Diving incident at Eagles Nest Sink

[tbone1004]

rough math.
1.5cfm SAC rate, should be about 2x elevated sac rate, but not out of the realm of possibility for a hypercapnia incident.
Assume 300ft for easy math of 10ata
Consumption is 15cfm
2x95's cave filled = 260cf of gas
260/15=17 minutes
17 minutes of kicking at a normal pace of 50fpm=850ft of bailout gas.

EoL at 1200ft puts you in the middle of the Pit if you are going off of those numbers. Have an extra AL80 in that room and that will get you another 250ft into the Ballroom where you have deco bottles staged. Is this thin? Yes if you subscribe to the numbers above being real. It does not give you much time to be in an excited state and stuck in one spot, doesn't give you much time to fix a problem, but few divers ever really plan on that sac rate of 1.5cfm lasting more than a couple of minutes

With a spare DPV they could have expected to be going at least 2x that kick speed out of there, and a 1.5cfm sac rate is about 3x of a normal sac rate when on a dpv and about 2.5x a relaxed kicking sac rate. Is this enough gas? I think in most peoples minds the answer is yes, but what it doesn't account for is sharing gas with anyone. This is same ocean diving where you can't plan on being your buddies lifeline to get out. IMHO leaving the CCR and a full bailout bottle where they did is what ultimately caused the dual fatality. What brought them to leaving full bottles and a functioning CCR back there is something that I doubt we will ever know. My dive buddies and I have discussed this many times, and have a mutual understanding that one is better than none and there is nothing and no one in a cave worth dying for. Harsh reality, but we plan close proximity solo diving because panic can cause too many problems in the water

edit: haven't read Bobby's post, but he's far more experienced than I am, so likely has some good personal experience info up there

 

[Capt Jim Wyatt]

I am really ashamed and disappointed in the behavior of some of the people .... Several of you are “leaders in the industry” and could have been a calming voice of reason asking the general public to give us time to complete our tasks, but instead you were on the front line demanding answers before we even had a time to get them together ourselves. You should be ashamed.

I agree I was and remain pissed off to read some of the demands being made, and accusations of a conspiracy to withhold information.

 

[Dsix36]

Here is my experience from an extremely similar dive there that could have easily ended the same way.


Eagles Nest incident, Feb 7, 2015

As most of you already know, I am not shy about posting my mistakes and screw ups for everyone’s enjoyment and education. In this instance I will keep my buddy anonymous by just calling him "Gizmo".

We had planned to continue our exploration beyond the end of the line on the downstream side and in an area called Revelation Space. I wanted to check the other direction in a small restriction that I had previously explored and Gizmo had a hankering to look in another area.

This was the fourth time that I had been back there and the second time for Gizmo. I had absolutely no worries or concerns as to the abilities of either of us to be able to pull this dive off safely and without incident. We did our planning and bailout gas calculations and had more than enough gas and then some on top of that too.

Day 1 - Set up dive to get stages in place. I was to lead and gizmo would follow. I brought my BOB (Bailout Rebreather) to give it a good test on this dive. I made a trip to 30' and dropped the two tanks of oxygen. Our plan was for Gizmo to hang two tanks of 50% on the line at 70' while I secured the two tanks of 32% to the line at 130'. Gizmo would drop a tank of 21/35 just prior to the pit and I would drop the final stage of 15/55 at the end of the line.

The only hiccup to this plan was that when I got to the first duck under and let off the scooter trigger I was negative as heck. I had to push off the rocks a couple of times as I was inflating to stay out of the silt. Yes, I know this was a big mistake. When I got to the pit, I stopped so Gizmo could drop his stage. I pointed to my stage and then to the rocky surface. Gizmo began unclipping his scooter and I just figured he was doing that to get at the stage. I suddenly looked and saw that he did not have a stage. In our convoluted conversation through the DSVs, I learned that he had dropped it prior to the duck under. We continued to the end of the line where I dropped my stage. We turned the dive, exited, and did out deco all without any further problems.

Upon our swim back to the steps, I was horrified to see my reels still hanging on the railing. I did the dive without them.

