That an OOA situation may also ocure due to somekind of malfunction that has nothing to do with gauges. Starting with an O-ring burst, all the way to hoze tear. And I may also add that with new regulators a free-flow may also do it. I made an exsperiment with one of the best regs around, the kind that gives you air so easily. The tank went from full to half full in less than 5 seconds in a shalow dive. Those incidents ARE VERY RARE, but nothing is 100% full-proof.
How does "real life" OOA looks like?
- Thread starter svidlano
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JimC
Contributor
Which is why you have a buddy, and a dive plan to allow for it.
Now, the only way to have an OOA emergency is if I have 2 major, catastrophic equipment failurs.. in a row.
Some minor equipment changes (H-Valve) makes that 4!
Now, the only way to have an OOA emergency is if I have 2 major, catastrophic equipment failurs.. in a row.
Some minor equipment changes (H-Valve) makes that 4!
Truy incredible... must be a super duper ultra high performance tank vacuuming regulator you have there... I couldn't empty half a tank in 5 seconds with just an open valve.... I could make a lot of noise though!
Conor... you say that your gauge was not fluctuating as you breathed... I am surprised as I would suspect that would certainly have veen the case.
:rofL: HA HA HA HA HA that's some funny stuff...funny cause its true....
I do find a flaw though...he might be referring to one of those spare air tanks.....
Conor
Guest
well. I dunno, its been a while, but we normally go through the cycle during the equipment checks twice of breathing off the reg and watching the needle. But thinking about it, if it was fully open when I done my check and was nearly closed after my buddy checked my tank, then the next check would be me breathing and him watching my guage......maybe I need to have a word with my buddy.
Conor... when a tank is near full a partially closed valve will probably not be noticed on the SPG, nor by the diver as extra breathing resistance because the higher tank pressure available to the first stage makes up for the smaller opening.
But when the tank is near empty the pressure presented to the first stage is not enough to keep up with the demand... the gauge needle will drop on inhalation and breathing will be hard.
Conor
Guest
Now it becomes clear, so he couldn't have noticed the needle dipping before the dive, but the muppet shouldn't have turned my air off in the first place!
Quite true...I've seen this happen. My dive buddy and I were doing a search and recovery dive low to zero vis....well, mostly zero. We did out pre-dive checks, both of us had air in our primary and back-up, 2800 psi each, so we hopped in. I was at about 1800 psi (meaning he had about 1400), when I felt him tell me we need to surface.
On the surface he shows me the new 'trick' he's learned. The gauge needle fluctuated as he was breathing....it would go down, and then as pressure built back up, the needle would slowly rise until he took another breath. The reg got a little bit harder to breath on at the end of the breath he was currently drawing.
We fully opened his valve and continued our search....never found what we were looking for, but hey we couldn't see a damn thing anyway, so we weren't disappointed.
Thee gauge may also fluxuate at depth with a full tank because of the additional volume requirements even though it may not at the surface. It of course gets worse as tank presure drops because the flow throught the partially closed valve is further reduced.
If thou art seeing that at the depths you dive Mike you need to add some more helium.
.... oh... you meant with a almost closed valve.
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