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Timeline of Diving Technology
A chronological list of notable events in the history of underwater diving
The timeline of underwater diving technology is a chronological list of notable events in the history of underwater diving.
Ancient Roman and Greek era.: There have been many instances of men swimming or diving for combat, but they always had to hold their breath, and had no diving equipment, except sometimes a hollow plant stem used as a snorkel.
About 500 BC: (Information originally from Herodotus): During a naval campaign the Greek Scyllis was taken aboard ship as prisoner by the Persian King Xerxes I. When Scyllis learned that Xerxes was to attack a Greek flotilla, he seized a knife and jumped overboard. The Persians could not find him in the water and presumed he had drowned. Scyllis made his way among all the ships in Xerxes's fleet, cutting each ship loose from its moorings; he used a hollow reed as snorkel to remain unobserved. Then he swam nine miles (15 kilometers) to rejoin the Greeks off Cape Artemisium.
The use of diving bells was recorded by the Greek philosopher Aristotle in the 4th century BC: "...they enable the divers to respire equally well by letting down a cauldron, for this does not fill with water, but retains the air, for it is forced straight down into the water."
1300 or earlier: Persian divers were using diving goggles with windows made of the polished outer layer of tortoiseshell.
15th century: Leonardo da Vinci made the first known mention of air tanks in Italy: he wrote in his Atlantic Codex (Biblioteca Ambrosiana, Milan) that systems were used at that time to artificially breathe under water, but he did not explain them in detail. Some drawings, however, showed different kinds of snorkels and an air tank (to be carried on the breast) that presumably should have no external connections. Other drawings showed a complete immersion kit, with a plunger suit which included a sort of mask with a box for air. The project was so detailed that it included a urine collector.
the Englishman John Lethbridge, a wool merchant, invented a diving barrel and successfully salvaged valuables from wrecks.
Start of modern diving
1772: the first diving dress using a compressed-air reservoir was successfully designed and built in 1772 by Sieur (old French for "sir" or "Mister") Fréminet, a Frenchman from Paris. Fréminet conceived an autonomous breathing machine equipped with a helmet, two hoses for inhalation and exhalation, a suite and a reservoir, dragged by and behind the diver, although Fréminet later put it on his back. Fréminet called his invention machine hydrostatergatique and used it successfully for more than ten years in the harbours of Le Havre and Brest, as stated in the explanatory text of a 1784 painting.
1837: Captain William H. Taylor demonstrated his "submarine dress" at the annual American Institute Fair at Niblo's Garden, New York City.
Canadian inventors James Eliot and Alexander McAvity of Saint John, New Brunswick patented an "oxygen reservoir for divers", a device carried on the diver's back containing "a quantity of condensed oxygen gas or common atmospheric air proportionate to the depth of water and adequate to the time he is intended to remain below".
W.H.Thornthwaite of Hoxton in London patented an inflatable lifting jacket for divers.
1843: Based on lessons learned from the Royal George salvage, the first diving school is set up by the Royal Navy.
1845 James Buchanan Eads designed and built a diving bell and began salvaging cargo from the bottom of the Mississippi River, eventually working on the river bottom from the mouth of the river at the Gulf of Mexico to Iowa.
1856: Wilhelm Bauer started the first of 133 successful dives with his second submarine Seeteufel. The crew of 12 was trained to leave the submerged ship through a diving chamber (airlock).
1866: Minenschiff, the first self-propelled (locomotive) torpedo, developed by Robert Whitehead (to a design by Captain Luppis, Austrian Navy), was demonstrated for the imperial naval commission on December 21.
1808: on June 17, SieurPierre-Marie Touboulic (fr) from Brest, a mechanic in Napoleon's Imperial Navy, patented the oldest known oxygen rebreather, but there is no evidence of any prototype having been manufactured. This early rebreather design worked with an oxygen reservoir, the oxygen being delivered progressively by the diver himself and circulating in a closed circuit through a sponge soaked in limewater. Touboulic called his invention Ichtioandre (Greek for 'fish-man').
1849: Pierre-Aimable de Saint Simon Sicard (a chemist) made the first practical oxygen rebreather. It was demonstrated in London in 1854.
1853: Professor T. Schwann designed a rebreather in Belgium; he exhibited it in Paris in 1878. It had a big backpack oxygen tank at pressure about 13 bar, and two scrubbers containing sponges soaked in caustic soda.
