RARE Billhead Mason Co Submarine Deep sea Diving Suits Helmet Pump 1883 Ships

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Seller: dalebooks (8.204) 100%, Location: Rochester, New York, Ships to: Worldwide, Item: 264018180657 VERY RARE Advertising Billhead William S. Mason & Company Steam Pumps, Sub-marine Diving and Apparatus for Raising Sunken Vessels & Boats Philadelphia, Pennsylvania 1883 For offer: a very rare billhead / letterhead! Fresh from a prominent estate in Upstate NY. Never offered on the market until now. Vintage, Old, Original, Antique, NOT a Reproduction - Guaranteed !! Great graphic of diving uniform, pump, ship, apparatus for raising sunken ships etc. Bill for Schooner Willie H Higgins and owners - L.A. Flanagan. For services of diver and use of apparatus ... examining vessels bottom. In very good condition. A couple holes punched at top / pinholes, fold marks. Please see photos. NOTE: this will be sent folded up. as found unless otherwise specified. If you collect 19th century American history, Americana photography, receipt, business related, advertisement ad, equipment, science / invention, treasure hunting, PA, etc. this is a treasure you will not see again! Add this to your image or paper / ephemera collection. Combine shipping on multiple bid wins! 1751 The history of underwater diving starts with freediving as a widespread means of hunting and gathering, both for food and other valuable resources such as pearls and coral, By classical Greek and Roman times commercial applications such as sponge diving and marine salvage were established, Military diving also has a long history, going back at least as far as the Peloponnesian War, with recreational and sporting applications being a recent development. Technological development in ambient pressure diving started with stone weights (skandalopetra) for fast descent. In the 16th and 17th centuries diving bells became functionally useful when a renewable supply of air could be provided to the diver at depth, and progressed to surface supplied diving helmets - in effect miniature diving bells covering the diver's head and supplied with compressed air by manually operated pumps - which were improved by attaching a waterproof suit to the helmet and in the early 19th century became the standard diving dress. Limitations in mobility of the surface supplied systems encouraged the development of both open circuit and closed circuit scuba in the 20th century, which allow the diver a much greater autonomy. These also became popular during World War II for clandestine military operations, and post-war for scientific, search and rescue, media diving, recreational and technical diving. The heavy free-flow surface supplied copper helmets evolved into lightweight demand helmets, which are more economical with breathing gas, which is particularly important for deeper dives and expensive helium based breathing mixtures, and saturation diving reduced the risks of decompression sickness for deep and long exposures. An alternative approach was the development of the "single atmosphere" or armoured suit, which isolates the diver from the pressure at depth, at the cost of great mechanical complexity and limited dexterity. The technology first became practicable in the middle 20th century. Isolation of the diver from the environment was taken further by the development of remotely operated underwater vehicles in the late 20th century, where the operator controls the ROV from the surface, and autonomous underwater vehicles, which dispense with an operator altogether. All of these modes are still in use and each has a range of applications where it has advantages over the others, though diving bells have largely been relegated to a means of transport for surface supplied divers. In some cases combinations are particularly effective, such as the simultaneous use of surface orientated or saturation surface supplied diving equipment and work or observation class remotely operated vehicles. Although the pathophysiology of decompression sickness in not yet fully understood, decompression practice has reached a stage where the risk is fairly low, and most incidences are successfully treated by therapeutic recompression and hyperbaric oxygen therapy. Mixed breathing gases are routinely used to reduce the effects of the hyperbaric environment on ambient pressure divers. FreedivingFurther information: Freediving Natural sponges have been harvested by free divers near the Greek island of Kalymnos since at least the time of Plato.Underwater diving was practiced in ancient cultures to gather food and other valuable resources such as pearls and precious coral, and later to reclaim sunken valuables, and to help aid military campaigns. Breathhold diving was the only method available, occasionally using reed snorkels in shallow water, and stone weights for deeper dives[1] Underwater diving for commercial purposes may have begun in Ancient Greece, since both Plato and Homer mention the sponge as being used for bathing. The island of Kalymnos was a main centre of diving for sponges. By using weights (skandalopetra) of as much as 15 kilograms (33 lb) to speed the descent, breath-holding divers would descend to depths up to 30 metres (98 ft) for as much as five minutes to collect sponges.[2] Sponges were not the only valuable harvest to be found on the sea floor; the harvesting of red coral was also quite popular. A variety of valuable shells or fish could be harvested in this way, creating a demand for divers to harvest the treasures of the sea, which could also include the sunken riches of other seafarers.