Deep diving
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225547057
2008-07-14T06:55:11Z
Kanazawakid
5363646
The meaning of the term '''deep diving''' is a form of [[technical diving]].<ref name=padi1>{{cite book |title=Encyclopedia of Recreational Diving, 3rd edition |last=Brylske |first=A. |year=2006 |publisher=[[PADI]] |location=United States |isbn=1878663011 }}</ref> It is defined by the level of the diver's [[diver training]], [[diving equipment]], [[breathing gas]], and surface support:
* in [[recreational diving]], 30 metres / 100 feet may be a "deep dive"
* in [[technical diving]], 60 metres / 200 feet may be a "deep dive"
* in [[surface supplied diving]], 100 metres / 330 feet may be a "deep dive"
Deep diving has had many different labels of certain depths, but the real importance is how much experience and how much training you have had.<ref name=padi1/><ref>{{cite book |author=Graver, D and Wohlers, R. |date=1984 |title=PADI Advanced Diver Manual |publisher=PADI |asin=B000KS6E5C |pages=234 }}</ref><ref>{{cite journal |author=Gleason, B |date=1994 |title=Technical or Recreational |journal=Los Angeles |volume=43 |issue=10 |pages=6 }}</ref><ref name=palmer>{{cite journal |last=Palmer |first=R. |title=Deep diving; The limits? (reprinted from Diver 1994; 39(7) July:21-22.) |journal=South Pacific Underwater Medicine Society journal |volume=27 |issue=3 |date=1997 |issn=0813-1988 |oclc=16986801 |url=http://archive.rubicon-foundation.org/6085 |accessdate=2008-07-05 }}</ref> For a beginning [[Recreational diving|open water diver]] eighteen metres (sixty feet) is an extreme depth and it is necessary to have additional training. Another important point is to not push yourself to achieving a certain depth. If you are going on a “deep dive” it is necessary to know why you are diving. This helps to increase discipline and to decrease the possibility of [[accident]] and [[Mental confusion|confusion]]. When deep diving it is essential for psychological and physiological fitness.<ref>{{cite journal |author=Scully, T |date=2007 |title=Allure of the Underwater World and Awful Ailments of the Deep |journal=Irish Medical Times |volume=41 |issue=33 |pages=60 }}</ref> When traveling deeper there are many different obstacles that could affect the dive. The issue of [[temperature]] and lighting make the [[Physical fitness|physical]] and [[Mental health|psychological]] wellness essential.<ref name=padi1/> It is easy to get [[Spatial disorientation|disoriented]] in the depths so being able to keep a level head is important. The pressure demands good [[Physical fitness|physical conditioning]].<ref>{{cite journal |author=Southerland, DG |title=Medical Fitness at 300 FSW |journal=In: Lang, MA and Smith, NE (eds). Proceedings of Advanced Scientific Diving Workshop |location=Smithsonian Institution |place=Washington, DC |date=2006 |url=http://archive.rubicon-foundation.org/4659 |accessdate=2008-07-05 }}</ref> There also times that may require increased [[Endurance|stamina]]. Along with lack of light and warmth there are also the possibilities of [[Ocean current|currents]] and [[Turbidity|visibility]].