1876: An English merchant seaman, Henry Fleuss, developed the first workable self-contained diving rig that used compressed oxygen. This prototype of closed-circuit scuba used rope soaked in caustic potash to absorb carbon dioxide so the exhaled gas could be re-breathed.
Diving helmets improved and in common use
1808: Brizé-Fradin designed a small bell-like helmet connected to a low-pressure backpack air container.
1820: Paul Lemaire d'Augerville (a Parisian dentist) invented and made a diving apparatus with a copper backpack cylinder, and with a counterlung to save air, and with an inflatable lifejacket connected. It was used down to 15 or 20 meters for up to an hour in salvage work. He started a successful salvage company.
1825: William H. James designed a self-contained diving suit that had compressed air in an iron container worn around the waist.
1827: Beaudouin in France developed a diving helmet fed from an air cylinder pressurized to 80 to 100 bar. The French Navy was interested, but nothing came of this.
Charles Anthony Deane and John Deane of Whitstable in Kent in England designed the first air-pumped diving helmet for use with a diving suit. It is said[by whom?]that the idea started from a crude emergency rig-up of a fireman's water-pump (used as an air pump) and a knight-in-armour helmet used to try to rescue horses from a burning stable. Others say that it was based on earlier work in 1823 developing a "smoke helmet". However the suit was not attached to the helmet, so a diver could not bend over or invert without risk of flooding the helmet and drowning. Nevertheless, the diving system is used in salvage work, including the successful removal of cannon from the British warship HMS Royal George in 1834-35. This 108-gun fighting ship sank in 65 feet of water at Spithead anchorage in 1783.
1837: Following up Leonardo's studies, and those of the astronomer Halley, Augustus Siebe developed surface supplied diving apparatus which became known as standard diving dress. By attaching the Deane brothers helmet to a suit, Augustus Siebe developed the Siebe "Closed" Dress combination diving helmet and suit, considered the foundation of modern diving dress. This was a significant evolution from previous models of "open" dress that did not allow a diver to invert. (Siebe-Gorman went on to manufacture helmets continuously until 1975).
1840: The Royal Navy uses Siebe closed dress for salvage and blasting work on the "Royal George", and subsequently the Royal Engineers standardise on this equipment.
1843: The Royal Navy establishes the first diving school.
1855: Joseph-Martin Cabirol patented a new model of standard diving dress, mainly issued from Siebe's designs. The suit was made out of rubberized canvas and the helmet, for the first time, includes a hand-controlled tap that the diver used to evacuate his exhaled air. The tap included on its turn a safety valve which prevented water from entering in the helmet. Until 1855 diving helmets were equipped with only three circular windows (for front, left and right sides). Cabirol's helmet introduced the later well known fourth window, situated in the upper front part of the helmet and allowing the diver to watch above him. Having been presented to the Exposition Universelle in Paris Cabirol's diving dress won the silver medal. These original diving dress and helmet are now preserved at the Conservatoire National des Arts et Métiers in Paris.
The first diving regulators
Diving set by Rouquayrol and Denayrouze with barrel-shaped air tank on the diver's back, depicted here in its surface-supplied configuration.
1838: Dr. Manuel Théodore Guillaumet invented a twin-hose demand regulator. On June 19, 1838, in London, England, a Mr. William Edward Newton filed a patent (no. 7695: "Diving apparatus") for a diaphragm-actuated, twin-hose demand valve for divers. However, it is believed that Mr. Newton was merely filing a patent on behalf of Dr. Guillaumet. The illustration of the apparatus in Newton's patent application is identical to that in Guillaumet's patent application; furthermore, Mr. Newton was apparently an employee of the British Office for Patents, who applied for patents on behalf of foreign applicants. It is demonstrated in surface-demand use. During the demonstration, use duration was limited to 30 minutes because the dive was in cold water without a diving suit.
1860: in Espalion (France), mining engineer Benoît Rouquayrol designed a self-contained breathing set with a backpack cylindrical air tank that supplied air through the first demand regulator to be commercialized (as of 1865, see below). Rouquayrol calls his invention régulateur ('regulator'), having conceived it to help miners avoid drowning in flooded mines.