[3] The Mediterranean had large amounts of sea trade. As a result, there were many shipwrecks, so divers were often hired to salvage whatever they could from the seabed. Divers would swim down to the wreck and choose the pieces to salvage.[4] Divers were also used in warfare. They could be used for underwater reconnaissance when ships were approaching an enemy harbor, and if underwater defenses were found, the divers would disassemble them if possible.[5] During the Peloponnesian War, divers were used to get past enemy blockades to relay messages and provide supplies to allies or troops that were cut off by the blockade.[6] These divers and swimmers were occasionally used as saboteurs, drilling holes in enemy hulls, cutting ships rigging and mooring lines. In Japan, the Ama divers began to collect pearls about 2,000 years ago.[7][8] Free-diving was the primary source of income for many Gulf nationals such as Qataris, Emiratis, and Bahrainis and Kuwaitis. As a result, Qatari, Emirati and Bahraini heritage promoters have popularized recreational and serious events associated with freediving, underwater equipment and related activities such as snorkeling.[9] Diving bellsFurther information: Diving bell Illustration of an occupied diving bell.The diving bell is one of the earliest types of equipment for underwater work and exploration.[10] Its use was first described by 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."[11] According to Roger Bacon, Alexander the Great explored the Mediterranean on the authority of Ethicus the astronomer. The earliest applications were probably for commercial sponge fishing.[citation needed] Diving bells were developed in the 16th and 17th century as the first significant mechanical aid to underwater diving. They were rigid chambers lowered into the water and ballasted to remain upright in the water and to sink even when full of air.[12] The first reliably recorded use of a diving bell was by Guglielmo de Lorena in 1535 to explore Caligula's barges in Lake Nemi.[13] In 1616, Franz Kessler built an improved diving bell.[14]:693[15] Sir William Phipps used a diving bell to salvage tremendous wealth from a sunken Spanish treasure ship.In 1658, Albrecht von Treileben was contracted by King Gustavus Adolphus of Sweden to salvage the warship Vasa, which sank outside Stockholm harbor in about 32m of water on its maiden voyage in 1628. Between 1663 and 1665 von Treileben's divers were successful in raising most of the cannon, working from a diving bell with an estimated free air capacity of about 530 litres for periods of about 15 minutes at a time in dark water with a temperature of about 4 °C.[16][17] In late 1686, Sir William Phipps convinced investors to fund an expedition to what is now Haiti and the Dominican Republic to find sunken treasure, despite the location of the shipwreck being based entirely on rumor and speculation. In January 1687, Phipps found the wreck of the Spanish galleon Nuestra Señora de la Concepción off the coast of Santo Domingo. Some sources say they used an inverted container as a diving bell for the salvage operation while others say the crew was assisted by Indian divers in the shallow waters. The operation lasted from February to April 1687 during which time they salvaged jewels, some gold and 30 tons of silver which, at the time, was worth over £200,000.[18] In 1691, Dr. Edmond Halley completed plans for a greatly improved diving bell, capable of remaining submerged for extended periods of time, and fitted with a window for the purpose of undersea exploration. The atmosphere was replenished by way of weighted barrels of air sent down from the surface.[19] In a demonstration, Halley and five companions dived to 60 feet (18 m) in the River Thames, and remained there for over an hour and a half. Improvements made to it over time, extended his underwater exposure time to over 4 hours.[20][21] In 1775, Charles Spalding, an Edinburgh confectioner, improved on Dr. Halley's design by adding a system of balance-weights to ease the raising and lowering of the bell, along with a series of ropes for signaling to the surface crew.[22] Spalding and his nephew, Ebenezer Watson, later suffocated off the coast of Dublin in 1783 doing salvage work in a diving bell of Spalding's design.[22] In 1689, Denis Papin had suggested that the pressure and fresh air inside a diving bell could be maintained by a force pump or bellows. His idea was implemented exactly 100 years later by the engineer John Smeaton who built the first workable diving air pump in 1789.[14][15] Surface supplied diving suitsFurther information: Diving suit John Lethbridge's diving dress built in the 1710s.In 1602, the Spanish military engineer Jerónimo de Ayanz y Beaumont developed the first documented diving dress. It was tested the same year in the Pisuerga river (Valladolid, Spain). King Philip the Third attended the demonstration.[citation needed] Two English inventors developed diving suits in the 1710s. John Lethbridge built a completely enclosed suit to aid in salvage work. It consisted of a pressure-proof air-filled barrel with a glass viewing hole and two watertight enclosed sleeves.[23] After testing this machine in his garden pond specially built for the purpose, Lethbridge dived on a number of wrecks: four English men-of-war, one East Indiaman, two Spanish galleons and a number of galleys. He became very wealthy as a result of his salvages. One of his better-known recoveries was on the Dutch Slot ter Hooge, which had sunk off Madeira with over three tons of silver on board.