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Underwater diving to a depth beyond the norm accepted by the associated community From Wikipedia, the free encyclopedia
Deep diving is underwater diving to a depth beyond the norm accepted by the associated community. In some cases this is a prescribed limit established by an authority, while in others it is associated with a level of certification or training, and it may vary depending on whether the diving is recreational, technical or commercial. Nitrogen narcosis becomes a hazard below 30 metres (98 ft) and hypoxic breathing gas is required below 60 metres (200 ft) to lessen the risk of oxygen toxicity. At much greater depths, breathing gases become supercritical fluids, making diving with conventional equipment effectively impossible regardless of the physiological effects on the human body. Air, for example, becomes a supercritical fluid below about 400 metres (1,300 ft).
For some recreational diving agencies, "Deep diving", or "Deep diver" may be a certification awarded to divers that have been trained to dive to a specified depth range, generally deeper than 30 metres (98 ft). However, the Professional Association of Diving Instructors (PADI) defines anything from 18 to 30 metres (59 to 98 ft) as a "deep dive" in the context of recreational diving (other diving organisations vary), and considers deep diving a form of technical diving.[1][page needed] In technical diving, a depth below about 60 metres (200 ft) where hypoxic breathing gas becomes necessary to avoid oxygen toxicity may be considered a deep dive. In professional diving, a depth that requires special equipment, procedures, or advanced training may be considered a deep dive.
Deep diving can mean something else in the commercial diving field. For instance early experiments carried out by COMEX using heliox and trimix attained far greater depths than any recreational technical diving. One example being its "Janus 4" open-sea dive to 501 metres (1,640 ft) in 1977.[2][3]
The open-sea diving depth record was achieved in 1988 by a team of COMEX and French Navy divers who performed pipeline connection exercises at a depth of 534 metres (1,750 ft) in the Mediterranean Sea as part of the "Hydra 8" programme employing heliox and hydrox. The latter avoids the high-pressure nervous syndrome (HPNS) caused by helium and eases breathing due to its lower density.[2][4][5] These divers needed to breathe special gas mixtures because they were exposed to very high ambient pressure (more than 54 times atmospheric pressure).
An atmospheric diving suit (ADS) allows very deep dives of up to 700 metres (2,300 ft).[6] These suits are capable of withstanding the pressure at great depth permitting the diver to remain at normal atmospheric pressure. This eliminates the problems associated with breathing pressurised gases. In 2006 Chief Navy Diver Daniel Jackson set a record of 610 metres (2,000 ft) in an ADS.[7][8]
On 20 November 1992 COMEX's "Hydra 10" experiment simulated a dive in an onshore hyperbaric chamber with hydreliox. Théo Mavrostomos spent two hours at a simulated depth of 701 metres (2,300 ft).[2][9][10][11][12]
Assumed is the surface of the waterbody to be at or near sea level and underlies atmospheric pressure.
Not included are the differing ranges of freediving – without breathing during a dive.
