It finally happened - my CCR tried to kill me

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stuartv

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I've been feeling pretty lucky to never have felt like I'd had an "oh, ****" moment while diving my rEvo. That is now behind me.

Short version: I was diving the Lady Luck in south FL on Sat. My unit passed a negative test before I got in. Then it proceeded to very slowly start flooding once I was in the water. At about 45 minutes in, I felt like it wasn't breathing right, but I wasn't sure if that was just in my head or not. I switched to BO and obviously that felt much better. I went back on the loop and it was the same, but I stayed on it. Partway up in my ascent, 3 of my 5 O2 sensors started giving me completely whacked out readings. All 3 were ones connected to my Predator controller. The 2 that are completely independent and connected to my NERD2 continued to read correctly and I completed my dive following my NERD2. My post-dive inspection found both scrubber baskets totally soaked. The exhale (top) counterlung had a normal amount (for a 90 minute dive) of moisture in it. The inhale counterlung has a LOT of caustic water in it.

"But did you die?" No. But, I think I felt the puff of air as the bullet went past my head.

Long version:

I got to Pompano Beach last Wed afternoon. I started to prep my rEvo for a blackwater night dive and immediately figured out that on my last dive before this trip my battery box had flooded. The circuit board inside it was toast. I scrambled around and was able to score a brand new replacement first thing the next (Thu) morning. I installed it and just barely was ready to dive in time for my boat that day (which was very fortuitously not scheduled until 1pm). My rEvo worked just fine for that dive. Post-dive cleanup, it looked totally fine on the inside. No unusual anything.

Fri morning, I dived again. My rEvo worked just fine again. Again, post-dive maintenance was totally normally. I opened it up, cleaned it up inside. There was normal moisture. It stayed open to dry out overnight.

Sat, we were back to diving in the afternoon. So, I prepped my unit at a leisurely pace that morning. The only unusual thing that I remember is that I had some trouble getting the scrubber cover to fully seat properly. I realized it was hitting on the O2 cylinder just a little bit, so I pushed the O2 cylinder to the side and the cover dropped into place. I put on new cylinders every day, so the ones for Sat were not the same ones I had used on any prior day.

I didn't think any more about that (my mistake!) and went through my Closed check list, which it passed (including a Negative test).

We splashed on the Lady Luck. It offers more depth, but I stayed on the main deck the whole time, so never went deeper than 125 feet. It was my first dive of the trip where I took my camera in the water. I was diving with 3 other guys who were all on OC (doubles, with deco cylinders). When we got down to the main deck, I started setting up my camera and dialing in settings. They took off and left me. Not unexpected. I swam around the main deck and ran into them once or twice. I noticed a couple of times as I swam around that it felt like it was just a tiny bit harder to inhale than normal. But, I was swimming slowly, not exerting myself, and it only caught my attention a couple of times, so I thought it was probably just in my head.

About 30-ish minutes in, I met the other guys back on the stern, where our boat was tied in. They signaled that they were going up ('cause OC sucks! LOL) and waved goodbye. I signaled that I would go up with them, but they gave me a questioning look and I thought "yeah, why go up now? I can stay down a lot longer than this." So, I stayed.

I made another lap of the main deck. Took some pictures. Dropped down into an open hold and came out. I started making my way back to the stern.

I should also note that on this day, my mask decided it was going to leak constantly. Most days, it only leaks a little. And usually not much at all until I start my ascent for some reason. But on this day, I was having to clear it constantly. So much that when I tried to take a picture of something on the floor, I really couldn't. I would clear my mask then try to look down through my camera's viewfinder and I would already have enough water in my mask that it would obscure my vision when I tried to look straight down.

So, now I'm 45 minutes in and almost all the way back to the stern to start my ascent. At this point, the work of breathing definitely seems a bit harder than normal. I decided to switch to bailout to see how that made me feel. I flipped my BOV to BO and breathed from that for the few seconds it took to pull out my OC BO reg and switch over to that. I mention that because that proves to me that I did in fact close the loop before I took it out of my mouth. Switching the BOV to BO IS how you close the loop.

Anyway, that dive being relatively shallow and knowing the other guys were not going to be doing a long dive, I only took one BO gas with me. An AL80 of TX18/45. It was plenty to get me out. But, I also knew that if I did my deco on that it would take a lot longer than if I stayed on the loop. So, I decided to switch back to the loop for my ascent if it seemed okay. I switched back and it was the same as before. Okay, but not "normal". But, my ppO2 was good and my rMS showed that my scrubber was still working off the top basket - not even into the bottom basket yet. I made the decision to continue my dive on the loop.