[15] At the same time, Andrew Becker created a leather-covered diving suit with a windowed helmet. The suit used a system of tubes for inhaling and exhaling, and Becker demonstrated his suit in the River Thames, London, during which he remained submerged for an hour. These suits were of limited use as there was still no practical system for replenishing the air supply during the dive.[24] Open diving dress 1842 sketch of the Deane brothers' diving helmet Standard diving dressIn 1405, Konrad Kyeser described a diving dress made of a leather jacket and metal helmet with two glass windows. The jacket and helmet were lined by sponge to "retain the air" and a leather pipe was connected to a bag of air.[14]:693 A diving suit design was illustrated in a book by Vegetius in 1511.[14]:554 Borelli designed diving equipment that consisted of a metal helmet, a pipe to "regenerate" air, a leather suit, and a means of controlling the diver's buoyancy.[14]:556 In 1690, Thames Divers, a short lived London diving company, gave public demonstrations of a Vegetius type shallow water diving dress.[14]:557 Klingert designed a full diving dress in 1797. This design consisted of a large metal helmet and similarly large metal belt connected by leather jacket and pants.[14]:560 In 1800 Peter Kreeft presented his diving apparatus to swedish king and used it successfully. In 1819 Augustus Siebe invented an open diving suit which only covered the top portion of the body. The suit included a metal helmet which was riveted to a waterproof jacket that ended below the diver's waist. The suit worked like a diving bell - air pumped into the suit escaped at the bottom edge. The diver was extremely limited in range of motion and had to move about in a more or less upright position. It wasn't until 1837 that Siebe changed the design to a closed system with only the hands left out of the suit with an air-tight encasing around the wrists.[25] The first successful diving helmets were produced by the brothers Charles and John Deane in the 1820s.[26] Inspired by a fire accident he witnessed in a stable in England,[27] he designed and patented a "Smoke Helmet" to be used by firemen in smoke-filled areas in 1823. The apparatus comprised a copper helmet with an attached flexible collar and garment. A long leather hose attached to the rear of the helmet was to be used to supply air - the original concept being that it would be pumped using a double bellows. A short pipe allowed excess air to escape. The garment was constructed from leather or airtight cloth, secured by straps.[28] The brothers had insufficient funds to build the equipment themselves so they sold the patent to their employer Edward Barnard. It was not until 1827 that the first smoke helmets were built by German-born British engineer Augustus Siebe. In 1828 they decided to find another application for their device and converted it into a diving helmet. They marketed the helmet with a loosely attached "diving suit" so that a diver could perform salvage work but only in a full vertical position, otherwise water entered the suit.[28] Siebe's improved design in 1873.In 1829, the Deane brothers sailed from Whitstable for trials of their new underwater apparatus, establishing the diving industry in the town. In 1834, Charles used his diving helmet and suit in a successful attempt on the wreck of Royal George at Spithead, during which he recovered 28 of the ship's cannon.[29] In 1836, John Deane recovered from the Mary Rose shipwreck timbers, guns, longbows, and other items.[30] By 1836, the Deane brothers had produced the world's first diving manual Method of Using Deane's Patent Diving Apparatus which explained in detail the workings of the apparatus and pump, as well as safety precautions.[31] Standard diving dressFurther information: Standard diving dressIn the 1830s, the Deane brothers asked Augustus Siebe to improve their underwater helmet design.[32] Expanding on improvements already made by another engineer, George Edwards, Siebe produced his own design; a helmet fitted to a full length watertight canvas diving suit.[33] Siebe introduced various modifications on his diving dress design to accommodate the requirements of the salvage team on the wreck of the HMS Royal George, including making the bonnet of the helmet detachable from the corselet. His improved design gave rise to the typical standard diving dress which revolutionised underwater civil engineering, underwater salvage, commercial diving and naval diving.[32] The watertight suit allowed divers to wear layers of dry clothing undernrath to suit the water temperature. These generally included heavy stockings, guernseys, and the iconic woolen cap that is still occasionally worn by divers.[34] Early diving workIn the early years of the diving suit, divers were often employed for cleaning and maintenance of seagoing vessels which could require the efforts of multiple divers. Ships that did not have diving suits available would commission diving companies to do underwater maintenance of ships hulls as a clean hull would increase the speed of the vessel. The average time spent diving for these purposes was between 4 and 7 hours.[34] The Office of the Admiralty and Marine Affairs adopted the diving suit in the 1860s. Divers duties included underwater repair of vessels, maintenance and cleaning of propellers, retrieval of lost anchors and chains, and removing seaweed and other fouling from the hull that could hinder movement.[34] Development of salvage diving operations Sinking of the Royal George.Royal George, a 100-gun first-rate ship of the line of the Royal Navy, sank undergoing routine maintenance work in 1782. Charles Spalding used a diving bell to recover six iron 12-pounder guns and nine brass 12-pounders in the same year.