Depth[nb 1] | Comments |
---|---|
12 m (39 ft) | Recreational diving limit for divers aged under 12 years old and EN 14153-1 / ISO 24801-1 level 1 (Supervised Diver) standard.[13] |
18 m (60 ft) | Recreational diving limit for Open Water Divers (e.g. PADI, NAUI). |
20 m (66 ft) | Recreational diving limit for EN 14153-2 ISO 24801-2 level 2 "Autonomous Diver" standard.[14] |
21 m (69 ft) | GUE Recreational Diver Level 1.[15] |
30 m (98 ft) | Recommended recreational diving limit for PADI Advanced Open Water divers[1][page needed] and GUE Recreational Diver Level 2.[15] Average depth at which nitrogen narcosis symptoms begin to be noticeable in adults. |
40 m (130 ft) | Depth limit for divers specified by Recreational Scuba Training Council[1][page needed] and GUE Recreational Diver Level 3.[15] Depth limit for a French level 2 diver accompanied by an instructor (level 4 diver), breathing air.[citation needed] |
50 m (160 ft) | Depth limit for divers breathing air specified by the British Sub-Aqua Club and Sub-Aqua Association.[16] |
60 m (200 ft) | Depth limit for a group of 2 to 3 French Level 3 recreational divers, breathing air.[17] |
66 m (217 ft) | Depth at which breathing compressed air exposes the diver to an oxygen partial pressure of 1.6 bar (23 psi). Greater depth is considered to expose the diver to an unacceptable risk of oxygen toxicity.[nb 2] |
100 m (330 ft) | One of the recommended technical diving limits. Maximum depth authorised for divers who have completed Trimix Diver certification with IANTD[18] or Advanced Trimix Diver certification with TDI.[19] |
156 m (512 ft) | Deepest scuba dive on compressed air (July 1999 in Puerto Galera, Philippines).[20] |
200 m (660 ft) | Limit for surface light penetration sufficient for plant growth in clear water, though some visibility may be possible farther down.[nb 3] |
230 m (750 ft) | First dive on a hydrox-rebreather (14 February 2023 in the Pearse Resurgence, New Zealand).[21] |
290 m (950 ft) | Deepest ocean dive on a rebreather (23 March 2014 in Gili Trawangan, Indonesia).[22] |
312 m (1,024 ft) | Deepest cave diving on a rebreather (6 January 2024 in Font Estramar, France). |
316 m (1,037 ft) | Deepest dive on a rebreather (10 October 2018 in Lake Garda, Italy).[23] |
332 m (1,089 ft) | Deepest scuba dive, deepest dive on trimix (18 September 2014 in Dahab, Egypt).[24][25] |
534 m (1,752 ft) | COMEX Hydra 8 dives on hydreliox (February 1988 offshore Marseille, France).[2][4][10] |
Deep diving has more hazards and greater risk than basic open-water diving.[26] Nitrogen narcosis, the "narks" or "rapture of the deep", starts with feelings of euphoria and over-confidence but then leads to numbness and memory impairment similar to alcohol intoxication.[1][page needed] Decompression sickness, or the "bends", can happen if a diver ascends too rapidly, when excess inert gas leaves solution in the blood and tissues and forms bubbles. These bubbles produce mechanical and biochemical effects that lead to the condition. The onset of symptoms depends on the severity of the tissue gas loading and may develop during ascent in severe cases, but is frequently delayed until after reaching the surface.[1][page needed] Bone degeneration (dysbaric osteonecrosis) is caused by the bubbles forming inside the bones; most commonly the upper arm and the thighs. Deep diving involves a much greater danger of all of these, and presents the additional risk of oxygen toxicity, which may lead to convulsions underwater. Very deep diving using a helium-oxygen mixture (heliox) or a hydrogen-helium-oxygen mixture (hydreliox) carries the risk of high-pressure nervous syndrome and hydrogen narcosis. Coping with the physical and physiological stresses of deep diving requires good physical conditioning.[27]
Using open-circuit scuba equipment, consumption of breathing gas is proportional to ambient pressure – so at 50 metres (164 ft), where the pressure is 6 bars (87 psi), a diver breathes six times as much as on the surface (1 bar, 14.5 psi). Heavy physical exertion makes the diver breathe even more gas, and gas becomes denser requiring increased effort to breathe with depth, leading to increased risk of hypercapnia – an excess of carbon dioxide in the blood. The need to do decompression stops increases with depth. A diver at 6 metres (20 ft) may be able to dive for many hours without needing to do decompression stops. At depths greater than 40 metres (131 ft), a diver may have only a few minutes at the deepest part of the dive before decompression stops are needed. In the event of an emergency, the diver cannot make an immediate ascent to the surface without risking decompression sickness. All of these considerations result in the amount of breathing gas required for deep diving being much greater than for shallow open water diving. The diver needs a disciplined approach to planning and conducting dives to minimise these additional risks.
Many of these problems are avoided by the use of surface supplied breathing gas, closed diving bells, and saturation diving, at the cost of logistical complexity, reduced maneuverability of the diver, and greater expense.
Both equipment and procedures can be adapted to deal with the problems of greater depth. Usually the two are combined, as the procedures must be adapted to suit the equipment, and in some cases the equipment is needed to facilitate the procedures.
