HEARING THE SOUND OF SILENCE

For years, I watched closed circuit rebreather (CCR) divers on boats, studying them as one would a bizarre species of insect. With all that gear, they inspired little envy. It looked far too technical – too much stuff, too expensive, too many potential dangers, too far out of my comfort range. However, the idea of no bubbles fascinated me. I continued my observation, and CCRs got smaller and lighter, more automated, more targeted towards recreational divers. I started researching different units and inquired at my local dive stores about course requirements and instructors. One day, the fascination became too much. I impulsively chose a rebreather that offered the features I wanted, and I committed to a CCR course.

Ever the teacher’s pet, I showed up for class with calculator in hand and my CCR textbook carefully read. Shortly thereafter, shock ensued. Classroom sessions were composed of history and physics lessons peppered with cautionary tales and dire warnings. By the time I laid eyes on my new rebreather, I was tempted to run for my car and the relative safety of southern California’s highways. However, once I had unwrapped and inspected my shiny CCR unit, abandonment became inconceivable. I went home, knowing I’d be back for my pool session.

Of course, before I could enter the pool,

I had to put my rebreather together, and this was a lesson in humility. Corrugated hoses for breathing, high-pressure hoses for injecting fresh diluent and oxygen into the breathing

“loop”, and HUD display, only formed a fraction of the never-ending list. They all had to be checked thoroughly, then placed into proper configuration. Although I was following a detailed checklist and had read the manual, I realised that my new toy was really a scary Rubik’s cube of dive gear.

I nervously grilled the instructor and doublechecked each of his replies with my unit’s manual. He watched me fumble around, patiently offering pointers here and there. After one-anda-half hours of countless expletives, I presented the instructor with my CCR. He closely examined the gear and asked me several questions about its assembly, the purpose of each part, and what I would expect underwater if individual components failed. I nervously answered his questions. Finally, he smiled at me and said, “Well done, gear up!”

The pool session began with us swimming in a circle, getting a feel for breathing on a loop. It was strange – not unpleasant, but I didn’t really understand the hoopla. It was significantly harder to breathe from than a regulator, and

It took two seconds to confirm that buoyancy skills cultivated as an open circuit diver rapidly disappear on closed circuit

it took two seconds to confirm that buoyancy skills cultivated as an open circuit diver rapidly disappear on closed circuit.

As I performed my skills, switching between closed circuit and open circuit bailout, removing and replacing my mask and exhaling through my nose, I noticed that I was running into the bottom of the pool quite a bit. I’d exhale to rise from the bottom, and nothing would happen. Argh – of course not! I was exhaling into an air loop that had constant volume.

At this point, I was questioning my own sanity. I loved diving open circuit, and I was good at it. Why had I felt such a pressing need to change things? The expense, the time, the humiliation – was it really worth it? Fortunately, there wasn’t much time to ponder this question. My first CCR ocean dive was half a day away, and I had gear to prepare.

When we descended into the ocean off of Catalina Island, it was a mess of chaotic new-diver buoyancy followed by skills, more skills, and trying not to squash any unfortunate creatures on the ocean floor. However, the subsequent dives were quite different.

We descended more gently, everyone weighted properly and felt more comfortable. The instructor ran us through extensive skills, and then signalled us to begin a short swim. Minutes later, it happened.

Silence. Blissful, amazing silence. The fish, it seemed, were everywhere – bat rays, normally skittish, approached to take a look at us before swimming away. Shy butterflyfish, most often glimpsed in a state of retreat, gathered indifferently in the water column. The kelp forest, inarguably beautiful on open circuit, became utterly magical.

Since I first dived, my deepest longing had been to feel closer to the ocean. This silence brought me closer to that dream than I have ever been. I no longer felt as if I was invading the place I loved. Half an hour later, our instructor signalled me to head for the surface. I climbed quietly back onto the boat, not wanting to break the spell, and began reluctantly removing my gear while staring longingly back at the ocean. I turned and caught a glimpse of our instructor, smiling widely. “Welcome to the world of rebreathers,” he said.