Diving watch

Breitling Avenger Seawolf, with a water resistance of 3,000 m (10,000 ft). The round feature on the watch case side at 9 o'clock is an integrated helium release valve.

Uses| Monitoring dive time by the diver

A diving watch, also commonly referred to as a diver's or dive watch, is a watch designed for underwater diving that features, as a minimum, a water resistance greater than 1.1 MPa (11 atm), the equivalent of 100 m (330 ft). The typical diver's watch will have a water resistance of around 200 to 300 m (660 to 980 ft), though modern technology allows the creation of diving watches that can go much deeper. A true contemporary diver's watch is in accordance with the ISO 6425 standard, which defines test standards and features for watches suitable for diving with underwater breathing apparatus in depths of 100 m (330 ft) or more. Watches conforming to ISO 6425 are marked with the word DIVER'S to distinguish ISO 6425 conformant diving watches from watches that might not be suitable for actual scuba diving.

To a large extent the diver's watch has been superseded by the personal dive computer, which provides an automatically initiated dive timer function along with real-time decompression computation and other (optional) functions.

## Contents

* 1 History
* 2 Characteristics
* 2.1 ISO 6425 standard for diving watches
* 2.2 Watch case
* 2.3 Elapsed time controller
* 2.3.1 Bezel markings
* 2.3.2 GMT dive watches
* 2.4 Crystal
* 2.5 Crown
* 2.6 Pushers
* 2.7 Helium release valve
* 2.8 Watch strap/bracelet
* 2.9 Legibility
* 2.10 Power-reserve indicator
* 3 Water resistance
* 3.1 Water resistance classification
* 3.2 Watches designed for extreme water resistance
* 3.2.1 Air-filled watches
* 3.2.2 Liquid-filled watches
* 3.2.3 Full ocean depth prototype/experimental watches
* 4 Maintenance
* 4.1 Precautions
* 5 See also
* 6 References
* 7 External links

## History

The history of efforts to use watches underwater and to make watches that are water resistant, or waterproof and to make dive watches goes back to perhaps the 17th century. In the 19th century water and dust resistant watches were usually one-off pieces custom made for a particular customer and described as "Explorer's Watches". Hard hat divers of that period sometimes placed common pocketwatches on the inside of their helmets in order to know the time spent under water.[1] Early in the 20th century such watches were industrially produced for military and commercial distribution. Like their predecessors early 20th century dive watches were developed in response to meet the needs of several different but related groups: explorers, navies, and professional divers.

In 1926, Rolex bought the patent for the “Oyster” watch case, featuring a hermetic seal. On 7 October 1927 an English swimmer, Mercedes Gleitze attempted to cross the English Channel with a new Rolex Oyster hanging round her neck by a ribbon on this swim. After more than 10 hours in the chilly water the watch remained sealed and kept good time throughout.[2]

Omega SA is credited as the creator of the world's first industrially produced diving watch intended for commercial distribution, the rectangular Omega "Marine" with a patented double sliding and removable case, introduced in 1932. After a series of trials undertaken by the Swiss Laboratory for Horology in Neuchâtel in May 1937, the watch was certified as being able to withstand a pressure of 1.37 MPa (13.5 atm), equivalent to a depth of 135 m (443 ft), without any water intake whatsoever.[3]

The vintage 1936 California Dial Radiomir Panerai

Following a request made by the Royal Italian Navy, in September 1935, for a luminous underwater watch for divers, Panerai offered "Radiomir" underwater timepieces in 1936. These watches were made by Rolex for Panerai.[4][5]

In addition, a large number of "canteen" style dive watches by Hamilton, Elgin or Waltham were made to military specification during and after World War II.[6] However, these watches were made in small numbers, and were not intended for large-scale commercial distribution. Today, interest in these watches is limited to collectors.[7]

Various models were issued by Blancpain in small quantities to the military in several countries, including US and French Navy combat diver teams. The Fifty Fathoms was worn by Jacques Cousteau and his divers during the underwater film "Le monde du silence", which won the Palme d'Or at the Cannes film festival in 1956, and in the US when TV star Lloyd Bridges wore a Blancpain Fifty Fathoms dive watch in a photo that appeared on the cover of the February 1962 edition of Skin Diver Magazine.[8]

File:Blancpain.jpgThe Blancpain Fifty Fathoms model family was introduced in the mid 1950s

Zodiac debuted their Sea Wolf line of waterproof watches at the 1953 Basel Fair as well.[9]

The Rolex Submariner, the first modern dive watch,[10] was introduced at the Basel Watch Fair in 1954. This coincided with the development of self-contained underwater breathing apparatus, known as scuba. In 1959, the United States Navy Experimental Diving Unit evaluated five diving watches that included the Bulova US Navy Submersible Wrist Watch, Enicar Sherpa Diver 600, Enicar Seapearl 600, Blancpain Fifty Fathoms, and the Rolex Oyster Perpetual.[11]

In 1961, Edox launched the Delfin line of watches, with industry-first double case backs for water resistance to 200 meters. They later released the Hydrosub line in 1963 featuring the first crown system with tension ring allowing depths of 500 meters.

In 1961, Rolex began to include a skindiver handbook with the Submariner, then available in two models, one water resistant to 200 m (660 ft), the other, less expensive version, to 100 m (330 ft). It was the choice of watch for the character of 007 in the first ten James Bond films, causing the "Sub" to achieve an iconic status.[12]

In 1964, Zuccolo Rochet & Cie issued the Grands Fonds 300 to Explosive Ordnance Disposal (EOD) units using a mechanical operation as electric interference could trigger off explosions. It used an easy clean system that allows freshwater to free up residue between the watch case/bezel.[13] Another notable function is the crown placed in the lower watchstrap to prevent snagging on objects during underwater operations.

The Tornek-Rayville TR-900 issued to the US Navy used tritium, later promethium on the dials and a moisture intrusion indicator, which changed color if water penetrated the watchcase. However, only 1000 existed as most of these watches were destroyed by the Navy upon their return due to strict hazardous waste disposal rules for equipment containing radioactive material.[14]

In 1965, Seiko put the 62MAS on the market, the first Japanese professional diver watch.[15]

US Marine diver with a diving watch and an analog depth gauge

During the 1960s, commercial work in the oceans and seas created professional diving organisations that needed more robust watches designed for diving operations at greater depths. This led to the development of the first 'ultra water resistant' watches like the Rolex Sea-Dweller 2000 (2000 ft = 610 m), that became available in 1967, and was produced in several variations, and the Omega Seamaster Professional 600m/2000 ft, also known as the "Omega PloProf" (Plongeur Professionnel), that became available in 1970, and was produced in several variations.[16][17][18][19][20][21]

In 1983, the US Navy Experimental Diving Unit evaluated several digital watches for use by US Navy divers.[22]

In 1996, the International Organization for Standardization (ISO) introduced the standards and features for diving watches regulated by the ISO 6425 – Divers' watches international standard.

Many contemporary sports watches owe their design to diving watches.

The vast majority of divers now use electronic, wrist-worn dive computers.[12] 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 profile can be calculated and displayed so that the diver can avoid decompression sickness.[23] Diving watches and depth gauges are still fairly commonly used by divers as backup instruments in case of dive computer malfunctions, although it is becoming more common to carry a backup dive computer with full decompression functionality for dives with significant planned decompression, as it is a safer option.[24][25]

## Characteristics

Seiko 7002-7020 Diver's 200 m Citizen Promaster Aqualand digital/analog JP2000-08E Diver's 200 m File:Citizen Hyper Aqualand Diver's Promaster MA9004-21E, digital quartz diving watch with depth gauge, opening of pressure sensor shown below.jpgCitizen Hyper Aqualand ProMaster MA9024-21E digital Diver's 200 m

Many companies offer highly functional diving watches. Whilst diving watches are primarily tool watches, some companies offer models that can in addition to this be regarded by some as jewellery or fine mechanical devices. Diving watches can be analog or digital. Besides pure analog and digital models some diving watch models combine digital and analog elements.

### ISO 6425 standard for diving watches

The standards and features for diver's watches are regulated by the International Organization for Standardization in the ISO 6425 standard; German Industrial Norm DIN 8306 is an equivalent standard. Besides water resistance standards to a minimum of 100 m depth rating ISO 6425 also provides minimum requirements for mechanical diver's watches (quartz and digital watches have slightly differing readability requirements) such as:

* Equipped with a diving time indicator (e.g. rotating bezel, digital display, or other). This device shall allow the reading of the diving time with a resolution of 1 min or better over at least 60 min.
* The presence of clearly distinguishable minute markings on the watch face.
* Adequate readability/visibility at 25 cm (9.8 in) in total darkness.
* The presence of an indication that the watch is running in total darkness. This is usually indicated by a running second hand with a luminous tip or tail.
* Magnetic resistance. This is tested by 3 exposures to a direct current magnetic field of 4,800 A/m. The watch must keep its accuracy to ± 30 seconds/day as measured before the test despite the magnetic field.
* Shock resistance. This is tested by two shocks (one on the 9 o'clock side, and one to the crystal and perpendicular to the face). The shock is usually delivered by a hard plastic hammer mounted as a pendulum, so as to deliver a measured amount of energy, specifically, a 3 kg hammer with an impact velocity of 4.43 m/s. The change in rate allowed is ± 60 seconds/day.
* Chemical resistance. This is tested by immersion in a 30 g/L NaCl solution for 24 hours to test its rust resistance. This test water solution has a salinity comparable to normal seawater.
* Strap/band solidity. This is tested by applying a force of 200 N (45 lbf) to each spring bar (or attaching point) in opposite directions with no damage to the watch or attachment point.
* The presence of an End Of Life (EOL) indicator on battery powered watches.

Testing diving watches for ISO 6425 compliance is voluntary and involves costs, so not every manufacturer present their watches for certification according to this standard.

