Diving watch
Encyclopedia
Watch
A watch is a small timepiece, typically worn either on the wrist or attached on a chain and carried in a pocket, with wristwatches being the most common type of watch used today. They evolved in the 17th century from spring powered clocks, which appeared in the 15th century. The first watches were...
designed for underwater diving
Underwater diving
Underwater diving is the practice of going underwater, either with breathing apparatus or by breath-holding .Recreational diving is a popular activity...
that features, as a minimum, a water resistance
Waterproofing
Waterproof or water-resistant describes objects relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or under water to specified depths...
greater than 10 atm (1 MPa), the equivalent of 100 m (328.1 ft). The typical diver's watch will have a water resistance of around 200 to 300 m (656.2 to 984.3 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 (328.1 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.
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". 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.Omega SA is credited as the creator of the world's first industrially produced diving watch intended for commercial distribution, the Omega "Marine", 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 13.5 atm (1.4 MPa), equivalent to a depth of 135 m (442.9 ft), without any water intake whatsoever.
Following a request made by the Royal Italian Navy
Regia Marina
The Regia Marina dates from the proclamation of the Kingdom of Italy in 1861 after Italian unification...
in September 1935 for a luminous underwater watch for divers Panerai
Panerai
Officine Panerai Marketing e Communicazioni Srl, a wholly owned subsidiary of Compagnie Financière Richemont S.A., designs, manufactures, markets and sells watches under the Officine Panerai brand through authorized dealers and company-owned boutiques worldwide. Giovanni Panerai founded Officine...
offered "Radiomir" underwater timepieces in 1936.
In addition, a large number of "canteen" style dive watches by Hamilton
Hamilton Watch Company
The Hamilton Watch Company was originally formed to produce high quality pocket watches and wristwatches mid-range and luxury. Hamilton would become a corporate conglomerate diversified in other operations...
, Elgin or Waltham
Waltham Watch Company
The Waltham Watch Company, also known as the American Waltham Watch Co. and the American Watch Co., produced about 40 million high quality watches, clocks, speedometers, compasses, time fuses and other precision instruments between 1850 and 1957...
were made to military specification during and after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. 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.
In 1953 Lip-Blancpain
Blancpain
Blancpain is a luxury Swiss watch manufacturer, founded in 1735 by Jehan-Jaques Blancpain. Blancpain went into bankruptcy and stopped production for a long period but was saved by Jean-Claude Biver, an executive with Omega. Blancpain is owned by the Swatch Group. Since 2002, Marc Hayek, the...
's Fifty Fathoms waterproof watch came on the market in France. 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
Palme d'Or
The Palme d'Or is the highest prize awarded at the Cannes Film Festival and is presented to the director of the best feature film of the official competition. It was introduced in 1955 by the organising committee. From 1939 to 1954, the highest prize was the Grand Prix du Festival International du...
at the Cannes film festival
Cannes Film Festival
The Cannes International Film Festival , is an annual film festival held in Cannes, France, which previews new films of all genres including documentaries from around the world. Founded in 1946, it is among the world's most prestigious and publicized film festivals...
in 1956, and in the US when TV star Lloyd Bridges
Lloyd Bridges
Lloyd Vernet Bridges, Jr. was an American actor who starred in a number of television series and appeared in more than 150 feature films. Bridges is best known for his role of Mike Nelson in Sea Hunt, the most-popular syndicated American TV series in 1958...
wore a Blancpain Fifty Fathoms dive watch in a photo that appeared on the cover of the February 1962 edition of Skin Diver Magazine.
The Rolex Submariner
Rolex Submariner
The Rolex Oyster Perpetual Submariner is a line of watches manufactured by Rolex, designed for diving and known for their resistance to water. The first Submariner was introduced to the public in 1954 at the Swiss Watch Fair...
was introduced at the Basel
Basel
Basel or Basle In the national languages of Switzerland the city is also known as Bâle , Basilea and Basilea is Switzerland's third most populous city with about 166,000 inhabitants. Located where the Swiss, French and German borders meet, Basel also has suburbs in France and Germany...
