Air rushing from the tank

[ClumsyCuttlefish]

Hello everybody!
There is a question I would like to ask. Let me describe the situation.
Last year I went with the group of divers on a diving trip to Curacao. The trip was organized by the diving travel agency/dive shop where I just passed my AOW course. (in Quebec). By the time of the trip I had only 10 dives, all part of my training and, consequently, all with the instructors. I rented all the gear at the shop as I did not have mine. That was my first sea experience and the DM knew that. The depth was 12m in average.
The first day and the first two dives went fine. I was a little bit shocked by the reality. The books said that you never separate from your buddy and you ascend together. My insta buddy was swimming away from me all the time and once I was short on air (yeah, too soon for my first dives in the sea) I thumbed up and he just waved good-by and stayed under the water. But that was not the real problem.
On the second day, while on a boat, shortly after I connected my regulator to the air tank (I did check the o-ring), the air started rushing out of the tank with a loud hiss. The DM (who was responsible of the trip) turned down the valve and suggested changing the tank. I asked him what might have caused the leak and he said that was the o-ring. . I changed the tank and this time asked the other DM to check the o-ring. He checked and said it was fine. Then the same picture again. Air is rushing from the tank ( not a mild leak, but a really noisy one with a fume). The DM came to me and closed the valve again, changed the tank and told me to keep the valve closed until the actual dive. Then he turned away and the “issue” was over. I felt very nervous and asked what I should do I this happens under the water. He answered that I would lose air quickly, so I just ascend. That was the end of his explanations. I do not need to explain how I felt during the dive. I swam really close to my buddy and did not think about the beauty around but about my tank.. Fortunately, the tank was silent under the water and I ended my dive normally.
I am still not sure if it was right to go underwater with such a problem? Should I have stayed on the boat?
Was it really a problem and what might have caused it?
Was it a normal reaction from the DM?
I would like to know for the future what to do in this situation.
Thanks!

 

[tstormdiver]

Sorry to hear you weren't able to enjoy your dives as you should have. As for the "same ocean" insta- buddy, it probably would have helped to have had a more detailed dive plan to see what his intentions were. He may have actually planned on diving solo & was "forced" to buddy up with someone or just had very poor (non existent) buddy skills,.. you never know. As for the leaking tank, it could have been several things. 1. bad or wrong sized o- rings, 2. the regulator was not seated correctly on the valve, 3. a dent or malformation of either the cylinder orifice or the regulator at the attachment point or an internal problem with the regulator. Under no circumstances should you dive with defective equipment. Either the equipment should be repaired, replaced or simply not dive. A dive is not worth your safety or life. underwater a small problem can become a huge problem very quickly & often very violently. Unfortunately poor quality/ maintained equipment is one of the pitfalls of renting equipment,... its a crap shoot. That is one reason I encourage people to get their own. You know how to use it, where its been, how its been treated, how & when it has been maintained.

 

[psiborg1812]

More than likely a reg problem. Either like tstorm said above, or the nut holding the yoke screw on might have been loose enough to cause an o-ring extrusion. The DM in this situation did not handle it correctly, IMHO, and should have either recognized the problem and fixed it, or given you a new regulator. Props to you for staying close to your buddy and making sure you had enough air periodically!

 

[Reef Tank]

A related question: if an O-ring fails catastrophically at depth will there still be a few minutes of pressure at the second stage?

 

[vjanelle]

Depends. Sometimes you can still breathe off of the reg.

 

[tstormdiver]

A related question: if an O-ring fails catastrophically at depth will there still be a few minutes of pressure at the second stage?

It also depends on how much air is in the cylinder, depth, & what size cylinder it is. Another consideration,.... is it the o-ring at the valve orifice or the neck o-ring of the cylinder? Believe it or not a leak from the HP hose will drain a cylinder much SLOWER (pin hole):shocked2: than a leak on a LP hose (much larger hole).

 

[ianr33]

A related question: if an O-ring fails catastrophically at depth will there still be a few minutes of pressure at the second stage?

With a full tank and a complete failure it will be somewhere between one and 2 minutes. Not long.

 

[Herbiehamshank]

Just thought i would share with you an incident i experienced last month whilst diving the Thistlegorm in Egypt. My buddy and i were returning to the boat after the dive. I had 70 bar and dive had gone fine. We were doing our safety stop at 5 metres where there was also a spare tank attached to the line by a rope ( in case anyone comes up short on air). After doing the full 3 minute safety stop i moved up the line to go to the surface. Unforrtunately the rope from the spare tank snagged on my tank and i tried several times to shrug my way free. Eventually my buddy unsnagged me and i moved off to complete the last 5 metres to the top. After 1 metre my air just stopped suddenly. As i only had the last 4 metres and my buddy was still below me i made it up to the surface with no real problem. Back on the boat we were trying to work out what happened as i knew i definitely had plenty of air. We went through the scene and then the penny dropped! He reached for my valve and turned it- straight back up to 70 bar. In my struggle to free myself from the rope, i must have caught the tap on the rope and the shrugging motion must have turned the tank off. I had definitely fully turned it on with a single turn back as is standard. What a relief that the very thing that was there to save me nearly ended up killing me. We all talked about this on the way back, and didnt think either of us did anythin wrong, but put it down as one of those things. next time i get tangled however, i will always check i still have air before moving away from my buddy at all!