### Watch case

The watch cases of diving watches must be adequately water (pressure) resistant and be able to endure the galvanic corrosiveness of seawater, so the cases are generally made out of materials like grade 316L or 904L austenitic stainless steel and other steel alloys with higher Pitting Resistance Equivalent factors (PRE-factors), titanium, ceramics and synthetic resins or plastics.[26][27][28] If metal bracelets are used they should be made of the same metal alloy as the watch case to prevent corrosion of the metal with the lower PRE-factor as it will act as a sacrificial anode. The case must also provide an adequate degree of protection against external magnetic influences and shocks, though diver's watches do not have to be able to endure strong magnetic fields and shocks. To make mechanical watch movements themselves shock resistant various shock protection systems can be used.

The cases of diving watches have to be constructed more stoutly than typical dress watches, because of the requirements necessary to withstand a seawater environment at depth. As a consequence diving watches are relatively heavy and large compared to dress watches made out of similar materials. Under water sheer weight is of less consequence than buoyancy, which a diver can address by a buoyancy compensator ("BC") vest. Before the introduction of other case materials diving watch cases were made of stainless steel. Stainless steel is however still often used as case material in contemporary diving watches.

### Elapsed time controller

File:Turning the bezel on a diving watch to mark a point in time.webmVideo: Setting the bezel of a diving watch to a dedicated point in time, typically the start time of the dive – one of the most important features of diving watches before dive computers became ubiquitous

Analog diving watches will often feature a rotating bezel, that allows for an easier reading of elapsed time of under one hour from a specific point. This is used to compute the length of a dive. (See Tachymeter.) Upon entering the water, the diver aligns the zero on the bezel with the minute (or sometimes second) hand, allowing the elapsed time to be read from the bezel. This saves the diver having to remember the exact water entry moment and having to perform arithmetic that would be necessary if the watch's regular dial was used. On diving watches the bezel is "unidirectional", i.e., it contains a ratchet so it can only be turned anti-clockwise to "increase" the apparent elapsed time, should the bezel be unintentionally rotated further during the dive. This is an important "fail safe" feature. If the bezel could be turned clockwise, this could suggest to a diver that the elapsed time is shorter than reality, thus indicating a falsely short elapsed time reading, and therefore falsely short saturation period, an assumption that can be highly dangerous. Some diving watch models feature a lockable bezel to minimize the chance of unintentional bezel operation under water.

The exclusive use of a rotating bezel is considered a rudimentary diving technique in the 21st century, suitable for basic, shallow single gas (air) diving only. Non-basic diving profiles and depths past 30 m (98 ft) require other more advanced timing and measuring methods to establish suitable decompression profiles to avoid decompression sickness. Besides for basic diving and as a backup for monitoring time during more complex preplanned diving, the one-way bezel can also be used for other situations in which a measurement of elapsed time of under one hour might be useful, like cooking.

Digital dive watches usually perform the elapsed time function by use of a standard stop watch function. Digital dive watches may also feature a depth gauge and logging features, but are not usually regarded as a substitute for a dedicated dive computer.

#### Bezel markings

Rolex Submariner model 16610 features a rotating bezel with non-uniform minute markings for the first 15 minutes

Most contemporary dive watches with non-uniform time markings – generally in one minute intervals for the first 15 or 20 minutes – on their bezels are the result of copying old bezel designs. In the past divers typically planned a dive to a certain maximum depth based on now obsolete US Navy dive tables, and dived according to the planned dive profile. If the dive profile allowed a bottom time of 35 minutes the diver, upon entering the water, would set the marker on the bezel, 35 minutes ahead of the minute hand. The diver calculated this with the 60 – bottom time formulae (60 − 35 = 25, for 35 minutes bottom time the diver would align the 25 minute bezel-mark with the minute hand). Once the minute hand reached the main-marker on the bezel the diver would begin his ascent to the surface. The one minute intervals scale helped with timing the ascent and whatever safety stop the diver deemed necessary. For contemporary diving methods the 15 or 20 minute "count-down" bezel is quite antiquated, yet still the only useful mechanical dive timing device available to date.[29] Modern dive watches now employ a “count-up” bezel, where the zero marker is aligned with the minute hand at the start of the dive. As time progresses, the diver can easily read elapsed time directly against the bezel markings.[30] A different type of bezels used on dive watches are (multiple) decompression time interval bezels as featured on Doxa and Jenny watches.[31][32] The bezel inlay containing the markings in the bezel ring can be made of metal or feature more scratch-resistant top materials like technical ceramic or synthetic sapphire.

#### GMT dive watches

There are some analog dive watches available with a GMT complication. GMT watches were designed for long-haul aircrew and other users who want to track time in different time zones. These watches have an additional GMT watch hand and in the case of diving watches can have a rotating bezel with 24-hours markings instead of minute markings used for reading of elapsed time. With the help of the GMT hand and a correctly adjusted 24-hours bezel the time in two different time zones can be easily read without having to perform arithmetic.

### Crystal

Invicta Automatic Pro Diver Watch 8926 has a flat crystal

Diving watches have relatively thick watch crystals. Sometimes domed crystals are used to enhance the pressure-resistance of the watch and to improve the watch face legibility under water. The typical materials used for crystals are acrylic glass, hardened glass and synthetic sapphire which all have their pros and cons. Acrylic glass is very resistant to breakage; it can easily be scratched, but small scratches can be buffed out with polishing compounds. Hardened glass is more scratch-resistant than acrylic glass and less brittle than sapphire. Sapphire is very scratch-resistant but less shatterproof than the other options. Anti-reflective coatings are generally applied on sapphire crystals to enhance the legibility of the watch. Some manufacturers use sapphire/hardened glass laminate crystals, where the scratch-resistance of sapphire is combined with the better shatter-resistance of hardened glass.

Watch crystals can also be applied as display backs to view the watch movement, but these are a rare feature on diving watches.

### Crown

Citizen Promaster Eco-Drive AP0440-14F Diver's 200 m with integrated crown shoulders

Analog diving watches must have a water resistant crown. Some models have the crown mounted in unconventional positions like 4, 8 or 9 o'clock to avert or reduce discomfort from the crown touching the wearers (left) wrist or back of the hand. Often the crown has to be unscrewed to set or adjust the time and date and afterwards retightened to restore the water resistance of the watch and minimize the chance of unintentional operation under water. There are also watch models where a locking handle, separate knob or an extra crown cover has to be manipulated before the crown can be operated. There are however models that have crowns that are operated like the crowns of non diver's analog watches. Screw down or otherwise locking crowns and traditionally operated water resistant crowns should not be operated under water. The watch case of diving and other tool watches often feature protruding crown protectors or (integrated) crown guards/shoulders for (semi-)recessing the crown and hence reduce mechanical damage and snagging risks.[33][34]

### Pushers

Digital and some analog chronograph diving watches – such as the Breitling Avenger Seawolf Chronograph[35] or Sinn U1000[36] – have specially designed push pieces that can be operated at depth without allowing water to enter the case.

### Helium release valve

Some diving watches intended for saturation diving at great depths are fitted with a helium or mixed breathing gas release or escape valve to prevent incidents such as the crystal from being blown off by an internal pressure build up caused by helium that has seeped into the watch case in helium enriched environments (helium atoms are the smallest natural gas particles found in nature) as the watch and diver adjust to normal atmospheric conditions. Other helium safe/for mixed-gas rated diving watches can withstand the helium used in certain diving situations by using gaskets that simply do not allow helium gas to enter the watch case in a harmful way in the first place.[37]

### Watch strap/bracelet

Stainless steel bracelet deployant clasp with divers extension

Nylon fabric strap used to minimize the chance of losing the watch

Watch straps or bracelets for diving watches are generally made of materials that are adequately water (pressure) resistant and able to endure the galvanic corrosiveness of seawater. In practical terms most diving watches feature a rubber, silicone rubber, FKM-rubber, polyurethane or fabric watch strap or a stainless steel or titanium metal link or mesh bracelet of adequate length to facilitate wearing the watch over a diving suit sleeve. For a wrist with a 200 mm (7.9 in) circumference wearing a 4 mm (0.16 in) thick diving suit sleeve increases the strap or bracelet length required the fit the watch over the sleeved wrist to 225 mm (8.9 in). For this bracelets often have a (concealed) divers extension deployant clasp by which the bracelet can be appropriately extended by approximately 20 mm (0.79 in) to 30 mm (1.2 in). Some watch straps allow an increase in length by adding a diving suit extension strap piece to the standard watch strap. If required more than one diving suit extension strap piece can be added to the standard watch strap. With increasing depth and rising water pressure the (sleeved) wrist of a diver is exposed to compression effects that have a shrinking effect on the wrist circumference. Many watch straps intended for diving watches have rippled or vented sections near the attachment points on the watch case to facilitate the required flexibility to strap the watch tightly for normal wear at the surface whilst keeping the watch sufficiently tightly in place on the divers wrist at depth. Metal link bracelets theoretically have more failure points compared to metal mesh bracelets and watch straps due to the use of link connection parts like split pins or screw pins.[38] One piece (NATO style[39]) nylon fabric straps that slide under the watch case through both spring bars (or attaching points between the watch case and strap) are used to minimize the chance of losing the watch due to a spring bar or attachment point failure.

