Page 42 - AlertDiver

I

t was dinner time at Divetech. As I walked past

the kitchen, I noticed two red lights blinking on

the side of the oven. Before I realized what I was

doing I had raised my hand to my mouth and

tilted an imaginary switch away from my face while

reciting to myself, “If you encounter a problem, bail out

to open-circuit scuba” — the mantra of the recreational

rebreather student.

I hadn’t even gotten my hands on a rebreather yet, but

I’d been doing a lot of reading. I had studied my training

manual for weeks, and on the flight to Grand Cayman I

carefully read every page of the owner’s manual for the

Poseidon MKVI, the rebreather I would be learning to

dive during Tek Week 2012. Once I actually started my

class I learned that checking my console was a better

response to a warning light, but I was still reassured by

my heightened awareness.

I’ve been diving for 20 years, but I have yet to venture

into technical diving. With the growing popularity of

recreational rebreathers, though, I saw an opportunity to

get a glimpse into that world.

Relearning Buoyancy Control

Apparently, in all my years as a diver I’ve been using

my breath to make fine adjustments to my buoyancy. I

know this because on my first day as a rebreather diver

my buoyancy control went to hell. The main difference

is this: When using a closed-circuit rebreather (CCR),

breathing doesn’t change the amount of gas in the system;

it simply moves a volume of gas back and forth between

your lungs and the unit’s counterlungs (gas reservoirs).

Thus, efforts to fine tune buoyancy with well-timed

inhalations led me to crash awkwardly into the bottom of

the pool on several occasions.

In addition to relearning buoyancy control, I had to get

over my desire to feel the familiar flood of cold, dry air

that a second-stage regulator delivers. I’ve always heard

divers talk about breathing normally while open-circuit

scuba diving, but breathing with a rebreather is much

40

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WINTER 2013

RESEARCH, EDUCATION & MEDICINE

//

A D V A N C E D D I V I N G

Learning to

Rebreathe

A recreational diver tries

closed-circuit

B y B r i a n H a r p e r

CHRIS PARSONS

Page 42 - AlertDiver_Winter2013