Watch Fair in 1954 which coincided with the development of self-contained underwater breathing apparatus, known as scuba
Scuba set
A scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
. In 1961 Rolex began to include a skindiver
Scuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
handbook with the Submariner, then available in two models, one water resistant to 200 m (656.2 ft), the other, less expensive version, to 100 m (328.1 ft). It was the choice of watch for the character of 007 in the first ten James Bond
James Bond
James Bond, code name 007, is a fictional character created in 1953 by writer Ian Fleming, who featured him in twelve novels and two short story collections. There have been a six other authors who wrote authorised Bond novels or novelizations after Fleming's death in 1964: Kingsley Amis,...
films, causing the "Sub" to achieve an iconic status.
In 1959, the United States Navy Experimental Diving Unit
United States Navy Experimental Diving Unit
The United States Navy Experimental Diving Unit is the primary source of diving and hyperbaric operational guidance for the US Navy...
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.
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
Rolex Sea Dweller
The Rolex Oyster Perpetual Date Sea-Dweller is a line of diver's watches manufactured by Rolex, with an underwater diving depth rating of for the vintage models and up to 3,900 metres for the most recent Sea-Dweller DEEPSEA model.-History:...
(2000 ft = 610 m) that became available in 1967 and was produced in several variations and the Omega Seamaster Professional 600m/2000ft also known as the "Omega PloProf" (Plongeur Professionel) that came available in 1970 and was produced in several variations.
In 1983, the US Navy Experimental Diving Unit evaluated several digital watches for use by US Navy divers.
In 1996 the International Organization for Standardization
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
(ISO) introduced the standards and features for diving watches regulated by the ISO 6425 - Divers' watches international standard. 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.
Many contemporary sports watches owe their design to diving watches.
The vast majority of divers now use electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
, wrist-worn dive computer
Dive computer
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.- Purpose :...
s. A dive computer or decompression meter is a device used by a scuba diver
Scuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
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
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
. Diving watches and depth gauge
Depth gauge
A depth gauge is a pressure gauge that displays the equivalent depth in water. It is a piece of diving equipment often used by SCUBA divers.Most modern diving depth gauges have an electronic mechanism and digital display. Older types used a mechanical mechanism and analogue display.A diver uses a...
s are however still commonly used by divers as backup instruments for overcoming dive computer malfunctions.
Characteristics
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
Mechanical watch
A mechanical watch is a watch that uses a mechanical mechanism to measure the passage of time, as opposed to modern quartz watches which function electronically. It is driven by a spring which must be wound periodically...
. Diving watches can be analog or digital
Digital clock
A digital clock is a type of clock that displays the time digitally, i.e. in cyphers, as opposed to an analog clock, where the time is displayed by hands. Digital clocks are often associated with electronic drives, but the "digital" description refers only to the display, not to the drive mechanism...
. 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 StandardizationInternational Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
in the ISO 6425 standard. Besides water resistance standards to a minimum of 100 meter depth rating ISO 6425 also provides minimum requirements for mechanical
Mechanical watch
A mechanical watch is a watch that uses a mechanical mechanism to measure the passage of time, as opposed to modern quartz watches which function electronically. It is driven by a spring which must be wound periodically...
diver's watches (quartz and digital watches have slightly differing readability requirements) such as:
- The presence of a unidirectional bezel with at least at every 5 minutes elapsed minute markings and a pre-select marker to mark a specific minute marking.
- 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 resistanceAntimagnetic watchAnti-magnetic watches are those that are able to run with minimal deviation when exposed to a certain magnetic field. The International Organization for Standardization issued a standard for magnetic resistant watches, which many countries have adopted.-ISO 764 magnetic resistant watches...
. This is tested by 3 expositions 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 resistanceShock resistant watchShock resistant is a common mark stamped on the back of wrist watches to indicate how well a watch copes with shocks.-ISO 1413 shock-resistant standard:...
. 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 salinitySalinitySalinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
comparable to normal seawaterSeawaterSeawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
. - 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 corrosivenessGalvanic series
The galvanic series determines the nobility of metals and semi-metals. When two metals are submerged in an electrolyte, while electrically connected, the less noble will experience galvanic corrosion. The rate of corrosion is determined by the electrolyte and the difference in nobility...
of seawater, so the cases are generally made out of materials like stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
, titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
, ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
s and synthetic resin
Synthetic resin
Synthetic resins are materials with a property of interest that is similar to natural plant resins: they are viscous liquids that are capable of hardening permanently. Otherwise, chemically they are very different from the various resinous compounds secreted by plants .The synthetics are of several...
s or plastics. The case must also provide an adequate degree of protection against external magnetic
Antimagnetic watch
Anti-magnetic watches are those that are able to run with minimal deviation when exposed to a certain magnetic field. The International Organization for Standardization issued a standard for magnetic resistant watches, which many countries have adopted.-ISO 764 magnetic resistant watches...
