helodriver87
Contributor
I just finished up what's apparently the first GUE Cave CCR course that's ever been run, so i thought I'd type up a quick report for anyone curious about the class.
I took CCR1 back in December and I’ve had the opportunity to build some experience on the unit in the recreational and T1 depth ranges since then. I felt fairly ready for a more challenging course and one of my long term goals has always been cave CCR diving, so I decided to go for it. The course is brand new, and intended to address certain specific skills that a CCR1 diver doesn’t have, but are critical for the cave environment and may not be as emphasized in the open water centric CCR2 course. So here’s a quick overview!
Day 1: Academics and Unit Assembly
The academic materials are still a work in progress, being a brand new class, but they cover the bulk of potential failure modes and resolutions in depth. Discussions focused on ways to recover/resolve issues and stay on the loop vs the “if in doubt, bail out” approach of CCR1. Planning was also a major focus and covered dil usage, bailout range, bailout stages, calculating scrubber duration, and O2 planning. Unit assembly was straightforward, and largely focused on making sure everything was in working order after travel.
Day 2: Peacock
The first dive plan was mainline P1 through Olsen with a focus on validating O2 and dil consumption. Being a GUE class, only the first half of the dive was relaxing. Shortly after turning, things started breaking. The first failure introduced was a loss of right post. This leads to the loss of the ADV and wing inflation, requiring manual dil addition to the counterlungs and manual wing inflation. This procedure is a bit busy at first, but gets much easier with more practice. Once we got back to our stages, we were able to offboard them via the O2 MAV, making the process much easier. I figured out that I could over add gas via the MAV, then use the extra to manually inflate the wing, minimizing time off the loop. The second dive was shorter and involved cue cards simulating excess O2 addition resulting in a hyperoxic loop. I got a couple of the steps swapped before recovering the loop, which wouldn’t have killed me, but would’ve unnecessarily delayed/complicated the troubleshooting process. A little while after resolving this one, I ended up getting my O2 bottle broken, driving me to SCR breathe all the way out of the cave. I thought this would be significantly harder than it actually turned out being. With proper dil selection, it’s pretty easy to maintain a reasonable PO2 and significantly extend your gas range. Kirill also had plenty of line work critiques, which proved to be something I needed to clean up all week. Big takeaways from today were some cave specific stuff that I should be better at and shifting my thinking away from an open circuit mentality.
Day 3: Peacock (again)
The plan for dive 1 was a long run up through Nicholson into the wishbone tunnel, past cisteen and back onto the mainline up towards challenge. Like before, things started breaking after we turned. This one was a solenoid failure alert and declining PO2, which ended up being a busted solenoid, driving us to manually control PO2 for a portion of the exit. This one went pretty smoothly. We also got to do some fun line entanglements on the way out. That’s one of many common problems that really becomes no big deal on CCR. With the gas clock effectively stopped, most common cave diving issues become annoyances. If you’re not changing depth, you’re not using dil/BO and your O2 consumption is the same. You can wait out or take your time with quite a few problems (deco is something to consider though). This dive finally ended with a zero vis exit after Kirill stole all of our lights along with the extras we brought just to be difficult. Like line entanglements, zero vis is pretty stress free. You have all the time in the world compared to OC. Once we got back to the chimney, we could see the line and daylight, so my buddy started up ahead of me. Kirill took this opportunity to tie my stage to the line, so I took the opportunity to leave it behind for him to carry up since I was practically in the cavern and carrying full on board bailout with a working breather. Cutting the line was an option, but I don’t think I would’ve been allowed to get that far. The second dive was a bailout scenario where we calculated our max bailout range and validated it by doing it. Our calculations turned out to be way conservative in terms of depth and consumption.