### Legibility

Lume applied on a diver's watch to make it readable in low light conditions

The dials and markers on the watch face and bezel have to be legible under water and in low light conditions. An indication that the watch is running in total darkness also has to be present. For easy legibility most diving watches have high contrasting, non-cluttered dials and markers with a large, easily identifiable minute hand. The markers for 3, 6, 9 and (especially) 12 o'clock on the watch face and the zero marker on the bezel of analogue diver's watches are usually conspicuously styled to prevent disorientation induced read out errors. A styling of the hands where no hand can temporarily totally overlay and hence obscure the position of another hand is also desirable to promote constant legibility and prevent read out errors. For low light conditions luminous phosphorescent non-toxic strontium-aluminate-based lume pigments marketed under brand names like Super-LumiNova, Lumibrite or NoctiLumina and tritium-based self-powered lighting devices called "gaseous tritium light source" (GTLS) are applied on the dials and markers. On digital diving watches, lighted displays are used for legibility under low light conditions.

### Power-reserve indicator

A diving watch with an electric battery powered movement must have an End-Of-Life (EOL) indicator, usually in the form of a two or four second jump of the second hand or a warning message on a digital display to safeguard against insufficient power reserve during underwater activities. Some electric and mechanical powered movement models have power reserve indicators that show the current power status of the watch.

## Water resistance

Omega Seamaster 300 M Chrono Diver Chronograph featuring pushers next to the crown

The International Organization for Standardization issued a standard for water resistant watches which also prohibits the term waterproof to be used with watches, which many countries have adopted.

Water resistance is achieved by the gaskets which forms a watertight seal, used in conjunction with a sealant applied on the case to help keep water out. The material of the case must also be tested in order to pass as water resistant.[40]

None of the tests defined by ISO 2281 for the Water Resistant mark are suitable to qualify a watch for scuba diving. Such watches are designed for everyday life and must be water resistant during exercises such as swimming. They can be worn in different temperature and pressure conditions but are under no circumstances designed for scuba diving.

The standards for diving watches are regulated by the ISO 6425 international standard. The watches are tested in static or still water under 125% of the rated (water) pressure, thus a watch with a 200 m rating will be water resistant if it is stationary and under 250 m of static water. The testing of the water resistance is fundamentally different from non-dive watches, because every watch has to be fully tested.

ISO 6425 water resistance testing of a diver's watch consists of:

* Immersion of the watch in 30 cm of water for 50 hours.
* Immersion of the watch in water under 125% of the rated pressure with a force of 5 N perpendicular to the crown and pusher buttons (if any) for 10 minutes.
* Immersion of the watch in 30 cm of water at the following temperatures for 5 minutes each, 40 °C, 5 °C and 40 °C again, with the transition between temperatures not to exceed 1 minute. No evidence of water intrusion or condensation is allowed.
* Immersion of the watch in a suitable pressure vessel and subjecting it to 125% of the rated pressure for 2 hours. The pressure must be applied within 1 minute. Subsequently, the overpressure shall be reduced to 0.3 bar within 1 minute and maintained at this pressure for 1 hour. No evidence of water intrusion or condensation is allowed.

Seiko SBBN007 Professional Diver's 300 m for mixed-gas diving

* For mixed-gas diving the watch has to be immersed in a suitable pressure vessel and subjecting it to 125% of the rated pressure for 15 days in a (helium enriched) breathing gas mix. Subsequently, the overpressure shall be reduced to normal pressure within 3 minutes. No evidence of water intrusion, condensation or problems caused by internal overpressure are allowed.
* An optional test originating from the ISO 2281 tests (but not required for obtaining ISO 6425 approval) is exposing the watch to an overpressure of 2 bar, no more than 50 μg/min of air is allowed to get inside the case.

Except the thermal shock resistance test all further ISO 6425 testing should be conducted at 18 °C to 25 °C temperature. The required 125% test pressure provides a safety margin against dynamic pressure increase events, water density variations (seawater is 2 to 5% denser than freshwater) and degradation of the seals.

Movement-induced dynamic pressure increase is sometimes the subject of urban myths and marketing arguments for diver's watches with high water resistance ratings. When a diver makes a fast swimming movement of 10 m/s (33 ft/s) (the best competitive swimmers and finswimmers cannot swim nearly that fast) physics dictates that the diver generates a dynamic pressure of 0.5 bars (50 kPa) or the equivalent of 5 meters of additional water depth.

### Water resistance classification

Watches are classified by their degree of water resistance, which roughly translates to the following (1 meter ≈ 3.28 feet):[41]

Water resistance rating | Suitability | Remarks

|
|

Water Resistant or 50 m | Suitable for swimming, no snorkeling water related work, and fishing. | NOT suitable for diving.
Water Resistant 100 m | Suitable for recreational surfing, swimming, snorkeling, sailing and water sports. | NOT suitable for diving.
Water Resistant 200 m | Suitable for professional marine activity and serious surface water sports. | Suitable for skin diving only. NOT suitable for scuba diving.
Diver's 100 m | Minimum ISO standard (ISO 6425) for scuba diving at depths NOT suitable for saturation diving. | Diver's 100 m and 150 m watches are generally old(er) watches.
Diver's 200 m or 300 m | Suitable for scuba diving at depths NOT suitable for saturation diving. | Typical ratings for contemporary diver's watches.
Diver's 300+ m for mixed-gas diving | Suitable for saturation diving (helium-enriched environment). | Watches designed for mixed-gas diving will have the DIVER’S WATCH xxx M FOR MIXED-GAS DIVING additional marking to point this out.

Note: The depth specified on the watch dial or case represents the results of tests done in the lab, not in the ocean.[40]

Some watches are rated in bars instead of meters. Since 1 bar is approximately the pressure exerted by 10 m of water, a rating in bars may be multiplied by 10 to be approximately equal to that based on meters. Therefore, a 20 bar watch is equivalent to a 200-meter watch. Some watches are rated in atmospheres (atm), which are about 1% greater than bars. In the United Kingdom, scuba divers and others often use the word atmosphere interchangeably with bar (1 atm = 1.01325 bar, or 101,325 Pa).

### Watches designed for extreme water resistance

Rolex Sea Dweller DEEPSEA model 116660, with a water resistance of 3,900 m (12,800 ft)

The design and actual availability of divers' watches certified for more than 1,000 to 1,200 metres (3,300 to 3,900 ft) is not explicable solely by practical diving needs nor crewed deep diving experiments, because of the constraints set by physiological limits for fit humans.[42] The diving depth record for off-shore (saturation) diving was achieved in 1988 by a team of professional divers of the Comex S.A., industrial deep-sea diving company performing pipe line connection exercises at a depth of 534 m (1,752 ft) of seawater (msw/fsw) in the Mediterranean Sea as part of the Hydra 8 programme.[43] In 1992, a Comex diver achieved a simulated 701 m (2,300 ft) of seawater depth in an on-shore hyperbaric chamber as part of the Hydra 10 programme. A Hydreliox (hydrogen–helium–oxygen) gas mixture was used as breathing gas.[44] The watches used during these scientific record dives were Rolex Sea-Dwellers with a 1,220 m (4,000 ft) depth rating and these feats were used in advertising.[45][46][47] The complexity, medical problems and physiological limits such as those imposed by high-pressure nervous syndrome and accompanying high costs of professional saturation diving to depths exceeding 300 m (984 ft) and the development of deep water atmospheric diving suits and remotely operated underwater vehicles in offshore oilfield drilling and production effectively nixed the need for ever deeper non-atmospheric crewed intervention in the ocean. These practical factors make watch depth ratings of more than 1,000 to 1,200 metres (3,300 to 3,900 ft) marketing and technical show off curiosities.

#### Air-filled watches

In 2022, Rolex introduced the Oyster Perpetual Deepsea Challenge Sea-Dweller (reference 126067), a full ocean depth capable watch with an official depth rating of 11,000 metres (36,090 ft). This watch represented in its launch year the most water resistant mechanical watch in serial production. To obtain this official depth rating, the watch is tested to a depth of 13,750 metres (45,110 ft) to offer the 25% safety reserve required by the ISO 6425 divers' watches standard. Normal surface air-filled watch cases and crystals designed for extreme depths must be dimensionally large to cope with the encountered water pressure. The Rolex Deepsea Challenge normal surface air-filled watch case has a diameter of 50.0 mm (1.97 in) and a thickness of 23.0 mm (0.91 in) (domed crystal thickness 9.5 mm (0.37 in)) and the grade 5 titanium case and bracelet weigh 251 g (8.9 oz).[48][49][50] The German H2O watch GmbH offers custom-made H2O Kalmar 2 25000M mechanical diving watches, that have been certified to a depth of 25,000 metres (82,020 ft), which is much deeper than full ocean depth. The titanium H2O Kalmar 2 25000M watch case has a diameter of 42.5 mm (1.67 in) and a thickness of 22.85 mm (0.900 in) (domed crystal thickness 8.25 mm (0.325 in)) and weighs 126 g (4.4 oz).[51]

#### Liquid-filled watches

The cases of some diving watches designed for extreme depths are filled with silicone oil or fluorinated oil[52] (oil in which all the hydrogen is replaced by fluorine) exploiting the relative incompressibility of liquids. This technology only works with quartz movements as a mechanical movement does not work properly in the oil-filled case. An example of these watches is the Sinn UX (EZM 2B), whose case is certified by Germanischer Lloyd for 12,000 m (39,000 ft), which is deeper than the Challenger Deep. However, the quartz controlled movement is only certified for 5,000 m (16,000 ft).[53] A problem with this technology is to accommodate for thermal expansion of the liquid contained inside the watch. The employed oil changes volume by 10% over a temperature range from −20 °C (−4 °F) to 60 °C (140 °F). This property endangers a traditional watch case since the crystal would blow out from any significant internal overpressure. On the UX (EZM 2B), the case back contains a large movable piston with an o-ring seal, allowing the liquid inside the watch case to expand and contract to adjust internal fluid volume and equalize with outside pressure.[54] The liquid filling improves the watch face legibility under water significantly, due to reduced refractive index differences between the watch crystal and its adjacent media and eliminates crystal fogging due to condensation. To obtain its water resistance the Sinn UX (EZM 2B) stainless steel watch case has a diameter of 44 mm, thickness of 13.3 mm and the case and bracelet weigh 105 g. This is dimensionally modest compared to air-filled diving watches designed for extreme depths.[55][56][57][58]

