconds you will be into an uncontrolled buoyant ascent (assuming there is some air in your suit or bc and if not you've probably dumped your weights) all your planning is out the window and the best you can hope is that you remember to exhale - which should be instinctive - and that you're not right under a boat!
I'm not suggesting that mental scenario planning is a bad thing but, unless you actually practice it repeatedly - and no-one is going to recommend that - instinct really does take over and your challenge to is survive the ascent rather than the OOA.
That said, I'm sure there are plenty of old salts around who really are experienced enough to stay cool and ascend briskly but safely from any depth. But this is the exception rather than the rule.
Paul.
Hi,
I suffered if that is the correct phrase, an OOA situation when still a wet behind the ears instructor.
It happened when taking 2 student DL’s in for their dive leading exercise.
As I was just standing back observing the first one carrying out his SEEDS briefing and buddy checks I forgot to tell him to include myself in the briefing and buddy check.
So everything went well until we got into the water. I being the instructor entered the water first and waited until they joined me, still observing the dive leader.
On the DL signalling down I descended along with the 2 student DL’s.
At around 8m I suddenly found to my consternation a lack of air from my DV?:eek:
Luckily I did not lose my head and calmly signalled up to the 2 student dive leaders and headed for the surface by finning fairly quickly.
Whether it was due to the fact that my final part breath was taken at 8m or my previous military training kicking in (23 years man & boy), I did not in fact panic, but made my way quite calmly to the surface where I treaded water whilst one of the student DL’s turned my air on!
Yes I had descended with my air turned off, and in fact found that as I breathed my last bit of air my brain seemed to recognise that:
a) The air was running out
b) That I needed to stop inhaling as there was no air to inhale.
As I say all ended well and we continued the dive with me glowing red from embarrassment.:o
Although at the debrief I made it known that although I should have been more careful, as I was also participating in the dive, the dive leader should have included me in briefing and buddy check.
But it just goes to show that no matter how experienced you may think you are, mistakes can and will happen.
Hamish
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