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Dudes (and dude-ettes),
I thought for the benefit of the readers of this list I would relate my
experiences yesterday on a 275' rebreather dive off of Catalina Island.
The day was sunny, warm, and the sea was flat calm. We anchored off of the
Isthmus, and were set to dive a sunken tower whose bottom was 240' deep.
The sand bottom sloped off to varying depths.
I was testing my CCR-155 rebreather with the AGA mask for deep dives. I
have a rebreather block on the front of the mask with the DSV ("Dive
Surface Valve") modified by Tracy Robinette to incorporate a open circuit
regulator as bailout.
I was in the water first, and waited for my partner, John McKenney to
follow. I waited at about 20 feet on the anchor line for about 10 minutes.
I have a beard, and did not trim it that morning (this is actually an
important fact). As such, I had some leakage in the AGA which I thought to
be minor - I was wrong.
Once John got in the water, we began our descent. At the anchor (which was
at 240'), John tied off his reel, and began to move down the slope toward
our eventual goal of 275. I should mention that the surface temp of the
water was about 70 degrees, but there was a rather harsh thermocline at
about 200 that dropped the temp to 50 degrees. I was wearing my SSI
Titanium wet suit, since the drysuit I bought recently leaked badly, and
was useless.
As I followed John on the line, I noticed that I had a lot of "gurgling" in
my hoses, what I didn't know is that I (once again, for you devoted readers
of my posts) had flooded my cannister). The amount of water that had
soaked my scrubber was enough to begin reducing its CO2 removal properties.
Combined with other factors (which I'll explain later), the net result was
that I started having a severe feeling of not being able to "catch my
breath". When we got to the end of John's line, he handed me his reel, and
continued on. I stood there (like a dummy) for a second, before I asked
him (over our comm units) what the hell he thought he was doing, handing me
his empty reel. (John loves to mess with me like that, since I am so
serious underwater, unlike on dry land).
He returned, and proceeded to reel in his line. Meanwhile, my breathing
rate had begun to climb like crazy - I just couldn't catch my breath. I
was breathing deeply, but I felt as though I was suffocating. I realized
that I needed to keep hold of his line to make my way back to the anchor,
so I swam hard to catch up with him and grab the line.
When I did that, my breathing rate shot through the roof. I was literally
starving for a fresh breath, and felt like if I didn't get one good breath
I was going to die.
We already had a fair amount of time at depth, so bolting for the surface
was not an option.
I want to tell you something from the bottom of my heart: Every single
fiber of my entire soul was shrieking for me to bail immediately. My brain
was flashing warnings like shotgun blasts, making me want to fly toward the
surface as fast as possible. I was convinced that I was finished, that I
was going to pass out and die right there.
I grabbed the line, and that tiny little kernel of thought and reason that
still existed in my brain told me that it knew what was going on - I had
flooded my cannister, and the CO2 removal was diminished, but not gone.
All I had to do was calm down, keep my cool, and complete the deco. I knew
that is was going to be painful, but that I could survive it, even though
every other part of my brain was telling me otherwise.
John noticed something wrong with me and gave me the "are you o.k?" sign
(the real one, btw) - I signaled back that no, I was not o.k. I pointed to
my center section to let him know that. (Yes, we had comm, but I had
really bad "helium voice" and was breathing too hard to even talk).
I then closed my eyes to calm down, and keep myself cool so I could proceed
with my regular deco. John thought I was about to pass out, and reached
over, and twisted my DSV to open circuit.
I was carrying a composite bailout bottle with compressed air, for our
planned gas switch at 120' - when he did that, I shot him a dirty look,
since I only had 23 cu. ft of gas in that bailout, and also in my present
stressed-out-to-the-max condition, the last thing I needed as a narcosis
hit at 260' of water.