#### Full ocean depth prototype/experimental watches

In January 1960, a Rolex Deep Sea Special prototype diving watch attached to the hull of the bathyscaphe Trieste reached a record depth of 10,913 ± 5 m (35,804 ± 16 ft) of seawater during a descent to the bottom of the "Western Pool" of the Challenger Deep, the deepest surveyed point in the oceans. The watch survived and tested as having functioned normally during its descent and ascent. The Deep Sea Special was a technology demonstration and marketing project, and the watch never went into production.[59][60][61][62]

In March 2012, a Rolex Oyster Perpetual Date Sea-Dweller Deepsea Challenge prototype diving watch attached to a manipulator arm of the DSV Deepsea Challenger descended to 10,908 m (35,787 ft) in the "Eastern Pool" of the Challenger Deep.[63][64][65] The watch was designed to be waterproof up to 1500 bar/15,000 m (49,213 ft) and functioned normally during its descent and ascent. The normal surface air-filled watch case has a diameter of 51.4 mm (2.02 in) and a thickness of 28.5 mm (1.12 in) (domed synthetic sapphire crystal 14.3 mm (0.56 in)) to cope with the water pressure at the deepest surveyed point in the oceans.[66][67][68]

Omega Seamaster Planet Ocean Ultra Deep Professional, strapped on Limiting Factor's manipulator

As of May 2019[update], the record for the deepest normally functioning experimental diving watch is held by the Omega Seamaster Planet Ocean Ultra Deep Professional after reaching a (revised) depth of 10,925 ± 4 m (35,843 ± 13 ft) of seawater during a descent to the bottom of the "Eastern Pool" of the Challenger Deep by the Five Deeps Expedition.[69][70][71] Two of these watches were attached to the outside of the Deep-Submergence Vehicle Limiting Factor: one on each of the main vessel's robotic arms and an additional one on the ultra-deep-sea lander Skaff.[72] Due to a technical problem the watch fixed to the ultra-deep-sea lander stayed on the bottom for two days before it and the lander were salvaged from an unrevised depth of 10,927 m (35,850 ft).[73][74] The normal surface air-filled watch case is made of (DNV GL certified) forged grade 5 Titanium alloy (same as the hull of the DSV Limiting Factor) has a 55 mm (2.17 in) diameter and is almost 28 mm (1.10 in) thick and has been tested and certified for up to 1500 bar/15,000 m (49,213 ft).[75]

## Maintenance

Casio G-Shock Frogman Tough Solar MULTIBAND6 GWF-1000BP-1JF digital Diver's 200 m on a polymer strap

Diving watch manufacturers recommend divers to have their diving watch pressure tested by a service and repair facility annually or every two to five years and have the seals or gaskets replaced. Besides that, simple maintenance by the owner is also important. Manufacturers recommend rinsing the watch in fresh water after use in seawater, but leaving a diver's watch in fresh water overnight is a good method to protect the watch from corrosion and to keep the crown, bezel, buttons and pressure sensors on digital ones working.[76] Some watch companies[example needed] have restricting or limiting policies like manufacturer service center maintenance and repair only in effect that can interfere with other precautionary and maintenance policies or expeditious turnaround, modification or long term support needs.

### Precautions

Divers have to inspect their watch and the wrist band for defects before every dive and especially in case it came into contact with dirt, gasoline or strong chemicals, powerful magnetic fields or was banged against something hard during use. Additionally, watches with mechanical movements should also be hand-wound or in case of automatic movements that can not be hand-wound given sufficient motion to self-wind before every dive to ensure a fully charged mainspring.[77]

## See also

* Engineering:Trench watch - Early wristwatch design used in World War I
* Engineering:Military watches - Wristwatch designed for military use
* List of 24-hour watch brands

## References

1. ↑ What Did Divers Use Before Dive Watches? By Roger Ruegger, WatchTime.com, May 2014
2. ↑ http://www.qualitytyme.net/pages/rolex_articles/m_gleitze.html The Vindication Swim: Mercedes Gleitze and Rolex take the plunge and become world-renowned... By John E. Brozek International Wristwatch Magazine, 24 September 2015
3. ↑ Omega Marine 1932 Museum Collection Limited Series
4. ↑ De Burton, Simon; Negretti, Giampiero (2008). Panerai: History. Flammarion-Pere Castor. ISBN 978-2080305411.
5. ↑ Radiomir 1936 - 47mm
6. ↑ "Dive watches". Monochrome-watches. 15 April 2016. https://monochrome-watches.com/technical-perspective-dive-watches.
7. ↑ "Submariner historical benchmarks". Rolex. http://www.rolex.com/en/.
8. ↑ DrStrong. "The Blancpain Fifty Fathoms". FiftyFathoms.net. http://www.fiftyfathoms.net/FiftyFathoms/FiftyFathoms.html.
9. ↑ "The Classic Zodiac Sea Wolf - A History" (in en-US). 2019-09-01. https://thespringbar.com/blogs/guides/the-zodiac-sea-wolf/.
10. ↑ Debunking the Fictitious History of the Fifty Fathoms by Jose Pereztroika, Perezcope.com, September 2023
11. ↑ Prickett, CM; Searle, Willard F, Jr (1959). "Miscellaneous Comments on Several Submersible Wrist Watches". Navy Experimental Diving Unit Technical Report NEDU-Evaluation-24-59. http://archive.rubicon-foundation.org/3833.
12. ↑ 12.0 12.1 Balfour, Michael (2005-06-09). "The diving watch: Licensed to thrill - down to 2 500 metres". Financial Times. http://search.ft.com/nonFtArticle?id=050609010555.
13. ↑ "ZRC and the French Navy". https://zrc1904.com/since-1904-a-brand-story/zrc-and-the-french-navy/.
14. ↑ "In-Depth: Diving with a Vintage Tornek-Rayville". https://www.hodinkee.com/articles/vintage-tornek-rayville-diving-in-depth.
15. ↑ "Seiko 62mas – The first professional diver watch by Seiko". http://www.fratellowatches.com/seiko-62mas-the-first-professional-diver-watch-by-seiko/.
16. ↑ "Rolex "Double Red" Sea-Dweller Submariner 2000". London Watch Company. http://www.londonwatchcompany.com/watches/Rolex-sea-dweller2.htm.
17. ↑ "Omega Seamaster 600 PloProf". DeskDivers. http://www.deskdivers.com/Site/PloProf.html.
18. ↑ Ruegger, Roger (2003-12-01). "Under Pressure Eine Zeitreise: Die Highlights auf dem Weg nach unten" (in de). Dive into Watches. Dive (into) Watches. https://diveintowatches.com/articles/eine-chronologie/.
19. ↑ Omega PloProf Book
20. ↑ Ploprof 600m and 1200m anyone ? part 1
21. ↑ Part II: Omega Ploprof 600 m and 1200 m comparison
22. ↑ Morrison, ES (1983). "Evaluation of Digital Diving Watches.". Navy Experimental Diving Unit Technical Report NEDU-Evaluation-2-83. http://archive.rubicon-foundation.org/4848.
23. ↑ Lang, M.A.; Hamilton, R.W. Jr (1989). Proceedings of the AAUS Dive Computer Workshop. United States: USC Catalina Marine Science Center. p. 231. http://archive.rubicon-foundation.org/4242. Retrieved 2008-05-02.
24. ↑ "Gear Review: Oceanic BUD". 19 August 2013. https://scubadiverlife.com/gear/gear-review-oceanic-bud/.
25. ↑ Davis, Andy (29 April 2023). "Technical diving: Redundant computers vs backup bottom timer and custom tables". https://scubatechphilippines.com/scuba_blog/backup-redundant-computers-technical-diving/.
26. ↑ Stainless Steel - Grade 316L - Properties, Fabrication and Applications
27. ↑ Stainless Steel - Grade 904L - Properties, Fabrication and Applications
28. ↑ Calculation of pitting resistance equivalent numbers (PREN)
29. ↑ Bezel markings explanation at Watchuseek Dive Watches Forum
30. ↑ Stover, Thomas (2022-02-19). "Counting Up Vs. Counting Down: Examining The Diver's Bezel, Countdown Bezel, And Chronograph" (in en-US). https://www.fratellowatches.com/divers-bezel-countdown-bezel-chronograph/.
31. ↑ THE DOXA SUB PROFESSIONAL SERIES, HOW TO USE THE SUB BEZEL at doxawatches.com
32. ↑ DECOMPRESSION BEZEL at jennywatches.com
33. ↑ [¨ A Closer Look At Crown Guards by Aleta Saeger, January 21, 2016]
34. ↑ Crown Guards by Teun van Heerebeek, October 29, 2018
35. ↑ The New Breitling Avenger Seawolf Chronograph
36. ↑ "The Sinn U1000". http://www.watchreport.com/2008/01/the-sinn-u1000.html.
37. ↑ Manual of a 1 000 m mixed gas diver's watch dealing with a Helium Escape Valve and other diving watch characteristics.
38. ↑ Illustrated article on the most common bracelet types
39. ↑ NATO wrist watch strap requirements by the UK MOD
40. ↑ 40.0 40.1 "Watch Industry Questions and Answers: Water-Resistance". Europa Star. VNU eMedia Inc. http://www.europastar.com/europastar/watch_tech/waterresistance.jsp.
41. ↑ "Frequently Asked Questions - About Seiko & Seiko Timepieces". Seiko Corporation. http://www.seikousa.com.
42. ↑ How Deep Can We Go? by Dennis Guichard December 4th, 2022
43. ↑ "Extreme Environment Engineering Departement Hyperbaric Experimental Centre - History". http://www.comex.fr/suite/ceh/histo/histo anglais.html.
44. ↑ Portrait of Theo Mavrotomos, legend and diving recordman
45. ↑ Comex S.A. HYDRA 8 and HYDRA 10 test projects
46. ↑ DEEP-DIVING-EXPERIMENTS
47. ↑ "COMEX Watches by Guill@ume and Delgado". http://doubleredseadweller.com/comex watch.htm.
48. ↑ The Record-Breaking Rolex Deepsea Challenge RLX Titanium (And It's Not A Prototype)
49. ↑ The Beast Of The Depths, The Titanium Rolex Deepsea Challenge 126067
50. ↑ Rolex Shatters Water-Resistance Records With Its First Titanium Watch
51. ↑ H2O KALMAR 2 25000M
52. ↑ "Bell & Ross Hydromax 11000 m technical specifications". http://www.bellross.com/download/notices/Hydromax-en.pdf.
53. ↑ Sinn HYDRO
54. ↑ Patent DE19647439 (A1) "Diver's watch used for serious underwater use"
55. ↑ "Extreme Dive Watches from TechnoMarine, Bell & Ross, MTM, and Sinn". http://www.watchreport.com/2007/08/extreme-dive-wa.html.
56. ↑ The Sinn Einsatzzeitmesser 2 (EZM2)
57. ↑ Case and movement certification for the Sinn UX (EZM 2B) liquid filled watch (German)
58. ↑ Case and movement certification for Liquid filled Sinn watches (German)
59. ↑ Rolex Deep Sea Special Prototype
60. ↑ The Deep Sea Special and the Display Models
61. ↑ Rare Watches: Voyage to the bottom of the sea: Part 1: Rolex Deep Special
62. ↑ The Rolex Deep Sea Special first DSS prototypes made between 1953 and the final deepest dive of Piccard and Walsh in 1960 and the later DSS display
63. ↑ The Rolex Deepsea Challenge
64. ↑ "Deepsea Challenge". National Geographic Society. http://deepseachallenge.com/.
65. ↑ ROLEX Sea-Dweller DEEPSEA Challenge
66. ↑ Rolex Deepsea Challenge Watch by Kyle Stults, March 20, 2012
67. ↑ James Cameron about the Rolex Deepsea Challenge
68. ↑ Rare Watches: Voyage to the bottom of the sea: Part 2: Rolex Deepsea Challenge
69. ↑ As deep as it gets
70. ↑ Omega Seamaster Planet Ocean Ultra Deep Professional – The New World’s Deepest Dive Watch (Field-Tested 10,927m)
71. ↑ "The Five Deeps Expedition Overview". fivedeeps.com. https://fivedeeps.com/home/expedition/.
72. ↑ The Omega Seamaster Planet Ocean Ultra Deep Professional Becomes The Deepest Diving Watch Ever
73. ↑ Omega's new watch was tested at the bottom of the Mariana Trench
74. ↑ "Deepest Submarine Dive in History, Five Deeps Expedition Conquers Challenger Deep". fivedeeps.com. https://fivedeeps.com/wp-content/uploads/2019/05/FDE-Challenger-Release-FINAL-5132019.pdf.
75. ↑ The Seamaster Planet Ocean Ultra Deep Professional
76. ↑ Operating, maintenance and precautions instructions for a diver's watch.
77. ↑ Seiko Cal. 7S26, 7S35 & 7S36 self-winding only Automatic Diver’s Watch Operating, maintenance and precautions instructions

