Karen van den Oever Continues to Push the Depth at Bushmansgat: Her New Record—246m

By Nuno Gomes. Images courtesy of Karen van den Ever.

Karen van den Oever, from Johannesburg, South Africa, has dived to a depth of 246.65 m/809 ft. This is equivalent to a dive to a depth of 296 m/971 ft when corrected for an altitude of 1550 m/5,085 ft above sea level. The dive was conducted on October 27, 2022, in Bushmansgat cave, South Africa, and is a new women’s world record cave dive. Karen bettered her own previous world record to a depth of 236.04m/770 ft  (283 m/924 ft correcting for altitude), also accomplished at Bushmansgat cave in 2021.

“I actually felt really good after the dive, a little tired but overall, quite good. I felt much better after this dive than the previous one. I’m happy that the dive went well, just thinking about what comes next. I have no definite plans going forward, we are looking into diving some of the caves in Namibia and also exploring some of the caves not yet dived in Zambia but no concrete plans yet.”—Karen van den Oever

Women have been making record deep dives for quite some time. Back in 1981, one of the first deep diving records was made by Sheck Exley’s wife, Mary Ellen Eckhoff (USA). She used a dive propulsion vehicle (DPV) to travel into Wakulla Springs cave, as well as staged tanks for decompression purposes. Mary Ellen dived on open circuit, together with Paul DeLoach and John Zumrick, and they reached a distance of 363 m/1192 ft and a depth of 80 m/260 ft, which was a major dive at the time.

In 1996, Dr. Ann Kristovich (USA), a friend of Jim Bowden, considerably extended the record, reaching a depth of 167 m/548 ft on open circuit at Zacaton cave, Mexico. Ann’s world record dive would remain in place for a long time.

It was not until the year 2000 that another woman, Claudia Serpierri (Italy), would beat the previous record, but this time in the sea (Mediterranean Sea). Claudia would reach a depth of 211 m/692 ft on open circuit, diving from a support ship. This dive remains the deepest sea dive by a woman to date.

Toward the end of 2001, Verna van Schaik (South Africa), was ready to challenge the women’s record. First, she did her deepest dive by reaching a depth of  186 m/610 ft  (223 m/732 ft correcting for altitude), on open circuit, at Bushmansgat cave in South Africa. This was not enough for her, and during her next expedition on October 25, 2004, Verna would go back to Bushmansgat cave to become the first South African woman to get her name in the Guinness Book of World Records by reaching a depth of  221 m/725 ft  (265 m/870 ft altitude corrected), on open circuit. Her deep support diver was the late Dave Shaw (Australia), on closed circuit, who died of respiratory insufficiency at a sub-250 m dive at Bushmansgat in 2005.

Following Verna van Schaik’s dive at Bushmansgat cave, two women divers died trying to break her record, as follows: 

In May 2010, French diver Brigitte Lenoir, died in Dahab, Egypt during a dive in the Red Sea. The accident took place at 147 m/482 ft while ascending from a 200 m/656 ft, on closed circuit. Her body was recovered with an ROV. 

In September 2017, Bulgarian technical diving instructor trainer, Teodora Balabanova, died attempting a dive to 231 m/754 ft, on open circuit, while her husband, Mihail Balabanov, suffered from decompression sickness. 

Karen van den Oever is a science graduate from the University of Witwatersrand in Johannesburg, South Africa, where she currently resides. Like Verna van Schaik, who now resides in New Zealand, she is a CMAS diving instructor, and also a former member of the University of the Witwatersrand Underwater Club. 

Her original cave, trimix and blending training was with me. I also trained her husband Francois Bain. 

Karen had previously dived to 201 m/660 ft (241 m/792 ft altitude corrected) on open circuit in Bushmansgat cave in South Africa’s Northern Cape province on February 27, 2020. That dive’s total dive time was 7 hours and 21 minutes. On March 26, 2021, Karen dove to 236.04 m/770 ft (283 m/924 ft), on open circuit, at Bushmansgat cave, using a bottom gas of trimix 6/85. The total dive time was 7 hours and 18 minutes. That dive is the current deep diving Guinness World Record (women).

Karen’s new world record dive, done on October 27, 2022, was made to a depth of 246.65 m/809 ft (296 m/971 ft), in Bushmansgat cave. The dive was done on open circuit, using a bottom gas of trimix 4/90, and with a total dive time of 8 hours and 14 minutes. The dive would not have been possible without a large team of support divers. 

Peter Reid was at 209 m/686 ft (251 m/823 ft); this was his personal deepest dive on closed circuit, and his total dive time was 6 hours and 20 minutes. Don Hauman did deep support at 110 m/361 ft (132 m/433 ft). Her husband Francois provided shallow support and surface support, together with the other team members.

Karen’s Total Narcotic Depth (TND) was 48.06 m/158 ft; the Equivalent Narcotic Depth (END) considering nitrogen only was 9.49 m/31.14 ft, and her maximum Partial Pressure of Oxygen (PO₂) was 1.03 Atm. Gradient factors: 40/75.

There were no serious incidents during the dive except that Karen suffered some mild High Pressure Nervous Syndrome (HPNS), which ultimately did not prevent her from going any deeper. Karen had some difficulties recovering the evidence tag from her maximum depth because of the tremors that she was experiencing as a result of the HPNS, but in the end she turned the dive mainly because she ran out of bottom time. 

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Nuno Gomes is a professional civil engineer, a CMAS technical diving instructor and a commercial diver. He was born in Lisbon, but his family relocated to South Africa during his youth. He now lives permanently in New York with his family. He has dived all over the world.

He used SCUBA (open circuit) to dive to a depth of 321.81 meters (1,056 feet), inclusive of rope stretch, in the Red Sea off the coast of Egypt near Dahab, in June 2005. The total dive time was 12 hours and 20 minutes. The descent took 14 minutes with two minutes spent at the bottom.

He also used SCUBA (open circuit) to dive to 282.6 meters (927 feet) in the Bushmansgat cave, in South Africa, in 1996. The cave is located at an altitude of 1,550 meters (5,086 feet) above sea level, which resulted in a decompression schedule for an equivalent sea level dive to a depth of 339 meters (1,112 feet) in order to prevent decompression sickness. The total dive time was 12 hours and 15 minutes with four minutes spent at the bottom of the cave.