I started up the anchor line. Partway up, all my O2 sensor readings on my controller, and the first sensor shown on my NERD just went haywire. 2 of the ones on my controller were showing 0.5 - 0.6, but #3 was showing 2.50 or something like that. #3 is shared via a splitter with my NERD. It is in position #1 on my NERD. #1 on the NERD was also showing the same effed up reading.

By this time, I was shallow enough that I knew I couldn't really have a ppO2 that high. And #s 2 and 3 on my NERD were still showing the expected values. So, I spent all my deco time at 20' and up just tracking #s 2 and 3 on my NERD and following the ascent it gave me. My controller had 2 sensors that were reading way low and one that was way high. The two low ones were pretty close, so the controller voted out the 3rd and it thought I got out with about 5 minutes of omitted deco. But, I knew from my depth and doing O2 flushes that the 2 sensors on my NERD were correct and I followed its ascent plan.

After I got out and got back to my hotel I opened up the unit. Both scrubber baskets were totally soaked. I presume that is what made it feel a bit hard to breathe. The top CL had a normal amount of lung butter in it, but no more. But, the lower CL had a ****-ton of water in it. I put my fingers in that water and a small nick on one finger instantly started to sting.

During my ascent, I rolled onto my side a few times to look up, to make sure I didn't ascend into a diver above me. I am thinking that one of those times rolling on my side resulted in that caustic water to getting on 3 of the sensors. I reckon that is when my readings all went haywire.

When I saw what was up inside my unit, I realized that if I had just happened to go into a head down orientation, that caustic water would probably have run right down through my inhale loop hose and I would have inhaled a big mouthful of it. I'm thinking that would probably have been really bad news for me... :(

I cleaned it all up that night and left everything open to dry. The next morning, I packed new sorb in both scrubber baskets. I checked the O2 sensors and 2 of them were still giving squirrely readings in air, so replaced them. I put on new cylinders and went diving at the Blue Heron Bridge. Max, 20 feet of depth. That seemed like a reasonable option for testing it out to see if it was back to working okay.

Sure enough, it worked fine. We did 100 minutes in the water and when I opened it up afterwards, it did not have any excess water inside.

I have been replaying the whole weekend in my mind over and over. Another small point clicked. When I was removing one of the cylinders from the rEvo at some point, I noticed that I had done a whole dive with it on my unit and one of the little "feet" of the mounting bracket was not actually down in the slot it was supposed to be in. At this point, I'm about 90% certain (only 90% because my memory seems **** these days..) that it was the O2 cylinder that I had on during the dive where it flooded. Meaning, when I assembled the unit in the parking lot of the BHB, I removed the cylinder I used the day before (during the Lady Luck dive) and that was when I noticed the tank fixation wasn't fully seated.

So, I am about 80% confident (because I like to arbitrarily quantify stuff) that what happened was that I didn't get the O2 cylinder's mounting bracket seated properly when I installed that cylinder on my rEvo on Sat morning. That resulted in the cylinder being twisted out of its correct position just enough to interfere with the scrubber cover. I was pushed it to the side and got the scrubber cover to seat. But, my theory is that it was still pushing against the side of the scrubber cover after everything was fully assembled.

And that resulted in just enough of a leak that it passed a somewhat cursory negative test, but still allowed a slow leak in the water.

Epilogue: I learned several things through all this. Quite a few, really. And I have some testing to do. Meanwhile, I'm sure a number of you (if you actually read this far) will have some good opinions on various mistakes that I made. I welcome hearing them. I wouldn't be sharing this story if I didn't hope to learn more from some of you. I'm just glad to still be hear to take the criticism!
 

Rollin Bonz

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@stuartv Glad you didn't die! Thanks for the write up. My buddy and I are beginning to feel the pull toward CCR. I'm glad to have write ups like these to remind us it's not a move to be taken lightly.

Looking forward to seeing replies and getting insight from (other) regular and knowledgeable CCR members.
 

happy-diver

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Cool!
 

fsardone

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Thanks for sharing.
Hindsight being always 20/20 I don not see how at the time of starting the chain of events you would have prevented it.
The only fail inthe decision making process I see (and only in hindsight) is the will to stay on the loop after initially bailing out.
This is normal behavior for anybody certified beyond MOD1 ...

My 2c.

Fabio
 

rjack321

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If you had gone head down and taken that slug of caustic water you might very well have died here...

Hopefully going forward you'll take more appropriate BO gases instead of just "any old cylinder that works" so you are less tempted to go back onto a compromised loop.
 