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
Incabloc shock protection system
The Incabloc shock protection system is the trade name for a spring-loaded mounting system for the jewel bearings that support the balance wheel in a mechanical watch, to protect the wheel's delicate pivots from damage in the event of physical shock, such as if the watch is dropped...
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 out of stainless steel. Stainless steel is however still often used as case material in contemporary diving watches.
Elapsed time controller
Tachymeter
A tachymeter or tacheometer is a type of theodolite used for rapid measurements and determines, electronically or electro-optically, the distance to target, and is highly automated in its operations. Such tachymeters are often used in surveying...
.) When the zero on the bezel is aligned with the watch's seconds or (usually) minutes hand on the water entry moment a diver can read off the elapsed time from the bezel. This saves the diver having to remember the exact water entry moment and having to perform arithmetic’s 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
Ratchet (device)
A ratchet is a device that allows continuous linear or rotary motion in only one direction while preventing motion in the opposite direction. Because most socket wrenches today use ratcheting handles, the term "ratchet" alone is often used to refer to a ratcheting wrench, and the terms "ratchet"...
so it can only be turned anti-clockwise to increase the apparent elapsed time. This is an important "fail safe" feature. If the bezel could be turned clockwise this could suggest to a diver that the elapsed time was 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
Dive profile
A dive profile is a two dimensional graphical representation of a dive showing depth and time.It is useful as an indication of the risks of decompression sickness and oxygen toxicity and also the volume of open-circuit breathing gas needed for a planned dive as these depend in part upon the depth...
and depths past 30 m (98.4 ft)
Deep diving
The meaning of the term deep diving is a form of technical diving. It is defined by the level of the diver's diver training, diving equipment, breathing gas, and surface support:...
require other more advanced timing and measuring methods to establish suitable decompression profiles to avoid decompression sickness
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
.
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
Cooking
Cooking is the process of preparing food by use of heat. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training...
.
Digital dive watches usually perform the elapsed timer function by use of a standard stop watch function. Digital dive watches may also feature a depth gauge
Depth gauge
A depth gauge is a pressure gauge that displays the equivalent depth in water. It is a piece of diving equipment often used by SCUBA divers.Most modern diving depth gauges have an electronic mechanism and digital display. Older types used a mechanical mechanism and analogue display.A diver uses a...
and logging features, but are not usually regarded as a substitute for a dedicated dive computer.
Bezel markings
Most contemporary dive watches with conspicuous 15 or 20 minute markings on their bezels are the result of copying a Rolex bezel design of the 1950s. Back then divers typically planned a dive to a certain maximum depth based on now obsolete US Navy dive tables, and dove according to the planned dive profile. If the dive profileDive profile
A dive profile is a two dimensional graphical representation of a dive showing depth and time.It is useful as an indication of the risks of decompression sickness and oxygen toxicity and also the volume of open-circuit breathing gas needed for a planned dive as these depend in part upon the depth...
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 15 or 20 minute 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.
Crystal
Diving watches have relatively thick watch crystals. Sometimes domed crystals are used to enhance the pressure resistance of the watch. The typical materials used for crystals are acrylic glassAcrylic glass
Poly is a transparent thermoplastic, often used as a light or shatter-resistant alternative to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate...
, hardened glass
Toughened glass
Toughened or tempered glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempering creates balanced internal stresses which cause the glass, when broken, to crumble into small granular chunks instead of...
and (synthetic) sapphire which all have their pros and cons. Acrylic glass is very break resistant but can easily be scratched. It has however the advantage 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 shatter proof than the other crystal options. Anti-reflective coatings are generally applied on sapphire crystals to enhance the legibility of the watch. Some manufacturers use sapphire/hardened glass laminate
Laminate
A laminate is a material that can be constructed by uniting two or more layers of material together. The process of creating a laminate is lamination, which in common parlance refers to the placing of something between layers of plastic and gluing them with heat and/or pressure, usually with an...
crystals, where the scratch resistance 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. Display backs are however a rare feature on diving watches.