The equipment used for deep diving depends on both the depth and the type of diving. Scuba is limited to equipment that can be carried by the diver or is easily deployed by the dive team, while surface-supplied diving equipment can be more extensive, and much of it stays above the water where it is operated by the diving support team.[citation needed]
Procedural adaptations for deep diving can be classified as those procedures for operating specialized equipment, and those that apply directly to the problems caused by exposure to high ambient pressures.
Amongst technical divers, there are divers who participate in ultra-deep diving on scuba below 200 metres (656 ft). This practice requires high levels of training, experience, discipline, fitness and surface support. Only twenty-six people are known to have ever dived to at least 240 metres (790 ft) on self-contained breathing apparatus recreationally.[20][28][nb 4][nb 5] The "Holy Grail" of deep scuba diving was the 300 metres (980 ft) mark, first achieved by John Bennett in 2001, and has only been achieved five times since.[citation needed] Due to the short bottom times and long decompression, scuba dives to these depths are generally only done for deep cave exploration or as record attempts.
The difficulties involved in ultra-deep diving are numerous. Although commercial and military divers[citation needed] often operate at those depths, or even deeper, they are surface supplied. All of the complexities of ultra-deep diving are magnified by the requirement of the diver to carry (or provide for) their own gas underwater. These lead to rapid descents and "bounce dives". This has led to extremely high mortality rates amongst those who practice ultra-deep diving.[citation needed] Notable ultra-deep diving fatalities include Sheck Exley, John Bennett, Dave Shaw and Guy Garman. Mark Ellyatt, Don Shirley and Pascal Bernabé were involved in serious incidents and were fortunate to survive their dives. Despite the extremely high mortality rate, the Guinness World Records continues to maintain a record for scuba diving[25] (although the record for deep diving with compressed air has not been updated since 1999, given the high accident rate). Amongst those who do survive significant health issues are reported. Mark Ellyatt is reported to have suffered permanent lung damage; Pascal Bernabé (who was injured on his dive when a light on his mask imploded[29]) and Nuno Gomes reported short to medium term hearing loss.[30][unreliable source?]
Serious issues that confront divers engaging in ultra-deep diving on self-contained breathing apparatus include:
In addition, "ordinary" risks like size of gas reserves, hypothermia, dehydration and oxygen toxicity are compounded by extreme depth and exposure and long in-water decompression times. Some technical diving equipment is simply not designed for the greater pressures at these depths, and reports of key equipment (including submersible pressure gauges) imploding are not uncommon.[citation needed]
Name | Location | T | A | Depth | Year |
---|---|---|---|---|---|
Ahmed Gabr[24][32][33] | Dahab, Egypt | OW | OC | 332 m (1,090 ft) | 2014 |
Nuno Gomes[28][34][35] | Dahab, Egypt | OW | OC | 318 m (1,040 ft) | 2005 |
Jarek Macedoński[23] | Lake Garda, Italy | OW | CCR | 316 m (1,040 ft) | 2018 |
Mark Ellyatt[36] | Phuket Island, Thailand | OW | OC | 313 m (1,030 ft) | 2003 |
Xavier Méniscus[37] | Font Estramar, France | C | CCR | 312 m (1,024 ft) | 2024 |
John Bennett[38][nb 6] | Puerto Galera, Philippines | OW | OC | 308 m (1,010 ft) | 2001 |
Frédéric Swierczynski[39] | Font Estramar, France | C | CCR | 308 m (1,010 ft) | 2023 |
