Friday, 07 June 2002 00:00

Learning to Climb Trees - Part 2

By Trevor Jackson - Esperance Star

There was actually a little bit of confusion just prior to the jump. Simon and I had agreed that because my descents were in general slower than his, that I would go first and set the pace on the way down. I positioned myself on the Starboard side of the duckboard to jump in, but the floats had appeared on the Port side of the boat, so Simon jumped first and I would overtake him in the top 10 metres after a short stop on the surface to get settled. At this stage our thoughts were fairly routine, and for a few moments it was just a normal dive. I gathered a left hand full of shot line and started to pull down; my right hand would work the button that controls the gas level in my counterlung and occasionally lift my computers into view so I could check that the PPO2 was being maintained at the required level. Down through 30, 40, 50, 60, 70, 80 and 90 things were fairly simple, we'd been to these branches often enough in our lead up dives. At around 100 things start to take on a different feel, the sun goes down and the moon comes up. Our helium rich bottom gas started to feel a little heavy in the mouthpiece. Through 120 and 130 we were branching out onto thinner and unscaled limbs, clouds came across the moon. The cyalumes on the lower half of the shot line came slowly into view like stars breaking through the cloudbank.

It was fully dark now, the light from our dangling torches made sweeping orbs, probing into the black. The gas got heavier and heavier so I consciously slowed the descent. Around about this point I remember saying, 'Holy shit this is a long way down'. The cylumes flicked by us slowly, red green, orange, no particular pattern, they were all I could see [at least I didn't have to look at my butt like the Kiwi did]. The point where I thought we should start seeing the bottom had past 10 metres back, for a second I thought we must have dropped the shot into a deep hole. A quick glance of the depth gauge revealed 157m, surely we must see something soon. The cylumes below took on a different arc, levelling out horizontally across the sand, and then there, peeking through the night, I saw the white sides of the Max Factor resting heavily on the bottom. Touchdown!

To the very tips of the leaves we had climbed, you could touch the sky from there, where the new growth presses upwards into the light, with my depth gauge reading 177metres, a rainforest had been conquered.

Right about now I'd like to waffle on about how mysterious and surreal it all seemed, but that would be fibbing. The truth is, it didn't seem any different for a little while, it was just like doing a night dive, and as long as we didn't think about that monolithic column of water pressing down on us, things would be fine. We took a half a minute to get soughted, checked the rebreathers were working ok, no leaks, constant O2 levels, yep shes sweet. I started to look around, the next thought that I recall was, 'don't tell me I've come all the way down here for a f***ing sand dive'! I couldn't see anything; the lights weren't penetrating far enough to show any wreck or part thereof. I looked down at my torch and saw that the glass had imploded, yet it still seemed to be working. I turned it off. Man it was black. Simon was behind me and off to the right. For a second, in a way, we were alone in the abyss.

Now if you want to know about gas physiology and the like then my buddy is the one you should talk to, hes the scientist. I knew enough however to know that the strange patterns I was beginning to see in the water above and ahead of me could have been caused by old brain not coping real well with the sudden descent. I checked the PPO2 again, took a quick glance at Einstein and noticed he was looking at this strange phenomenon also, 'Great we're both crazy,' I muttered. Slowly the patterns began to take a more comprehendible form; it looked like black wallpaper with large white flecks. 'What the hell IS that?' I asked myself. I remembered where I was, I remembered why I was there, and I remembered the 268 sailors that lay here. This was the Australian Hospital Ship Centaur. The white flecks across the face of this black wall were fish, trillions of them, don't ask me what species, I wouldn't have a clue.

We had literally 90 secs of bottom time left. There was no time to unclip a reel and spool over to the ship, and we had planned not to leave the shot line without first attaching a line. I had to make what I thought at the time to be a selfish call. I turned around to Simon and gestured that he should wait for a second with his lights shining. I took off towards the wreck in the hope I could guide him over if I could still see the wreck and the cyalumes at the same time. Arriving beside the hull the seconds had ticked away. As I cast my disbelieving eyes up at this great monolith, and as Simons torch cast a shadow of my considerable girth against the side of the wreck, I knew that visiting hours were up at this Hospital.

A funny thing about climbing giant trees is that you've also got to climb down, you can't just jump. Another funny thing about trees and treeclimbers is that whilst trees take CO2 and turn it into Oxygen, treeclimbers do the opposite, turning O2 into CO2. If a treeclimber produces too much CO2, and is too high up a tree, then things get sticky, branches sway, a climber can get dizzy, a climber can fall.

