Out of air emergencies

[CycloneFever]

There's a pretty good thread going on talking about how to with with an OOA situation. Can you rely on your buddy, should you carry a pony, etc. I've got a question about the root cause of the problem.

Is there anything that can cause OOA other than sucking it down too fast and/or not paying attention to your SPG? Seems to me that any diver can pretty easily avoid this situation by paying attention to what they are doing. What am I missing?

 

[Monkey_Gland]

Malfunction of any number of bits of kit I should say...1st Stage, o-rings etc

 

[TSandM]

You aren't missing anything. The primary cause of being out of gas is breathing all the gas in your tank -- going too deep, not paying attention to your gas consumption.

There ARE equipment malfunctions that can lose all your gas -- A freeflow you can't stop is probably the most common, but you can blow o-rings, have hoses blow, or even have the tank neck o-ring fail. But those malfunctions are far less common than someone simply not monitoring their gas.

 

[siikik]

Once, I had an o-ring that caused a small leak... It was the o-ring on the cylinder where the first stage connects, so I would have never noticed it since it wasn't but a tiny stream of bubbles... thanks to my buddy that day! As it ended up, it actually sealed itself at depth, so no issues, but I replaced it right away. Never had one do that, they usually "blow" when you first turn the air on.

However, to answer your OOA question, you could have a leak that you don't notice. That would use up air faster than normal. If you've been diving a while, you should have a good idea of what your SAC is and can guess how much time at depth you have... if your air seems to be going faster than you expect, look at other causes. Of course, this is presuming you're not doing anything different that would make you consume air faster, i.e. strenuous activities, etc.

But back to the basics... you should be watching your gauges. And use whatever secondary source you feel comfortable with... If you'd be more comfortable with a pony, rather than relying on an "instant buddy" then get one. If you dive with the same people all the time and know they will be there, that works too. Better yet, do both!


Ken

 

[String]

Is there anything that can cause OOA other than sucking it down too fast and/or not paying attention to your SPG? Seems to me that any diver can pretty easily avoid this situation by paying attention to what they are doing. What am I missing?

Most are caused by diver stupidity not reading gauges. However you can get uncontrolled freeflows, hoses rupturing, o-rings failing, regulators falling apart, contaminated gas, diaphragm on reg tearing and many other failures that can leave that particular air source unusable.

 

[Diveral]

Both me and my buddy have been hung up inside wrecks before. We both were able to extract ourselves before OOA was a possibility but I can see where it would be a concern for an snare/entrapment or lost diver/silt-out/dive-light failure situation.

I hd an o-ring failure once, beggining of dive with plenty of air. My buddy's second stage came apart under water once.

AL

 

[herman]

You have not missed anything. Pretty much all OOAs are due to 2 divers neglect, the diver AND his buddy. IMO, it is the responcibility of both (all) divers to monitor the teams gas. Dive with me and you will be asked what your pressure is and I will respond with mine on a fairly regular basis, how often is determined by the dive and how well I know you. An OK is not an acceptable answer and if you respond with anything other than what I expect I will stop and determine why before the dive continues.
With the excetion of a first stage that stops delivering air to the second stages- which is very rare, even a major equipment failure does not instantly make you OOA, you may quickly run out of gas but not instantly. A major failure may require you to get a little creative about getting to the gas you still have but it is still there. Not that I would recommend it but even having the first stage totally stop delivering air can be worked around....it's not pretty but it can be done if you keep your wits about you.

 

[Teamcasa]

Most are caused by diver stupidity not reading gauges. However you can get uncontrolled freeflows, hoses rupturing, o-rings failing, regulators falling apart, contaminated gas, diaphragm on reg tearing and many other failures that can leave that particular air source unusable.

I would agree with this but temper it a bit by replacing stupidity with compliancy, distraction and lack of situational awareness. In addition, gear failure does happen but not nearly as often as diver caused problems.

 

[Thalassamania]

I posted these before, involve air sharing as a result of something other than "running out of air." They're short enough to repost here to save you the trouble of linking.