Krzysztof Starnawski[40] | Lake Garda, Italy | OW | CCR | 303 m (994 ft) | 2018 |
Will Goodman[22] | Gili Trawangan, Indonesia | OW | CCR | 290 m (951 ft) | 2014 |
Xavier Méniscus[41] | Font Estramar, France | C | CCR | 286 m (938 ft) | 2019 |
Nuno Gomes[28][42] | Boesmansgat, South Africa | C | OC | 283 m (928 ft) | 1996 |
Krzysztof Starnawski[43] | Dahab, Egypt | OW | CCR | 283 m (928 ft) | 2011 |
Jim Bowden[44] | Zacatón, Mexico | C | OC | 282 m (925 ft) | 1994 |
Krzysztof Starnawski[45][46] | Lake Viroit, Albania | C | CCR | 278 m (912 ft) | 2016 |
Han Ting | GuangXi, China | C | CCR | 277 m (909 ft) | 2023 |
Gilberto de Oliveira[28][47] | Lagoa Misteriosa, Brazil | C | OC | 274 m (899 ft) | 2002 |
Nuno Gomes[28] | Dahab, Egypt | OW | OC | 271 m (889 ft) | 2004 |
David Shaw[28][48][nb 6] | Boesmansgat, South Africa | C | DR | 271 m (889 ft) | 2004 |
Frédéric Swierczynski | Mescla, France | C | CCR | 267 m (876 ft) | 2016 |
Pascal Bernabé[28] | Corsica, France | OW | OC | 266 m (873 ft) | 2005 |
Sheck Exley[28][49][nb 6] | Nacimiento del Mante, Mexico | C | OC | 265 m (869 ft) | 1989 |
Krzysztof Starnawski[50][51] | Hranice Abyss, Czechia | C | CCR | 265 m (869 ft) | 2015 |
Sheck Exley[28][44][nb 6] | Zacatón, Mexico | C | OC | 264 m (866 ft) | 1989 |
Luca Pedrali[52] | Lake Garda, Italy | OW | CCR | 264 m (866 ft) | 2017 |
Sheck Exley[28][44][nb 6] | Boesmansgat, South Africa | C | SCUBA | 263 m (863 ft) | 1993 |
Xavier Méniscus[53] | Font Estramar, France | C | CCR | 262 m (860 ft) | 2015 |
Mark Ellyatt[citation needed] | Phuket Island (?), Thailand | OW | OC | 260 m (853 ft) | 2003 |
Qian Chen[54] | Daxing Spring, China | C | CCR | 258 m (846 ft) | 2023 |
John Bennett[38][nb 6] | Puerto Galera, Philippines | OW | OC | 254 m (833 ft) | 2000 |
Michele Geraci[55] | Bordighera, Italy | OW | OC | 253 m (830 ft) | 2014 |
Jordi Yherla[56] | Font Estramar, France | C | CCR | 253 m (830 ft) | 2014 |
Nuno Gomes[28] | Boesmansgat, South Africa | C | OC | 252 m (827 ft) | 1994 |
Don Shirley[57] | Boesmansgat, South Africa | C | CCR | 250 m (820 ft) | 2005 |
Wacław Lejko[58][59][nb 6] | Lake Garda, Italy | OW | OC | 249 m (817 ft) | 2017 |
Xavier Méniscus[60] | Font Estramar, France | C | CCR | 248 m (814 ft) | 2013 |
Karen van den Oever[61] | Boesmansgat, South Africa | C | OC | 246 m (807 ft) | 2022 |
Xavier Méniscus | Goul de la Tannerie, France | C | CCR | 246 m (807 ft) | 2023 |
C.J. Brossett[62] | Gulf of Mexico | OW | OC | 245 m (804 ft) | 2019 |
Richard Harris, Craig Challen[63] | Pearse Resurgence, New Zealand | C | CCR | 245 m (804 ft) | 2020 |
Frédéric Swierczynski[64][65] | Red Lake, Croatia | C | CCR | 245 m (804 ft) | 2017 |
Guy Garman[66][nb 6] | St. Croix, U.S. Virgin Islands | OW | OC | 244 m (800 ft) | 2015 |
Dariusz Wilamowski[67] | Lake Garda, Italy | OW | OC | 243 m (797 ft) | 2012 |
Xavier Méniscus | Goul de la Tannerie, France | C | CCR | 243 m (797 ft) | 2019 |
Alexandre Fox | Goul de la Tannerie, France | C | CCR | 242 m (794 ft) | 2017 |
Jim Bowden[68] | Zacatón, Mexico | C | OC | 240 m (800 ft) | 1993 |
Xavier Méniscus | Goul de la Tannerie, France | C | CCR | 240 m (787 ft) | 2014 |
Pascal Bernabé[69] | Fontaine de Vaucluse, France | C | OC | 240 m (787 ft) | 1997 |