Crown
Pushers
Digital and some analog chronographChronograph
A chronograph is a timepiece or watch with both timekeeping and stopwatch functions as well as other functions. Pocket watch chronographs were produced as early as the 18th century but did not become popular until the 1820s...
diving watches - such as the
Breitling
Breitling
Breitling is a luxury brand of Swiss watches produced by Breitling SA, a private company headquartered in Grenchen, Canton of Solothurn . The company exclusively offered Certified Chronometers in all models since 2000...
Avenger Seawolf Chronograph or Sinn
Sinn (watchmaker)
Sinn is a high end watch-making company based in Frankfurt am Main, Germany that was established by pilot and flight instructor Helmut Sinn in 1961.-History:...
U1000 - 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 divingSaturation diving
Saturation diving is a diving technique that allows divers to reduce the risk of decompression sickness when they work at great depth for long periods of time....
at great depths are fitted with a helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
or mixed breathing gas
Breathing gas
Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...
release or escape valve
Helium release valve
A helium release valve, or helium escape valve, as it is also called, is a feature found on some diving watches. It provides functionality for professional divers operating at great depths for prolonged periods of time or under saturation....
to prevent 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
Covalent radius
The covalent radius, rcov, is a measure of the size of an atom that forms part of one covalent bond. It is usually measured either in picometres or angstroms , with 1 Å = 100 pm....
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.
Watchstrap/bracelet
Watchtstraps or bracelets for diving watches are generally made out 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 rubberRubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...
, silicone rubber
Silicone rubber
Silicone rubber is an elastomer composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations...
, polyurethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...
or fabric watchstrap or a stainless steel or titanium metal link or mesh
Chain Mail
"Chain Mail" is a single by Mancunian band James, released in March 1986 by Sire Records, the first after the band defected from Factory Records. The record was released in two different versions, as 7" single and 12" EP, with different artworks by John Carroll and, confusingly, under different...
bracelet of adequate length to facilitate wearing the watch over a diving suit
Diving suit
A diving suit is a garment or device designed to protect a diver from the underwater environment. A diving suit typically also incorporates an air-supply .-History:...
sleeve.
For a wrist with a 200 mm (7.9 in) circumference
Circumference
The circumference is the distance around a closed curve. Circumference is a special perimeter.-Circumference of a circle:The circumference of a circle is the length around it....
wearing a 4 mm (0.15748031496063 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 deployment clasp by which the bracelet can be appropriately extended by approximately 20 mm (0.78740157480315 in) to 30 mm (1.2 in).
Some watchstraps allow an increase in length by adding a diving suit extension strap piece to the standard watchstrap. If required more than one diving suit extension strap piece can be added to the standard watchstrap.
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 watchstraps 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 exaggerated tight for normal wear at the surface whilst keeping the watch adequately tight in place on the divers wrist at depth.
Metal link bracelets theoretically have more failure points compared to metal mesh bracelets and watchstraps due to the use of link connection parts like split pins or screw pins. One piece (NATO style) nylon
Ballistic nylon
Ballistic nylon is a thick, tough, synthetic nylon fabric used for a variety of applications. Ballistic nylon was originally developed by the DuPont corporation as a material for flak jackets to be worn by World War II airmen...
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
The dials and markers on the watch faceClock face
A clock face is the part of an analog clock that displays the time through the use of a fixed numbered dial or dials and moving hands. In its most basic form, recognized universally throughout the world, the dial is numbered 1–12 indicating the hours in a 12-hour cycle, and a short hour hand...
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.
For low light conditions luminous phosphorescent
Phosphorescence
Phosphorescence is a specific type of photoluminescence related to fluorescence. Unlike fluorescence, a phosphorescent material does not immediately re-emit the radiation it absorbs. The slower time scales of the re-emission are associated with "forbidden" energy state transitions in quantum...
non-toxic strontium aluminate
Strontium aluminate
Strontium aluminate is a solid odorless, nonflammable, pale yellow powder, heavier than water. It is chemically and biologically inert. When activated with a suitable dopant , it acts as a photoluminescent phosphor with long persistence of phosphorescence...
based lume
Lume
Lume is a short term for the luminous phosphorescent glowing solution applied on watch dials. There are some people who "relume" watches, or replace faded lume...