| Wikimedia Commons has media related to:

Diving watch (category)

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## External links

* The NHV-30 (НВЧ-30) diving watch
* Xavier Markl, Monochrome-watches, A technical perspective Dive Watches
* Jose Pereztroika, The Fictitious History of the Blancpain Fifty Fathoms, Perezcope Magazine

* v
* t
* e

Underwater diving

* Diving modes
* Atmospheric pressure diving
* Freediving
* Saturation diving
* Scuba diving
* Snorkeling
* Surface-supplied diving
* Unmanned diving

Diving equipment

| Basic equipment|

* Diving mask
* Snorkel
* Swimfin

|

Breathing gas|

* Bailout gas
* Bottom gas
* Breathing air
* Decompression gas
* Emergency gas supply
* Heliox
* Nitrox
* Oxygen
* Travel gas
* Trimix

Buoyancy and
trim equipment|

* Buoyancy control device
* Power inflator
* Dump valve
* Diving weighting system
* Ankle weights
* Integrated weights
* Trim weights
* Weight belt

Decompression
equipment|

* Decompression buoy
* Decompression cylinder
* Decompression trapeze
* Dive computer
* Diving shot
* Jonline

Environmental
protection|

* Atmospheric diving suit
* Diving suit
* Dry suit
* Sladen suit
* Standard diving suit
* Rash vest
* Wetsuit
* Dive skins
* Hot-water suit

Helmets
and masks|

* Anti-fog
* Diving helmet
* Free-flow helmet
* Lightweight demand helmet
* Reclaim helmet
* Standard diving helmet
* Diving mask
* Band mask
* Half mask
* Full-face mask

Instrumentation|

* Bottom timer
* Depth gauge
* Dive computer
* Dive timer
* Diving compass
* Diving watch
* Pneumofathometer
* Submersible pressure gauge

Mobility
equipment|

* Diving bell
* Closed bell
* Wet bell
* Diving stage
* Diver propulsion vehicle
* Advanced SEAL Delivery System
* Cosmos CE2F series
* Dry Combat Submersible
* Human torpedo
* Motorised Submersible Canoe
* R-2 Mala-class swimmer delivery vehicle
* SEAL Delivery Vehicle
* Shallow Water Combat Submersible
* Siluro San Bartolomeo
* Wet Nellie
* Wet sub
* Necker Nymph
* Swimfins
* Monofin
* Towboard

Safety
equipment|

* Alternative air source
* Bailout block
* Bailout bottle
* Bolt snap
* Buddy line
* Distance line
* Dive light
* Dive reel
* Diver's cutting tool
* Diver's knife
* Diver's telephone
* Through-water communications
* Diving bell
* Diving safety harness
* Emergency gas supply
* Lifeline
* Screw gate carabiner
* Line marker
* Octopus regulator
* Pony bottle
* Rescue tether
* Safety helmet
* Shark-proof cage
* Surface marker buoy
* Personal locator beacon

Underwater
breathing
apparatus|

* Atmospheric diving suit
* Diving cylinder
* Burst disc
* Diving cylinder valve
* Diving helmet
* Diving regulator
* Single-hose regulator
* Twin-hose regulator
* Regulator malfunction
* Regulator freeze
* Full face diving mask
* Reclaim helmet
* Open-circuit scuba
* Scuba set
* Bailout bottle
* Decompression cylinder
* Independent doubles
* Manifolded twin set
* Scuba manifold
* Pony bottle
* Sidemount
* Sling cylinder
* Scuba replacement
* Standard diving dress
* Diving rebreather
* Carbon dioxide scrubber
* Carleton CDBA
* CDLSE
* Cis-Lunar
* Cryogenic rebreather
* CUMA
* DSEA
* Dolphin
* Electro-galvanic oxygen sensor
* FROGS
* Halcyon PVR-BASC
* Halcyon RB80
* IDA71
* Interspiro DCSC
* KISS
* LAR-5
* LAR-6
* LAR-V
* LARU
* Porpoise
* Dräger Ray
* Siebe Gorman CDBA
* Siva
* Viper
* Surface-supplied diving equipment
* Air line
* Diver's umbilical
* Diving air compressor
* Hookah
* Sea Trek
* Snuba
* Standard diving dress

Diving
equipment
manufacturers|

* AP Diving
* Apeks
* Aqua Lung America
* Aqua Lung/La Spirotechnique
* Beuchat
* René Cavalero
* Cressi-Sub
* Dacor
* DESCO
* Dive Xtras
* Divex
* Diving Unlimited International
* Drägerwerk
* Fenzy
* Maurice Fernez
* Technisub
* Oscar Gugen
* Heinke
* HeinrichsWeikamp
* Johnson Outdoors
* Mares
* Morse Diving
* Nemrod
* Oceanic Worldwide
* Porpoise
* Sub Sea Systems
* Shearwater Research
* Siebe Gorman
* Submarine Products
* Suunto

Diving support equipment

| Breathing gas|

* Air filtration
* Booster pump
* Carbon dioxide scrubber
* Cascade filling system
* Diver's pump
* Diving air compressor
* Diving air filter
* High pressure breathing air compressor
* Low pressure breathing air compressor
* Gas blending
* Gas blending for scuba diving
* Gas panel
* Gas reclaim system
* Gas storage bank
* Gas storage quad
* Gas storage tube
* Helium analyzer
* Nitrox production
* Membrane method of gas concentration
* Pressure swing adsorption
* Oxygen analyser
* Oxygen compatibility

|

Decompression
equipment|

* Built-in breathing system
* Decompression tables
* Dive computer
* Diving bell
* Bell cursor
* Closed bell
* Clump weight
* Launch and recovery system
* Wet bell
* Diving chamber
* Diving stage
* Jersey upline
* Recreational Dive Planner
* Saturation system

Platforms|

* Dive boat
* Boarding stirrup
* Canoe and kayak diving
* Combat Rubber Raiding Craft
* Diving platform (scuba)
* Liveaboard
* Subskimmer
* Diving support vessel
* HMS Challenger (K07)
* Moon pool
* Underwater habitat
* Aquarius Reef Base
* Continental Shelf Station Two
* Helgoland Habitat
* Jules' Undersea Lodge
* Scott Carpenter Space Analog Station
* SEALAB
* Tektite habitat