[35] In 1839 Major-General Charles Pasley, at the time a Colonel of the Royal Engineers, commenced operations. He had previously destroyed some old wrecks in the Thames and intended to break up the Royal George with gunpowder charges and then salvage as much as possible using divers.[36] The Deane brothers were commissioned to perform salvage work on the wreck. Using their new air-pumped diving helmets, they managed to recover about two dozen cannons.[37] Pasley's diving salvage operation set many diving milestones, including the first recorded use of the buddy system in diving, when he gave instructions to his divers to operate in pairs.[35][37] In addition, the first emergency swimming ascent was made by a diver after his air line became tangled and he had to cut it free. A less fortunate milestone was the first medical account of a diving barotrauma. The early diving helmets had no non-return valves, so if a hose was severed near the surface, the ambient pressure air around the diver's head rapidly drained from the helmet to the lower pressure at the break, leaving a pressure difference between the inside and outside of the helmet that could cause injurious and sometimes life-threatening effects. At the British Association for the Advancement of Science meeting in 1842, Sir John Richardson described the diving apparatus and treatment of diver Roderick Cameron following an injury that occurred on 14 October 1841 during the salvage operations.[38] Pasley recovered 12 more guns in 1839, 11 more in 1840, and 6 in 1841. In 1842 he recovered only one iron 12-pounder because he ordered the divers to concentrate on removing the hull timbers rather than search for guns. Other items recovered, in 1840, included the surgeon's brass instruments, silk garments of satin weave "of which the silk was perfect", and pieces of leather; but no woollen clothing.[39] By 1843 the whole of the keel and the bottom timbers had been raised and the site was declared clear.[40] Self-contained air supply equipmentA drawback to the equipment pioneered by Deane and Siebe was the requirement for a constant supply of air pumped from the surface. This restricted the movements and range of the diver and was also potentially hazardous as the supply could get cut off for a number of reasons. Early attempts at creating systems that would allow divers to carry a portable breathing gas source did not succeed, as the compression and storage technology was not advanced enough to allow compressed air to be stored in containers at sufficiently high pressures. By the end of the nineteenth century, two basic templates for scuba, (self-contained underwater breathing apparatus), had emerged; open-circuit scuba where the diver's exhaust is vented directly into the water, and closed-circuit scuba where the diver's unused oxygen is filtered from the carbon dioxide and recirculated.[41] A scuba set is characterized by full independence from the surface during use, by providing breathing gas carried by the diver. Early attempts to reach this autonomy from the surface were made in the 18th century by the Englishman John Lethbridge, who invented and successfully built his own underwater diving machine in 1715. The air inside the suit allowed a short period of diving before it had to be surfaced for replenishment. Open-circuit scubaFurther information: Scuba setNone of those inventions solved the problem of high pressure when compressed air must be supplied to the diver (as in modern regulators); they were mostly based on a constant-flow supply of the air. The compression and storage technology was not advanced enough to allow compressed air to be stored in containers at sufficiently high pressures to allow useful dive times. An early diving dress using a compressed air reservoir was designed and built in 1771 by Sieur Fréminet of Paris who conceived an autonomous breathing machine equipped with a reservoir, dragged behind the diver or mounted on his back.[42][43] Fréminet called his invention machine hydrostatergatique and used it successfully for more than ten years in the harbors of Le Havre and Brest, as stated in the explanatory text of a 1784 painting.[44][45] The Frenchman Paul Lemaire d'Augerville built and used autonomous diving equipment in 1824,[46] as did the British William H. James in 1825. James' helmet was made of "thin copper or sole of leather" with a plate window, and the air was supplied from an iron reservoir.[47] A similar system was used in 1831 by the American Charles Condert, who died in 1832 while testing his invention in the East River at only 20 feet (6 m) deep. After having travelled to England and discovering William James' invention, the French physician Manuel Théodore Guillaumet, from Argentan in (Normandy), patented the oldest known regulator mechanism in 1838. Guillaumet's invention was air-supplied from the surface and was never mass-produced due to problems with safety. The Rouquayrol-Denayrouze apparatus was the first regulator to be mass-produced (from 1865 to 1965). In this picture the air reservoir presents its surface-supplied configuration. Divers dressed in the Apparatus Invented by MM Rouquayrol and DenayrouzeAn important step in the development of open circuit scuba technology was the invention of the demand regulator in 1864 by the French engineers Auguste Denayrouze and Benoît Rouquayrol. Their suit was the first to supply air to the user by adjusting the flow according to the diver's requirements. The system still had to use surface supply, as the storage cylinders of the 1860s were not able to withstand the high pressures necessary for a practical self-contained unit.