pigments marketed under brand names like Super-LumiNova
Super-LumiNova
Super-LumiNova is a brand name under which strontium aluminate based non-radioactive and non-toxic photoluminescent or afterglow pigments for illuminating markings on watch dials, hands and bezels, etc. in the dark are marketed...
or NoctiLumina and tritium based self-powered lighting
Self-powered lighting
Tritium illumination is the use of gaseous tritium, a radioactive isotope of hydrogen, to create visible light. Tritium emits electrons through beta decay, and when they interact with a phosphor material, fluorescent light is created, a process called radioluminescence...
devices called "gaseous tritium light source" (GTLS) is applied on the dials and markers. On digital diving watches lighted displays are used for low light conditions legibility.
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
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
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 gasket
Gasket
thumb|sright|250px|Some seals and gaskets1. [[o-ring]]2. fiber [[Washer |washer]]3. paper gaskets4. [[cylinder head]] [[head gasket|gasket]]...
s 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.
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 meter rating will be water resistant if it is stationary and under 250 meters 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.
- 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
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
is 2 to 5% denser than freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
) 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 (32.8 ft/s) (the best competitive swimmers
Swimming (sport)
Swimming is a sport governed by the Fédération Internationale de Natation .-History: Competitive swimming in Europe began around 1800 BCE, mostly in the form of the freestyle. In 1873 Steve Bowyer introduced the trudgen to Western swimming competitions, after copying the front crawl used by Native...
and finswimmers
Finswimming
Finswimming is the progression of a swimmer using monofins or normal swimfins either on the water surface or underwater, using only muscle strength. It is a discipline of underwater sports. The competition distances are same as for swimming...
can not nearly swim that fast) physics dictates that the diver generates a dynamic pressure of 0.5 bar
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...
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):| 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. | NOT suitable for diving. |
| Diver's 100 m | Minimum ISO standard (ISO 6425) for scuba diving Scuba diving Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater.... 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 Saturation diving Saturation diving is a diving technique that allows divers to reduce the risk of decompression sickness when they work at great depth for long periods of time.... (helium enriched environment). |
Watches designed for mixed-gas diving will have the DIVER’S WATCH L 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.
Some watches are rated in bars
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...
instead of meters. Since 1 bar is the 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
Atmosphere (unit)
The standard atmosphere is an international reference pressure defined as 101325 Pa and formerly used as unit of pressure. For practical purposes it has been replaced by the bar which is 105 Pa...
(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
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
).
Watches designed for extreme water resistance
The diving depth record for off-shore (saturation) diving
Saturation diving
Saturation diving is a diving technique that allows divers to reduce the risk of decompression sickness when they work at great depth for long periods of time....
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 of seawater (msw) (1,752 ft) in the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
. In 1992 a Comex diver achieved a record of 701 msw (2,300 ft) in an on-shore hyperbaric chamber. A hydrogen-helium-oxygen gas mixture was used as breathing gas
Breathing gas
Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...
. The watches used during this scientific record dives were Rolex Sea-Dwellers with a 1220 m (4,002.6 ft) depth rating and these feats were used in advertising.
The complexity, medical problems and accompanying high costs of professional saturation diving
Saturation diving
Saturation diving is a diving technique that allows divers to reduce the risk of decompression sickness when they work at great depth for long periods of time....
to extreme depths and the development of deep water atmospheric diving suit
Atmospheric diving suit
An atmospheric diving suit or ADS is a small one-man articulated submersible of anthropomorphic form which resembles a suit of armour, with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere...
s and remotely operated underwater vehicles in offshore oilfield drilling and production effectively nixed the need for ever deeper non-atmospheric manned intervention in the ocean.
Air filled watches
In 1960 a Rolex Deep Sea Special prototype diving watch attached to the hull of the bathyscapheBathyscaphe
A bathyscaphe is a free-diving self-propelled deep-sea submersible, consisting of a crew cabin similar to a bathysphere, but suspended below a float rather than from a surface cable, as in the classic bathysphere design....
Trieste
Bathyscaphe Trieste
The Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe with a crew of two, which reached a record maximum depth of about , in the deepest known part of the Earth's oceans, the Challenger Deep, in the Mariana Trench near Guam, on January 23, 1960, crewed by Jacques Piccard ...
reached a record depth of 10,916 msw (35,813 ft) during a descend to the bottom of the Challenger Deep
Challenger Deep
The Challenger Deep is the deepest known point in the oceans, with a depth of to by direct measurement from submersibles, and slightly more by sonar bathymetry . It is located at the southern end of the Mariana Trench near the Mariana Islands group...