1864: Benoît Rouquayrol met navy officer Auguste Denayrouze for the first time, in Espalion, and on Denayrouze's initiative, they adapted Rouquayrol's invention to diving. After having adapted it, they called their recently patented device appareil plongeur Rouquayrol-Denayrouze ('Rouquayrol-Denayrouze diving apparatus'). The diver still walked on the seabed and did not swim. The air pressure tanks made with the technology of the time could only hold 30 atmospheres, allowing dives of only 30 minutes at no more than ten metres deep; during surface-supplied configuration the tank was also used for bailout in the case of a hose failure. The durations of 6 to 8 hours on a tankful without external supply recorded for the Rouquayrol set in the book Twenty Thousand Leagues Under the Sea by Jules Verne, are wildly exaggerated fiction.
1865: on August the 28th the French Navy Minister ordered the first Rouquayrol-Denayrouze diving apparatus and large scale production started.
Gas and air cylinders appear
Late 19th century: Industry began to be able to make high-pressure air and gas cylinders. That prompted a few inventors down the years to design open-circuit compressed air breathing sets, but they were all constant-flow, and the demand regulator did not come back until 1937.
1893: Louis Boutan invented the first underwater camera and made the first underwater photographs.
1900: Louis Boutan published La Photographie sous-marine et les progrès de la photographie (The Underwater Photography and the Advances in Photography), the first book about underwater photography.
Decompression sickness recognised as a problem
1841: First documented case of decompression sickness occurred, reported by a mining engineer who observed pain and muscle cramps among coal miners working in mine shafts air-pressurized to keep water out.
1870: Bauer[who?] published outcomes of 25 paralyzed caisson workers.
From 1870 to 1910 all prominent symptoms/causes of decompression sickness were established: explanations at the time included: cold or exhaustion causing reflex spinal cord damage; electricity caused by friction on compression; or organ congestion and vascular stasis caused by decompression.
1871: The St LouisEads Bridge employed 352 compressed air workers including Dr. Alphonse Jaminet as the physician in charge. There were 30 seriously injured and 12 fatalities. Dr. Jaminet himself suffered a case of decompression sickness when he ascended to the surface in four minutes after spending almost three hours at a depth of 95 feet in a caisson, and his description of his own experience was the first such recorded.
1872: The similarity between decompression sickness and iatrogenic air embolism as well as the relationship between inadequate decompression and decompression sickness were noted by Friedburg.[clarification needed] He suggested that intravascular gas was released by rapid decompression and recommended: slow compression and decompression; four-hour working shifts; limit to maximum depth 44.1 psig (4 ATA); using only healthy workers; and recompression treatment for severe cases.
1873: Dr. Andrew Smith first used the term "caisson disease" to describe 110 cases of decompression sickness as the physician in charge during construction of the Brooklyn Bridge. The project employed 600 compressed air workers. Recompression treatment was not used. The project chief engineer Washington Roebling suffered from caisson disease. (He took charge after his father John Augustus Roebling died of tetanus.) Washington's wife, Emily, helped manage the construction of the bridge after his sickness confined him to his home in Brooklyn. He battled the after-effects of the disease for the rest of his life. During this project, decompression sickness became known as "The [Grecian] Bends" because afflicted individuals characteristically arched their backs: this is possibly reminiscent of a then fashionable women's dance maneuver known as the Grecian Bend.
1878: Paul Bert published La Pression barométrique, providing the first systematic understanding of the causes of DCS.
from 1903 to 1907: Professor Georges Jaubert, invented Oxylithe, a mixture of peroxides of sodium (Na2O2) and potassium with a small amount of salts of copper or nickel, which produces oxygen in the presence of water.
Several sources, including the 1991 US Navy Dive Manual (pg 1-8), state that the MK V Deep Sea Diving Dress was designed by the Bureau of Construction & Repair in 1905, but in reality, the 1905 Navy Handbook shows British Siebe-Gorman helmets in use. Since the earliest know MK V is dated 1916, these sources are probably referring to the earlier MK I, MK II, MK III & MK IV Morse and Schrader helmets.
The first rebreather with metering valves to control the supply of oxygen was made.
1915: The submarine USS F-4 was salvaged from 304 feet establishing the practical limits for air diving. Three US Navy divers, Frank W. Crilley, William F. Loughman, and Nielson, reached 304 fsw using the MK V dress.
The basic design of the MK V dress was finalized by including a battery-powered telephone, but several more detail improvements were made over the next two years.
1917: The Bureau of Construction & Repair adopted the MK V helmet and dress, which remained the standard for US Navy diving until the introduction of the MK 12 in the late seventies.
