Jon dived the 254m record with ATX 100s, same set-up was used for the 308m dive as far as I've been able to ascertain: -
Under Pressure – A World Record Dive
Sabang Beach, Puerto Galera, Philippines: The delays were starting to wear us down; This was the third morning there had been a last minute cancellation. We sat around in Captn Greggs looking at the weather and feeling sorry for ourselves. It was 7 am on the 4th June. The last three days had all begun at 3am and the combination of sleepless nights & early starts was beginning to take it’s toll.
Jim Noble sat typing another e-mail explaining the delay to some of the sponsors. Jim’s help had been vital to getting the series of dives this far. He was the event organiser and had helped enormously in raising the funds needed. Jim and co-supervsior Noel Godfrey, who had flown in from Wales in the UK, both had more than twenty years experience in the physical training corps of the British army. Their attention to detail would be important to our success, and my safety, it had come from years of running miltary diving expeditions.
Chuck Driver, owner of Captn Greggs, my former deep ocean depth record partner, would this time be part of the support team. (In 1999 we had broken the 153m/500 ft mark four times on dives together and our 200m/656 ft dive was, at the time, the deepest oceananic dive ever completed. It was bettered by Barte Vestor who set a challenging 225m/738 ft mark later the same year).
As with previos record dives Axel Lehward would be the first diver I would see on my ascent, meeting me at 122m/400 ft. Axel had worked incredibly hard preparing the dive support platform with Tom Tom and they had made several stability improvements on last year’s design. Although the dive would be a solo dive (unilke the 1999 joint dive with Chuck) we had decided to keep two decent lines, this time with periodical pipes between the two lines. The second line would give us a working line for the team and provide me with a second reference point, hopefully minimizing the chance of disorientation.
Daran Bull would meet me at 91m/300 ft. He had worked with me on Mark Andrews deep air dive, I knew him to be a calm and very good deep diver. During the build up his common sense approach to things helped a lot as he worked to ensure the ardeous task of mixing tanks was completed.
Mark Cox was also with the team right through the training, all the way to the 155m/506 ft training, but unfortunately he would not be available for the final dive.
Jorge Marques, another close friend, was also working with us again. Like many of the other team members he had sacrificed a lot to be here. His support diver role would take him to a depth of 140m/ 460 ft, shattering his native country’s (Portugese) record.
Jorge’s dive made me realise how lucky I was; the experience level of the team was stunning, seated around me that morning were some of the best deep divers in the world. Now all we had to do was put it all together. Other team member commitments meant that tommorrow would be the last opportunity for the attempt.
This type of pressure was something that I had tried desparately to avoid. Jim Bowden, who had dove to 282m/ 925 ft in the Zacaton cave system (still the deepest open cicuit dive ever completed), had warned me to avoid time and media pressure, but now it was there. The rest of the day was spent checking and rechecking the equipment and mixes. I tried to stay away from most of the checks, concentrating instead on my mental preparation. The delays had started to drain my energy so I left the team to it and went home to my family.
Like most of the team I had another restless night and for the first time I questioned why was I doing this.
Apon waking both the weather and my mood had improved. When I arrived at the shop Noel, Jim, Axel and Tom Tom had already left with the platform and the rest of the team loaded the tanks, making sure the only thing I needed to do was dive. The trip to the site was about an hour, further than I had thought but we were rewarded with a beaming Tom Tom: “lt looks good John”. The countless workouts and weeks of training were over.
The “O Three drysuit” donated by Sean and Kevin made getting into the six tank set up hot work. The dive was also to be a test for the suit: Without it the four degree bottom tempertures waiting for me, would quickly sap my strength and coordination But I had to be careful not to over heat in the twenty eight degree surface waters where I would spend most of my time decompressing, this meant the normal thick undersuit was out.