I made it back to the Max Factor ok. Simon had darted off to check out a fire extinguisher which lay about 5 metres away and I had started my pull up the long line. I shone my lights down on him to help his investigation, and then he left the bottom. The video taken on the boat the night before the dive shows the good doctor explaining the dangers of high CO2 partial pressures to some of the support team. It was irony at its finest. Simon's rebreather has a giant 4.5 kg scrubber and we knew before the dive that my 2.5 kg Co2 Scrubber was going to be pushed to the limit on the bottom. We did not and do not see this as a fault with the unit. For its rated max depth of 100m this is more than adequate, but we were climbing a bigger tree and had it in mind through out the build up that a Co2 'hit' was a remote possibility. We trained for it, put back up systems in place, if it happened we'd be ready. It happened.

At about 165m I began to feel short of breath, I knew I should not be so I pushed the button on the front of my unit that flushes the counterlungs with fresh gas. I inhaled through the mouthpiece and exhaled through my nose, spilling the counterlung gas out through the edges of my mask. In turn the button I was pushing fed fresh gas into the unit and after a few seconds using that procedure the old counterlung gas was flushed completely out of the unit. Unfortunately, just as the CO2 had taken quite a few minutes to build up to a toxic level, it would take just as long to work its way out of my system, and in the meantime, I was not in a nice place. I had to keep flushing and keep ascending, ever mindful that there was no escape option here; I couldn't abseil down the tree.

My head was throbbing and I felt sick, I felt like I would lose consciousness for a second, then I went into a plateau where everything seemed ok. I got up to about 120 when it hit me again, harder. Delirious. We learned later that this temporary feeling of wellbeing was the most dangerous point, I almost lost my grip on the branches, and the fall was unthinkable. I tried to concentrate, I thought about my friends on the boat and how I wasn't going to make them search for a marker float that was never to come. For them I would fight this monster off. I thought about my family, how my brother, the toughest man alive had rung me and told me he felt giddy and sick to the stomach as we steamed out past the Cape. I thought about my mother and how she never stopped me from going that extra step, in anything I ever wanted to do. I would fight this barstard coz I knew he didn't have my stamina, he would only last another few minutes, I hung onto the line. The light began to come, the cyalumes passed by one by one, the sun began to rise, and with a fresh breeze beginning to blow, I pulled up at 100metres.

Simon had ascended much slower than me. Things in the noggin had settled back to normal except for a throbbing headache which was to last for days in one form or another. The next step was to get back into the fold of the normal dive plan. In my pocket was a tiny plastic booklet which outlined all of the deco schedules we would follow, both in an emergency and if things were going well. I flicked through the book to find the appropriate runtime. Surprisingly things were still perfectly on schedule and I was due to ascend to 80 and stop for a few mins. The only problem was that I still couldn't see Simon below me. The procedure for separation was that we would both shoot a lift bag to the surface. If we were off the line the pickup boat would deploy with an entirely independent team of support divers with a backup shot line which could be deployed down to the lost diver. I must admit to beginning to feel a little anxious looking down the line of cyalumes and not seeing Simon. The time to ascend to 80 had arrived and I strained to see him, his entire outfit was black, including his unit. I thought about shooting the lift bag to let the surface know we were separated. I reached around and felt for a reel, unclipped it and looked down again. I gave it another minute, then finally, Simon's torch glared up at me, faintly, but he was there all right. Phew!

Once we'd re-established contact the dive was fairly bog standard. Climbing further and further down the tree was comfortable and easy. Darryl Waters, our first support diver met us bang on schedule at 45 metres, asked few questions like, 'Are you alive?', and then took off to stage his share of the deco bottles on the downline. Shortly after, Dean Wort and Lynn Taylor joined us and from that point on we were accompanied right through to the surface for a final runtime of 3hrs and 44 mins.

Back on board the crew had cleared the loungeroom out and put together what looked like a mobile hospital ward. A massive bed had been made up on the floor and we were quickly into bed and onto the pure O2 for an hour. Darryl took our blood pressures every 15 mins or so and after the hour was up he said something official and doctor like, 'Congratulations gentlemen, you've just completed one hour of post dive oxygen therapy, BP's are normal, symptoms of DCS nil'. Everyone in the room applauded. I jumped up and asked for a smoke. I was refused. I looked down at Simon who was still lying there with his O2 reg still in place, 'So what are we going to do for kicks now?' I asked. Simon simply shrugged and said, 'Don't know mate, but we'll think of something.'