 

[Dsix36]

Day 2 - The big dive. I was going to bring my BOB again since it worked flawlessly the day before and this is the diving that I actually built it for. That plan changed when the revo dream would not turn on. I took BOB to my truck and grabbed another BO tank instead. Our dive plan called for us to turn the dive at 35 minutes from leaving the mound. This was only 5 minutes more than our previous exploration dive to this area, but it did add quite a bit of extra deco due to the depths involved. Originally, I was going to lead again since I have more experience here, but we made a change. Since I had the faster scooter, Gizmo would lead so that I could grab the 21/35 and move it further into the cave (as per our original plan) and still be able to catch up very quickly. This was not the most perfect plan since we would be separated momentarily, but in the interest of the timeframe it seemed appropriate at the time. This all went smoothly and we reached the end of the line to clip off the scooters and proceed through the restriction. We navigated the restriction, went through the halocline, went right at the T and made our way upward into Revelation Space. We went left at the next T (one we placed last dive when we ran line to finish going around the room). This is when Gizmo showed me his light was flickering. I immediately pulled my backup primary and handed it to him. His light came back on and he refused my light. I swam a bit before tying in and heading to the little restriction that I was there to explore. I went the opposite direction from my previous attempt and promptly found a serious dead end and silted myself out completely, much like the previous time. I slowly turned and came out of my silt cloud and untied my reel. I went to Gizmo who was filming the area. I looked at my runtime and signaled to turn the dive. I was leading the exit. Past the T, down the slope, past another T, through the halocline, and to the rock (or placement for the line) just before going through the restriction. I stopped and waited to make sure that Gizmo is on the proper side of the line to make the exit, since he had this problem on our last dive. I finally look back to see him on the other side of the halocline taking his sweet time and filming some more. I quickly swim toward him, point at my computer, and signal for him to follow me. I get back to the rock and when he gets next to me I place his right hand on the line before I go upward and out the restriction.

My stage tank and scooter are very close to the exit area and when I come out I move myself sideways before grabbing my stuff. I clip my stage on and grab my scooter. I look up to make sure Gizmo is ready. I don't see him. I turn and look at the restriction to see if he is having problems getting out again. Nothing, not a damn thing anywhere. I cover my light and look up, look down, go up slightly and look again. Still nothing. This all seemed like an eternity, but in reality was only a few seconds. I finally caught a glimmer of light. It was left of the restriction and was moving further away. When I got to the light, I could see that Gizmo was trying to come up but could not get through. He was working his way along the crevice the wrong direction. I could see that the crevice opened up just a couple of feet further in the direction of his travel. When he reached this area, I could finally touch his hands. I grabbed his hand in an attempt to let him know that I was there. He was trying to get through but was not having much luck. Somehow the line is now in his left hand, and I see that he has removed a BO tank and has it in his right hand. I grab the tank and place it in the silt outside the crevice. I look at the opening and try to calculate if he will fit. I think he might be able to make it but he is keeping his head up and thus his RB tank are hitting the top. I reach down and grabbed the rebreather and forced his face into the silt. I began pulling and wiggling to get him out. I concluded that this was not going to work. In an attempt to communicate, I formed a fist and put his hand on top of it to signal hold. I then took his hand and rolled his fingers under to form his own fist. I grabbed his tank, swam it to the line, clipped it off, and headed into the zero vis restriction to go get him and lead him to the proper way out. The line was loose and pulled off the placement. I banged and thumped into everything in my effort to reach my buddy. I went what I thought was double the distance to reach him with no luck. Great, he got out and will be waiting for me. Now all I have to do is get my butt out of here too. I work my way out and the first thing I see is Gizmo's tank still clipped to the line. Crap, he did not get out. I cover my light and look all over. I even go up a bit and look towards the exit thinking he might have freaked out and took off. I see nothing and realize right then and there, that I have a seriously hard decision to make.