Noel ran through a check list, making sure that all members of the team had their mixes positioned correctly. This seemingly mundane chore and deciplined approach to the dives, was one of the factors which ensured the success of the project. I rested and composed myself on the surface for ten minutes and also used the time to fit the helmet that had two Halcyon flash lights attached. I carried two other flash lights, both Pinceton Tec and unlike previous dives where lights had either imploded, or flooded all the lights performed well. (I would have preferred to carry a primary light as well, but despite all the glamorous advertising you see I could not find a company that was willing to risk their light!)
Jorge was next to me on the working line, he began his descent a few minutes before me, his role being to check my first gas switch and then wait in case there was a problem in the early stages.
I had decided to carry a 40 cu/ft tank of 16/45 mix to start the decent but as soon as I began my descent I regretted it. It was clipped between my legs and banged annoyingly against them. My desent was fast; around thirty metres per minute and I soon reached the 91m/300ft tag clipping off the 40 cubic tank and switching to my bottom mix before beginning my final drop.
The darkness closed around me as I sped past Jorge and dropped through the 140m/460ft mark. As the vizibility dropped, the suspended particals speeding past added to the disorientating effect. At 160m/524ft a wave of disorientation hit me as I lost track of the line. I slowed my descent, tracking from left to right to find the line. After a few seconds I found it and with a sigh of relief I speeded up the descent. The visibility was still dropping and by 180m/590 ft I could barely see the second descent line which was only two metres from me.
I looked at my computers, both had passed 207m/680 ft. (I knew that when converted, it would make me at a real depth of just over 200m / 656 ft seawater.) I had primed myself to expect an increase in breathing resistence although it never came. The Apex 100 regulators were superb, likewise the Tx 50’s I used for decompression. Suddenly my vision went... the world was a blur... HPNS I thought (I had had a mild case of HPNS on my dive to 200m /656 ft with Chuck)... again I slowed the descent and with another two or three metres it cleared.
I realised that I had just passed through a thermocyline, it was probably this that had lead to the blured effect. The water was now bitterly cold. Glancing at my gauge I knew that I had lots of gas left. I soon passed the 225m/738 ft mark knowing that I was now in new territory. Vizibility was now bad, down to between 1 and 3m, both computers were locked out reading 252m/833 ft – converted to saltwater 246m/808 ft.
I carried on down, now focusing on the depth markers and after a couple of minutes I saw the 250m marker. I was surprised that it took so long to reach it from where the computers had locked up (and sometimes wander how deep I really went). Later we measured the line dry at 254m/833ft. I clipped off the signed slate reading it for the first time. Both Jim Noble and Allan Nash, the two judges, had signed it and added comments. I looked around straining to make out anything through the flashlight beams. Total blackness.
I started my ascent letting the line run through my fingers, the overall objective of the next six hours being to prevent bubble formation. I started at 25m per minute and at 180m/590ft I slowed to 15m/50ft per minute. By 150m/495ft I had slowed to 10m adding 30 second stops every 10m/33ft to ensure a slow ascent. Looking up from 140m/462ft and seeing the silhouette of Axel I relaxed a little. On reaching him he handed me a slate and pencil, I wrote ‘250m’ and carried on up.
From Axel it was up to Daran; the long decompression was only just starting. I extended each gas switch point with the exception of the 150m/490ft, this ensured that the new gas was fully circulated, it also made the most of the high PPO2 in the new mix. Because of the increased off gassing at the switch points I cut time from the stops just above them resulting in no increase in the overall dive time. I used seven different mixes for decompression, finishing on oxygen at 6m. Chuck, John Millard and Peter Wilson all helped with the required switches. Weighing up the pros and cons I had decided to rotate the O2 with a helium rich mix at the 6m stop. This was aimed at protecting my lungs (After a short period on oxygen the blood vessels constrict, shortly after this the pulmonary tissues start to swell. This dual effect cuts back on the offgassing process. Heluim back switching was aimed at ensuring a cleaner decompession. On top of this the scheduled breaks from oxygen helped to buffer the toxic effects caused by breathing oxygen for to long.)
cont'd...