{| class="wikitable" style="margin: 1em auto 1em auto"
|+ '''Deep Diving'''
! width="150"|Depth<ref group=nb>All depths specified for sea water. Fractionally deeper depths may apply in relation to freshwater due to its lower density</ref> || width="385"|Comments
|-
| align="center"|40 feet/12 meters|| Recreational diving limit for divers aged under 12 years old
|-
| align="center"|60 feet/18 meters|| Recreational diving limit for divers without basic open water certification<ref group=nb>Divers who are undergoing training, and non-divers taking "discover scuba diving" (or "resort") courses</ref>
|-
| align="center"|100 feet/30 meters|| Recommended recreational diving limit for divers.<ref name=padi1/> Average depth at which [[nitrogen narcosis]] symptoms begin to appear in adults
|-
| align="center"|130 feet/40 meters|| Absolute recreational diving limit for divers specified by North American diver training agencies<ref name=padi1/>
|-
| align="center"|180 feet/55 meters|| Technical diving limit for "extended range" divers breathing compressed air
|-
| align="center"|214 feet/65 meters|| Depth at which compressed air results in [[oxygen toxicity]]
|-
| align="center"|330 feet/100 meters|| Technical diving limit for divers breathing [[trimix]]. Recommended technical diving limit
|-
| align="center"|660 feet/200 meters|| Absolute limit for surface light penetration<ref group=nb>Assuming crystal clear water; surface light may disappear completely at much shallower depths in murky conditions</ref>
|}
==Particular problems associated with deep dives==
Deep diving obviously has more consequences and dangers than basic open water diving.<ref>{{cite journal |author=Egstrom GH |title=Historic Perspective: Scientific Deep Diving and the Management of the Risk. |journal=In: Lang, MA and Smith, NE (eds). Proceedings of Advanced Scientific Diving Workshop |location=Smithsonian Institution |place=Washington, DC |date=2006 |url=http://archive.rubicon-foundation.org/4653 |accessdate=2008-07-05 }}</ref> [[Nitrogen narcosis]], or the “narks” or “rapture of the deep”, starts with feelings of euphoria and over-confidence but then lead to numbness and memory impairment similar to [[alcohol intoxication]]. [[Decompression sickness]], or the “bends”, is when the gas bubbles of nitrogen get caught in the joints on an ascent. Yet, the effects tend to be delayed until reaching the surface. Bone degeneration ([[dysbaric osteonecrosis]]) is caused by the bubbles forming inside the bones; most commonly the upper arm and the thighs. [[Air embolism]] causes [[Unconsciousness|loss of consciousness]] and speech and visual problems. This tends to be life threatening, but sometimes the symptoms resolve before the [[recompression chamber]] are needed. All these are harms and possibly worse effects of deep diving.
* High [[breathing gas]] consumption. Gas consumption is proportional to pressure - so at 50 metres / 165 feet (6 bar) a diver breathes 6 times as much as on the surface (1 bar). Heavy physical exertion causes even more gas to be breathed.
* Increased [[nitrogen narcosis]]. This causes stress and inefficient thinking in the diver. When breathing [[breathing gas|air]] many divers find 40 metres / 130 feet a safe maximum depth.
* The need to do [[decompression stop]]s increases with depth. A diver at 6 metres may be able to dive for many hours without needing to do decompression stops. At depths greater than 40 metres / 130 feet, 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]]. The diver needs a disciplined approach to planning and conducting dives and needs to carry extra gas for the decompression stops to reduce the risk of being unable to complete the stops.
* Drifting. If long decompression stops are carried out in a [[tides|tidal]] current, the divers may drift away from their [[boat]] cover or a safe exit point on the shore.
* Increased breathing effort. Gas becomes [[Density|denser]] and the effort required to breathe increases with depth (work of breathing).
* Increasing risk of [[carbon dioxide poisoning]].
* [[Oxygen toxicity]].
* [[High pressure nervous syndrome]].
Deep diving also requires some different equipment than if you were just shallow or surface diving. For example, a watch is crucial so that the diver can keep up and stay within the limits of the planned dive and count the decompression times. Weights are also very necessary when deep diving to hold position for decompression and also to stay at the bottom for the needed length of time.
==Dealing with depth==
* Carry larger volumes of [[breathing gas]] to compensate for the increased gas consumption and decompression stops.
* [[Rebreather]]s are much more efficient consumers of gas than open circuit scuba.
* Use helium-based breathing gases such as [[trimix]] to reduce nitrogen narcosis and stay beyond the limits of oxygen toxicity.
* A [[diving shot]], a [[decompression trapeze]] or a [[decompression buoy]] can help divers return to their surface safety cover at the end of a dive.
