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Encyclopedia > Scuba diving

Scuba diving is swimming underwater while using self-contained breathing equipment. Image File history File links Mergefrom. ... Diving in the sense of going underwater, has these purposes. ... A scuba diver in usual sport diving gear SCUBA is an acronym for Self-Contained Underwater Breathing Apparatus. ...

Scuba divers exploring fish and coral.
Scuba divers exploring fish and coral.

By carrying a source of compressed air, the scuba diver is able to stay underwater longer than with the simple breath-holding techniques used in Snorkeling and Free-diving, and is not hindered by air-lines to a remote air source. The scuba diver typically swims underwater by using fins attached to the feet. However, some divers also move around with the assistance of a DPV (Diver Propulsion Vehicle), commonly referred to as a "scooter", or by using surface-tethered devices called sleds, which are pulled by a boat. Image File history File linksMetadata Download high resolution version (1024x768, 142 KB) This image was originally posted to Flickr as alyosha is certified. ... Image File history File linksMetadata Download high resolution version (1024x768, 142 KB) This image was originally posted to Flickr as alyosha is certified. ... For other uses, see Fish (disambiguation). ... Extant Subclasses and Orders Alcyonaria    Alcyonacea    Helioporacea Zoantharia    Antipatharia    Corallimorpharia    Scleractinia    Zoanthidea [1][2]  See Anthozoa for details For other uses, see Coral (disambiguation). ... A scuba diver in usual sport diving gear SCUBA is an acronym for Self-Contained Underwater Breathing Apparatus. ... An underwater scene just beneath the surface. ... A snorkeler amid corals on a coral reef near Fiji. ... Freedive photographer Free-diving is an aquatic sport, considered an extreme sport, in which divers attempt to reach great depths unassisted by breathing apparatus. ... A Diver Propulsion Vehicle or a DPV is an item of diving equipment used by scuba divers to increase their range while underwater where their endurance is restricted due to limited availability of breathing gas and need to avoid decompression sickness. ...


The term SCUBA arose during World War II and originally referred to USA combat frogmen's oxygen rebreathers, developed by Dr. Christian Lambertsen for underwater warfare. Today, scuba typically usually refers to the in-line open-circuit equipment, developed by Emile Gagnan and Jacques-Yves Cousteau, in which compressed gas (usually air) is inhaled from a tank and then exhaled into the water. However, rebreathers (both semi-closed circuit and closed circuit) are also self-contained systems (as opposed to surface-supplied systems) and are therefore classified as scuba. Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... For the Wizard of Oz series character, see Frogman (Oz character). ... This article is about the breathing apparatus. ... Dr. Christian J. Lambertsen developed US Navy frogmens rebreathers in the early 1940s for underwater warfare. ... Emile Gagnan (born November 1900) was a French engineer and co-inventor (together with Jacques-Yves Cousteau) of the demand-valve used for the first Scuba equipment (Aqua-Lung) in 1943. ... Jacques-Yves Cousteau in 1976. ... This article is about the breathing apparatus. ...


Although the word 'SCUBA' is an acronym for "Self Contained Underwater Breathing Apparatus", it has also become acceptable to refer to scuba as 'scuba equipment' or 'scuba apparatus'—an example of the linguistic RAS syndrome. A scuba diver in usual sport diving gear SCUBA is an acronym for Self-Contained Underwater Breathing Apparatus. ... It has been suggested that this article or section be merged with Backronym and Apronym (Discuss) Acronyms and initialisms are abbreviations, such as NATO, laser, and ABC, written as the initial letter or letters of words, and pronounced on the basis of this abbreviated written form. ... The fundamental item of diving equipment used by divers is the SCUBA equipment, such as the Aqualung or Rebreather. ... RAS syndrome (Redundant Acronym Syndrome syndrome) is a common tendency to use one of the words which make up an acronym or initialism as well as the abbreviation itself, thus in effect repeating that word. ...


For the history of diving, see Timeline of underwater technology. Timeline of underwater technology // Pre-industrial Several centuries BC: (Relief carvings made at this time show Assyrian soldiers crossing rivers using inflated goatskin floats. ...

Contents

Diving classification

A scuba diver, as seen from below.
A scuba diver, as seen from below.

Scuba diving is still evolving, but general classifications have grown up to describe various diving activities. These classifications include but are not limited to: Scuba diver. ... Scuba diver. ... Diving in the sense of going underwater, has these purposes. ...