Remotely operated
underwater vehicles|

* 8A4-class ROUV
* ABISMO
* Atlantis ROV Team
* CURV
* Épaulard
* Global Explorer ROV
* Goldfish-class ROUV
* Kaikō ROV
* Long-Term Mine Reconnaissance System
* Mini Rover ROV
* OpenROV
* ROV KIEL 6000
* ROV PHOCA
* Scorpio ROV
* Sea Dragon-class ROV
* Seabed tractor
* Seafox drone
* Seahorse ROUV
* SeaPerch
* SJT-class ROUV
* T1200 Trenching Unit
* VideoRay UROVs

Safety equipment|

* Diver down flag
* Diving shot
* Hyperbaric lifeboat
* Hyperbaric stretcher
* Jackstay
* Jonline
* Reserve gas supply

General|

* Diving ladder
* Hot water system
* Downline

Freediving

| Activities|

* Aquathlon
* Apnoea finswimming
* Freediving
* Haenyeo
* Pearl hunting
* Ama
* Snorkeling
* Spearfishing
* Underwater football
* Underwater hockey
* Underwater ice hockey
* Underwater rugby
* Underwater target shooting

|

Competitions|

* Nordic Deep
* Vertical Blue
* Disciplines
* Constant weight (CWT)
* Constant weight without fins (CNF)
* Dynamic apnea (DYN)
* Dynamic apnea without fins (DNF)
* Free immersion (FIM)
* No-limits apnea (NLT)
* Static apnea (STA)
* Skandalopetra diving
* Variable weight apnea (VWT)
* Variable weight apnea without fins

Equipment|

* Diving mask
* Diving suit
* Fins
* Hawaiian sling
* Monofin
* Polespear
* Snorkel (swimming)
* Speargun
* Water polo cap

Freedivers|

* Deborah Andollo
* Peppo Biscarini
* Sara Campbell
* Derya Can Göçen
* Goran Čolak
* Carlos Coste
* Robert Croft
* Mandy-Rae Cruickshank
* Yasemin Dalkılıç
* Leonardo D'Imporzano
* Flavia Eberhard
* Şahika Ercümen
* Emma Farrell
* Francisco Ferreras
* Pierre Frolla
* Flavia Eberhard
* Mehgan Heaney-Grier
* Elisabeth Kristoffersen
* Loïc Leferme
* Enzo Maiorca
* Jacques Mayol
* Audrey Mestre
* Karol Meyer
* Stéphane Mifsud
* Alexey Molchanov
* Natalia Molchanova
* Dave Mullins
* Patrick Musimu
* Guillaume Néry
* Herbert Nitsch
* Umberto Pelizzari
* Annelie Pompe
* Michal Risian
* Stig Severinsen
* Tom Sietas
* Aharon Solomons
* Martin Štěpánek
* Walter Steyn
* Tanya Streeter
* William Trubridge
* Devrim Cenk Ulusoy
* Danai Varveri
* Alessia Zecchini
* Nataliia Zharkova

Hazards|

* Barotrauma
* Drowning
* Freediving blackout
* Deep-water blackout
* Shallow-water blackout
* Hypercapnia
* Hypothermia

Historical|

* Ama
* Octopus wrestling
* Swimming at the 1900 Summer Olympics – Men's underwater swimming

Organisations|

* AIDA International
* Scuba Schools International
* Australian Underwater Federation
* British Freediving Association
* Confédération Mondiale des Activités Subaquatiques
* Fédération Française d'Études et de Sports Sous-Marins
* Performance Freediving International

Professional diving

| Occupations|

* Ama
* Commercial diving
* Commercial offshore diving
* Hazmat diving
* Divemaster
* Diving instructor
* Diving safety officer
* Diving supervisor
* Haenyeo
* Media diving
* Underwater photography
* Underwater videography
* Military diving
* Army engineer diver
* Clearance diver
* Frogman
* Police diving
* Public safety diving
* Scientific diving
* Underwater archaeology

|

Underwater work|

* Commercial offshore diving
* Dive guide
* Diver training
* Recreational diver training
* Hyperbaric welding
* Nondestructive testing
* Pearl hunting
* Police diving
* Public safety diving
* Salvage diving
* Scientific diving
* Sponge diving
* Submarine pipeline
* Underwater archaeology
* Underwater demolition
* Underwater photography
* Underwater search and recovery
* Underwater videography

Tools & equipment|

* Abrasive waterjet
* Airlift
* In-water surface cleaning
* Brush cart
* Cavitation cleaning
* Pressure washing
* Lifting bag
* Remotely operated underwater vehicle
* Silt screw
* Snoopy loop
* Thermal lance
* Tremie
* Water jetting

Underwater
weapons|

* Limpet mine
* Speargun
* Hawaiian sling
* Polespear

| Underwater
firearm|

* Gyrojet
* Mk 1 Underwater Defense Gun
* Powerhead
* Underwater pistols
* Heckler & Koch P11
* SPP-1 underwater pistol
* Underwater revolvers
* AAI underwater revolver
* Underwater rifles
* ADS amphibious rifle
* APS underwater rifle
* ASM-DT amphibious rifle

|

Recreational diving

| Specialties|

* Altitude diving
* Cave diving
* Deep diving
* Ice diving
* Muck diving
* Open-water diving
* Rebreather diving
* Sidemount diving
* Solo diving
* Technical diving
* Wreck diving

|

Diver
organisations|

* British Sub-Aqua Club (BSAC)
* Cave Divers Association of Australia (CDAA)
* Cave Diving Group (CDG)
* Comhairle Fo-Thuinn (CFT)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Federación Española de Actividades Subacuáticas (FEDAS)
* Fédération Française d'Études et de Sports Sous-Marins (FFESSM)
* International Association for Handicapped Divers (IAHD)
* National Association for Cave Diving (NACD)
* Woodville Karst Plain Project (WKPP)

Diving tourism
industry|

* Environmental impact of recreational diving
* Scuba diving tourism
* Shark tourism
* Sinking ships for wreck diving sites

Recreational
dive sites|

| Reef diving
regions|

* Arrecifes de Cozumel National Park
* Great Barrier Reef
* iSimangaliso Marine Protected Area
* Poor Knights Islands
* Table Mountain National Park Marine Protected Area

|

Reef dive
sites|

* Artificial reef
* Gibraltar Artificial Reef
* Shark River Reef
* Osborne Reef
* Palancar Reef
* Underwater artworks
* Cancún Underwater Museum
* Christ of the Abyss
* The Diver
* Molinere Underwater Sculpture Park

Wreck diving
regions|

* Chuuk Lagoon
* Maritime Heritage Trail – Battle of Saipan
* Whitefish Point Underwater Preserve
* Wreck Alley, San Diego

Wreck dive
sites|

* HMS A1
* HMS A3
* Engineering:USS Aaron Ward
* Abessinia
* Aeolian Sky
* Albert C. Field
* Andrea Doria
* Antilla
* Antilles
* Aquila
* Engineering:USS Arkansas
* HMS Boadicea
* Bianca C.
* Booya
* HMSAS Bloemfontein
* Breda
* HMAS Brisbane
* Bungsberg
* HMAS Canberra
* Carl D. Bradley
* Carnatic
* SMS Dresden
* Dunraven
* Eastfield
* HMT Elk
* Ellengowan
* RMS Empress of Ireland
* HMS Falmouth
* Fifi
* SS Francisco Morazan
* Fujikawa Maru
* Fumizuki
* SATS General Botha
* USNS General Hoyt S. Vandenberg
* HMS Ghurka
* Glen Strathallan
* SAS Good Hope
* Gothenburg
* Herzogin Cecilie
* Hilma Hooker
* Hispania
* HMS Hood
* HMAS Hobart
* Igara
* James Eagan Layne
* Captain Keith Tibbetts
* King Cruiser
* SMS Kronprinz
* Kyarra
* HMS Laforey
* USAT Liberty
* Louis Sheid
* Engineering:USS LST-507
* SMS Markgraf
* Mikhail Lermontov
* HMS M2
* Maine
* Maloja
* HMS Maori
* Marguerite
* SS Mauna Loa
* USAT Meigs
* Mendi
* USCGC Mohawk
* Mohegan
* RMS Moldavia
* HMS Montagu
* MV RMS Mulheim
* Nagato
* Oceana
* Engineering:USS Oriskany
* Oslofjord
* P29
* P31
* Pedernales
* Persier
* HMAS Perth
* SAS Pietermaritzburg
* Piłsudski
* Pool Fisher
* HMS Port Napier
* Preußen
* President Coolidge
* PS Queen Victoria
* Radaas
* Error: {{Ship}} missing prefix (help)
* RMS Rhone
* Rondo
* Rosehill
* Error: {{Ship}} missing prefix (help)
* Royal Charter
* Rozi
* HMS Safari
* Salem Express
* Engineering:USS Saratoga
* Engineering:USS Scuffle
* HMS Scylla
* HMS Sidon
* Engineering:USS Spiegel Grove
* Stanegarth
* Stanwood
* Stella
* HMAS Swan
* Engineering:USS Tarpon
* Thesis
* Thistlegorm
* Toa Maru
* Torrey Canyon
* SAS Transvaal
* Tulagi
* Tulamben
* U-40
* U-352
* U-1195
* Um El Faroud
* Varvassi
* Walter L M Russ
* Washingtonian (1913)
* HMNZS Wellington
* Engineering:USS Yancey
* Yongala
* Zenobia
* Zealandia
* Zingara

Cave diving
sites|

* Devil's Throat at Punta Sur
* Engelbrecht
* Fossil Cave
* Piccaninnie Ponds
* Pollatoomary
* Sistema Ox Bel Ha
* Sistema Sac Actun
* Sistema Dos Ojos
* Sistema Nohoch Nah Chich