[48] The first open-circuit scuba system was devised in 1925 by Yves Le Prieur in France. Inspired by the simple apparatus of Maurice Fernez and the freedom it allowed the diver, he conceived an idea to make it free of the tube to the surface pump by using Michelin cylinders as the air supply, containing three litres of air compressed to 150 kilograms per square centimetre (2,100 psi; 150 bar). The "Fernez-Le Prieur" diving apparatus was demonstrated at the swimming pool of Tourelles in Paris in 1926. The unit consisted of a cylinder of compressed air carried on the back of the diver, connected to a pressure regulator designed by Le Prieur adjusted manually by the diver, with two gauges, one for tank pressure and one for output (supply) pressure. Air was supplied continually to the mouthpiece and ejected through a short exhaust pipe fitted with a valve as in the Fernez design,[49] however, the lack of a demand regulator and the consequent low endurance of the apparatus limited the practical use of LePrieur's device.[50]:1–9 Le Prieur's design was the first autonomous breathing device used by the first scuba diving clubs in history - Racleurs de fond founded by Glenn Orr in California in 1933, and Club des sous-l'eau founded by Le Prieur himself in Paris in 1935.[51] Fernez had previously invented the noseclip, a mouthpiece (equipped with a one-way valve for exhalation) and diving goggles, and Yves le Prieur just joined to those three Fernez elements a hand-controlled regulator and a compressed-air cylinder. Fernez's goggles didn't allow a dive deeper than ten metres due to "mask squeeze", so, in 1933, Le Prieur replaced all the Fernez equipment (goggles, noseclip and valve) by a full face mask, directly supplied with constant flow air from the cylinder. In 1942, during the German occupation of France, Jacques-Yves Cousteau and Émile Gagnan designed the first successful and safe open-circuit scuba, known as the Aqua-Lung. Their system combined an improved demand regulator with high-pressure air tanks. Émile Gagnan, an engineer employed by the Air Liquide company, miniaturized and adapted the regulator to use with gas generators, in response to constant fuel shortage that was a consequence of German requisitioning. Gagnan's boss, Henri Melchior, knew that his son-in-law Jacques-Yves Cousteau was looking for an automatic demand regulator to increase the useful period of the underwater breathing apparatus invented by Commander le Prieur,[52] so he introduced Cousteau to Gagnan in December 1942. On Cousteau's initiative, the Gagnan's regulator was adapted to diving, and the new Cousteau-Gagnan patent was registered some weeks later in 1943.[53] Mistral twin-hose regulator mounted on a diving cylinder. The regulator is formed by the ensemble of the mouthpiece and the regulator body, joined on each of its sides by the two hoses. The rear of the regulator is connected to the high-pressure valve of the cylinder.1. Hose2. Mouthpiece3. Valve4. Harness5. Backplate6. CylinderAir Liquide started selling the Cousteau-Gagnan regulator commercially as of 1946 under the name of scaphandre Cousteau-Gagnan or CG45 ("C" for Cousteau, "G" for Gagnan and 45 for the 1945 patent). The same year Air Liquide created a division called La Spirotechnique, to develop and sell regulators and other diving equipment. To sell his regulator in English-speaking countries Cousteau registered the Aqua-Lung trademark, which was first licensed to the U.S. Divers company (the American division of Air Liquide) and later sold with La Spirotechnique and U.S. Divers to finally become the name of the company, Aqua-Lung/La Spirotechnique, currently located in Carros, near Nice.[54] In 1948 the Cousteau-Gagnan patent was also licensed to Siebe Gorman of England,[55][verification needed] when Siebe Gorman was directed by Robert Henry Davis.[56] Siebe Gorman was allowed to sell in Commonwealth countries, but had difficulty in meeting the demand and the U.S. patent prevented others from making the product. This demand was eventually met by Ted Eldred of Melbourne, Australia, who had been developing a rebreather called the Porpoise. When a demonstration resulted in a diver passing out, he began to develop the single-hose open-circuit scuba system, which separates the first and second stages by a low-pressure hose, and releases exhaled gas at the second stage. This avoided the Cousteau-Gagnan patent, which protected the twin-hose scuba regulator.[citation needed] In the process, Eldred also improved performance of the regulator.[citation needed][clarification needed] Eldred sold the first Porpoise Model CA single hose scuba early in 1952. In 1957, Eduard Admetlla i Lázaro used a version made by Nemrod to descend to a record depth of 100 metres (330 ft).[57] Early scuba sets were usually provided with a plain harness of shoulder straps and waist belt. The waist belt buckles were usually quick-release, and shoulder straps sometimes had adjustable or quick release buckles. Many harnesses did not have a backplate, and the cylinders rested directly against the diver's back. The harnesses of many diving rebreathers made by Siebe Gorman included a large back-sheet of reinforced rubber.[citation needed] Early scuba divers dived without any buoyancy aid.