Within recreational diving there are those who are considered professional divers, because they maintain a professional standard of training and skills and may need to carry professional liability insurance. It has been suggested that this article or section be merged with Underwater diving. ... Military diving is a branch of professional diving carried out by world armed forces. ... // This page describes a type of scuba diver. ... Clearance Diver is the British Navys official name for the usual sort of general-purpose naval work diver. ... Recreational diving is a type of diving that uses SCUBA equipment for the purpose of leisure and enjoyment. ... Pink Anemonefish hiding in tentacles Underwater photography is the process of taking photographs while underwater. ... Dutch fishermen using tridents in the 17th century Spearfishing is a form of fishing that has been popular the whole world over for centuries. ... Beaching a casualty while providing artificial respiration Diver rescue, following an accident, is the process of avoiding or limiting further exposure to diving hazards and bringing a SCUBA diver to safety. ... Professional Diving is a type of diving where the diver is paid for their work. ... Technical diving is a form of SCUBA diving that exceeds the scope of recreational diving. ... Inside the cave at Cave Stream, New Zealand Caving is the recreational sport of exploring caves. ... Cavern diving is where SCUBA divers dive into a cavelike area called a cavern. ... The meaning of term deep diving depends on the level of the divers 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... Ice diving is a type of penetration diving where the dive takes place under ice. ... This article does not cite any references or sources. ... Professional diving is diving for payment. ... This article is about people called professionals. ... This article is about people called professionals. ... Liability insurance is a part of the general insurance system of risk transference. ...


Some consider technical diving to be a subset of recreational diving, but others separate it out due to the extensively different training equipment and knowledge needed for technical dives.


Public safety diving and military diving may be classified as commercial diving because they make a living from their pursuit of diving; however, public safety divers (police or rescue) and military divers have a different mission from the typical commercial diver. Scientific diving is used by marine scientists (including diving marine biologists and underwater archaeologists), as a tool for collecting their research data. Rescue refers to operations that usually involve the saving of life, or prevention of injury. ... Underwater archaeology is the study of past human life, behaviours and cultures using the physical remains found in salt or fresh water or buried beneath water-logged sediment. ...


Diving Issues

Divemaster ready to dive Shark and Yolanda reef at Rās Muhammad, Sharm el-Sheikh.
Divemaster ready to dive Shark and Yolanda reef at Rās Muhammad, Sharm el-Sheikh.

This section looks at some of the physiological issues posed by diving. Image File history File linksMetadata Download high-resolution version (1159x1554, 511 KB) Photograph taken on Four Seasons dive boat at Sharm el-Sheikh, Egypt File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Swimfin Scuba diving Metadata This file... Image File history File linksMetadata Download high-resolution version (1159x1554, 511 KB) Photograph taken on Four Seasons dive boat at Sharm el-Sheikh, Egypt File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Swimfin Scuba diving Metadata This file... View of the Red Sea and Tiran Island from the Sheraton Sharm hotel. ... Physiology (in Greek physis = nature and logos = word) is the study of the mechanical, physical, and biochemical functions of living organisms. ...


Breathing underwater

For more information, see diving regulator.

Water normally contains dissolved oxygen from which fish and other aquatic animals extract all their required oxygen as the water flows past their gills. Humans lack gills and do not otherwise have the capacity to breathe underwater unaided by external devices. A gas pressure regulator has one or more valves in series, which let the gas out of a gas cylinder in a controlled way, lowering its pressure at each stage. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... For other uses, see Fish (disambiguation). ... In aquatic organisms, gills are a respiratory organ for the extraction of oxygen from water and for the excretion of carbon dioxide. ... An underwater scene just beneath the surface. ...


Early diving experimenters quickly discovered it is not enough simply to supply air in order to breathe comfortably underwater. As one descends, in addition to the normal atmospheric pressure, water exerts increasing pressure on the chest and lungs — approximately 1 bar or 14.7 psi for every 33 feet or 10 meters of depth — so the pressure of the inhaled breath must exactly counter the surrounding or ambient pressure in order to inflate the lungs. Look up air in Wiktionary, the free dictionary. ... This article is about pressure in the physical sciences. ... The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... Psi has multiple meanings: Psi (letter) (Ψ, ψ) of the Greek alphabet Psi (Cyrillic) (Ñ°, ѱ), letter of the early Cyrillic alphabet, adopted from Greek Psi (parapsychology) Psi (instant messaging client), a popular Jabber client program J/ψ particle, a subatomic particle Wavefunction in Quantum Mechanics, ψ In mathematics, Ψ is used to denote the angle between... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ... metre or meter, see meter (disambiguation) The metre is the basic unit of length in the International System of Units. ...


