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Boesmansgat
Depth reached by Nuno Gomes on 1996-08-23 as published on his own site; the Mail & Guardian reported 283.3 m in 1996 and a 2002 GUE report quotes 286 m. Treat the bottom depth as about 282-286 m depending on source and water level.
A very deep flooded dolomite sinkhole on a private game farm in the Northern Cape, at roughly 1,500 m altitude. It is known for extreme-depth record dives, including the current Guinness women's record, and is not a public dive site.
Boesmansgat (Afrikaans for 'Bushman's hole') is a water-filled sinkhole in dolomite on Mount Carmel, a game farm near the road between Kuruman and Danielskuil in South Africa's Northern Cape. Divers reach the water by scrambling down from the surface and squeezing through a narrow crack; below it the flooded chamber opens out into a very large, deep void.
The sinkhole is famous for depth. Sheck Exley reached the bottom at 263 m in 1993, Nuno Gomes went to 282.6 m in 1996, and in 2022 Karen van den Oever made the dive Guinness World Records lists as the deepest scuba dive by a woman, 246.56 m. Published figures for the deepest point vary between about 282 m and 286 m, partly because the water level has changed over the decades.
The altitude matters as much as the depth. Because the surface lies at about 1,500 m, air pressure at the lake is lower than at sea level, so decompression has to be planned as if the dive were deeper than the gauge shows; Gomes's 1996 dive was treated as roughly equivalent to a 337-339 m sea-level dive. Dives here are long, multi-gas expeditions with large support teams.
Boesmansgat has also seen deaths. A diver lost in the 1990s was found on the slope at about 270 m by Dave Shaw in 2004, and Shaw died in early 2005 while trying to recover him.
The site is on private land and no public access procedure was found. It should be read as an expedition venue, not as a destination for visiting divers.
Địa chất
Boesmansgat is a collapse sinkhole in dolomite. Accounts describe a small entrance crack leading into a flooded chamber that widens rapidly with depth, with a silty floor at the bottom.
Nước, dòng chảy và lũ lụt
The water is clear and was about 19 C when measured on dives in 1996 and 2002, but brown mud on the walls absorbs light. A 2002 report noted that the water level had fallen over time, which made older depth markers on fixed ropes inaccurate.
Tại sao điều này quan trọng
Divernet describes Boesmansgat as the third-deepest known sinkhole in the world. It has hosted a series of depth records: Exley's 263 m in 1993, Gomes's 282.6 m in 1996, Verna van Schaik's 221 m women's record in 2004, and Karen van den Oever's 236.04 m (2021) and 246.56 m (2022) dives, the latter recognised by Guinness World Records.
Điều kiện
About 19 C in reports from 1996 and 2002; no recent measurement found. Visibility was described as clear, with silt on the bottom. The altitude of about 1,500 m changes decompression requirements.
Phạm vi thông thường từ các nguồn đã công bố, không phải điều kiện hiện tại.
Lịch sử khảo sát và khám phá
| 1988-04-04 | Diaan Hanekom and Nuno Gomes dived to 123 m. [4] |
| 1993-08 | Sheck Exley reached 263 m, the first diver to reach the bottom. [4] [6] |
| 1996-08-23 | Nuno Gomes reached 282.6 m on a solo dive lasting about twelve hours. [4] [6] |
| 2004-10 | Dave Shaw reached 270 m on a rebreather and located the body of a diver lost in the 1990s. [4] |
| 2005-01 | Dave Shaw died during the recovery attempt; his support diver survived with serious decompression illness. [4] |
| 2021-03 | Karen van den Oever reached 236.04 m with support from a South African club. [5] |
| 2022-10-27 | Karen van den Oever reached 246.56 m, listed by Guinness World Records as the deepest scuba dive by a woman. [7] |
Lối vào và địa điểm lặn
One natural entrance is documented: a small crack, roughly 1.5 m by 3 m, through which divers drop to the water. It is on a private farm and not publicly accessible.
Để định hướng, không dùng để điều hướng. Các chấm rỗng là vị trí gần đúng.
Tài liệu tham khảo thêm
Mọi thông tin trên trang này kèm theo nguồn (18)
| Thông tin | Trạng thái | Nguồn |
|---|---|---|
| Boesmansgat is on Mount Carmel, a game farm near the road between Kuruman and Danielskuil in the Northern Cape. | Đã báo cáo | [1] [2] |
| Area-level coordinates rounded from the published location of the sinkhole between Kuruman and Danielskuil; the exact entrance is on private land.Rounded to 0.1 degree on purpose (restricted private site). | Đã báo cáo | [3] [1] |
| The sinkhole lies at about 1,500-1,550 m above sea level.Gomes's history page gives 1,550 m; GUE gives about 1,500 m; Divernet gives 1.55 km. | Đã báo cáo | [4] [1] [5] |
| Nuno Gomes reached 282.6 m in Boesmansgat on 1996-08-23.Mail & Guardian (1996) reported 283.3 m measured on the descent line; GUE (2002) quotes 286 m for the deepest point reported by Gomes. Water level changes also alter the figure. | Nguồn thông tin mâu thuẫn | [4] [6] |
| Corrected for altitude for decompression purposes, Gomes's 282.6 m dive is given as equivalent to 339 m at sea level.The history page gives 339 m; the record page gives 337 m. | Nguồn thông tin mâu thuẫn | [4] [6] |
| On 1988-04-04 Diaan Hanekom and Nuno Gomes reached 123 m. | Đã báo cáo | [4] |
| In August 1993 Sheck Exley dived to 263 m and became the first diver to reach the bottom. | Đã báo cáo | [4] [6] |
| In late October 2004 Dave Shaw reached 270 m on a rebreather and found the body of a diver lost in the 1990s. | Đã báo cáo | [4] |
| Dave Shaw died during the early-2005 attempt to recover that body; his death was attributed to respiratory failure linked to gas density at depth.Secondary account on Nuno Gomes's site; Wikipedia dates the death to 2005-01-08. | Đã báo cáo | [4] |
| Verna van Schaik reached 221 m in Boesmansgat in 2004, a women's depth record.Gomes's page gives 2004-10-25; Wikipedia gives 2004-11-24. | Nguồn thông tin mâu thuẫn | [4] |
| Karen van den Oever reached 236.04 m in Boesmansgat in March 2021. | Đã báo cáo | [5] |
| Guinness World Records lists Karen van den Oever's dive of 246.56 m in Boesmansgat on 2022-10-27, lasting 8 h 11 min, as the deepest scuba dive by a woman.Divernet (2022-10-30) printed 246.65 m before Guinness verification. | Đã xác minh | [7] |
| Water temperature of about 19 C was reported in 1996 and 2002.Both observations are more than 20 years old. | Có thể đã lỗi thời | [4] [1] |
| A 2002 trip report noted that the water level had dropped over time, so depth markers on ropes placed in the early 1990s were no longer accurate. | Có thể đã lỗi thời | [1] |
| Divers drop through a small crack, roughly 1.5 m by 3 m, to reach the water. | Đã báo cáo | [1] |
| Boesmansgat is a dolomite sinkhole. | Đã báo cáo | [8] |
| Divernet describes Boesmansgat as the world's third-deepest known sinkhole. | Đã báo cáo | [5] |
| No public access procedure, fee or permit scheme for diving Boesmansgat was found; the documented dives in 2021 and 2022 were supported expedition-style dives organised with a South African club. | Đã báo cáo | [1] [2] [5] |
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