1918: the "Ohgushi's Peerless Respirator" was first patented. Invented in 1916 by Riichi Watanabi and the blacksmith Kinzo Ohgushi, and used with either surface supplied air or a 150 bar steel scuba cylinder holding 1000 litres free air, the valve supplied air to a mask over the diver's nose and eyes and the demand valve was operated by the diver's teeth. Gas flow was proportional to bite force and duration. The breathing apparatus was used successfully for fishing and salvage work and by the military Japanese Underwater Unit until the end of the Pacific War.
Around 1920: Hanseatischen Apparatebau-Gesellschaft made a 2-cylinder breathing apparatus with double-lever single-stage demand valve and single wide corrugated breathing tube with mouthpiece, and a "duck's beak" exhalent valve in the regulator. It was described in a mine rescue handbook in 1930. They were successors to Ludwig von Bremen of Kiel, who had the licence to make the Rouquayrol-Denayrouze apparatus in Germany.
De Corlieu left the French Navy to fully devote himself to his invention.
Experimental dives using helium-oxygen mixtures sponsored by the US Navy and Bureau of Mines.
Due to post World War I cutbacks, the US Navy found it had only 20 divers qualified to dive deeper than 90 feet when salvaging the submarine S-51.
Fernez-Le Prieur self-contained underwater breathing apparatus was demonstrated to the public in Paris, and adopted by the French Navy.
Draeger introduced a rescue breathing apparatus that the wearer could swim with. Previous devices served only for submarine escape and were designed to provide buoyancy so that the wearer was lifted to the surface without effort, the diving set had weights, which made it possible to dive for search and rescue after an accident.
1927: US Navy School of Diving and Salvage was re-established at Washington Navy Yard, and the Experimental Diving Unit brought from Pittsburgh to Washington Navy Yard.
1928: Davis invented the Submersible Decompression Chamber (SDC) diving bell.
In April Louis de Corlieu registered a new patent (number 767013, which in addition to two fins for the feet included two spoon-shaped fins for the hands) and called this equipment propulseurs de natation et de sauvetage (which can be translated as "swimming and rescue propulsion device").
In San Diego, California, the first sport diving club was started by Glenn Orr, Jack Prodanovich and Ben Stone, called the San Diego Bottom Scratchers. As far as it is known, it did not use breathing sets; its main aim was spearfishing.
More is known of Yves Le Prieur's constant-flow open-circuit breathing set. It is said that it could allow a 20-minute stay at 7 meters and 15 minutes at 15 meters. It has one cylinder feeding into a circular fullface mask. Its air cylinder was often worn at an angle to get its on/off valve in reach of the diver's hand.
In France a sport diving club was started, called the Club des Sous-l'Eau = "club of those [who are] under the water". It did not use breathing sets as far as is known. Its main aim was spearfishing. ("Club des Sous-l'Eau" was later realized to be a homophone of "club des soulôts" = "club of the drunkards", and was changed to 'Club des Scaphandres et de la Vie Sous L'Eau' = "Club of the diving apparatuses and of underwater life".)
On the French Riviera, the first known sport scuba diving club Club Des Scaphandres et de la Vie Sous L'eau (The club for divers and life underwater) was started by Le Prieur & Jean Painleve. It used Le Prieur's breathing sets.
1937: US Navy published its revised diving tables based on the work of O.D. Yarbrough.
1937: The American Diving Equipment and Salvage Company (now known as DESCO) developed a heavy bottom-walking-type diving suit with a self-contained mixed-gas helium and oxygen rebreather.
1939: After floundering for years, even producing his fins in his own flat in Paris, De Corlieu finally started mass production of his invention in France. The same year he rented a licence to Owen P. Churchill for mass production in the United States. To sell his fins in the USA Owen Churchill changed the French De Corlieu's name (propulseurs) to "swimfins", which is still the English name. Churchill presented his fins to the US Navy, who decided to acquire them for its Underwater Demolition Team (UDT).
Hans Hass and Hermann Stelzner of Drager, in Germany made the M138 rebreather. It was developed from the 1912 escape set, a type of rebreather used to exit sunken submarines. The M138 sets were oxygen rebreathers with a 150 bar, 0.6 liter tank and appeared in many of his movies and books.
1934: René Commeinhes, from Alsace, invented a breathing set working with a demand valve and designed to allow firefighters to breathe safely in smoke-filled environments.
1937: Georges Commeinhes, son of René, adapted his father's invention to diving and developed a two-cylinder open-circuit apparatus with demand regulator. The regulator was a big rectangular box between the cylinders. Some were made, but WWII interrupted development.