By always providing the breathing gas at ambient pressure, modern demand valve regulators ensure the diver can inhale and exhale naturally and virtually effortlessly, regardless of depth. Air is the most common and only natural breathing gas. ... A gas pressure regulator has one or more valves in series, which let the gas out of a gas cylinder in a controlled way, lowering its pressure at each stage. ...


Because the diver's nose and eyes covered by a diving mask; the diver cannot breathe in through the nose, except when wearing a full face diving mask. However, inhaling from a regulator's mouthpiece becomes second nature very quickly. A diving mask Snorkeler wearing a soft silicone diving mask A diving mask is an item of diving equipment that allows scuba divers, free-divers, and snorkelers to see clearly underwater. ... A diver in a pool wearing an AGA full face mask A diver wearing an Ocean Reef full face mask A full-face diving mask is a type of diving mask worn by SCUBA divers so that they can talk with the surface or other divers. ... Nemrod twin-hose diving regulator made in the 1980s. ...

The "Alfa" flag - Designates a vessel engaged in underwater operations with restricted maneuverability
The "Alfa" flag - Designates a vessel engaged in underwater operations with restricted maneuverability [1]

The most commonly used scuba set today is the open circuit 2-stage diving regulator, coupled to a single pressurized gas cylinder. This 2-stage arrangement differs from Emile Gagnan's and Jacques Cousteau's original 1942 design, known as the Aqua-lung, in which the cylinder's pressure was reduced to ambient pressure in a single stage. The 2-stage system has significant advantages over the original single-stage design. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The system of international maritime signal flags is a way of representing individual letters of the alphabet in signals to or from ships. ... A scuba diver in usual sport diving gear SCUBA is an acronym for Self-Contained Underwater Breathing Apparatus. ... A gas pressure regulator has one or more valves in series, which let the gas out of a gas cylinder in a controlled way, lowering its pressure at each stage. ... Emile Gagnan (born November 1900) was a French engineer and co-inventor (together with Jacques-Yves Cousteau) of the demand-valve used for the first Scuba equipment (Aqua-Lung) in 1943. ... Jacques-Yves Cousteau (June 11, 1910 - June 25, 1997) was a French naval officer, explorer and researcher who studied the sea and all forms of life in water. ... ...

The diver down flag - Designates a diver is in the water
The diver down flag - Designates a diver is in the water

In the two-stage design, the first stage regulator reduces the cylinder pressure of about 200 bar (3000 psi) to an intermediate level of about 10 bar (145 psi). The second stage demand valve regulator, connected via a low pressure hose to the first stage, delivers the breathing gas at the correct ambient pressure to the diver's mouth and lungs. The diver's exhaled gases are exhausted directly to the environment as waste. The first stage typically has at least one outlet delivering breathing gas at unreduced tank pressure. This is connected to the diver's pressure gauge or computer, in order to show how much breathing gas remains. Image File history File links Diver_Down_flag. ... Image File history File links Diver_Down_flag. ... A gas pressure regulator has one or more valves in series, which let the gas out of a gas cylinder in a controlled way, lowering its pressure at each stage. ...


Less common, but becoming increasingly available, are closed and semi-closed rebreathers. Open-circuit sets vent off all exhaled gases, but rebreathers reprocess each exhaled breath for re-use by removing the carbon dioxide buildup and replacing the oxygen used by the diver. Rebreathers release few or no gas bubbles into the water, and use much less oxygen per hour because exhaled oxygen is recovered; this has advantages for research, frogman, photography, and other applications. Modern rebreathers are more complex and more expensive than sport open-circuit scuba, and need special training and maintenance to safely use. Inspiration Closed Circuit Diving Rebreather Description A rebreather is a type of breathing equipment that provides a breathing gas containing oxygen and recycles exhaled gas. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Pretorian Guards, Roman Soldiers Military has two broad meanings. ...