Incident 1:

I was diving at Pt. Lobos, CA with my Assistant Instructor. We were at about 40 FSW, 15 minutes into our dive. Louis, after signaling me, took off in pursuit of a large eagle ray, I was along side of him, about 2 feet back. He suddenly stopped, spat out his regulator and pointed to his mouth (signaling me to buddy-breathe). I gave him my regulator and we settled into a two-breath-each rhythm while maintaining our neutral buoyancy. We were under a very dense kelp canopy and had to buddy-breathe while traveling about 100 yards to a point where we could surface. We did so without further incident, surfaced, returned to our surf mats and to shore. Later examination of his regulator second stage showed that he had bitten off a tab from his mouthpiece and it had lodged in the regulator behind the actuating lever in such a fashion as to cut off his air supply. After some experimentation I found that in this circumstance, if I attempted to depress the purge button I could feel it stick and that if I sharply stuck the second stage it would then function.

Incident 2 (link goes to the entire story):

Frank, Ken and I descended into fifty feet of water over the rocky canyons off San Jose Creek. It was Ling Cod city. I shot three. I just stacked them up on my spear. Ken tapped me on the shoulder and slashed his hand across his throat. He pointed to Frank, pointed to me and banged his fists together. He pointed to himself and raised his thumb. I gave him an okay. Ken started up and I went after Frank.

Frank was the only UC diver I knew (not Berkeley might I add, but Santa Barbara) who was not a great buddy, but he was a faculty member and a strong swimmer. We were at about fifty feet, he was out ahead and I was having trouble gaining on him. Over the next few minutes he managed to stay about twenty feet in front of me, just at the limit of visibility. As I almost caught him and I feel a tap on my shoulder. There's Ken, snorkel in place, pointing to his mouth. I gave him my regulator. Two breaths, I took two, Ken took two. Ken's hand began to gyrate, I recognized the motions from the previous day.

To review ... were at fifty feet, we're buddy breathing, Ken has an empty tank. I've got a spear with three dead Lings on it. Frank's again disappearing at the limit of visibility. There is a shark in the area. I review my options and choke back an initial impulse to give Ken my spear with the dead fish, my tank, make a free ascent and tread air back to shore. Ken and I continue to buddy breathe. I give Ken the spear with the bloody fish, point to myself and then in the direction Frank had gone and bang my fists together. I point at Ken and raise my thumb. Ken nods, flashes the okay and starts up. I go after Frank.

Incident 3 (not really OOA, but we had to share air anyway):

I was diving with three recently authorized research divers at a location where there is a large permanent gill net that all divers had been instructed to stay well clear of. We were diving as two separate buddy pairs. My buddy and I had completed our dive and were returning to shore on the surface when one member of the other team surfaced alone, near the net. I asked him were his buddy was and he said he did not know, that was why he surfaced. I looked around for bubbles and saw some coming up not far away. I told my buddy and the other diver to follow me and dove down on the bubbles. I found the "missing" diver tangled in the net, struggling to get free. She had gotten into the net as she surfaced since the current had bowed the top of the net over her. She had first taken out her knife to cut herself free but had dropped it, and it was now out of reach on the bottom. She had then tried to take off her tank and had somehow managed to wind her intermediate pressure hose around her neck and was now badly fouled in the net. I signaled the two divers with me to buddy-up and stay clear. I approached the fouled diver, got her attention, and had her shift from her regulator to my octopus. I helped her to complete the removal of her tank and we surfaced together, leaving her tank in the net. After settling her down, my buddy and I submerged and recovered her tank from the net and her knife from the bottom.

 

[Peter Guy]

My guess would be the most common gear failure that results in being OOA is a free flow -- and THAT is something you will almost always know because it ain't subtle! Yes, there are a few situations where you might get tripped up -- driving a scooter or in very heavy current -- but in most situations, you'll be very aware you have a problem some time before you are OOA.

Otherwise the initial reason is faulty planning of the dive which is then followed by faulty execution (i.e., not having enough gas to do the dive you plan to do and then not watching your gauges to see if you ACTUALLY have enough gas).