The Unicorn
Tim, Charlotte, and the ship staff boarded the Sita and sailed north to the remains of the cargo ship, Unicorn. N10'9.699 E099'50.929 was the exact location of the downed vessel and it took a little over an hour to reach the target. The day was heavy with dark clouds and everyone knew that they would be wet soon, dive or no. Tim had dropped a shot line near the bow area and tied an anchor line to the forward mast of the Unicorn a few weeks earlier so it was easier to locate. The group of 3 went over the dive plan one last time.

We were to descend to the mast area at 35 meters. The visibility would likely be under 6 feet so we would attach a wreck reel to the mast and use that as a reference when we left for the bow. The tip of the bow was sitting at 42 meters. This was to be my first time this deep and I did not know what the effects of nitrogen narcosis would be on my system so my job was simple. Hold on to the reel line and swim behind Tim through the cloud of bottom particles. After 9 minutes at depth we would start our ascent to 15 meters for a simulated decompression stop.

As compressed nitrogen builds up in the blood the danger of decompression sickness (DCI) rises. The deeper you go the more compressed nitrogen enters your tissues. If you were to stay too deep too long your nerve, muscle, skin, and fatty tissues would contain dangerous levels of expanding nitrogen bubbles and incur the wrath of "the bends". Also, below 30 meters the nitrogen begins to interfere with your nervous system and the diver can experience euphoric drunkenness. When you're narced you start to forget what time it is, how deep you are, and what you are doing.

Technical divers deal with these issues several ways. 1st they use blended gases that reduce the percentage of nitrogen in the mix. Extra oxygen and replacement helium can replace the amount of dangerous nitrogen in the air. They will also take long decompression stops to slowly work the nitrogen out of the blood. This can sometimes take several hours and require multiple tanks of air- way beyond my training. Deep divers also practice mental task mapping by imagining the stages of each dive in repetition. This deals with the dangers of being narced at depth so that the brain can automatically execute each stage of the dive.

The first dive was a loss because we missed the mast on decent. We went down the wrong shot line and ended up in the bridge area which was too deep for my training. The second dive was a success, however, and I can vividly remember the skeleton of the Unicorn fade into view through the silt of the thermocline. The eerie mast came into view and we did the dive according to the plan. Covered in fisherman's nets, the Unicorn looked like an embalmed mummy awaiting burial. As we hovered over the bow fish came to inspect the intruders. We were grave robbers.

After 9 minutes the party ascended to 15 meters for 3 minutes, then 10 meters for 3 minutes and finally to 5 meters for 3 minutes. This increased the safety of the dive by bleeding out any dangerous levels of nitrogen. At 5 meters I watched the pin-prick of rain needle the rolling pane of glass that was the surface above me. A storm had landed on us and the sea was churning in anger at the intruders. Aboard the Sita, we set our course for Koh Tao.