For some diving, gas mixtures other than normal atmospheric air (21% oxygen, 78% nitrogen, 1% other) can be used, so long as the diver is properly trained in their use. The most commonly used mixture is Enriched Air Nitrox, which is air with extra oxygen, often with 32% or 36% oxygen, and thus less nitrogen, reducing the effect of decompression sickness and nitrogen narcosis. General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Nitrox refers to any gas mixture composed (excluding trace gases) of nitrogen and oxygen; this includes normal air which is approximately 79% nitrogen and 21% oxygen (although around 1% is actually other gases). ... Decompression sickness (DCS), the diver’s disease, the bends, or caisson disease is the name given to a variety of symptoms suffered by a person exposed to a reduction in the pressure surrounding their body. ... Nitrogen narcosis or inert gas narcosis is a reversible alteration in consciousness producing a state similar to alcohol intoxication in scuba divers at depth. ...


Several other common gas mixtures are in use, and all need specialized training. Oxygen with helium and a reduced percentage of nitrogen is known as trimix, for example. For other uses, see Helium (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Trimix is a breathing gas, consisting of oxygen, helium and nitrogen, and is often used in deep commercial diving and during the deep phase of dives carried out using Technical diving techniques. ...


In cases of technical dives more than one cylinder may be carried, each containing a different gas mixture for a distinct phase of the dive, typically designated as Travel, Bottom, and Decompression. These different gas mixtures may be used to extend bottom time, reduce inert gas narcotic effects, and reduce decompression times. Technical diving is a form of SCUBA diving that exceeds the scope of recreational diving. ...


Injuries due to changes in air pressure

For a full list, see Diving hazards and precautions

Divers must avoid injuries caused by changes in air pressure. The weight of the water column above the diver causes an increase in air pressure in any compressible material (wetsuit, lungs, sinus) in proportion to depth, in the same way that atmospheric air causes a pressure of 14.7 lbs per square inch at sea level. Pressure injuries are called barotrauma and can be quite painful, in severe cases causing a ruptured eardrum or damage to the sinuses. To avoid them, the diver equalizes the pressure in all air spaces with the surrounding water pressure when changing depth. The middle ear and sinus are equalized using one of two techniques. Divers face specific physical and health risks when they go underwater (e. ... A surfer in a wetsuit. ... Human respiratory system The lungs flank the heart and great vessels in the chest cavity. ... Sinus may refer to: In anatomy, where a sinus is a sac or cavity in any organ or tissue: Paranasal sinus, an air cavity in the cranial bones, especially those near the nose Sinus (anatomy), description of the general term Anal sinuses, the furrows which separate the columns in the... Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding gas or liquid. ...


The first technique is known as the "Valsalva maneuver", which involves pinching the nose and gently attempting to exhale through it. The second technique is known as the "Frenzel maneuver", which involves using the throat muscles in a swallowing motion. This maneuver is more difficult to master than the Valsalva maneuver. In medicine, the Valsalva maneuver is performed by forcibly exhaling against closed lips and pinched nose, forcing air into the middle ear if the Eustachian tube is open. ...


The mask is equalized by periodically exhaling through the nose. If a drysuit is worn, it too must be equalized by inflation and deflation, similar to a buoyancy compensator. A buoyancy compensator (or buoyancy control device, BC or BCD) is a piece of diving equipment worn by divers to provide: life saving emergency buoyancy both underwater and on the surface. ...


Effects of breathing high pressure gas

Decompression sickness

The diver must avoid the formation of gas bubbles in the body, called decompression sickness or 'the bends', by releasing the water pressure on the body slowly at the end of the dive and allowing gases trapped in the bloodstream to gradually break solution and leave the body, called "off-gassing." This is done by making safety stops or decompression stops and ascending slowly using dive computers or decompression tables for guidance. Decompression sickness must be treated promptly, typically in a recompression chamber. Administering enriched-oxygen breathing gas or pure oxygen to a decompression sickness stricken diver on the surface is a good form of first aid for decompression sickness, although fatality or permanent disability may still occur. Decompression sickness (DCS), the diver’s disease, the bends, or caisson disease is the name given to a variety of symptoms suffered by a person exposed to a reduction in the pressure surrounding their body. ... A Decompression Stop is a period of time a diver must spend at a constant depth in shallow water at the end of a dive in order safely to eliminate inert gases from the divers body to avoid decompression sickness. ... A wrist watch sized dive computer incorporating an electronic compass A dive computer or decompression meter is a device used by a scuba diver to measure the time and depth of a dive so that a safe ascent rate can be calculated and displayed so that the diver can avoid... Dive Tables, Decompression Tables or Tables are printed cards or booklets that allow divers to determine for a particular dive profile and breathing gas, the Decompression stops required for that dive in order to avoid decompression sickness. ... A recompression chamber is a pressure vessel used to treat divers suffering from certain diving disorders such as decompression sickness. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... First aid is a series of simple, life-saving medical techniques that a non-doctor or layman can be trained to perform. ...