Day 4: Little River
This was our first day in high flow, and I was a little worried. Especially with regards to workload. Getting CO2’d on OC sucks. Getting CO2’d on a rebreather is a bad day. But it turns out that going rebreather speed (slow as hell) is an effective way to manage it. We swam most of the way to the well casing before turning it. On the way back, we got hit with more failures, ultimately resulting in manually controlling PO2 via MAV off the HUD with a failed controller and using the backup computer to run deco. The second dive was to the harper tunnel. I got the wonderful experience of losing my right post and exiting with no ADV or wing. After getting back to safeties, we initially plugged safeties into the wing since the general profile of the cave was up from there, so we shouldn’t need any more dil and might want the O2 MAV. So naturally, Kirill broke our O2 bottles, forcing us to offboard our safeties while SCR breathing all the way out to our deco bottles, which we then plugged in to run offboard deco gas.
Day 5: Ginnie
My buddy wasn’t able to dive today, so this last dive was basically an experience dive introducing scootering while on CCR. I was worried it would be hard to keep up with, but buoyancy actually felt easier, as my breathing wasn’t hiding slight negative or positive conditions. We parked scooters and safeties and the Henkel and swam back 4 Ts before turning the dive and finishing up with 30 or so minutes of deco.
Key Takeaways:
A good rebreather team is pretty strong and resource rich. Short of a total flood or major scrubber failure, there’s not a lot that can truly force you off the loop permanently. There are so many more options for problem resolution on CCR than open circuit and most of the time you have a ton of time and resources to figure it out. Those options are also the most challenging part of the class. There’s so much more to consider than “shut down the post and thumb the dive”. There are multiple solutions, some better than others, and the rebreather mindset of taking your time and thinking it through is critical. I also allowed some basic skills to get sloppy (mainly line work) and this class was a great refresher for me. This class felt like a major step forward from CCR1 towards actually using the unit to do what it was designed for. CCR1 was a learner’s permit to get comfortable on the JJ. Cave CCR taught me how to actually start using it the way it was intended to be used. The days were pretty long, and frustrating at times, but I feel significantly more confident that I can safely take it into a cave now. Before this class, I liked the JJ. After learning more about what I can do with it and what kind of options it gives me in the cave environment, I love it. And I feel like a lot of my basic skills and comfort on the unit in general grew over the course of the week.
I took CCR1 back in December and I’ve had the opportunity to build some experience on the unit in the recreational and T1 depth ranges since then. I felt fairly ready for a more challenging course and one of my long term goals has always been cave CCR diving, so I decided to go for it. The course is brand new, and intended to address certain specific skills that a CCR1 diver doesn’t have, but are critical for the cave environment and may not be as emphasized in the open water centric CCR2 course. So here’s a quick overview!
Day 1: Academics and Unit Assembly
The academic materials are still a work in progress, being a brand new class, but they cover the bulk of potential failure modes and resolutions in depth. Discussions focused on ways to recover/resolve issues and stay on the loop vs the “if in doubt, bail out” approach of CCR1. Planning was also a major focus and covered dil usage, bailout range, bailout stages, calculating scrubber duration, and O2 planning. Unit assembly was straightforward, and largely focused on making sure everything was in working order after travel.
Day 2: Peacock
The first dive plan was mainline P1 through Olsen with a focus on validating O2 and dil consumption. Being a GUE class, only the first half of the dive was relaxing. Shortly after turning, things started breaking. The first failure introduced was a loss of right post. This leads to the loss of the ADV and wing inflation, requiring manual dil addition to the counterlungs and manual wing inflation. This procedure is a bit busy at first, but gets much easier with more practice. Once we got back to our stages, we were able to offboard them via the O2 MAV, making the process much easier. I figured out that I could over add gas via the MAV, then use the extra to manually inflate the wing, minimizing time off the loop. The second dive was shorter and involved cue cards simulating excess O2 addition resulting in a hyperoxic loop. I got a couple of the steps swapped before recovering the loop, which wouldn’t have killed me, but would’ve unnecessarily delayed/complicated the troubleshooting process. A little while after resolving this one, I ended up getting my O2 bottle broken, driving me to SCR breathe all the way out of the cave. I thought this would be significantly harder than it actually turned out being. With proper dil selection, it’s pretty easy to maintain a reasonable PO2 and significantly extend your gas range. Kirill also had plenty of line work critiques, which proved to be something I needed to clean up all week. Big takeaways from today were some cave specific stuff that I should be better at and shifting my thinking away from an open circuit mentality.