Whitrzac

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Does the revo have a positive test in the setup/predive checklist? That might have caught the issue
 

stuartv

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Thanks for sharing.
Hindsight being always 20/20 I don not see how at the time of starting the chain of events you would have prevented it.
The only fail inthe decision making process I see (and only in hindsight) is the will to stay on the loop after initially bailing out.
This is normal behavior for anybody certified beyond MOD1 ...

My 2c.

Fabio

My current level is considered MOD 1. But, it is IANTD Advanced Recreational Trimix, so my depth limit is 170' (50m?) and use of trimix with at least 18% O2. I know that the "norm" for MOD1 is "when in doubt, bail out." I also have been told by many sources that MOD2 and on emphasizes problem resolution underwater and staying on the loop as much as possible.

As a result, I have been trying to approach my diving on that basis that I should give some thought to resolving issues underwater when I can.

Also, I gave thought to whether I was starting to experience a CO2 hit. I was (and am) pretty sure that was not it. My breathing rate was not elevated. My rMS showed that I was still using the top scrubber basket. I had been barely working at all. I didn't feel any other physical effects. I only felt like it seemed a bit harder to inhale than usual.

Anyway.... maybe that was more info than is relevant. What I really wanted to say is, can you clarify what you mean by the fail in the decision process? I think you mean that I SHOULD have stayed on BO, instead of going back on the loop. But then your comment that "this is normal behavior for anybody certified beyond MOD1" gives me pause to wonder if I have fully understood your point.

If you had gone head down and taken that slug of caustic water you might very well have died here...

Hopefully going forward you'll take more appropriate BO gases instead of just "any old cylinder that works" so you are less tempted to go back onto a compromised loop.

Exactly my thought on the potential results of inhaling that caustic.

As I alluded to above, another thought I carry around is that I am aiming to continue my training to MOD2 (soon) and, eventually, MOD3. As such, I have been trying to foster my own mindset of staying on the loop unless I can't. I'll certainly grant you that, given my current level of training, it's a fair point to say "your CURRENT training is when in doubt, bail out, so that's you should have done. Adhering to your current training means that you should not have gone back on the loop." What BO gas I was carrying was somewhat irrelevant - as long as it was enough (per my training).

One thing that has really stood out in my mind is learning what it feels like to be diving with a partially flooded loop. I reckon that's not something one would ever get during training. At least, not on purpose. At the time, it did not click what the problem was. In retrospect, it probably should have been pretty easy to deduce. But I didn't. Now that I know that feeling, I think future me would be VERY reluctant to go back on the loop for any reason, in that situation. The idea of inhaling caustic scares the crap outta me.

Does the revo have a positive test in the setup/predive checklist? That might have caught the issue

No. The rEvo Closed Checklist ends with a negative test, but no positive test.
 

stuartv

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Thanks for sharing.
Hindsight being always 20/20 I don not see how at the time of starting the chain of events you would have prevented it.
The only fail inthe decision making process I see (and only in hindsight) is the will to stay on the loop after initially bailing out.
This is normal behavior for anybody certified beyond MOD1 ...

My 2c.

Fabio

I critique myself for a failure at the start of the chain. And, by start of the chain, I mean when I assembled the unit.

When I put it together and the lid wouldn't go on right, I found that pushing the O2 cylinder to the side allowed the scrubber cover to drop down and seat. That has never happened before. I have never had a cylinder interfere with putting on the scrubber cover. I consider it a failure to have not investigated why that happened. If I had, I might have noticed that the mounting bracket was not seated properly. I would have fixed that, if I noticed it. And, my suspicion is that I would have then not had a leak at all.

I think it is important to notice even the little things and not dismiss them as inconsequential. And that is precisely what I did when I pushed on the cylinder to seat the cover, but looked no further into it.
 

rjack321

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Does the revo have a positive test in the setup/predive checklist? That might have caught the issue
I don't have a revo but my experiences on 2 other units are that positive and negative checks are next to useless for detecting small leaks. Bubble checks on the other hand, are critical for detecting small leaks. Despite the large volume of water in Stewart's revo it took a whole dive to get there so I consider it slow and/or small. Compared to having a hose disconnected for instance.
 

stuartv

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I don't have a revo but my experiences on 2 other units are that positive and negative checks are next to useless for detecting small leaks. Bubble checks on the other hand, are critical for detecting small leaks. Despite the large volume of water in Stewart's revo it took a whole dive to get there so I consider it slow and/or small. Compared to having a hose disconnected for instance.

Thank you for making that point! My internal audit had not gotten there yet. I did not get anyone to give me a bubble check at the start and I absolutely should have. I will call myself out for being complacent. It was the 3rd day in a row of diving. It wasn't leaking the first 2 days - and I did do a bubble check on the first day.
 
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