Freshwater
dives|

* Ewens Ponds
* Little Blue Lake

Training sites|

* Capernwray Dive Centre
* National Diving and Activity Centre
* Stoney Cove

Open ocean
diving|

* Blue-water diving
* Black-water diving

Diving safety

* Ergonomics of diving equipment
* Human factors in diving safety
* Life support system
* Safety-critical system

| Diving hazards|

* Trait anxiety
* Cold shock response
* Decompression
* List of diving hazards and precautions
* Nitrogen narcosis
* Overconfidence effect
* Oxygen toxicity
* Panic
* Penetration diving
* Seasickness
* Silt out
* Single point of failure
* Task loading
* Uncontrolled decompression

|

Consequences|

* Barotrauma
* Decompression sickness
* Drowning
* Hypothermia
* Hypoxia
* Hypercapnia
* Hypothermia

Risk
management|

* Checklist
* Hazard identification and risk assessment
* Hazard analysis
* Job safety analysis
* Risk assessment
* Risk control
* Hierarchy of hazard controls
* Incident pit
* Lockout-tagout
* Permit To Work
* Redundancy
* Safety data sheet
* Situation awareness
* Diving team
* Bellman
* Chamber operator
* Diver's attendant
* Diving supervisor
* Diving systems technician
* Life support technician
* Stand-by diver
* Equipment safety
* Breathing gas quality
* Testing and inspection of diving cylinders
* Hydrostatic test
* Sustained load cracking
* Diving regulators
* Breathing performance of regulators
* Occupational safety and health
* Approaches to safety
* Job safety analysis
* Risk assessment
* Toolbox talk
* Housekeeping
* Association of Diving Contractors International
* Code of practice
* Contingency plan
* Diving regulations
* Emergency procedure
* Emergency response plan
* Evacuation plan
* Hazardous Materials Identification System
* Hierarchy of hazard controls
* Administrative controls
* Engineering controls
* Hazard elimination
* Hazard substitution
* Personal protective equipment
* International Marine Contractors Association
* Occupational hazard
* Biological hazard
* Chemical hazard
* Physical hazard
* Psychosocial hazard
* Occupational hygiene
* Exposure assessment
* Occupational exposure limit
* Workplace health surveillance
* Safety culture
* Code of practice
* Health and safety representative
* Operations manual
* Safety meeting
* Standard operating procedure

Diving
procedures|

* Ascending and descending
* Emergency ascent
* Boat diving
* Canoe and kayak diving
* Buddy diving
* Decompression
* Decompression practice
* Pyle stop
* Ratio decompression
* Dive briefing
* Dive log
* Dive planning
* Scuba gas planning
* Diver communications
* Diving hand signals
* Diving line signals
* Diver voice communications
* Diver rescue
* Diver training
* Doing It Right
* Drift diving
* Gas blending for scuba diving
* Night diving
* Solo diving
* Water safety

Incidents|

| Diver rescues|

* Tham Luang cave rescue

|

Early diving|

* John Day (carpenter)
* Charles Spalding
* Ebenezer Watson

Freediving|

* Loïc Leferme
* Audrey Mestre
* Nicholas Mevoli
* Natalia Molchanova

Professional
diving|

* Johnson Sea Link accident
* Offshore diving incidents
* Byford Dolphin diving bell accident
* Drill Master diving accident
* Star Canopus diving accident
* Venture One diving accident
* Waage Drill II diving accident
* Wildrake diving accident
* Professional diver fatalities
* Roger Baldwin
* John Bennett
* Victor F. Guiel Jr.
* Craig M. Hoffman
* Peter Henry Michael Holmes
* Edwin Clayton Link
* Gerard Anthony Prangley
* Pier Skipness
* Robert John Smyth
* Albert D. Stover
* Richard A. Walker
* Lothar Michael Ward
* Joachim Wendler
* Death of Bradley Westell
* Arne Zetterström

Scuba diving
fatalities|

* Ricardo Armbruster
* Allan Bridge
* David Bright
* Berry L. Cannon
* Cotton Coulson
* Cláudio Coutinho
* E. Yale Dawson
* Deon Dreyer
* Milan Dufek
* Sheck Exley
* Maurice Fargues
* Guy Garman
* Steve Irwin
* Jim Jones
* Henry Way Kendall
* Artur Kozłowski
* Chris and Chrissy Rouse
* Kirsty MacColl
* Agnes Milowka
* François de Roubaix
* Dave Shaw
* Wesley C. Skiles
* Dewey Smith
* Rob Stewart
* Esbjörn Svensson
* Josef Velek

Diving medicine

| Diving
disorders|

* List of signs and symptoms of diving disorders
* Cramps
* Motion sickness
* Surfer's ear

| Pressure
related|

* Aerosinusitis
* Air embolism
* Alternobaric vertigo
* Barodontalgia
* Barostriction
* Barotrauma
* Compression arthralgia
* Decompression illness
* Dental barotrauma
* Dysbarism
* Pulmonary barotrauma

| Oxygen|

* Freediving blackout
* Hyperoxia
* Hypoxia
* Oxygen toxicity

|

Inert gases|

* Avascular necrosis
* Decompression sickness
* Isobaric counterdiffusion
* Taravana
* Dysbaric osteonecrosis
* High-pressure nervous syndrome
* Hydrogen narcosis
* Nitrogen narcosis

Carbon dioxide|

* Hypercapnia
* Hypocapnia

Breathing gas
contaminants|

* Carbon monoxide poisoning

Immersion
related|

* Asphyxia
* Drowning
* Hypothermia
* Immersion diuresis
* Instinctive drowning response
* Laryngospasm
* Salt water aspiration syndrome
* Swimming-induced pulmonary edema

Treatment|

* Demand valve oxygen therapy
* First Aid
* Hyperbaric medicine
* Hyperbaric treatment schedules
* In-water recompression
* Oxygen therapy
* Therapeutic recompression

Personnel|

* Diving Medical Examiner
* Diving Medical Practitioner
* Diving Medical Technician
* Hyperbaric nursing

Screening|

* Atrial septal defect
* Fitness to dive
* Psychological fitness to dive

Research|

| Researchers in
diving physiology
and medicine|

* Arthur J. Bachrach
* Albert R. Behnke
* Paul Bert
* George F. Bond
* Robert Boyle
* Albert A. Bühlmann
* John R. Clarke
* Guybon Chesney Castell Damant
* William Paul Fife
* John Scott Haldane
* Robert William Hamilton Jr.
* Leonard Erskine Hill
* Brian Andrew Hills
* Felix Hoppe-Seyler
* Christian J. Lambertsen
* Simon Mitchell
* Charles Momsen
* John Rawlins R.N.
* Charles Wesley Shilling
* Edward D. Thalmann
* Jacques Triger

|

Diving medical
research
organisations|

* Aerospace Medical Association
* Divers Alert Network (DAN)
* Diving Diseases Research Centre (DDRC)
* Diving Medical Advisory Council (DMAC)
* European Diving Technology Committee (EDTC)
* European Underwater and Baromedical Society (EUBS)
* National Board of Diving and Hyperbaric Medical Technology
* Naval Submarine Medical Research Laboratory
* Royal Australian Navy School of Underwater Medicine
* Rubicon Foundation
* South Pacific Underwater Medicine Society (SPUMS)
* Southern African Underwater and Hyperbaric Medical Association (SAUHMA)
* Undersea and Hyperbaric Medical Society (UHMS)
* United States Navy Experimental Diving Unit (NEDU)

Law

* Civil liability in recreational diving
* Duty of care
* List of legislation regulating underwater diving
* Investigation of diving accidents

History of underwater diving

* Aqua-Lung
* History of decompression research and development
* History of scuba diving
* List of researchers in underwater diving
* Porpoise regulator
* Standard diving dress
* Timeline of diving technology
* Underwater diving in popular culture
* Vintage scuba

Publications

| Manuals|

* NOAA Diving Manual
* U.S. Navy Diving Manual
* Basic Cave Diving: A Blueprint for Survival

|

Standards and
Codes of Practice|

* DIN 7876

General non-fiction|

* The Darkness Beckons
* Goldfinder
* The Last Dive
* Shadow Divers

Training and registration

| Diver
training|

* Diving instructor
* Diving school
* Occupational diver training
* Commercial diver training
* Military diver training
* Public safety diver training
* Scientific diver training
* Competence and assessment
* Competency-based learning
* Skill assessment
* Refresher training (diving)
* Diver training standard
* Recreational diver training
* Introductory diving
* Skills
* Diver navigation
* Diver trim
* Ear clearing
* Frenzel maneuver
* Valsalva maneuver
* Finning techniques
* Scuba skills
* Buddy breathing
* Low impact diving
* Diamond Reef System
* Surface-supplied diving skills
* Underwater searches
* Teaching methods
* Muscle memory
* Overtraining
* Stress exposure training

|

Organisations|

* European Underwater Federation (EUF)
* International Diving Regulators and Certifiers Forum (IDRCF)
* International Diving Schools Association (IDSA)
* International Marine Contractors Association (IMCA)
* List of diver certification organizations
* National Oceanic and Atmospheric Administration (NOAA)
* Nautical Archaeology Society
* Universal Referral Program
* World Recreational Scuba Training Council (WRSTC)

| Commercial diver
certification
authorities|

* Australian Diver Accreditation Scheme (ADAS)
* Commercial diver registration in South Africa
* Divers Institute of Technology
* Health and Safety Executive (HSE)
* Department of Employment and Labour

|

Commercial diving
schools|

* Divers Academy International

Free-diving
certification
agencies|

* AIDA International (AIDA)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Performance Freediving International (PI)
* Scuba Schools International (SSI)