World War II
1939: Georges Commeinhes offered his breathing set to the French Navy, which could not continue developing uses for it because of WWII.
1942: Georges Commeinhes patented a better version of his scuba set, now called the GC42 ("G" for Georges, "C" for Commeinhes and "42" for 1942). Some are made by the Commeinhes' company.
1942: with no relation with the Commeinhes family, Émile Gagnan, an engineer employed by the Air Liquide company, obtained a Rouquayrol-Denayrouze apparatus (property of the Bernard Piel company in 1942) in Paris. He miniaturized and adapted it to gas generators, since the Germans occupy France and confiscated the French fuel for war purposes. Gagnan's boss and owner of the Air Liquide company, Henri Melchior, decided to introduce Gagnan to Jacques-Yves Cousteau, his son-in-law, because he knows that Cousteau is looking for an efficient and automatic demand regulator. They met in Paris in December 1942 and adapted Gagnan's regulator to a diving cylinder.
1943: after fixing some technical problems, Cousteau and Gagnan patented the first modern demand regulator.
Air Liquide built two more aqualungs: these three are owned by Cousteau but also at the disposal of his first two diving companions Frédéric Dumas and Taillez. They use them to shoot the film Épaves (Shipwrecks), the first underwater film shot using scuba sets.
In July Commeinhes reached 53 metres (about 174 feet) using his GC42 breathing set off the coast of Marseille.
In October, and not knowing about Commeinhes's exploit, Dumas dived with a Cousteau-Gagnan prototype and reached 62 metres (about 200 feet) off Les Goudes, not far from Marseille. He experienced what is now called nitrogen narcosis.
1944: Commeinhes died in the liberation of Strasbourg in Alsace. His invention was overtaken by Cousteau's invention.
Hans Hass later said that during WWII the German diving gear firm Dräger offered him an open-circuit scuba set with a demand regulator. It may have been a separate invention, or it may have been copied from a captured Commeinhes-type set.
Early 1944: the USA government, to try to stop men from being drowned in sunken army tanks, asked the company Mine Safety Appliances (MSA) for a suitable small escape breathing set. MSA provided a small open-circuit breathing set with a small (5 to 7 liters) air cylinder, a circular demand regulator with a two-lever system similar to Cousteau's design (connected to the cylinder by a nut and cone nipple connection), and one corrugated wide breathing tube connected to a mouthpiece. This set was stated to be made from "off-the-shelf" items, which shows that MSA already had that regulator design; also, that regulator looks like the result of development and not a prototype; it may have arisen around 1943. In an example recovered in 2003 from a submerged Sherman tank in the Bay of Naples, the cylinder was bound round in tape and tied to a lifejacket. These sets were too late for the D-day landings in June 1944, but were used in the invasion of the south of France and in the Pacific war.
1945: In Toulon, Cousteau showed the film Épaves to the Admiral Lemonnier. The Admiral then made Cousteau responsible for the creation of the underwater research unit of the French Navy (the GRS, Groupe de Recherches Sous-marines, nowadays called the CEPHISMER). GRS' first mission was to clear of mines the French coasts and harbours. While creating the GRS, Cousteau only had at his disposal the two remaining Aqua-Lung prototypes made by l'Air Liquide in 1943.
Air Liquide created La Spirotechnique and started to sell Cousteau-Gagnan sets under the names of scaphandre Cousteau-Gagnan ('Cousteau-Gagnan scuba set'), CG45 ("C" for Cousteau, "G" for Gagnan and "45" for 1945, year of their first postwar patent) or Aqua-Lung, the latter for commercialization in English-speaking countries. This word is correctly a tradename that goes with the Cousteau-Gagnan patent, but in Britain it has been commonly used as a generic and spelt "aqualung" since at least the 1950s, including in the BSAC's publications and training manuals, and describing scuba diving as "aqualunging".
Yves Le Prieur invented a new version of his breathing set. Its fullface mask's front plate was loose in its seating and acted as a very big, and therefore, very sensitive diaphragm for a demand regulator: see Diving regulator#Demand valve.
The first known underwater diving club in Britain, "The Amphibians Club", is formed in Aberdeen by Ivor Howitt (who modified an old civilian gas mask) and some friends. They called underwater diving "fathomeering", to distinguish from jumping into water.