, 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.
At the BaselWorld
BaselWorld
Baselworld Watch and Jewellery Show is a trade show for the watch and jewellery industry organized annually in the city of Basel, Switzerland. The international show unites about 2,100 exhibitors from over 45 countries, including the leading watch and jewelry brands, as well as companies...
watch and jewellery show 2009, the CX Swiss Military Watch 20'000 FEET diving watch with an official depth rating of 6000 m (19,685 ft) was introduced. This watch represented in its launch year, 2009, the most water resistant (mechanical) watch
Automatic watch
An automatic or self-winding watch is a mechanical watch, whose mainspring is wound automatically by the natural motion of the wearer's arm, providing energy to run the watch, to make it unnecessary to manually wind the watch. A watch which is not self-winding is called a manual watch...
in production. For obtaining this official depth rating the water resistance is tested to a depth of 7500 m (24,606.3 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. To obtain its water resistance the CX Swiss Military Watch 20'000 FEET solid titanium watch case has a diameter of 46.0 mm, thickness of 28.5 mm (domed crystal thickness 10 mm) and the case and bracelet weigh 265 g.
Liquid filled watches
The cases of some diving watches designed for extreme depths are filled with silicone oilSilicone oil
A silicone oil is any polymerized siloxanes with organic side chains. They are formed of alternating silicon-oxygen atoms or siloxane, rather than carbon atoms . Other species attach to the tetravalent silicon atoms, not to the divalent oxygen atoms which are fully committed to forming the...
or fluorinated oil (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
Germanischer Lloyd
The Germanischer Lloyd SE is a classification society based in the city of Hamburg, Germany. As a technical supervisory organization Germanischer Lloyd conducts safety surveys on more than 7,000 ships with over 100 Mio GT...
for 12000 m (39,370.1 ft), which is deeper than the Challenger Deep
Challenger Deep
The Challenger Deep is the deepest known point in the oceans, with a depth of to by direct measurement from submersibles, and slightly more by sonar bathymetry . It is located at the southern end of the Mariana Trench near the Mariana Islands group...
. However, the quartz controlled movement is only certified for 5000 m (16,404.2 ft). At extreme liquid pressures, the metal tube or the glass vial that shields the movement's quartz crystal oscillator in a quartz movement
Quartz clock
A quartz clock is a clock that uses an electronic oscillator that is regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks are at least an order of magnitude more accurate than good mechanical clocks...
will eventually implode and the movement will stop functioning. The watch battery
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
is another critical part that might fail under extreme liquid pressure.
A problem with this technology is to accommodate for thermal expansion
Thermal expansion
Thermal expansion is the tendency of matter to change in volume in response to a change in temperature.When a substance is heated, its particles begin moving more and thus usually maintain a greater average separation. Materials which contract with increasing temperature are rare; this effect is...
of the liquid contained inside the watch. The employed oil changes volume by 10% over a temperature range from -20 °C to 60 °C. 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. The liquid filling improves the watch face legibility under water significantly, due to reduced refractive index
Refractive index
In optics the refractive index or index of refraction of a substance or medium is a measure of the speed of light in that medium. It is expressed as a ratio of the speed of light in vacuum relative to that in the considered medium....
differences between the watch crystal and its adjacent media and discards of 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.
Maintenance
Most manufacturers recommend divers to have their diving watch pressure tested by an authorized service and repair facility annually or every two to three years and have the seals replaced. Besides that, simple maintenance by the owner is also important. Most 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, buttons and pressure sensors on digital ones working.Precautions
Divers have to inspect their watch and wrist band for defects before every dive and especially in case it came into contact with 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.External links
- Dive watch reviews and images by www.watchreport.com
- Licensed to Dive (nine divers’ watches comparative test) by Martina Richter - WatchTime October 2007
- DeskDivers - In Depth Dive Watch reviews fully illustrated
- A Journey in Time. The remarkable story of Seiko p. 85 - p. 88
- Image collection of diving watches sorted by brand (Watchuseek Dive Watches Forum Images sub forum)
- Timekeeping: The Dive Watch, Deconstructed Explaining the Basics, Debunking the Myths