Our planning had enough BO gas for my last little search effort, but I had already pushed everything to maximum. In the next few seconds I did all the calculations and thinking, which I ever want to do, in a situation like this. I remembered my training, it is better for one diver to die than two divers. How long do I stay in an effort to find him? He has kids and a wife, I have a girlfriend and cats. If I continue looking and my RB fails, I am dead, story over. I remember wishing that I had my BOB with me. I made an informed decision that Gizmo was leaving this cave with me, right now. I went back into the black, on a slack line, and went after him. This time I went deeper, into the bottom of the halocline room and to the back wall. I was out of the silt and could see the entire cloud that encased the restriction and the crevice. I swam all the way to the T and looked both directions for any sign of disturbance and thought to myself, that there is absolutely no way that there was any further travel either way. I returned to the outer edge of the cloud and wedged myself in the crevice. I began working my way toward the restriction. If Gizmo was there, I would have to find him. My hand felt something on the line. I quickly figured out that it was a ball from a reel. Hooray, Gizmo tied on and all I have to do is follow the line to get to him. As I fumble with the wad of lines to learn my new path, I find that it is now caught on my BO tank. In the short battle to pull it free, I discover that it was my own reel that unwound and got caught. Crap, well time to sort this out. Think again! My right fin has line in it too and it is wrapped around my leg. In the next minute or so, I lose control of my buoyancy and end up planted on the bottom, I inflate and plaster myself to the ceiling. I remove my fin, unwrap the line from my leg and replace my fin. Now all that is left is to get my reel loose. Z knife to the rescue and I am free again. I continue my pursuit of Gizmo but exit the area without him again.

 

[Dsix36]

His tank is still there and I am struck with the realization that I am going to have to leave him there to die. There was nothing more that I could do. I looked at my computer and saw that my TTS was 540 minutes and was still a long way from the entrance. I left his tank there, just in case he did get to it, grabbed my stuff and hit the trigger. My head was in a real fog and I was already mourning the loss of my buddy. How do I explain this to his family? How much deco will I have? Am I going to get bent? Do not slow down for anything, I must get to my first deco stop ASAP.

My first stop was 180'. I must say that trim, buoyancy, and stops were perfect and effortless. It is almost like someone or something was helping me. When I reached my 150' stop, I started to hear funny noises and seeing funny flickers. Great news, I am already have mental and visual disturbances. I guess that I am not getting out of here after all. It gets worse, and worse until I finally look up to see a diver. I put my hand out to the side, shine my light on my hand, and signal OK. I am not very sure about my state of mind at this point, but I really think that I heard through his DSV - Oh thank God! This is when it registered in my mind, that this diver might be Gizmo. He turned and headed back out. I could tell by the markings on his tank that it was him. All of the grief and funeral planning went away instantly and I was able to focus more on my own survival.

I knew that my scrubber time could be stretched, but I had no idea when it was going to expire. Damn, where was that BOB when I really needed it? I knew that I was already effectively out of diluent. I knew that I still had plenty of oxygen. I knew that there were still a bunch of BO tanks for off board. I decided that plan of attack for deco would be. When I reached the mound and the 32%, I would off board it and dil flush to get the helium out faster. I would run high PO2 (1.3) from 70'. I would run high PO2 (1.4) from 50'. At 20' I would drop the PO2 to 1.0 and also do a couple of air breaks. At 10' would be pure O2.

I only saw one tank when I reached the mound. No problem since I only needed one any way. Time to verify MOD and to my shock, I discovered it to be 50%. Well then, dil flush will have to wait until 70'. When I got to 70' and looked up, I could see Gizmos feet at the edge of the chimney. I pulled my slate, wrote 32% on both sides, pulled my SMB, pulled my reel, and sent it up. Gizmos saw it and brought a tank down to me. I did my dil flush, changed my computers and was extremely happy to see the TTS dropping drastically.

The rest of deco was uneventful, long, and boring. I had my trusty MP3 player for tunes. I had a borrowed heated vest, which I am sure made the difference between a minor bend and a chamber ride or even death.

When Gizmo cleared deco and exited the water, I still had 93 minutes at 10' to go. My total runtime was 530 minutes.

I began feeling pain in my right shoulder during my 20’ stop. It got worse after the dive. I stopped at a gas station and bought aspirin and breathed 120cf of oxygen on the drive home. By the time I was home, the pain was pretty much gone. Both ankles and knees felt fatigued for a couple of days, but all seems fine now.

I know that I made mistakes. I know that I made some bad decisions. I will learn from my mistakes, but I stand by my decisions and would do the same thing again without falter. The one thing that really bothers me about the entire thing is the fact that I was so focused on Gizmos BO tank being there, that I never once looked or noticed that his scooter was gone. I also never noticed that the stage tank of 21/35 was not present during my exit either.