Nitrogen narcosis

Nitrogen narcosis or inert gas narcosis is a reversible alteration in consciousness producing a state similar to alcohol intoxication in divers who breathe high pressure gas at depth. The mechanism is similar to that of nitrous oxide, or "laughing gas," administered as anesthesia. Being "narced" can impair judgment and make diving very dangerous. Narcosis starts to affect the diver at 66 feet (20 metres), or 3 atmospheres of pressure. At 66 feet, Narcosis manifests itself as slight giddiness. The effects increase drastically with the increase in depth. Jacques Cousteau famously described it as the "rapture of the deep". Nitrogen narcosis occurs quickly and the symptoms typically disappear during the ascent, so that divers often fail to realize they were ever affected. It affects individual divers at varying depths and conditions, and can even vary from dive to dive under identical conditions. However, diving with trimix or heliox prevents narcosis from occurring. Nitrogen narcosis or inert gas narcosis is a reversible alteration in consciousness producing a state similar to alcohol intoxication in scuba divers at depth. ... Jacques-Yves Cousteau (June 11, 1910 - June 25, 1997) was a French naval officer, explorer and researcher who studied the sea and all forms of life in water. ... Trimix is a breathing gas, consisting of oxygen, helium and nitrogen, and is often used in deep commercial diving and during the deep phase of dives carried out using Technical diving techniques. ...


Oxygen toxicity

Oxygen toxicity occurs when oxygen in the body exceeds a safe "partial pressure" (PPO2). In extreme cases it affects the central nervous system and causes a seizure, which can result in the diver spitting out his regulator and drowning. Oxygen toxicity is preventable provided one never exceeds the established maximum depth of a given breathing gas. For deep dives, (generally past 130 feet / 39 meters) "hypoxic blends" containing a lower percentage of oxygen than atmospheric air are used. For more information, see Oxygen toxicity. Oxygen toxicity or oxygen toxicity syndrome is severe hyperoxia caused by breathing oxygen at elevated partial pressures. ... This article is about epileptic seizures. ... Oxygen toxicity or oxygen toxicity syndrome is severe hyperoxia caused by breathing oxygen at elevated partial pressures. ...


Refraction and underwater vision

A diver wearing an Ocean Reef full face mask
A diver wearing an Ocean Reef full face mask

Water has a higher refractive index than air; it's similar to that of the cornea of the eye. Light entering the cornea from water is hardly refracted at all, leaving only the eye's crystalline lens to focus light. This leads to very severe hypermetropia. People with severe myopia, therefore, can see better underwater without a mask than normal-sighted people. Light rays bend when they enter from one medium to another of different densities making it possible to form images on the retina of our eyes by focussing the rays on the retina. ... An Ocean Reef full face diving mask I took this photo myself with a camera This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... An Ocean Reef full face diving mask I took this photo myself with a camera This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ... For other uses, see Eye (disambiguation). ... The lens or crystalline lens is a component of the eye. ... Hyperopia (or more rarely, hypermetropia), also known as farsightedness or longsightedness, is a defect of vision caused by an imperfection in the eye (often when the eyeball is too short), causing inability to focus on near objects, and in extreme cases causing a sufferer to be unable to focus on... Normal vision. ...


Diving masks and diving helmets and fullface masks solve this problem by creating an air space in front of the diver's eyes. The refraction error created by the water is mostly corrected as the light travels from water to air through a flat lens, except that objects appear approximately 34% bigger and 25% closer in salt water than they actually are. Therefore total field-of-view is significantly reduced and eye-hand coordination must be adjusted. A diving mask Snorkeler wearing a soft silicone diving mask A diving mask is an item of diving equipment that allows scuba divers, free-divers, and snorkelers to see clearly underwater. ... Diving helmets are worn by divers who need to speak and hear underwater. ... A diver in a pool wearing an AGA full face mask A diver wearing an Ocean Reef full face mask A full-face diving mask is a type of diving mask worn by SCUBA divers so that they can talk with the surface or other divers. ... Refraction error is an error in the focussing of light by the human eye. ... Light rays bend when they enter from one medium to another of different densities making it possible to form images on the retina of our eyes by focussing the rays on the retina. ...


