Most Important CCR Skill
Manually maintaining PO2, bailing out, simulated failed electronics- what’s the most important skill for a new rebreather diver? Hint: It’s none of those.
Closed Circuit Rebreather (CCR) diving carries unique risks compared to open circuit (OC) diving. We need unique risk mitigation tools to deal with those risks. When open circuit diving “if you’re breathing you’re ok” is generally a true statement, this isn’t true with CCR diving. Hypoxia Hypercapnia and Hyperoxia manifest in the CCR loop. While all the course skills are important, it’s the surface skills that become paramount for CCR divers after certification.
A while ago I was getting a metal plate installed in my elbow after a mountain biking accident. As they were getting me set up for surgery I remember the surgeon entering the room and asking a series of questions. The first was “what is the patient’s name?” The second was “which arm are we working on?”. I was a bit concerned as I drifted into my medically induced nap – why didn’t he know those things already?! After surgery I did some research on surgeon’s checklists. They start with the most simple questions. That’s because it’s easy to skip the simple questions but if you take the time to ask them your chance of making a simple mistake plummets. That was true of the surgery checklists, they dramatically reduced accidents in surgery. Accidents like – operating on the good arm or the wrong person. Ask the simple questions, do the simple checks – makes good sense.
How does this translate from the OR to the CCR? Rebreathers have more components and systems than open circuit. That means they have more failure modes. It’s not often (or maybe ever) that a CCR fails and the user is immediately at risk. The more likely situation is that the user omits an important – often simple – procedure or reaction and it leads to an accident. This also happens in open circuit diving. I’ve seen plenty of divers “run out of gas” before the dive because their air wasn’t turned on, divers giant striding with their mask still on the boat, cave divers realizing the left their fins in the car after they clip all their cylinders on. These aren’t necessarily catastrophic but they show us how unorganized and non-procedural we can be.
The reality is that OC and CCR divers should have the same discipline when it comes to surface skills, but we tend to fixate on the CCR crowd for some reason. Surface skills encompass the workbench, gear up and predive check.
The Work Bench
We need to build our unit correctly and we need to build the unit with confidence. Modern CCRs, especially the ones I teach are incredibly easy to assemble. Toss it on the tailgate and 15 mins later you’re done. That’s an awesome testament to advanced in design but it also puts us in a pickle. It’s so simple we’ll blaze through it. When we go to get in the water we won’t necessarily remember packing the scrubber – as an example. This small nagging lack of confidence can stack with other problems to take your focus off the ball. There’s one way to give you a pile of confidence in your build, as well as insure it’s done correctly. Use the manufacturer’s build checklist. There isn’t another cheat, hack or method that will ensure things build well and you know you did it correctly. Use a checklist and physically mark items off as you go. Yes, it’s adds time to the build and it feels unnecessary but that’s your golden ticket to build confidence. Experienced CCR divers have forgotten to pack their scrubber, install critical parts, and other “simple” mistakes from the build.
Don’t take service bench problems under the water. If something doesn’t work, replace it. High confidence in your equipment will stave off the heebie jeebies and allow you to enjoy the dive. There’s a subset of divers I see, I call them “failure divers”, who are always having stuff break underwater. It’s almost like they purposely mistreat their equipment so the debrief can be about how they handled the issue. Don’t do this. Treat your stuff well, get it serviced, replace things as they break. Every night, charge your lights and prep your things. Gear will fail on its own, don’t give it any wiggle room to fail because of your decision to not maintain it.
The Gear Up
At the dive site or on the boat there’s a series of tasks to get done. It’s wildly overlooked to get these tasks done in an efficient and organized manner. Why? Because in the inevitable event we get distracted or rushed, we’re prepared. People who take 2 hours to get prepped for a dive because they’re losing and finding gear aren’t who we want to be. People who are ready in 5 minutes but forgot their regulators at home are also not our goal. The sweet spot is the step-by-step gear-up that has room to be rushed without missing any steps.
The predive check
Once you have your CCR gear-up rhythm and you have a few hours under your belt the predive checklist seems stupid. You will want to skip it. Many do with zero realized consequences. It’s so easy to skip. The value of the check seems to dimmish as you become more independent and experienced because it covers the simple stuff. That’s why it’s so important though, we need to validate the simple stuff with our dive buddies.
Imagine a busy dive boat, it’s hot, you want to get in the water. The crew keeps asking questions about CCRs, there’s music blasting, it’s wildly distracting, rushed and you want to go underwater. This is the scenario that you should design your predive check around. If you design a 45 minute predive check you will be more likely to skip it. Obviously, there is a point where you’re excluding too much, but a good CCR predive can be done quickly, it can be interrupted (that’s the whole point of it being written) and can be done when you don’t want to do it.
My suggestion here is twofold: Understand the importance and purpose of surface skills and make them happen. I’m not suggesting reinventing the wheel and developing a new predive acronym. There are a ton of pre-slash checklists out there. Adopt the one your manufacturer made and use it, especially when you don’t want to