A severe risk in ultra-deep air diving is deep water blackout, or depth blackout, a loss of consciousness at depths below 50 metres (160 ft) with no clear primary cause, associated with nitrogen narcosis, a neurological impairment with anaesthetic effects caused by high partial pressure of nitrogen dissolved in nerve tissue, and possibly acute oxygen toxicity.[70] The term is not in widespread use at present, as where the actual cause of blackout is known, a more specific term is preferred. The depth at which deep water blackout occurs is extremely variable and unpredictable.[71] Before the popular availability of trimix, attempts were made to set world record depths using air. The extreme risk of both narcosis and oxygen toxicity in the divers contributed to a high fatality rate in those attempting records. In his book, Deep Diving, Bret Gilliam chronicles the various fatal attempts to set records as well as the smaller number of successes.[72] From the comparatively few who survived extremely deep air dives:
Depth[nb 7] | Year | Name | Location | E | Comment |
---|---|---|---|---|---|
94 m (308 ft) | 1947 | Frédéric Dumas[72] | Mediterranean Sea | OW | A member of the GRS (Groupement de Recherches Sous-marines, Underwater Research Group headed by Jacques Cousteau). |
100 m (330 ft) | 1957 | Eduard Admetlla[73] | Isla de Las Palomas | OW | Head of the Underwater Section of the «Submarine Research and Recovery Centre» |
102 m (335 ft) | 1969 | Frank Salt[72] | Chinhoyi Caves | C | |
106 msw (345 fsw) | 1988 | Marty Dunwoody[72] | Bimini | OW | Women's deep dive record |
107 msw (350 fsw) | 1961 | Hal Watts[72] | Florida | OW | |
109 msw (355 fsw) | 1961 | Jean Clarke Samazen[72] | Florida | OW | |
110 msw (360 fsw) | 1965 | Tom Mount, Frank Martz[72] | Florida | OW | |
120 msw (390 fsw) | 1965 | Hal Watts, A.J. Muns[72] | Florida | OW | |
126 m (415 ft) | 1970 | Hal Watts[72] | Mystery Sink | C | |
131 m (430 ft) | 1959 | Ennio Falco, Alberto Novelli, Cesare Olgiai | Gulf of Naples | OW | Employing the Pirelli Explorer, "Maior" model, a two-stage regulator (patented by Novelli and Buggiani) equipped with a lung bag and soda lime filter for CO2 removal, in order to reuse the exhaled air. Only two of the three divers managed to reach the depth in a certified way: Novelli, the organizer of the event and inventor of the regulator, forgot to punch the plate for proving the descent.[74] |
134 msw (437 fsw) | 1968 | Neal Watson, John Gruener[72][75] | Bimini | OW | |
135 msw (440 fsw) | 1971 | Ann Gunderson[72][nb 6] | Bahamas | OW | Women's deep dive record |
139 msw (452 fsw) | 1990 | Bret Gilliam[72] | Roatán | OW | Unusually, Gilliam remained largely functional at depth and was able to complete basic maths problems and answer simple questions written on a slate by his crew beforehand. |
142 m (466 ft) | 1971 | Sheck Exley[76][nb 6] | Andros Island | OW | Exley was only supposed to go down to 91 m (299 ft) in his capacity as a safety diver (although he had practised several dives to 120 m (390 ft) in preparation), but descended to search for the dive team after they failed to return on schedule. Exley almost made it to the divers, but was forced to turn back due to heavy narcosis and nearly blacking out. |
146 msw (475 fsw) | 1993 | Bret Gilliam[72] | EL Salvador | OW | Again, Gilliam reported no effects from narcosis or oxygen toxicity. |
150 msw (490 fsw) | 1994 | Dan Manion[72] | Nassau | OW | 155 msw (506 fsw) claimed, but not officially recognised.[77] Manion reported he was almost completely incapacitated by narcosis and has no recollection of time at depth.[28] |
156 m (512 ft) | 1999 | Mark Andrews[20] | Puerto Galera, Philippines | OW | At the maximum depth of 156.4 metres (513 ft) Andrews lost consciousness, his deep support diver John Bennett (on mixed gas), inflated his BC to initiate his ascent. While ascending he regained consciousness. |
E Environment: OW = Open water, C = Cave |
In deference to the high accident rate, the Guinness World Records have ceased to publish records for deep air dives, after Manion's dive.[28]
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