However, what he did revealed to me the answer to my dilemma: Those two
open circuit breaths I took were like liquid gold in my lungs - they
immediately began to thank me and stop hurting so bad. Regardless of how
good it felt, the thinking part of my brain was still in control, so I
immediately switched back to closed circuit, and began to breathe like a
steam locomotive again. I knew that I couldn't survive on that bailout gas
alone, and that I had to conserve it as much as possible, no matter how
much it hurt.
I elected to go with one of the four deco tables we had worked out on the
surface that I carried with me, and began to do my stops. I had 60 minutes
of decompression to go through, all the while feeling like I couldn't
breathe, my brain screaming for me to shoot to the surface, and shaking
like a leaf from the cold water.
The small part of my brain that could still think did some quick
calculations, and determined that I could have 2 breaths of open circuit
every minute, and use the 17 cu. ft. of the diluent mix to purge the
counterlung every three minutes.
I can't tell you what kind of hell that 60 minutes was, I really can't. I
don't wish that kind of pain on anyone. Once I finished my deco
completely, I swam back to the ladder on the boat, and couldn't even climb
up with my gear on.
Once onboard, I felt better within 30 minutes. I had a severe headache
that went away pretty quickly. I feel great today, and ready for another
dive on Saturday.
On the boat, I spoke to John about my experience, and then later, I called
Rod Farb and spoke to him - seems like (according to Rod, who has a lot of
experince with the CCR), one thing about the AGA is that since it is made
out of soft material, it "moves" in and out with each breath. You don't
realize it, but on closed circuit, this means extra work for your
diaphragm. When you are at depth, your diaphragm is working hard to move
gas, and when coupled with the movement of the AGA, it makes it harder to
take a full breath. He told me that the same can somtimes be true when
using smaller diameter hoses and a mouthpiece. The net result (especially
when you couple that with reduced CO2 scrubbing efficency) is the feeling
that you can't catch your breath. Panic and stress then set in, as your
brain can't understand why you can't breathe.
I have to say that I am really glad that I had the presence of mind to
control my primal urges to bolt to the surface, which were as strong as I
have ever felt. I firmly believe that 9 out of 10 divers would have opted
for the surface solution, which would have guaranteed them a stay at the
Catalina Hyperbaric Chamber, or worse - killed them.
I am also glad that I was diving with someone who is as experienced and
cool-under-fire as John. Because of all the extreme warnings I was getting
in my brain, it was nearly impossible for me to figure out the quick
solution to my immediate problem. His response to my dilemma may very well
have saved my life.
I have to admit, that part of me didn't want to post this, since it is
something that is just a little bit embarrassing (I do have a fair level of
testosterone after all), but since there are going to be a whole bunch of
new closed circuit rebreather divers on this list, I felt that it was
information I should share.
The lessons learned are as follows:
#1 - Follow Rule #1 - Dive with someone who knows their shit, they may save
your ass.
#2 - If you want to use a full face mask with your rebreather, you'd better
call Tracy Robinette and get one of his blocks - with the stress level I
was under and my hyper involuntary breathing rate, I would have drowned
trying to remove that mask underwater to switch to a regular open circuit
regulator. I'll use my FFM for shallow depths from now on (less than
150').
#3 - No matter what, ALWAYS listen to the tiny part of your brain that
thinks logically - Don't let panic take over - it will kill you deader than
shit.
#4 - When you have an incident, contact someone who can explain to you what
was going on, so you develop a better understanding of what to look out
for, and how to deal with it better in the future.
I hope this baring of my weenie soul has taught some of you a good lesson,
or at least informed you of something to look out for when you dive closed
circuit.
My understanding from Rod is that these kinds of things have happened to
all kinds of experienced divers, so it would appear that while maybe not as
serious as what I went through, these issues should not be dismissed.
I also want to say, that though I write about John and Rod trying to kill
me in my "Last Dive" series, I am eternally grateful that these guys are on
my side - I wouldn't be here today if it wasn't for them...
Kevin "Call me the Crash-Test Dummy of Rebreathers"
HeyyDude
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