(This affects underwater photography: a camera seeing through a flat window in its casing is affected the same as its user's eye seeing through a flat mask window, and so its user must focus for the apparent distance to target, not for the real distance.)


Divers who need corrective lenses to see clearly outside the water would normally need the same prescription while wearing a mask. Generic and custom corrective lenses are available for some two-window masks. Custom lenses can be bonded onto masks that have a single front window.


On rare occasions, commando frogmen use special contact lenses instead, to see underwater without the large glass surface of a diving mask, which can reflect light and give away the frogman's position. For the Wizard of Oz series character, see Frogman (Oz character). ... A pair of contact lenses, positioned with the concave side facing upward. ...


As a diver changes depth, he must periodically exhale through his nose to equalize the internal pressure of the mask with that of the surrounding water. Swimming goggles which only cover the eyes do not allow for equalization and thus are not suitable for diving.


Controlling buoyancy underwater

Diver under the Salt Pier in Bonaire.
Diver under the Salt Pier in Bonaire.

To dive safely, divers need to be able to control their rate of descent and ascent in the water. Ignoring other forces such as water currents and swimming, the diver's overall buoyancy determines whether he ascends or descends. Equipment such as the diving weighting systems, diving suits (Wet, Dry & Semi-dry suits are used depending on the water temperature) and buoyancy compensators can be used to adjust the overall buoyancy. When divers want to remain at constant depth, they try to achieve neutral buoyancy. This minimizes gas consumption caused by swimming to maintain depth. Image File history File links 7008_aquaimages. ... Image File history File links 7008_aquaimages. ... Anthem: Tera di Solo y suave biento Capital (and largest city) Kralendijk Official languages Dutch Government See Politics of the Netherlands Antilles  - Bonaire Administrator  - Governor of N.A. Frits Goedgedrag Constitutional monarchy part of the Netherlands Antilles  Area  - Total 288 km² 111 sq mi  Population  - 2001 census 10,791  - Density... In physics, buoyancy is the upward force on an object produced by the surrounding fluid (i. ... Divers wear weighting systems, weight belts or weights, generally made of lead, to counteract the buoyancy of other diving equipment, such as diving suits and aluminium diving cylinders. ... Two divers, one wearing a 1 atmosphere diving suit and the other standard diving dress, preparing to explore the wreck of the RMS Lusitania, 1935 A diving suit is a garment or device designed to protect a diver from the underwater environment. ... A buoyancy compensator (or buoyancy control device, BC or BCD) is a piece of diving equipment worn by divers to provide: life saving emergency buoyancy both underwater and on the surface. ...


The downward force on the diver is the weight of the diver and his equipment minus the weight of the same volume of the liquid that he is immersed in; if the result is negative, that force is upwards. Diving weighting systems can be used to reduce the diver's weight and cause an ascent in an emergency. Diving suits, mostly being made of compressible materials, shrink as the diver descends, and expand as the diver ascends, creating unwanted buoyancy changes. The diver can inject air into some diving suits to counteract this effect and squeeze. Buoyancy compensators allow easy and fine adjustments in the diver's overall volume and therefore buoyancy. For open circuit divers, changes in the diver's lung volume can be used to adjust buoyancy. For other uses, see Weight (disambiguation). ... The volume of a solid object is the three-dimensional concept of how much space it occupies, often quantified numerically. ... Negative has meaning in several contexts: Look up negative in Wiktionary, the free dictionary. ... Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding gas or liquid. ... A scuba diver in usual sport diving gear SCUBA is an acronym for Self-Contained Underwater Breathing Apparatus. ...


Avoiding losing body heat

Water conducts heat from the diver 25 times[1] better than air, which can lead to hypothermia even in mild water temperatures. Symptoms of hypothermia include impaired judgment and dexterity, which can quickly become deadly in an aquatic environment. In all but the warmest waters, divers need the thermal insulation provided by wetsuits or drysuits. In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... Hypothermia is a condition in which an organisms temperature drops below that Required fOr normal metabolism and Bodily functionS. In warm-blooded animals, core [[body Temperature]] is maintained nEar a constant leVel through biologic [[homEostasis]]. But wheN the body iS exposed to cold Its internal mechanismS may be unable... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... A surfer in a wetsuit. ... drysuits are used in a number of sports to provide a barrier between the occupant and cold water. ...