Siebe Gorman and/or Heinke started making Cousteau-type aqualungs in England. Siebe Gorman made those first patented aqualungs at Chessington from 1948 to 1960, popularly known as tadpole sets. Siebe Gorman and the Royal Navy expected aqualungs to be used with weighted boots for bottom-walking for light commercial diving: see Aqua-lung#"Tadpoles".
1948 or 1949: Rene's Sporting Goods shop in California imported aqualungs from France. Two graduate students, Andy Rechnitzer and Bob Dill obtained a set and began to use it for underwater research. Hollywood noticed Aqualungs and was interested.
The movie "The Frogmen" was released. It was set in the Pacific Ocean in WWII. In its last 20 minutes, it shows USA frogmen, using bulky 3-cylindered aqualungs on a combat mission. This equipment use is anachronistic (in reality they would have used rebreathers), but it shows that aqualungs were available (even if not widely known of) in the USA in 1951.
Cousteau-type aqualungs went on sale in the USA.
Ted Eldred in Melbourne, Australia started making for public sale the Porpoise (make of scuba gear). This was the world's first commercially available single-hose scuba unit and was the forerunner of most sport SCUBA equipment produced today. Only about 12,000 were made.
After World War II Lambertsen called his 1940-1944 rebreather LARU (for Lambertsen Amphibious Respiratory Unit) but as of 1952 Lambertsen renamed his invention and coined the acronym SCUBA (for "self-contained underwater breathing apparatus"). During the following years this acronym was used, more and more, to identify the Cousteau-Gagnan apparatus, taking the place of its original name (Aqualung). In Britain the word aqualung, used for any demand-valve-controlled open-circuit scuba set, still continues to be used nowadays; in old times it was sometimes inaccurately for any scuba set including rebreathers.
Public interest in scuba diving takes off
1953: National Geographic Magazine published an article about Cousteau's underwater archaeology at Grand Congloué island near Marseille. This started a massive public demand for aqualungs and diving gear, and in France and America the diving gear makers started making them as fast as they could. But in Britain Siebe Gorman and Heinke kept aqualungs expensive, and restrictions on exporting currency stopped people from importing them. Many British sport divers used home-made constant-flow breathing sets and ex-armed forces or ex-industrial rebreathers. In the early 1950s, diving regulators made by Siebe Gorman cost £15, which was an average week's salary.
After the supply of war-surplus frogman's drysuits ran out, free-swimming diving suits were not readily available to the general public, and as a result many scuba divers dived with their skin bare except for swimming trunks. That is why scuba diving used often to be called skindiving. Others dived in homemade drysuits, or in thick layers of ordinary clothes.
After the supply of war-surplus frogman's fins dried up, for a long time fins were not available to the public, and some had to resort to such things as gluing marine ply to plimsolls.
1954: USS Nautilus, the first nuclear-powered submarine, was launched.
The first manned dives in the bathyscaphe FNRS-2 were made.
The first scuba certification course in the USA was offered by the Los Angeles County Department of Parks and Recreation. The training program was created by Albert Tillman and Bev Morgan now known as LA County Scuba.
In the USA, MSA advertised (in Popular Mechanics magazine) a two-cylinder aqualung-like open-circuit diving set using the MSA regulator.
Underwater hockey (octopush) was invented by four navy sub-aqua divers in Southsea who got bored swimming up and down and wanted a fun way to keep fit.
US Navy published decompression tables that allowed for repetitive diving.
Around this time, some British scuba divers started making homemade diving demand regulators from industrial parts, including Calor Gas regulators. (Since then, Calor Gas regulators have been redesigned, and this conversion is now impossible.)
Later, Submarine Products Ltd in Hexham in Northumberland, England designed round the Cousteau-Gagnan patent and marketed recreational diving breathing sets at an accessible price. This forced Siebe Gorman's and Heinke's prices down and started them selling to the sport diving trade. (Siebe Gorman gave its drysuit the tradename "Frogman".) Because of this better availability of aqualungs, BSAC adopted a policy that rebreathers were unacceptable for recreational diving.[original research?] In the USA, some oxygen diving clubs developed down the years. Eventually, the term of the Cousteau-Gagnan patent expired, and it could be legally copied.
1968: An excursion dive to 1025 fsw was made from a saturation depth of 825 fsw at NEDU.
1969: The first known rebreather with electronic monitoring was produced. The Electrolung, designed by Walter Starke, was subsequently bought by Beckman Instruments, but discontinued in 1970 after a number of fatalities.
