Basic SCUBA (Air Supply) Equipment Faliure: How frequent does it happen?

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The really oddball stuff (clogged dip tubes and such) you just read about because they make a much better story than I was an idiot and ran out of gas or similar.

I had a dip tube clog leaving approximately 1700 psi unusable in the tank.

I had a regulator freeze shut.

I had a regulator first stage freeflow that emptied the tank.

I had an inflator o-ring extrude.

Redundant air is good.



Sent from my SPH-L710 using Tapatalk 2
 
speaking of tanks clogging... the weirdest "failure" I've ever seen was last year. I had a diver who at some point during the dive gave the OOA sign and wanted to share air. So I gave him my reg.

I took his reg and purged it, air came out.
I looked at his SPG, there was more than enough air in the tank.

I didn't get it at all... I tried to give him back his reg to try it again and he refused and gave the sign to abort the dive.

Once on the surface he said that the regulator was breathing really wet and when he went head down just before he gave me the OOA sign all he got out of the reg was water.

It seemed ok when we tried it again so we were pretty puzzled, until we took the reg off and turned the tank upside down and opened the valve.... water sprayed out in a jet for several seconds, like a fire extinguisher. The tank must have had several litres of water in it.

And it was pretty gross too, tbh. I'm happy he was the one who ended up swallowing a mouth full of that water and not me. It was hard to find the guilty party too.... The operator didn't know who had rented that particular tank last and since they fill their tanks 3 at a time nobody noticed that it was empty.

R..
 
Myself, I have close to 100 dives with one bad experience. My first OW dive without an instructor (dive #6) and my GF's rental SPG was off by 500 psi. When she gave me the OOA signal, I was perplexed because she started out with more air (500 psi) than myself. Needless to say, it highly motivated us to buy our own equipment and humbled us into reconsidering the way we dive. Other than that, I'm happy to report I've experienced no air supply problems or equipment failures.
 
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speaking of tanks clogging... the weirdest "failure" I've ever seen was last year. I had a diver who at some point during the dive gave the OOA sign and wanted to share air. So I gave him my reg.

I took his reg and purged it, air came out.
I looked at his SPG, there was more than enough air in the tank.

I didn't get it at all... I tried to give him back his reg to try it again and he refused and gave the sign to abort the dive.

Once on the surface he said that the regulator was breathing really wet and when he went head down just before he gave me the OOA sign all he got out of the reg was water.

It seemed ok when we tried it again so we were pretty puzzled, until we took the reg off and turned the tank upside down and opened the valve.... water sprayed out in a jet for several seconds, like a fire extinguisher. The tank must have had several litres of water in it.

And it was pretty gross too, tbh. I'm happy he was the one who ended up swallowing a mouth full of that water and not me. It was hard to find the guilty party too.... The operator didn't know who had rented that particular tank last and since they fill their tanks 3 at a time nobody noticed that it was empty.

R..
A friend of mine saw something similar once in Cozumel. He was in a group doing a pretty deep, downward-sloping swim through, using steel 120s. Almost as soon as they entered the swim through, one of the divers signaled OOA. My friend donated, fortunately having a long hose that facilitated the exit. On the surface, the valve was removed, revealing that the tank had no dip tube any more, and there was about a liter of very rusty water in it. Since then, the dive operator has stopped using the island's bulk tank filler and now fills its own tanks.
 
A friend of mine saw something similar once in Cozumel. He was in a group doing a pretty deep, downward-sloping swim through, using steel 120s. Almost as soon as they entered the swim through, one of the divers signaled OOA. My friend donated, fortunately having a long hose that facilitated the exit

Without a long hose or a redundant air source, we would be reading about another fatality.

That's why it makes me crazy when dive ops take OW divers to places where "Everything will be OK" except for the times when it isn't.

OW training simply doesn't cover how to be prepared for a sudden OOA in a narrow overhead, or OOA with a significant deco obligation and insufficient gas.

Also, the clogged tank problem is more common than people realize. There are at least four reports of it on SB in the last few year that I noticed, and there are probably more, and there are definitely more that never make it to SB.

flots.
 
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The clogged tank thing is real. We were on a dive a couple of years ago off Puerto Morelos. Hanging above people on a wreck I saw a lady go head down and then swim to the divemaster for air. On the surface she had 1600# but the air stopped when she went vertical. Hard for us to carry ponys to Mexico so it made me think about spare airs.
 
Is it due to unskilled compressor usage or past OOA situations without tank inspection, that water and finally rust flakes end up inside the tank? Or are people rolling the tank valves in sand and then fail to remove the sand prior to filling? Thanks for warning. I never came to think that such a situation would be "probable".

Sent from my GT-S7710 using Tapatalk
 
Is it due to unskilled compressor usage or past OOA situations without tank inspection, that water and finally rust flakes end up inside the tank? Or are people rolling the tank valves in sand and then fail to remove the sand prior to filling? Thanks for warning. I never came to think that such a situation would be "probable".

There are a few ways for it to happen, but the most common is poor compressor maintenance or filling procedures. Also, tanks that never get inspected sometimes build up corrosion or crap on the inside that eventually makes it into the tank valve and maybe the diver's reg.

Usually the dip tube keeps it out of the reg, but dip tubes sometimes fall out, sometimes corrode or break off and sometimes were never there to start with.

The short story is that you always have to be ready for any breath to be your last and to have a plan for handling it. Not just for tank problems, but for reg problems too. I saw a reg split in half, just sitting on the tank, on a boat. Underwater, it would have been an instant OOA.

flots.
 
The clogged tank thing is real. We were on a dive a couple of years ago off Puerto Morelos. Hanging above people on a wreck I saw a lady go head down and then swim to the divemaster for air. On the surface she had 1600# but the air stopped when she went vertical. Hard for us to carry ponys to Mexico so it made me think about spare airs.

same thing happened to my wife in Cozumel several years ago, head down vertical no air, 1/2 tank
 
I'm nowhere near as experienced as many of the posters that have already given their lists. I have seen or experienced a few events, though, and found that most of the time they are trivially easy to deal with in a Rec environment.

I have had the following:
1) Overflow/dump valve fail on BCD (I had modified an old horse collar and this was my second dive with it.) No big deal, dive with very little or no air in my BCD anyway. Took it home and repaired the valve.
2) Minor freeflows due to cold water. Not full on freeze-ups but some 5 second freeflows here and there. (I've witnessed these, not had them happen to me personally.)
3) O-ring blown on a tank valve at the surface. No big deal, back on the boat, swap tanks and get wet.
4) A couple of minor second stage leaks and a minor first stage leak. Dribbling bubbles isn't a big deal, in my opinion. Watch the pressure gauge and repair during SI.

I keep my dive profiles conservative (as if I had a choice--still an air hog) and know how to service/repair my own gear. That, pre-dive inspections, and keeping a calm demeanor makes all of these equipment malfunctions non-issues.
 
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