I had built my dive plan for a deeper dive before deciding whether I was dive fit following my decompression incident. During these months, I returned to dive fitness (on my own estimation) and at 10 months post accident felt my confidence and fitness levels were high enough to attempt a deep dive.
Once the date of the dive was agreed, support divers would need arranging and briefing and the dive tanks filling. The tanks alone for myself and fourteen support divers would take 3 full days to fill, and use almost 60 cubic metres of helium. The tanks were filled just two days before the dive; this (in hindsight) was too close as the process was stressful along with loading the dive boat during a squall that had recently blown in. I had insufficient sleep that night and would have made an excuse to postpone the dive had the weather not been decided that by providing gail force winds that day.
During the next few days, I felt like the storm clouds were passing in my mind, I started to feel as good as I would need to soon. The following week passed easily and I managed several practice dives in less than ideal conditions. The day before the dive I went to bed early mindful of the current windy conditions. I woke up to blue skies and calm seas and I felt as carefree as a 6 metre support diver! The journey to the divesite was 4 hours of smooth seas and I felt absolute confidence, which helped to ease all the support divers anxieties and put the whole boat into business mode.
The descent went very smoothly, the unusual currents would go down then up then get weaker then stronger, but mainly because of the slack tide window and neaps dive time, the tides didn’t have a detrimental effect. Once 180m depth came, it brought with it the darkness. Underwater lighting has come along way in the last year and its now possible to virtually guarantee operation to 300m (with the right lights of course!)
My head mounted lights shone onto the down line and every once in a while I would check my depth on the taped measurements against my depth gauges.
By 250m I still felt in charge, my lowish helium content added the sort of (couple of pints) confidence that would help avoid helium tremors and other HPNS symptoms. The water temperature was chilling, but my dry suit kept the icy water out, I noticed the shakes in my body and hands, but couldn’t really say whether it was the cold externally or internally or helium induced tremors. By 280m I started to grip the line tighter to slow down, I checked my back gas contents gauge and was not impressed by the figure! I had reached my gas turn around pressure by 300m. I didn’t seem overly concerned and this concerned me! I dropped to 310m and looked again at the gauge, 20 bar behind schedule and planned drop time exceeded by one minute. At this time I looked down and saw a ghost like image of some kind of large hydroid, I scanned my eyes from left to right to check for any visual abnormalities and to check the distance more exactly of my jelly like visitor. The little checks I do told me that my concentration was sometimes stalling into a complacent mind lock and this set the narcosis alarm bells ringing. This hydroid looked on coarse to hit my descent line and looked over 2 metres in length!
The deeper stops came and went without drama, which was not surprising due to the slow ascent rate. The first gas switch was my only concern the rest would be easy. Because of the minimal time at depth, the risk was acceptable. The journey to the first support diver was uneventful (ish), I met Sveinung at 90m and he handed me a 15l of Trimix 14/56. Phil gave me a similar tank at 75m, as did Khun Gai at 60m.
During the stops, I ate fun size mars bars and banana pieces while the support divers were having their lunch. I knew this because of the chicken bones that were raining down around me. Small fish were closing in all of a sudden, to peck at all the goodies – I hoped a toilet flush wasn’t coming next.