In the case of a wetsuit, the suit is designed to minimize heat loss. Wetsuits are generally made of neoprene that has small gas cells, generally nitrogen, trapped in it during the manufacturing process. The poor thermal conductivity of this expanded cell neoprene means that wetsuits reduce loss of body heat by conduction to the surrounding water. The neoprene in this case acts as an insulator. Neoprene is the DuPont Chemical trade name for a family of synthetic rubbers based on polychloroprene. ...


The second way in which wetsuits reduce heat loss is to trap a thin layer of water between the diver's skin and the insulating suit itself. Body heat then heats the trapped water. Provided the wetsuit is reasonably well-sealed at all openings (neck, wrists, legs), this reduces water flow over the surface of the skin, reducing loss of body heat by convection, and therefore keeps the diver warm (this is the principle employed in the use of a "Semi-Dry")

Spring Suit and Steamer.
Spring Suit and Steamer.

In the case of a drysuit, it does exactly that: keeps a diver dry. The suit is sealed so that frigid water cannot penetrate the suit. Drysuit undergarments are often worn under a drysuit as well, and help to keep layers of air inside the suit for better thermal insulation. Some divers carry an extra gas bottle dedicated to filling the dry suit. Usually this bottle contains argon gas, because of its better insulation as compared with air. Image File history File linksMetadata Download high-resolution version (2304x3456, 3100 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Wetsuit Scuba diving User:Miskatonic Metadata This file contains additional information, probably added from the digital camera or... Image File history File linksMetadata Download high-resolution version (2304x3456, 3100 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Wetsuit Scuba diving User:Miskatonic Metadata This file contains additional information, probably added from the digital camera or... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ...


Drysuits fall into two main categories neoprene and membrane; both systems have their good and bad points but generally they can be reduced to:

  • Membrane: high level of diver maneuverability due to the thinness of the material, however that also means that heavy weight undersuit is required if diving in cooler water.
  • Neoprene: low level of diver maneuverability due to the material being considerably thicker than membrane material (even when dealing with compressed neoprene) however the neoprene provides a higher level of insulation for the diver.

Avoiding skin cuts and grazes

Diving suits also help prevent the diver's skin being damaged by rough or sharp underwater objects, marine animals or coral. Two divers, one wearing a 1 atmosphere diving suit and the other standard diving dress, preparing to explore the wreck of the RMS Lusitania, 1935 A diving suit is a garment or device designed to protect a diver from the underwater environment. ...


Diving longer and deeper safely

There are a number of techniques to increase the diver's ability to dive deeper and longer:

Technical diving is a form of SCUBA diving that exceeds the scope of recreational diving. ... Surface supplied diver at the Monterey Bay Aquarium, Monterey, California Surface supplied diving refers to divers using equipment supplied with breathing gas using an umbilical cord from the surface, often from a diving support vessel but possibly, indirectly via a diving bell. ... Diving helmets are worn by divers who need to speak and hear underwater. ... Saturation diving is a diving technique that allow divers to remain at great depth for long periods of time, by living under pressure in special living chamber complexes affixed to a diving support vessel, oil platform or other floating work station. ... A decompression chamber is a pressure vessel used in surface supplied diving to allow the divers to complete their decompression stops at the end of a dive on the surface rather than underwater. ...

Being mobile underwater

The diver needs to be mobile underwater. Streamlining dive gear will reduce drag and improve mobility. Personal mobility is enhanced by swimfins and Diver Propulsion Vehicles. Other equipment to improve mobility includes diving bells and diving shots. A pair of Viper® swimfins. ... A Diver Propulsion Vehicle or a DPV is an item of diving equipment used by scuba divers to increase their range while underwater where their endurance is restricted due to limited availability of breathing gas and need to avoid decompression sickness. ... Diving bell A diving bell also known as a wet bell is a cable-suspended airtight chamber, open at the bottom like a moon pool structure, that is lowered underwater to operate as a base or a means of transport for a small number of divers. ... A diving shot is an item of diving equipment consisting of a weight, a line and a buoy. ...