Day 3: Peacock (again)
The plan for dive 1 was a long run up through Nicholson into the wishbone tunnel, past cisteen and back onto the mainline up towards challenge. Like before, things started breaking after we turned. This one was a solenoid failure alert and declining PO2, which ended up being a busted solenoid, driving us to manually control PO2 for a portion of the exit. This one went pretty smoothly. We also got to do some fun line entanglements on the way out. That’s one of many common problems that really becomes no big deal on CCR. With the gas clock effectively stopped, most common cave diving issues become annoyances. If you’re not changing depth, you’re not using dil/BO and your O2 consumption is the same. You can wait out or take your time with quite a few problems (deco is something to consider though). This dive finally ended with a zero vis exit after Kirill stole all of our lights along with the extras we brought just to be difficult. Like line entanglements, zero vis is pretty stress free. You have all the time in the world compared to OC. Once we got back to the chimney, we could see the line and daylight, so my buddy started up ahead of me. Kirill took this opportunity to tie my stage to the line, so I took the opportunity to leave it behind for him to carry up since I was practically in the cavern and carrying full on board bailout with a working breather. Cutting the line was an option, but I don’t think I would’ve been allowed to get that far. The second dive was a bailout scenario where we calculated our max bailout range and validated it by doing it. Our calculations turned out to be way conservative in terms of depth and consumption.
Day 4: Little River
This was our first day in high flow, and I was a little worried. Especially with regards to workload. Getting CO2’d on OC sucks. Getting CO2’d on a rebreather is a bad day. But it turns out that going rebreather speed (slow as hell) is an effective way to manage it. We swam most of the way to the well casing before turning it. On the way back, we got hit with more failures, ultimately resulting in manually controlling PO2 via MAV off the HUD with a failed controller and using the backup computer to run deco. The second dive was to the harper tunnel. I got the wonderful experience of losing my right post and exiting with no ADV or wing. After getting back to safeties, we initially plugged safeties into the wing since the general profile of the cave was up from there, so we shouldn’t need any more dil and might want the O2 MAV. So naturally, Kirill broke our O2 bottles, forcing us to offboard our safeties while SCR breathing all the way out to our deco bottles, which we then plugged in to run offboard deco gas.
Day 5: Ginnie
My buddy wasn’t able to dive today, so this last dive was basically an experience dive introducing scootering while on CCR. I was worried it would be hard to keep up with, but buoyancy actually felt easier, as my breathing wasn’t hiding slight negative or positive conditions. We parked scooters and safeties and the Henkel and swam back 4 Ts before turning the dive and finishing up with 30 or so minutes of deco.
Key Takeaways:
A good rebreather team is pretty strong and resource rich. Short of a total flood or major scrubber failure, there’s not a lot that can truly force you off the loop permanently. There are so many more options for problem resolution on CCR than open circuit and most of the time you have a ton of time and resources to figure it out. Those options are also the most challenging part of the class. There’s so much more to consider than “shut down the post and thumb the dive”. There are multiple solutions, some better than others, and the rebreather mindset of taking your time and thinking it through is critical. I also allowed some basic skills to get sloppy (mainly line work) and this class was a great refresher for me. This class felt like a major step forward from CCR1 towards actually using the unit to do what it was designed for. CCR1 was a learner’s permit to get comfortable on the JJ. Cave CCR taught me how to actually start using it the way it was intended to be used. The days were pretty long, and frustrating at times, but I feel significantly more confident that I can safely take it into a cave now. Before this class, I liked the JJ. After learning more about what I can do with it and what kind of options it gives me in the cave environment, I love it. And I feel like a lot of my basic skills and comfort on the unit in general grew over the course of the week.