1971: Scubapro introduced the Stabilization Jacket, commonly called stab jacketin England, and Buoyancy Control (or Compensation) Device (BC or BCD) elsewhere.
1990: During operations in the Campos basin of Brazil, saturation divers from the DSV Stena Marianos performed a manifold installation for Petrobras at 316 metres (1,037 ft) depth in February 1990. When a lift bag attachment failed, the equipment was carried by the bottom currents to 328 metres (1,076 ft) depth, and the Brazilian diver Adelson D'Araujo Santos Jr. made the recovery and installation.
Divex and Kirby-Morgan developed the Divex UltraJewel 601 gas-reclaim system in response to rising helium costs.
2016 September: First prototype, for scientific research purposes, of an underwater navigation system that guides divers visualizing his/her georeferenced position within the 3d map of the underwater site displayed on a tablet device.[clarification needed]
^In 1784 Fréminet sent six copies of a treatise about his machine hydrostatergatique to the chamber of Guienne (nowadays called Guyenne). On April 5, 1784, the archives of the Chamber of Guienne (Chambre de Commerce de Guienne) officially recorded: Au sr Freminet, qui a adressé à la Chambre six exemplaires d'un précis sur une « machine hydrostatergatique » de son invention, destinée à servir en cas de naufrage ou de voie d'eau déclarée.
^Charles Griswold to Professor Silliman, Lyme CT, 21 Feb 1820; from "The Beginning of Modern Submarine Warfare, under Captain-Lieutenant David Bushnell, Sappers and Miners, Army of the Revolution;" Henry L. Abbot (pamphlet, 1881); reproduced by Frank Anderson (Archon Books and Shoe String Press, Hamden CT, 1966); pp 26-28
^Bevan, John (1990). "The First Demand Valve?"(PDF). SPUMS Journal. South Pacific Underwater Medicine Society. 20 (4): 239-240.Reprinted from Diver (U.K. magazine) of February 1989
^Staff. "Le scaphandre autonome" (in French). Archived from the original on 30 October 2012. Retrieved 2017. Un brevet semblable est déposé en 1838 par William Newton en Angleterre. Il y a tout lieu de penser que Guillaumet, devant les longs délais de dépôt des brevets en France, a demandé à Newton de faire enregistrer son brevet en Angleterre où la procédure est plus rapide, tout en s'assurant les droits exclusifs d'exploitation sur le brevet déposé par Newton. (A similar patent was filed in 1838 by William Newton in England. There is every reason to think that owing to the long delays in filing patents in France, Guillaumet asked Newton to register his patent in England where the procedure was faster, while ensuring the exclusive rights to exploit the patent filed by Newton.)
^On November 14, 1838, Dr. Manuel Théodore Guillaumet of Argentan, Normandy, France, filed a patent for a twinhose demand regulator; the diver was provided air through pipes from the surface. The apparatus was demonstrated to, and investigated by, a committee of the French Academy of Sciences: "Mèchanique appliquée – Rapport sur une cloche à plongeur inventée par M. Guillaumet" (Applied mechanics – Report on a diving bell invented by Mr. Guillaumet), Comptes rendus, vol. 9, pages 363-366 (September 16, 1839).
^Also from "le scaphandre autonome" Web site: "Reconstruit au XXe siècle par les Américains, ce détendeur fonctionne parfaitement, mais, si sa réalisation fut sans doute effective au XIXe, les essais programmés par la Marine Nationale ne furent jamais réalisés et l'appareil jamais commercialisé." (Reconstructed in twentieth century by the Americans, this regulator worked perfectly; however, although it was undoubtedly effective in the nineteenth century, the test programs by the French Navy were never conducted and the apparatus was never sold.)
^Staff. "oxylithe". Dictionaires de francaise Larousse (in French). Editions Larousse. Retrieved 2017. Mélange de peroxydes de sodium et de potassium, avec un peu de sels de cuivre ou de nickel, qui, en présence d'eau, dégage de l'oxygène
^In the 1950s capitaine de frégate (Commander) Philippe Tailliez still was thinking that De Corlieu conceived his fins for the first time in 1924 (in fact he's started ten years earlier). See page 14 in Capitaine de frégate PHILIPPE TAILLIEZ, Plongées sans câble, Arthaud, Paris, January 1954, Dépôt légal 1er trimestre 1954 - Édition N° 605 - Impression N° 243 (in French)