[58] In emergency they had to jettison their weights. In the 1960s adjustable buoyancy life jackets (ABLJ) became available. One early make, since 1961, was Fenzy. The ABLJ is used for two purposes: to adjust the buoyancy of the diver to compensate for loss of buoyancy at depth, mainly due to compression of the neoprene wetsuit) and more importantly as a lifejacket that will hold an unconscious diver face-upwards at the surface, and that can be quickly inflated. It was put on before putting on the cylinder harness. The first versions were inflated with a small carbon dioxide cylinder, later with a small direct coupled air cylinder. An extra low-pressure feed from the regulator first-stage lets the lifejacket be controlled as a buoyancy aid. This invention in 1971 of the "direct system,"[citation needed] by ScubaPro, resulted in what was called a stabilizer jacket or stab jacket, and is now increasingly known as a buoyancy compensator (device), or simply "BCD".[citation needed] Closed-circuit scubaFurther information: Rebreather and Frogman Henry Fleuss (1851-1932) improved the rebreather technology.The alternative concept, developed in roughly the same time frame was closed-circuit scuba. The body consumes and metabolises only a part of the oxygen in the inhaled air at the surface, and an even smaller fraction when the breathing gas is compressed as it is in ambient pressure systems underwater. A rebreather recycles the used breathing gas, while constantly replenishing it from the supply so that the oxygen level does not get dangerously depleted. The apparatus also has to remove the exhaled carbon dioxide, as a buildup of CO2 levels would result in respiratory distress due to hypercapnia.[41] The earliest known oxygen rebreather was patented on 17 June 1808 by Sieur Touboulic from Brest, mechanic in Napoleon's Imperial Navy, 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.[59][60] The earliest practical rebreather relates to the 1849 patent from the Frenchman Pierre Aimable De Saint Simon Sicard.[61] The first commercially practical closed-circuit scuba was designed and built by the diving engineer Henry Fleuss in 1878, while working for Siebe Gorman in London.[14][62] His apparatus consisted of a rubber mask connected by a tube to a bag, with (estimated) 50–60% O2 supplied from a copper pressure tank and CO2 chemically absorbed by rope yarn in the bag soaked in a solution of caustic potash. The system allowed use for about three hours.[14][63] Fleuss tested his device in 1879 by spending an hour submerged in a water tank, then one week later by diving to a depth of 5.5 metres (18 ft) in open water, upon which occasion he was slightly injured when his assistants abruptly pulled him to the surface.[citation needed] The Fleuss apparatus was first used under operational conditions in 1880 by the lead diver on the Severn Tunnel construction project, who was able to travel 1,000 feet (300 m) in the darkness to close several submerged sluice doors in the tunnel; this had defeated the best efforts of hard hat divers due to the danger of their air supply hoses becoming fouled on submerged debris, and the strong water currents in the workings.[14] Fleuss continually improved his apparatus, adding a demand regulator and tanks capable of holding greater amounts of oxygen at higher pressure. Davis Submerged Escape Apparatus being tested at the submarine escape test tank at HMS Dolphin, Gosport, 14 December 1942.Sir Robert Davis, head of Siebe Gorman, improved the oxygen rebreather in 1910[14][63][64] with his invention of the Davis Submerged Escape Apparatus, the first rebreather to be made in quantity. While intended primarily as an emergency escape apparatus for submarine crews, it was soon also used for diving, being a handy shallow water diving apparatus with a thirty-minute endurance, and as an industrial breathing set.[63] The Davis apparatus comprised a rubber breathing bag containing a canister of barium hydroxide to scrub exhaled carbon dioxide and a steel cylinder holding approximately 56 litres (2.0 cu ft) of oxygen at a pressure of 120 bars (1,700 psi), with a valve to allow the user to add oxygen to the bag. The set also included an emergency buoyancy bag on the front of to help keep the wearer afloat. The DSEA was adopted by the Royal Navy after further development by Davis in 1927.[65] The rig comprised a rubber breathing/buoyancy bag containing a canister of barium hydroxide to scrub exhaled CO2 and, in a pocket at the lower end of the bag, a steel pressure cylinder holding approximately 56 litres (2.0 cu ft) of oxygen at a pressure of 120 bars (1,700 psi). The cylinder was equipped with a control valve and was connected to the breathing bag. Opening the cylinder's valve admitted oxygen to the bag at ambient pressure. The rig also included an emergency buoyancy bag on the front of to help keep the wearer afloat. The DSEA was adopted by the Royal Navy after further development by Davis in 1927.[65] In 1912 the German firm Drägerwerk of Lübeck introduced their own version of standard diving dress using a gas supply from an injector-circulated oxygen rebreather and no surface supply.[66] A 1945 British navy frogman with Davis apparatus.In the 1930s, Italian sport spearfishers began to use the Davis rebreather. Italian manufacturers received a license from the English patent holders to produce it. This practice soon came to the attention of the Italian Navy, The Italians developed similar rebreathers for the combat swimmers of the Decima Flottiglia MAS, especially the Pirelli ARO which was used effectively in World War II.[63][67] During the 1930s and all through World War II, the British, Italians and Germans developed and extensively used oxygen rebreathers to equip the first frogmen. The British used the Davis apparatus for submarine escape, but they soon adapted it for their frogmen during World War II. Germans used the Dräger rebreathers,[68] which were also originally designed as submarine escape sets and only adapted for use by frogmen during World War II. During the Second World War, captured Italian frogmen's rebreathers influenced improved designs for British rebreathers.