==Ultra-deep diving==
Amongst [[technical diving|technical divers]], there are certain elite divers who participate in ultra-deep diving diving on SCUBA (using [[rebreather|closed circuit rebreathers]] and [[heliox]]) below 660 feet/200 metres. Ultra-deep diving requires extraordinarily high levels training, experience, fitness and surface support. Only seven persons are known to have ever dived below a depth of 800 feet on self contained breathing apparatus.<ref>{{cite web |author=Gomes, N |url=http://www.nunogomes.co.za/rec.htm |title=Verified dives below 200 metres |accessdate=2008-06-14}}</ref><ref>{{cite web |author=Scubarecords.com |url=http://www.scubarecords.com/DeepRecords.htm |title=Recorded Deep Dives Below 200m |accessdate=2008-06-14}}</ref><ref group=nb>Statistics exclude military divers (classified), and commercial divers (although commercial diving to that depth is unknown on SCUBA).</ref> That is fewer than the [[List_of_Apollo_astronauts#People_who_have_walked_on_the_Moon|number of people who have walked on the surface of the moon]]. The Holy Grail of deep diving was the 1000 ft. mark, first achieved John Bennett in 2001, and only achieved once (or possibly twice) since.
{| class="wikitable" style="margin: 1em auto 1em auto"
|+ '''Verified dives below 800 feet'''
! width="125"|Name|| width="125"|Location|| width="125"|Depth|| width="125"|Year
|-
| align="center"|[[Nuno Gomes (diver)|Nuno Gomes]]|| align="center"|Red Sea<br />Red Sea<br />South Africa<br />South Africa|| align="center"|1,056 feet<br />890 feet<br />927 feet<br />826 feet|| align="center"|2005<br />2004<br />1996<br />1994
|-
| align="center"|[[Pascal Bernabé]]|| align="center"|Mediterranean<br />Mediterranean|| align="center"|1,083 feet<br />873 feet|| align="center"|2005<br />2005
|-
| align="center"|[[David Shaw (diver)|David Shaw]]<ref name=died group=nb>Subsequently died during diving accidents.</ref>|| align="center"|South Africa|| align="center"|888 feet|| align="center"|2004
|-
| align="center"|G.M de Oliveira|| align="center"|Brazil|| align="center"|898 feet|| align="center"|2002
|-
| align="center"|[[John Bennett (diver)|John Bennett]]<ref name=died group=nb/>|| align="center"|Philippines<br />Philippines|| align="center"|1,010 feet<br />833 feet|| align="center"|2001<br />2001
|-| align="center"|[[Santa Clause (diver)|Santa Clause]]<ref name=died group=nb/>|| align="center"|Ricks Pool<br />Philippines|| align="center"|2,00 feet<br />833 feet|| align="center"|2001<br />2001
|-
| align="center"|[[Jim Bowden (diver)|Jim Bowden]]|| align="center"|Mexico<br />Mexico|| align="center"|925 feet<br />825 feet|| align="center"|1994<br />1993
|-
| align="center"|[[Sheck Exley]]<ref name=died group=nb/>|| align="center"|South Africa<br />Mexico|| align="center"|863 feet<br />867 feet|| align="center"|1993<br />1989
|-
|}
In 2003 [[Mark Ellyatt]] is believed to have dived to a depth of 1,032 feet, but that dive has not been independently verified.
==See also==
* [[Decompression sickness]]
* [[Breathing gas]]
* [[Heliox]]
* [[Hydreliox]]
* [[High pressure nervous syndrome]]
* [[Oxygen toxicity]]
* [[Trimix (breathing gas)|Trimix]]
== References ==
{{Reflist}}
== Footnotes ==
<references group=nb/>
== Further reading ==
* {{cite journal |author=Dent, W |title=AAUS Deep Diving Standards. |journal=In: Lang, MA and Smith, NE (eds). Proceedings of Advanced Scientific Diving Workshop |location=Smithsonian Institution |place=Washington, DC |date=2006 |url=http://archive.rubicon-foundation.org/4669 |accessdate=2008-07-05 }}
==External links==
*[http://www.divinglore.com/RecreationalDeepDiving.htm Recreational Deep Diving]
[[Category:Underwater diving]]
[[it:Immersione profonda]]