I later found out that one of my cats had died while I was in the cave. Perhaps she was the angel that was looking over me that day? Maybe if my BOB had turned on I would have made different decisions? These are questions that I will ask myself for a long time. I do not think that any diver can know for certain what their reactions and thought process will be during an incident. On a different day, maybe I would have done things differently. I am truly grateful that both Gizmo and I are able to be here today with no permanent physical damage, the mental damage will hopefully dwindle in time.

I should clarify my thought process in regards to my deco and PO2 I used. I have lied to my computer about the helium percentage in the past, but this time was not going to be one of them. I know that helium will really penalize me with a lot of extra deco time and thus the switch to 32% for dil. I wanted to get the helium out of my body as quickly as possible to help limit my deco time. I am of the firm belief that getting shallow is very important in regards to having adequate OC gas in the event of a RB failure. I also belief that there is strong evidence of O2 seizures with high partial pressures of O2 at 20’ or deeper, but I belief there is much less evidence of such seizures at 10’. I think that CNS is highly subjective and I have been over 160% many times. I began running a higher than normal PO2 in an effort to get me out of the water faster. I knew that this would punish me with high CNS but I then went to 1.0 at 20’ and included a couple of dil flushes to somewhat equate to air breaks. Knowing that my 10’ stop would be my longest, I opted to run pure O2 at that time in hopes of not having an O2 seizure. I am not advocating this type of planning and have no scientific background or studies to back me up. This is all just what I have been able to learn and understand from all the information that is available. I was running a GF of 50/90 and pushed it via using the ceiling function on my Predators. Due to a couple of cells drifting, I was convinced that my actual GF was closer to 50/100 or 50/110 and from personal experience, I knew that I get little niggles at 100 GFs.

 

[boulderjohn]

This is when I stopped all actions and just told myself to calm down, as long as I had the functioning CCR I had nothing but time.

Bobby's thoughts reminded me of an incident with which I was peripherally involved. In it, two divers on rebreathers got into a serious problem in a severe restriction, and they had to work very, very hard to exit. One of them panicked at least once during that effort. In relating the story, the other diver said that he, too, was on the edge of panic, with a growing sense that he was not going to make it. Like Bobby, he got control of himself by remembering that he had nothing but time, and he was able to pause long enough to gain the sense of calm he needed to continue. I cannot help but think that if the other diver had done the same thing, he might have survived.

We have been reminded in this thread that physical exertion brings on a buildup of CO2, as it did with David Shaw. We have been reminded that it is a buildup of CO2 that leads to panic, and panic leads to more CO2 buildup. It would be easy to underestimate the effects of prolonged and vigorous activity on your ability to function effectively under those circumstances.

These dives are well beyond any training agency's certification ability. At this level problems compound very quickly and the difference between more experience and tragedy can be razor thin.

For those reading this thread who are not cave divers, this idea needs to be stressed. As a certified cave diver with a fair amount of experience, I know just enough to have a glimpse--but only a glimpse--of how far the dive in this thread dive and the dive I mentioned above were beyond my training and experience. In reading this thread, I have been shaking my head in wonder on more than one occasion.

 

[apitkin]

These dives are well beyond any training agency's certification ability. At this level problems compound very quickly and the difference between more experience and tragedy can be razor thin.

Hit the nail on the head there.

By the way, I didn't mean to give the idea the restriction is 'easy', just that it is possible to go through it easily on one day and then have a big problem another day. It is quite wide, and easy to get off the correct route, and once off it the restriction is impassable in back mount. The line should of course be in the BM route, but it is easy for it to get pulled out of it.

 

[EricTheDood]

Read through the whole thread. Watched the videos.

Cave diving's not for me.

Sympathies to the families of the lost divers.

 

[Compressor]

I'M late to this thread but am extremely saddened to hear of the fatalities. May they both rest in peace. God bless them.

 

[Bobby]

Hit the nail on the head there.

Thanks

By the way, I didn't mean to give the idea the restriction is 'easy', just that it is possible to go through it easily on one day and then have a big problem another day. It is quite wide, and easy to get off the correct route, and once off it the restriction is impassable in back mount. The line should of course be in the BM route, but it is easy for it to get pulled out of it.

No worries my friend. I simply wanted to point out that there is a difference in experience which makes a difference in what one might consider easy or difficult.