No gas -- what do you do?

[300bar]

Still no idea how it happened. Had just used the reg on the dive before, but I went to deploy this reg at 70' and wham, bubbles and no more usable second stage.

Still doesn't make sence, bubbles means, reg is delivering air.

I've also seen someone's mouthpiece come off in the water. While it's still possible to breathe the reg, if it happened to me, I'd just go to my backup, and not to a buddy. Would obviously then thumb the dive.

Been there done that, once made a dive without a mouthpiece, just to see if it was doable. Had my altair on the ready.
But can be done with eaze.

 

[Rainer]

(Again) I don't see why you wouldn't try your own backup reg *while* you go to/flash your buddy. You can do both at once. A buddy isn't going to get to you faster than you can stick your own secondary in your mouth. If it (likely) too doesn't work, then your buddy is already on his way, deploying another reg for you to try.

 

[Bubbletrubble]

Why not spend a couple seconds switching to the backup reg while signaling a buddy to share air? A malfunction involving the lever mechanism (lever breaks or bends, diaphragm falls off as described by Rainer, diaphragm tears, etc.) could result in diver not being able to initiate flow through a second stage.

If you think about the design of a second stage, you could come up with a number of faults that could occur with varying likelihood.

I realize that this isn't exactly the same thing, but if a mouthpiece ziptie failed, the diver might think that the primary was malfunctioning when the mouthpiece simply wasn't attached to anything. It would take a not-very-observant person to overlook the fault in this example. Switching to the alternate would be appropriate in this case.

[Edited later: I see that others have already mentioned several of my points. I'm slow.]

 

[Scott]

For me, I'm going for my buddy.
I could understand their position on going to backup. There would still be a few breaths of gas left in the back up hose, even enough to get to the surface from a shallow depth.
Not saying that's the best solution but it is a possible option.

 

[Rainer]

Still doesn't make sence, bubbles means, reg is delivering air.

My hand was on the (now bare) purge lever. That will cause gas to flow (everywhere). Inhaling without a diaphragm cover, however, just doesn't work. The reg is functionally useless at that point. I know, I tried breathing it.

Been there done that, once made a dive without a mouthpiece, just to see if it was doable. Had my altair on the ready.
But can be done with eaze.

Um, not if you need your hands for other things.

 

[300bar]

Is it possible the hose you're breathing from is kinked? I guess, but that doesn't seem very likely. Can a diaphragm fall out? Yes. If it does, I'm sucking water, and I'm going to my buddy's gas before trying to figure out why. Can the threads fail at the first stage? I guess, and see above. Etc., etc..

My policy, unless I know what the problem is, is to go to a different gas source before investigating. In singles, that's a buddy (for me).

Please explain, I've seen a whole heap of failiures, but NEVER that one.
How can that happen

 

[Thalassamania]

As I just posted in another thread:

I was diving at Pt. Lobos, CA with my Assistant Instructor. We were at about 40 FSW, 15 minutes into our dive. My buddy, 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.

 

[TSandM]

Well, a diaphragm failure is going to cause you to take on water . . . in that case, I WOULD go to my alternate reg. I was talking about a sudden and complete lack of delivery of gas to the mouthpiece. Can anybody think of a failure that will do that, and not deliver water instead?

Okay, Thal, I posted while you were writing. There's one.

 

[300bar]

My hand was on the (now bare) purge lever. That will cause gas to flow (everywhere). Inhaling without a diaphragm cover, however, just doesn't work. The reg is functionally useless at that point. I know, I tried breathing it.

No diaphram will cause a gas flow.
Not possible, no diaphram means the lever will not be depressed, so no gas flow.

Um, not if you need your hands for other things.

Had on hand on my light and the other on my alt air, so yes can be done.

 

[Blackwood]

Please explain, I've seen a whole heap of failiures, but NEVER that one.
How can that happen

Ask Rainer, it was his. But as he mentioned above, we don't know how it happened. We arrived at 70 feet, and when he went to deploy deco gas, there was no face plate on that second stage, nor was the diaphragm in place.

No diaphram will cause a gas flow.
Not possible, no diaphram means the lever will not be depressed, so no gas flow.

Bubbles everywhere because he hit the lever with his finger, and there was no diaphragm to contain it the flow of gas.