2nd Stage Swivel Failure/airshare

[rchrds]

C and I were diving in a project cave in Tennesse, where the visibility is normally in the 6 foot range. Our plan for the dive was to continue the survey of the cave, so in that vein, C was perhaps 10 feet away from me on the other end of a shot with the tape in one hand and the line in the other. I was on the other end of the shot, with my survey book and pencil, and the "dumb" end of the tape. We had just completed the shot in an area of the cave where it is approximately 30 feet wide, and the passage is roughly triangular, with a low wide silty floor, and a narrower ceiling perhaps 10 feet above the floor. The line runs about 4 feet above the floor in this area, making it visible from anywhere in the middle of the passage, but no at the lower corners, due to the fair visibility. All three divers were diving sidemount as is our standard. We were about an hour into the dive, making good progress on the survey, with the third in our party about 20 feet ahead, scouting line placements and looking for side passages when I heard a freeflow of bubbles. I immediately turned back to C to see a huge cloud of bubbles and swam quickly over to her. Not immediately being able to ascertain her problem due to the bubbles I pulled the regulator out of my mouth and handed it over to her. She immediately took it, moving her left hand, where it then became obvious that something was wrong with the connection between her left reg and it's hose. I quickly turned off her left bottle (she was too shaken to manage it) and then realized that I had not ever switched to my other regulator. I groped for it, and not able to find it in a hurry, tapped my reg in her mouth, which we both understood to mean i needed it back. She passed my reg over, I cycled two breaths, and handed it back, during which time I found the reg on my right and switched to it. We then paused, and I managed to ask her if her other regulator was working, which she replied that it was, and switched to it. Now back on our own gas supplies, we gathered our breath, and took stock of our position. In managing the emergency, she had lost control of her bouyancy, and floated to the ceiling. I of course followed, but this resulted in both of us at the ceiling of the passage. I was able to sink a few feet and see the line, so we were lucky in that aspect. We managed to signal our third (who was unaware of the situation) and exited the cave. On the surface we conducted a debrief.

What went wrong? Her left side swivel retention bolt had come loose, resulting in the swivel falling apart in the water. The swivel was new, had never been serviced, and had only been on three dives before. It was NOT an onmiswivel. We chalked that up to going cheap and purchasing a swivel with a known history of failure.

The larger issue was why did we end up air sharing? She related that as soon as the swivel exploded, she managed to hold the two parts in her hand tightly enough for her regulator to deliver some air through the mouthpiece (though she suffered freeze burns on her hands through 2mm gloves.) In the excitement, she was unable to find her opposite regulator, which was hanging about 2.5 inches from her neck on the right side. We both use a standard reg retention method, which is a small swivelling bolt snap on a removable bungee on the regulator which clips to a snug loop around the neck. This keeps both regulators a small bolt snap away from the neck. However, her neck loop had become loose over the last couple of months, adding 2 inches to the distance from her neck. In addition, she had used the right reg previously, and not tucked all of the 26" hose back behind her, allowing the regulator to hang in a direction that she was not used to. Interestingly enough, a similar situation had happened to me, placing my regulator in almost exactly the same position (though not quite as loose on the neck loop) and I was unable to find mine as well in a hurry. Multitasked, neither of us found our opposite regulator quickly, forcing the temporary air share- all because each regulator was approximately two inches from their anticipated positions.

Secondarily, during the incident, we lost contact with the line. Had this been a larger or more complicated passage this could have been a very significant issue. When her issues started, she focused on controlling the swivel, and began breathing deeper, in anticipation of having to switch regulators and a touch of panic after not finding her second regulator. This increased her bouyancy enough to start an upward drift away from the line. Reacting to an emergency, I knowingly swam from the line, as air trumps direction every time. Had this been a very tall passage, I would have most likely had to deflate her wing as well as close her tank, which might have complicated the air share even more.

What was our take away? Drills. Drills and a bit of cheap maintenance. We had been using the neck loops for over two years, and they had slowly worked their way looser and looser until they were where they were at at the time. 50 cents of bungee.

Drills. We were not rehearsing a quick change of regulator, something that you could do all day long while making the swim commute to the survey front every day. We never had issues, because when switching tanks, which might only happen once or twice in a dive typically, we had plenty of time to fish for them, and when not doing other things, they are easy to find. Bottle shutdown drills. Though I practice them, she had not since her initial cave training, as we rarely make dives that are not working dives, purely for the purpose of working on skills.

We were also lucky, in that when surveying we are rarely within eyesight of each other, and depending on the length of the shot, can be as far as 100 feet apart (the length of our tape.) With our safety man out front and unaware, we could have been potentially too far apart to help each other.

In closing, the loss of one regulator should not have been an emergency. It was a reason to turn the dive, particularly since we had no stage bottles with which we could swap a second stage in the cave. Our rusty emergency skills allowed what should have been a 5 second inconvenience stretch into a potentially life threatening 1 minute air share and loss of line drill.

Jason

[whodunit68]

The single most important takeaway i got is that you're all ok! I experienced a similar incident with more or less similar resulte andit was eye-opening. Thanks for posting and I'm really glad All is fine.

[Kelly Jessop]

Her left side swivel retention bolt had come loose, resulting in the swivel falling apart in the water.

Glad your emergency had a happy ending. I experienced the same thing with a swivel in somewhat of the same manner (amazing how Murphy knows when to strike). I've heard suggestions on using Loc-tite on the bolt,but decided to get rid of the swivels altogether. Incidentally,kudos to you for doing what you said in another thread about discussing incidents.

[Scuba Coop]

Yeah! I agree. Double the kudos!..And good post.

[stairman]

Ive had my bungeed necklace reg move over to the side a bit and couldnt feel it right away as well. I wont use a swivel but have a solid elbow that seems safer. Glad everyone is OK and a learning experience for us all.

[adam0321]

I will not use a swivel on my primary tanks. I have them on my stage and deco Regs though.

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[LCF]

Some very good takeaway points here. I know that if something isn't where I expect it to be, I fumble -- not what you want to have to do in an urgent situation.

I have been thinking a LOT about emergency responses, because it's now been a year and a half since I've taken any instruction at all. Although we do S-drills and valve drills from time to time, it's not like having things sprung on you. I had been considering asking one of my instructors to spend a day with me this next trip, just going over protocols and doing some drilling. It may be an even better idea that I had thought. I wonder how many people do anything like that?

[cavermatt]

Thanks for sharing Jason.

I had a barrel o-ring blow on an elbow one time, the only time I have seen one go. First, I heard the rush of air, then inhaled a breath that was mostly water. Since the reg was not delivering air, I dropped the second stage out of my mouth and shut down the tank. Then I found my second reg, luckily it was on a necklace and easy to find. Next the offending regulator somehow fell off... I had tightened it with a wrench before the dive, it was the first dive with the elbow.

Jason makes a great point, practice shut down drills, know where your valve knobs are and be able to use them with cold hands. Being able to find your second reg is just as important.
Most people dive solo in sidemount because of the redundancy, but if you cannot quickly manage a problem, it does not matter how much gas you have.

My little incident was on a short easy dive and I had tons of gas. But it does open your eyes, practice and know your gear.

[adam0321]

Any one ever have s roll off in sm?

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[icestac]

Any one ever have s roll off in sm?

My wife managed to in her sidemount class. Not sure how, but I am sure the cause was the valve was only slightly opened. She tested both regs in the water pre-dive and they worked. She handled herself very well in the water when she did make the switch to the offending reg. She said she got about a breath and a half, then nothing. She simply switched back to her other reg and turned the dive.