Recreational scuba
certification
agencies|

* American Canadian Underwater Certifications (ACUC)
* American Nitrox Divers International (ANDI)
* Association nationale des moniteurs de plongée (ANMP)
* British Sub-Aqua Club (BSAC)
* Comhairle Fo-Thuinn (CFT)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Federación Española de Actividades Subacuáticas (FEDAS)
* Fédération Française d'Études et de Sports Sous-Marins (FFESSM)
* Federazione Italiana Attività Subacquee (FIAS)
* Global Underwater Explorers (GUE)
* International Association for Handicapped Divers (IAHD)
* International Association of Nitrox and Technical Divers (IANTD)
* International Diving Educators Association (IDEA)
* Israeli Diving Federation (TIDF)
* National Association for Cave Diving (NACD)
* National Academy of Scuba Educators (NASE)
* National Association of Underwater Instructors (NAUI)
* Nederlandse Onderwatersport Bond (NOB)
* Professional Association of Diving Instructors (PADI)
* Professional Diving Instructors Corporation (PDIC)
* Sub-Aqua Association (SAA)
* Scuba Diving International (SDI)
* Scuba Educators International (SEI)
* Scottish Sub Aqua Club (ScotSAC)
* Scuba Schools International (SSI)
* Türkiye Sualtı Sporları Federasyonu (TSSF)
* United Diving Instructors (UDI)
* YMCA SCUBA Program

Recreational scuba
certification
levels|

* Advanced Open Water Diver
* Autonomous diver
* CMAS* scuba diver
* CMAS** scuba diver
* Dive leader
* Divemaster
* Diving instructor
* Introductory diving
* Low Impact Diver
* Master Instructor
* Master Scuba Diver
* Open Water Diver
* Rescue Diver
* Solo diver
* Supervised diver

Scientific diver
certification
authorities|

* American Academy of Underwater Sciences (AAUS)
* CMAS Scientific Committee

Technical
certification
agencies|

* American Nitrox Divers International (ANDI)
* British Sub-Aqua Club (BSAC)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Diving Science and Technology (DSAT)
* Federazione Italiana Attività Subacquee (FIAS)
* Global Underwater Explorers (GUE)
* International Association of Nitrox and Technical Divers (IANTD)
* National Association of Underwater Instructors (NAUI)
* Professional Association of Diving Instructors (PADI)
* Professional Diving Instructors Corporation (PDIC)
* Technical Diving International (TDI)
* Trimix Scuba Association (TSA)
* Technical Extended Range (TXR)

| Cave
diving|

* Cave Divers Association of Australia (CDAA)
* Cave Diving Group (CDG)
* Global Underwater Explorers (GUE)
* National Association for Cave Diving (NACD)
* National Speleological Society#Cave Diving Group (CDG)
* National Association of Underwater Instructors (NAUI)
* Technical Diving International (TDI)

|

Underwater sports

| Surface snorkeling|

* Finswimming (surface swimming & bi-fins)

|

Snorkeling/breath-hold|

* Spearfishing
* Underwater football
* Underwater hockey
* Underwater rugby
* Underwater target shooting

Breath-hold|

* Aquathlon (underwater wrestling)
* Apnoea finswimming
* Freediving
* Underwater ice hockey

Open Circuit Scuba|

* Immersion finswimming
* Sport diving (sport)
* Underwater orienteering
* Underwater photography (sport)

Rebreather|

* Underwater photography (sport)

Sports governing
organisations|

* International
* AIDA International
* Confédération Mondiale des Activités Subaquatiques)
* National
* Australian Underwater Federation
* British Octopush Association
* British Underwater Sports Association
* Comhairle Fo-Thuinn
* Federación Española de Actividades Subacuáticas
* Fédération Française d'Études et de Sports Sous-Marins
* South African Underwater Sports Federation
* Türkiye Sualtı Sporları Federasyonu
* Underwater Society of America)

Freediver Federations|

* AIDA International
* AIDA Hellas
* British Freediving Association (BFA)
* Confédération Mondiale des Activités Subaquatiques (CMAS)

Sports federations|

* Australian Underwater Federation (AUF)
* British Octopush Association (BOA)
* British Underwater Sports Association (BUSA)
* Federación Española de Actividades Subacuáticas (FEDAS)
* Fédération Française d'Études et de Sports Sous-Marins (FFESSM)
* South African Underwater Sports Federation (SAUSF)
* Türkiye Sualtı Sporları Federasyonu (TSSF)
* Underwater Society of America (USOA)

Underwater divers

| Pioneers of diving|

* Aquanaut
* Jacques Cousteau
* Hans Hass
* Arne Zetterström

|

Underwater scientists and archaeologists|

* Michael Arbuthnot
* Robert Ballard
* George Bass
* Mensun Bound
* Louis Boutan
* Hugh Bradner
* Cathy Church
* Eugenie Clark
* James P. Delgado
* Sylvia Earle
* John Christopher Fine
* George R. Fischer
* Anders Franzén
* Honor Frost
* David Gibbins
* Robert F. Marx
* Charles T. Meide
* Mark M. Newell
* John Peter Oleson
* Margaret Rule
* Gunter Schöbel
* E. Lee Spence
* Robert Sténuit
* Peter Throckmorton

Scuba record holders|

* Sheck Exley
* Nuno Gomes

Underwater filmmakers|

* Samir Alhafith
* David Attenborough
* Ramón Bravo
* Ivan Tors
* Andrew Wight

Underwater photographers|

* Tamara Benitez
* Georges Beuchat
* Adrian Biddle
* Jonathan Bird
* Eric Cheng
* Neville Coleman
* Jacques Cousteau
* John D. Craig
* Ben Cropp
* Bernard Delemotte
* David Doubilet
* John Christopher Fine
* Dermot FitzGerald
* Rodney Fox
* Ric Frazier
* Stephen Frink
* Peter Gimbel
* Monty Halls
* Hans Hass
* Henry Way Kendall
* Rudie Kuiter
* Joseph B. MacInnis
* Luis Marden
* Agnes Milowka
* Noel Monkman
* Steve Parish
* Zale Parry
* Pierre Petit
* Leni Riefenstahl
* Peter Scoones
* Brian Skerry
* Wesley C. Skiles
* E. Lee Spence
* Philippe Tailliez
* Ron and Valerie Taylor
* Albert Tillman
* John Veltri
* Stan Waterman
* Jiang Wenhao
* Michele Westmorland
* John Ernest Williamson
* J. Lamar Worzel

Underwater explorers|

* Caves
* Sheck Exley
* Martyn Farr
* Jill Heinerth
* William Hogarth Main
* Rick Stanton
* Bill Stone
* John Volanthen
* Reefs
*   * Wrecks
* Clive Cussler
* Aristotelis Zervoudis

Science of underwater diving

| Diving
physics|

* Breathing performance of regulators
* Buoyancy
* Archimedes' principle
* Neutral buoyancy
* Diffusion
* Molecular diffusion
* Force
* Gas law
* Amontons's law
* Boyle's law
* Charles's law
* Combined gas law
* Dalton's law
* Gay-Lussac's law
* Ideal gas law
* Oxygen fraction
* Permeation
* Pressure
* Absolute pressure
* Ambient pressure
* Atmospheric pressure
* Gauge pressure
* Hydrostatic pressure
* Metre sea water
* Partial pressure
* Psychrometric constant
* Solubility
* Henry's law
* Saturation
* Solution
* Supersaturation
* Surface tension
* Hydrophobe
* Surfactant
* Torricellian chamber
* Underwater vision
* Snell's law
* Weight
* Apparent weight

|

Diving
physiology|

* Artificial gills
* Circulatory system
* Blood shift
* Patent foramen ovale
* Perfusion
* Systemic circulation
* Cold shock response
* Diving reflex
* Equivalent narcotic depth
* Lipid
* Maximum operating depth
* Metabolism
* Physiological response to water immersion
* Respiration
* Blood–air barrier
* Breathing
* CO₂ retention
* dead space
* Gas exchange
* Hypocapnia
* Normocapnia
* Respiratory exchange ratio
* Respiratory quotient
* Respiratory system
* Work of breathing
* Tissue
* Underwater vision

| Decompression
theory|

* Decompression models:
* Bühlmann decompression algorithm
* Haldane's decompression model
* Reduced gradient bubble model
* Thalmann algorithm
* Thermodynamic model of decompression
* Varying Permeability Model
* Equivalent air depth
* Equivalent narcotic depth
* Maximum operating depth
* Oxygen window in diving decompression
* Physiology of decompression
* Pulmonary circulation

|

Diving
environment|

| Diving
environment
classification|

* Altitude diving
* Benign water diving
* Confined water diving
* Deep diving
* Inland diving
* Inshore diving
* Muck diving
* Night diving
* Open water diving
* Open ocean diving
* Black-water diving
* Blue-water diving
* Penetration diving
* Cave diving
* Ice diving
* Wreck diving
* Recreational dive sites
* Underwater environment

|

Environmental
impact|

* Environmental impact of recreational diving
* Low impact diving

Environmental
factors|

* Algal bloom
* Currents:
* Current
* Longshore drift
* Ocean current
* Rip current
* Tidal race
* Undertow
* Upwelling
* Ekman transport
* Halocline
* List of diving hazards and precautions
* Reef
* Coral reef
* Stratification
* Thermocline
* Tides
* Turbidity
* Wind wave
* Breaking wave
* Surf
* Surge
* Wave shoaling

Special interest groups

* Artificial Reef Society of British Columbia (ARSBC)
* CMAS Europe
* Diving Equipment and Marketing Association (DEMA)
* Divers Alert Network (DAN)
* Green Fins
* Historical Diving Society
* Nautical Archaeology Society (NAS)
* Naval Air Command Sub Aqua Club
* Project AWARE
* Reef Life Survey
* Save Ontario Shipwrecks (SOS)
* SeaKeys
* Sea Research Society

Other

* Submarine escape training facility

* Category
* Commons
*   * Glossary
* Indexes: dive sites
* divers
* diving
*   * Outline
* Portal

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