2nd-stage swivel failure in Cenote Cristalino, Mexico - 06-Nov-2010

[Sludge]

the right angles I know of don't rotate.

Every one I've seen does.

[icestac]

I don't think he was talking about a rotating 90 degree - the right angles I know of don't rotate.

Every one I've seen does.

It just allows the second stage to rotate around the "X axis" (if you can call it that) in the same way the second stage can freely rotate when connected to the fitting on most hoses.

All of this talking about rotating swivels really makes my head spin...

[FW]

This is from the Sidemount forum, but pretty well covers Steve's cause of the swivel trouble.

I've fought these things for years. I have a couple of customers that INSIST on them. Plus, when I did some sidemounting it was the only way to get the fit I wanted. But they started leaking every ten dives or so and had to be reassembled.

Several weeks ago I ran across a service bulletin that says you MUST use Loc-Tite when assembling them. That opens up a whole new window on things. Maybe they're useful after all...

[whodunit68]

This is from the Sidemount forum, but pretty well covers Steve's cause of the swivel trouble.

agreed, thanks Forrest. Unfortunately I saw that afterwards....

[sskasser]

<snip> Ok, so now I have Gabriel's reg and he has one and he checks his pressure seeing that he has plenty of air and we both signal thumbs-up and "ok" to exit immediately. After a few metres, he asks again if I'm ok and he maintains touch contact with me (to say "hey buddy, I'm here with you and we're going out together") - this was very good. ...<snip>....Gabriel uses a double short-hose configuration which keeps the 2nd-stages separate. It looks clean and also would have avoided this problem....<snip>

First off, glad you're ok, Steve!

What issues (or were there any) did you encounter during the airshare with Gabriel using double short-hose configuration? "We've" discussed the theoretical implications ad nauseum, but here's some real data and I'd love to hear how it went.

Thanks for sharing such a great detailed report!

Shirley

[whodunit68]

It just allows the second stage to rotate around the "X axis" (if you can call it that) in the same way the second stage can freely rotate when connected to the fitting on most hoses.

Thanks for explaining!

First off, glad you're ok, Steve!

What issues (or were there any) did you encounter during the airshare with Gabriel using double short-hose configuration? "We've" discussed the theoretical implications ad nauseum, but here's some real data and I'd love to hear how it went.

Thanks for sharing such a great detailed report!

Shirley

Thanks, Shirley. Yes, I can. Interestingly, I asked Gabriel how he does an air share. His answer was that first he tries to match configuration with his dive team. In sidemount, the likelihood of an airshare is very low. However, if a situation arose where he must, he says he would just pass the bottle. At one point during the scenario, it seemed as if he was preparing to do just this (right before my right valve was turned back on).
It was not easy to share with the short hose especially around the back of his neck but we did it. He made it pretty easy to do. We would have made it out of the cave. Frankly, his setup sure looked cleaner and the short hose configuration wasn't all that much different than sharing air with someone in a recreational setup, though it's been simulated eons since I did that.

[BobK]

So I gather that you were diving sidemount, yet when you had a failure you shut down the wrong tank ? I always thought that one of the porported benefits of sidemount diving was that you could easily isolate the tank with the problem, yet this incident shows that is not always true.
Can you explain in more detail why this occured ? I'm really not trying to be adversarial, but this seems to be contrary to one of the main "safety benefits" I have read about sidemounting.

[skip]

My 90-degree angle does not "swivel" or "rotate." It's locked at 90-degrees. However it does rotate after the elbow turn where the second stage screws on (so the second stage rotates).

skip

[skip]

So I gather that you were diving sidemount, yet when you had a failure you shut down the wrong tank ? I always thought that one of the porported benefits of sidemount diving was that you could easily isolate the tank with the problem, yet this incident shows that is not always true.
Can you explain in more detail why this occured ? I'm really not trying to be adversarial, but this seems to be contrary to one of the main "safety benefits" I have read about sidemounting.

I've never seen this benefit. I wear one reg on a necklace, just like backmount and the other one is in my mouth (just like backmount). when a freeflow occurs it's not easy to determine if it's the one in your mouth or the one on your necklace unless you remove the one in your mouth and look at it. if a tank valve goes (or din o-ring?), making the source of freeflow at the tank, then it's a bit easier (i would imagine).

skip

[Sludge]

My 90-degree angle does not "swivel" or "rotate." It's locked at 90-degrees. However it does rotate after the elbow turn where the second stage screws on (so the second stage rotates).

Yes, they all do.