[63] Some British armed forces divers used bulky thick diving suits called Sladen suits, one version of which had a flip-up faceplate to let the diver use binoculars when on the surface.[69] In 1939, Christian Lambertsen developed an oxygen rebreather he called the Lambertsen Amphibious Respirator Unit (LARU) and patented it in 1940.[70][71] He later renamed it the Self Contained Underwater Breathing Apparatus, which, contracted to SCUBA, eventually became the generic term for both open circuit and rebreather autonomous underwater breathing equipment. Lambertson demonstrated the apparatus to the Office of Strategic Services (OSS)[72] who hired him to lead the program to build up the dive element of their maritime unit.[72] After World War II, military frogmen continued to use rebreathers since they do not make bubbles which would give away the presence of the divers. Saturation divingFurther information: Saturation divingOnce saturation is achieved, the amount of time needed for decompression depends on the depth and gases breathed and is not affected by longer exposure.[73] The first intentional saturation dive was done on 22 December 1938, by Edgar End and Max Nohl who spent 27 hours breathing air at 101 feet (30.8 m) in the County Emergency Hospital recompression facility in Milwaukee, Wisconsin. Their decompression lasted five hours leaving Nohl with a mild case of decompression sickness that resolved with recompression.[74] Albert R. Behnke proposed exposing divers to raised ambient pressures long enough for the tissues to saturate with inert gases in 1942.[75][76] In 1957, George F. Bond began the Genesis project at the Naval Submarine Medical Research Laboratory proving that humans could withstand prolonged exposure to different breathing gases and increased environmental pressures.[75][77] This was the beginning of saturation diving and the US Navy's Man-in-the-Sea Program.[73] The first commercial saturation dives were performed in 1965 by Westinghouse to replace faulty trash racks at 200 feet (61 m) on the Smith Mountain Dam.[74] Peter B. Bennett is credited with the invention of trimix breathing gas as a method to eliminate high pressure nervous syndrome. In 1981, at the Duke University Medical Center, Bennett conducted an experiment called Atlantis III, which involved taking divers to a depth of 2,250 feet (685.8 m), and slowly decompressing them to the surface over a period of 31-plus days, setting an early world record for depth in the process.[78] Atmospheric diving suitsFurther information: Atmospheric diving suitThe atmospheric diving suit is a small one-man submersible of anthropomorphic form with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere. Although atmospheric suits were developed during the Victorian era, none of these suits were able to overcome the basic design problem of constructing a joint which would remain flexible and watertight at depth without seizing up under pressure.[79][80][81] Early designs John Lethbridge's diving dress, the first enclosed diving suit, built in the 1710s.In 1715, British inventor John Lethbridge constructed a "diving suit". Essentially a wooden barrel about 6 feet (1.8 m) in length with two holes for the diver's arms sealed with leather cuffs, and a 4-inch (100 mm) viewport of thick glass. It was reportedly used to dive as deep as 60 feet (18 m), and was used to salvage substantial quantities of silver from the wreck of the East Indiaman Vansittart which sank in 1718 off the Cape Verde islands.[82] The first armored suit with real joints, designed as leather pieces with rings in the shape of a spring (also known as accordion joints), was designed by Englishman W. H. Taylor in 1838. The diver's hands and feet were covered with leather. Taylor also devised a ballast tank attached to the suit that could be filled with water to attain negative buoyancy. While it was patented, the suit was never actually produced. It is considered that its weight and bulk would have rendered it nearly immobile underwater.[82] Lodner D. Phillips designed the first wholly enclosed ADS in 1856. His design comprised a barrel-shaped upper torso with domed ends and included ball and socket joints in the articulated arms and legs. The arms had joints at shoulder and elbow, and the legs at knee and hip. The suit included a ballast tank, a viewing port, entrance through a manhole cover on top, a hand-cranked propeller, and rudimentary manipulators at the ends of the arms. Air was to be supplied from the surface via hose. There is no indication, however, Phillips' suit was ever constructed.[82] ADS, built by Carmagnolle brothers in 1882, was the first anthropomorphic design.The first properly anthropomorphic design of ADS, built by the Carmagnolle brothers of Marseilles, France in 1882, featured rolling convolute joints consisting of partial sections of concentric spheres formed to create a close fit and kept watertight with a waterproof cloth. The suit had 22 of these joints: four in each leg, six per arm, and two in the body of the suit. The helmet possessed 25 individual 2-inch (50 mm) glass viewing ports spaced at the average distance of the human eyes.[79] Weighing 830 pounds (380 kg), the Carmagnole ADS never worked properly and its joints never were entirely waterproof. It is now on display at the French National Navy Museum in Paris.