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DeliciousKuruman (global-adventures.us): One of the deepest caves in the world is located in the Northern Cape province of South Africa. Bushman's Hole, or Boesmansgat, is approximately 930 feet (283 meters) deep and only partially explored. Mike Rathbourne was one the first divers exploring the sinkhole in 1977. Over the years, the underwater cave has attracted many divers.
Nuno Gomes, a South African explorer of Portuguese descent, reached a depth of 927 feet (282.6 meters) in Bushman's Hole. Calculating decompression times on the dive that lasted 12 hours and 15 minutes was complicated due to the fact that the entrance to the cave, believed to be the third deepest in the world, is located at an altitude of 5,000 feet (1,524 meters).
After a fast 15 minute decent, Gomes did see the bottom of the cave. "I saw a lunar type landscape of grey silt with the odd small rock sticking out, and there was some slack rope on the flat bottom," Gomes writes on his website. "There 
were holes in the grey silt where the weights had gone in, as well as a small ledge which I had to get past to reach the deepest spot about [16 feet] five meters away horizontally. There was only one way, I had to swim whilst taking up the slack on the rope. Since I was negatively buoyant and had no time to inflate the wings (buoyancy aids) I landed on all fours. My worst nightmare came true: a silt-out at the bottom of a very deep cave with a slack guideline while on all fours and under the influence of nitrogen narcosis and helium tremors. My first priority was to stand up without losing balance or becoming tangled in or losing the line; the quads and two side - mounts did not help. I tried to swim up but failed and became dizzy. I relaxed and inflated the wings; it took [66 pounds] 30kg of lift to ascend fifteen meters and get out of the mud and silt."
Sheck Exley was an early explorer of Bushman's Hole. During an expedition in August 1993, he reached a depth of 863 feet (263 meters). During the dive, he experienced a serious case of high pressure nervous syndrome (HPNS) that included blurred vision and intense, uncontrollable tremors.
Gomes explored the cave during numerous expeditions before making his record-breaking dive. In 1981, the civil engineer from Johannesburg did reach a depth of 250 feet (76 meter). A 400 feet (122 meter) dive in 1988 did mark an African dive record. During the Exley expedition in 1993, Gomes used sonar scans to survey Bushman's Hole.
The cave is located on a privately owned 11,000 acres game farm. A huge crater leads to a swimming hole often covered with duckweed. After descending through a narrow chimney, the main chamber is reached. Approximately 770 by 250 feet (235 by 76 meters), lights cannot penetrate far enough to see the other side, let alone the bottom.
Bushman's Hole developed into an epicenter for cave-divers from around the world. For some, the dream of going where no one has gone before ended in the abyss. Eben Leyden, an experienced South African diver, suffered an arterial embolism after descending too quickly. Deon Dryer had logged over 200 dives when the South Africa Cave Diving Association asks him to help as a support diver on an expedition set to further explore the system. On a practice dive, Dryer suddenly disappeared into the abyss after exchanging hand signals with his buddy during ascend. The most likely case for the death is deep-water blackout from carbon dioxide buildup, the team assembled by Nuno Gomes said after his disappearance.
Dreyer's body remained in the cave for over 10 years until David Shaw made an attempt to recover it. Shaw, an Australian airline pilot and one of only a few divers who ventured to depths below 800 feet (244 meters), used rebreathers to explore the abyss. On October 28, 2004, Shaw broke the depth record using a rebreather, the depth record using a rebreather during a cave dive, the depth record at altitude on a rebreather, and the depth record running a line with a rebreather - all in Bushman's Hole.
Only 10 weeks later, he died on January 8, 2005 during an attempt to recover the body of Deon Dryer. Shaw filmed his dive and ultimately his dead. He ran into difficulties when he cut Dreyer's harness and the body unexpectedly began to float. Loose lines wrapped around Dryer's remains appear to have gotten entangled with Shaw's cable light, and the physical effort of trying to free him ultimately led to his drowning. While retrieving the dive equipment, the support team pulled up the two bodies on the next day.
A plaque erected at the entrance to Bushman's Hole remembers Deon Dreyer and other divers that perished exploring the unknown.
The video about David Shaw’s last dive is available on YouTube here.
Photo: www.imagine-your-world.com
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