Diving incident at Eagles Nest Sink

[Bobby]

Ok I keep quiet and listen a lot but one question keeps going thru my mind that I have not seen addressed much in the forum..

From the report, one diver his CC loop was open and out of his mouth. The inhale side of the loop was crushed. Question is: Did this damage come while exiting the restriction or after his unconsciousness?

I have only seen one post that said maybe the pressure from the depth crushed the loop once the dilute ran out or hitting the surface of rock in the cave. Maybe the damage to the loop happened in the restriction, He goes on OC as bailout and exits the restriction. Then Second diver gets stuck in restriction removes CCR and drops it exiting restriction causes a silt out and has buoyancy problems. Now both are now on OC as bailout. It has been assumed here that the diver who had on the CCR that it was operational until the end.

I am not the expert , I am an OC cave diver, so I will defer to the experts here on CCR to look at it from this different angle for educational purpose. What caused the loop failure by crushing and when it happened would make a big difference I think... Ideas ?

Understand that the term "crushed" does not mean damaged when referring to a CCR counter lung. When you inhale the CCR counter lungs deflate as you are taking the gas out of them and into your lungs. When we refer to a counter lung "crushing" that means there is not enough gas in the counter lung to take a full breath. Since the loop was out of the diver mouth the exhale counter lung likely filled with water, however the exhale side would not necessarily flood if the orientation of the CCR is at the right angle & not changed. Though the lung was crushed it likely was still functional.

There are multiple reason why the inhale side was crushed. Diver could have breathed down to the end, after loosing the loop he could have been negative and it crushed as he descended, both, etc.

 

[Basking Ridge Diver]

Understand that the term "crushed" does not mean damaged when referring to a CCR counter lung.

My limited exposure to a CCR is the Loop is the hose that goes from the DSV to the Counter Lung. I believe it was the hose "Loop" that was crushed.

But the person that wrote the report may need to validate the Counter Lung or the Loop was physically crushed...

 

[archer1960]

If it occurs. My instructor had us do it. I haven't seen it done since, in 10 or so times with an OW class, nor have I ever seen it discussed with them.

I have seen it done at ~70' in real life. The DM on a dive in Coz had a small stream of bubbles coming from his 1st stage, and did the remove/work/don sequence while the group hung out and watched him do it.

 

[tbone1004]

My doubles setup has all the weight in a v-weight and the backplate. Totally inaccessible while wearing the rig. So yeah, need to play with this in a swimming pool with a bailout.

don't bother, it's a useless skill that shouldn't be practiced, especially in doubles. If you are planning on doing something where you have to remove your backmount rig, then buy sidemount. If you come across something that looks cool but you won't fit in backmount, then turn around, buy a sidemount rig and take a class in true sidemount diving for restrictions, and then go back and try it. Don't try to remove doubles, it's completely pointless these days with the quality of sidemount gear we have now

 

[BLKOPSDVR]

I have tried to keep up with the thread but might have missed some of the info. Not a rebreather diver myself. In regards to doffing the CCR, would the process be to close the loop, leaving the mouthpiece in place and breathing OC from the BOV? Or would the diver go on their long hose to give more slack to manipulate the gear?

It's already been discussed that removing the CCR would not be something really planned for but is there a best practice, BOV vs. Long Hose, for if you have to?

I can't imagine the level of anxiety pushing gear through, getting to the other side, losing contact with gear, shooting to the ceiling and having the reg ripped from your mouth as you and your gear separate. Now somewhat pinned to the ceiling and OOG. In my opinion even if the buddy was in touch contact at the time of the lost gear, that would be a hell of a lot to deal with and sort out without even getting to the search for lost gear.

Appreciate the great discussion in this thread and the teams that took care of these guys after the event.
Ron

 

[sea_ledford]

I have tried to keep up with the thread but might have missed some of the info. Not a rebreather diver myself. In regards to doffing the CCR, would the process be to close the loop, leaving the mouthpiece in place and breathing OC from the BOV? Or would the diver go on their long hose to give more slack to manipulate the gear?

It's already been discussed that removing the CCR would not be something really planned for but is there a best practice, BOV vs. Long Hose, for if you have to?

Completely depends on the CCR set up and planned procedures. Switching to OC on a BOV is easiest, but you would have loop length issues, high risk of flooding issues and most likely not as high performance 2nd stage as on a long hose. It also depends on what the BOV (if present) is plumbed to. If it is to the on board gas, that isn't much volume to deal with at any depth, let alone at 300'. If I were to remove my CCR for any reason, I would switch to offboard after closing the loop.

Regarding crushed loop hoses, it could mean next to nothing if the hoses are very flexible like on an inspiration, or it could mean significant damage if they are wire reinforced hoses like Coopers. Since the description didn't mention cooper hoses, I assume they were stock JJ's. I'm not familiar with JJ's to know how resistant to crushing those are.

-Chris

 

[Bobby]

My limited exposure to a CCR is the Loop is the hose that goes from the DSV to the Counter Lung. I believe it was the hose "Loop" that was crushed.

But the person that wrote the report may need to validate the Counter Lung or the Loop was physically crushed...

We, CCR divers, use the term "loop" rather loosely. I have said that I flooded my "loop" what I was referring to meant one time that my exhale lung was flooded & then recovered & flushed. Another time I meant that the entire unit flooded due to part of the "loop" failing & causing an entire system flood.

 

[DiverBear]

I'm sure this is a stupid question, but as a newbie OW (only) diver, I've got to ask. Is it impossible to buddy breathe from a CCR?

I think there was an older military rebreather that was set up for this as a bailout for second person. The BB idea is kinda kinky, but having to inhale, exhale close DSV then pass it off to other guy wait for them to go through all of that and give it back is a long time holding (no) breath. Even calm I think it would be difficult without there being a second loop permanently plumbed.

Also, scrubbers weren't usually tested for that kind of load but in an emergency (or playing in a pool) I suppose it's an option!

Also the loop hoses to the mouthpiece usually aren't very long and the rigs are kind of cumbersome.

 

[EricTheDood]

Will this incident change the way people approach advanced cave dives?

What are the possible (additional) contingencies that can avert disaster in a similar situation, i.e. restrictions at extreme depths? Redundant sidemount rebreathers? Additional rebreathers placed next to safety/stage bottles?

Sure, there's the cost of multiple CCRs, but since people draw parallels between Eagle's Nest and Everest, perhaps the budgets and preparation should be comparable as well. The stakes are the same.

 

[PfcAJ]

Will this incident change the way people approach advanced cave dives?

I think the real takeaway here is not to take your rig off (unless you're specifically configured for that).

Even with extra gas in the water survival is next to impossible because of the drysuit buoyancy.