Pt 3 – Reflections of a Rebreather Rookie

In part two of this series on rebreather diving, I described choosing and buying my CCR. In this final installment, I will discuss training on my CCR and my subsequent journey practicing and diving with the it.

Training on my rebreather

Now came the fun part, and the hard part: learning how to dive it. I set up a class with my instructor friend at a nearby quarry. I spent five days learning all the ins and outs of my rebreather. We started in the classroom with theory and then moved onto practical matters including assembly, disassembly, cleaning, and maintenance. Aside from training on land, we conducted several dives per day.

You may have heard that buoyancy is completely different when diving a CCR. Believe it! You have no idea how much you use lung volume and breath control to fine tune your buoyancy. On open circuit, if you want to ascend just a few feet to swim over an obstacle, just take an extra big breath. That does not work in the closed-circuit world. The volume of gas in the breathing loop stays the same. When you exhale, the gas goes into the counter lungs. When you inhale, you pull gas out of the counter lungs. But overall, the volume of gas is the same, hence your buoyancy stays the same. It takes a lot of getting used to.

Besides buoyancy, I learned about emergency procedures like bailing out to open circuit, diluent flushes, operating the unit in both manual and electronic modes, and so much more. At the end of each day, I had to disassemble the unit, clean it, pack new CO2 absorbent, and reassemble it for the next day. CCRs do require more hands-on work prior to the dive and post dive than open circuit equipment, but I did not find this to be a problem. With practice, these procedures go quickly and are absolutely essential to identify and rectify any problems with the CCR while still on the surface.

I can honestly say that learning to dive my CCR was one of the most frustrating experiences of diving career. As my instructor said, it’s like riding a roller coaster. Some dives are like slowly climbing the hill and you think this isn’t so bad, I can do this. Other dives are like flying down the hill, screaming, feeling out of control, wondering why you ever thought this was a good idea. That’s a pretty good description. You must persist. Keep trying. Keep practicing. Keep learning. Things do get better. Class days were long, and by the end of the week I was no expert but felt competent. Once the class was over, it was up to me to put in the time and effort to improve.

Post-training experience

You may have heard the old the joke about the young man in New York City who sees an old man on the street carrying a violin case. The young man says, “Excuse me, how do I get to Carnegie Hall?” The old man replies, “Practice!” The key to becoming a good CCR diver (or any kind of diver) is start with good instruction so you learn proper technique, and then practice, practice, practice. You must put in the time and effort to improve. It does not happen by chance.

After my initial training on my rebreather, I spent hours and hours diving the local quarry. I saw parts of that quarry I had never seen before, and I’ve been diving there 25 years! Besides practicing every skill from class, I worked on buoyancy and trim. Not only was I able to reduce the amount of weight I was wearing, but I was able to get in better horizontal trim by shifting the position of the weights.

Building my experience slowly and incrementally, I dove in the quarry for a year before heading out on the Great Lakes. My first boat dives on my CCR were pretty basic. I dove shallow wrecks and stayed out of decompression. Handling the unit in the water turned out to be the easy part. It was more of an adjustment getting used to donning the unit on the boat, dealing with bail out bottles and other topside logistics.

As I gained experience and confidence (both in myself and the PRISM 2), I gradually increased the complexity of the dives. The second summer of wreck diving with my CCR I dove deeper wrecks and started doing dives requiring staged decompression. I really started to appreciate the benefits of CCR diving. I love the logistics of rebreather diving. Filling 26 cubic foot tanks rather than double 104s saves time, money and space while traveling. Another benefit is only needing two bail out bottles instead of multiple deco bottles, again saving gas, filling time, money, and space.

Aside from the logistical benefits, I also enjoy diving a CCR on the wrecks. As I noted in part one of this series, one benefit of rebreather diving I was not interested in trying out was increased bottom time. The Great Lakes are cold and my usual 60-90 minute run times are as long as I want to do. However, having hours of contingency gas rather than minutes greatly increases my safety margin. Of course, the other advantages like moist, warm breathing gas and reduced weight are nice too. One of my favorite times diving a rebreather is climbing the boat ladder at the end of the dive!

Was it worth it?

In a word, yes! In retrospect, it seems that all the puzzle pieces fell into place for me. I was able to find a CCR that I knew had good local support for a reasonable price. After my initial training, I spent hours and hours diving and practicing. I have embarked upon more advanced training to further refine my skills. Last year I began working on Trimix CCR training and CCR Cave Diver training. Both courses have taught me a lot and greatly increased my proficiency.

In my experience, the disadvantages of CCR diving tend to be exaggerated. Some of the negatives I heard were that CCRs are unreliable, and I’ll miss more dives due to malfunctions than I’ll be able to make. I also heard about the hours of pre-dive preparation and hours of post-dive maintenance required. Neither turned out to be true. So far, I have not missed any dives because of CCR malfunctions. Rebreathers do require more pre-dive and post-dive care then open circuit equipment, but not hours and hours. I will say that if you are not a disciplined person, if you like to just throw your dive gear in the back of the truck after a dive and unpack it tomorrow (or the next day), a rebreather is not for you.

I found that the benefits of rebreather diving that CCR divers preach are generally true. Your gas supply does last much longer than your open circuit supply. If you dive trimix a lot, you will see significant cost savings on helium. The gas is warm and moist and comfortable to breathe. A rebreather and associated gear are easier to pack and carry on dive trips than open circuit gear. A CCR weighs less than doubles so it is easier to carry and easier to climb boat ladders. These are my observations. You may find them valid, or you may not. As I said in part one of this series, the path I took may not be the right path for you.

A rebreather is a tool. Is it a tool you need? I don’t know. It’s up to you to figure that out. Switching to closed circuit diving requires a huge investment. An investment of time, effort, and money. You have to decide whether a rebreather holds enough benefit for you to make the investment.