Scuba dive training and certification agencies

Recreational scuba diving does not have a centralized certifying or regulatory agency, and is mostly self regulated. There are, however, several large diving organizations that train and certify divers and dive instructors, and many diving related sales and rental outlets require proof of diver certification from one of these organizations prior to selling or renting certain diving products or services. This page lists SCUBA diver training organizations. ...


The largest international certification agencies that are currently recognized by most diving outlets for diver certification include:

The British Sub-Aqua Club or BSAC is the governing body of recreational diving in Britain. ... The National Association of Underwater Instructors (NAUI) is a SCUBA diver training organization concerned with promoting dive safety through education. ... The Professional Association of Diving Instructors (PADI) is the worlds largest recreational diving membership and diver training organization founded by John Cronin and Ralph Erikson. ... Scuba Schools International or SSI is an organization that teaches the skills involved in scuba diving. ... YMCAs in the United States and Canada use this logo. ...

See also

A scuba diver approaching the "1,000 Steps" dive site in Bonaire.
A scuba diver approaching the "1,000 Steps" dive site in Bonaire.
Scuba diving, grouped
Scuba diving, grouped

Image File history File links Download high resolution version (690x800, 174 KB)1000 Steps beach and dive site on Bonaire. ... Image File history File links Download high resolution version (690x800, 174 KB)1000 Steps beach and dive site on Bonaire. ... Anthem: Tera di Solo y suave biento Capital (and largest city) Kralendijk Official languages Dutch Government See Politics of the Netherlands Antilles  - Bonaire Administrator  - Governor of N.A. Frits Goedgedrag Constitutional monarchy part of the Netherlands Antilles  Area  - Total 288 km² 111 sq mi  Population  - 2001 census 10,791  - Density... Altitude diving is significant in recreational diving because the decompression stops used for dives at altitude are different from those used for the same dive profile at sea level. ... ... Decompression sickness (DCS), the diver’s disease, the bends, or caisson disease is the name given to a variety of symptoms suffered by a person exposed to a reduction in the pressure surrounding their body. ... The fundamental item of diving equipment used by divers is the SCUBA equipment, such as the Aqualung or Rebreather. ... Diver training is essential for safe diving. ... Diving in the sense of going underwater, has these purposes. ... Divers face specific physical and health risks when they go underwater (e. ... This article identifies popular recreational diving sites around the world and describes the features of a dive site. ... These are the laws of physics that govern the physics of the SCUBA diver and of diving equipment: Buoyancy - when in water, the density of the materials in the divers body and in the divers equipment determine whether the diver floats or sinks Boyles law - as pressure... Diving Signals are a form of Sign language used by SCUBA divers to communicate when underwater. ... Two divers, one wearing a 1 atmosphere diving suit and the other standard diving dress, preparing to explore the wreck of the RMS Lusitania, 1935 A diving suit is a garment or device designed to protect a diver from the underwater environment. ... Drift diving is a type of recreational diving where the diver is transported by the currents caused by the tide. ... Sea Hunt was an American television adventure series from syndicator Ziv TV that ran from 1958 to 1961 and was popular in repeats for decades afterwards. ... A snorkeler amid corals on a coral reef near Fiji. ... This article identifies popular recreational snorkeling sites around the world and describes the features of those sites. ... Snuba diving provides a fun and exciting combination of scuba and snorkeling for first time users. ... Technical diving is a form of SCUBA diving that exceeds the scope of recreational diving. ... Timeline of underwater technology // Pre-industrial Several centuries BC: (Relief carvings made at this time show Assyrian soldiers crossing rivers using inflated goatskin floats. ... Pink Anemonefish hiding in tentacles Underwater photography is the process of taking photographs while underwater. ... Underwater Videography is the branch of underwater photography concerned with capturing underwater moving images either as a recreational diving or commercial documentary or movie making activity. ... This article does not cite any references or sources. ... Like-A-Fish Technologies is an Israeli business that is developing a system to extract breathable air from water. ... Image File history File links Scuba-diving. ... Image File history File links Scuba-diving. ...

Sources

External links

  • Brief history of diving - From antiquity to the present.
  • Divers Alert Network - Diving Emergencies/Hyperbaric Chamber Assistance.
  • Scuba diving travel guide from Wikitravel
  • WikiScuba - A wiki devoted to scuba diving.

 
 

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