[80] Another design was patented in 1894 by inventors John Buchanan and Alexander Gordon from Melbourne, Australia. The construction was based on a frame of spiral wires covered with waterproof material. The design was improved by Alexander Gordon by attaching the suit to the helmet and other parts and incorporating jointed radius rods in the limbs. This resulted in a flexible suit which could withstand high pressure. The suit was manufactured by British firm Siebe Gorman and trialed in Scotland in 1898. American designer MacDuffy constructed the first suit to use ball bearings to provide joint movement in 1914; it was tested in New York to a depth of 214 feet (65 m), but was not very successful. A year later, Harry L. Bowdoin of Bayonne, New Jersey, made an improved ADS with oil-filled rotary joints. The joints use a small duct to the interior of the joint to allow equalization of pressure. The suit was designed to have four joints in each arm and leg, and one joint in each thumb, for a total of eighteen. Four viewing ports and a chest-mounted lamp were intended to assist underwater vision. Unfortunately there is no evidence that Bowdoin's suit was ever built, or that it would have worked if it had been.[82] Atmospheric diving suits built by German firm Neufeldt and Kuhnke were used during the salvage of gold and silver bullion from the wreck of the British ship SS Egypt, an 8,000 ton P&O liner that sank in May 1922. The suit was relegated to duties as an observation chamber at the wreck's depth, and was successfully used to direct mechanical grabs which opened up the bullion storage. In 1917, Benjamin F. Leavitt of Traverse City, Michigan, dived on the SS Pewabic which sank to a depth of 182 feet (55 m) in Lake Huron in 1865, salvaging 350 tons of copper ore. In 1923, he went on to salvage the wreck of the British schooner Cape Horn which lay in 220 feet (67 m) of water off Pichidangui, Chile, salvaging $600,000 worth of copper. Leavitt's suit was of his own design and construction. The most innovative aspect of Leavitt's suit was the fact that it was completely self-contained and needed no umbilical, the breathing mixture being supplied from a tank mounted on the back of the suit. The breathing apparatus incorporated a scrubber and an oxygen regulator and could last for up to a full hour.[83] In 1924 the Reichsmarine tested the second generation of the Neufeldt and Kuhnke suit to 530 feet (160 m), but limb movement was very difficult and the joints were judged not to be fail-safe, in that if they were to fail, there was a possibility that the suit's integrity would be violated. However, these suits were used by the Germans as armored divers during World War II and were later taken by the Western Allies after the war. In 1952, Alfred A. Mikalow constructed an ADS employing ball and socket joints, specifically for the purpose of locating and salvaging sunken treasure. The suit was reportedly capable of diving to depths of 1,000 feet (300 m) and was used successfully to dive on the sunken vessel SS City of Rio de Janeiro in 328 feet (100 m) of water near Fort Point, San Francisco. Mikalow's suit had various interchangeable instruments which could be mounted on the end of the arms in place of the usual manipulators. It carried seven 90-cubic foot high pressure cylinders to provide breathing gas and control buoyancy. The ballast compartment covered the gas cylinders. For communication, the suit used hydrophones.[84] Peress' Tritonia Two divers, one wearing the "Tritonia" ADS and the other standard diving dress, preparing to explore the wreck of the RMS Lusitania, 1935.Although various atmospheric suits had been developed during the Victorian era, none of these suits had been able to overcome the basic design problem of constructing a joint which would remain flexible and watertight at depth without seizing up under pressure.[citation needed] Pioneering British diving engineer, Joseph Salim Peress, invented the first truly usable atmospheric diving suit, the Tritonia, in 1932 and was later involved in the construction of the famous JIM suit. Having a natural talent for engineering design, he challenged himself to construct an ADS that would keep divers dry and at atmospheric pressure, even at great depth. In 1918, Peress began working for WG Tarrant at Byfleet, United Kingdom, where he was given the space and tools to develop his ideas about constructing an ADS. His first attempt was an immensely complex prototype machined from solid stainless steel. In 1923, Peress was asked to design a suit for salvage work on the wreck of SS Egypt which had sunk in the English Channel. He declined, on the grounds that his prototype suit was too heavy for a diver to handle easily, but was encouraged by the request to begin work on a new suit using lighter materials. By 1929 he believed he had solved the weight problem, by using cast magnesium instead of steel, and had also managed to improve the design of the suit's joints by using a trapped cushion of oil to keep the surfaces moving smoothly. The oil, which was virtually non-compressible and readily displaceable, would allow the limb joints to move freely at depths of 200 fathoms (1,200 ft; 370 m), where the pressure was 520 psi (35 atm). Peress claimed that the Tritonia suit could function at 1,200 ft (370 m) although this was never proven.[85] In 1930, Peress revealed the Tritonia suit.[86] By May it had completed trials and was publicly demonstrated in a tank at Byfleet. In September Peress' assistant Jim Jarret dived in the suit to a depth of 123 m (404 ft) in Loch Ness. The suit performed perfectly, the joints proving resistant to pressure and moving freely even at depth. The suit was offered to the Royal Navy which turned it down, stating that Navy divers never needed to descend below 90 m (300 ft). In October 1935 Jarret made a successful deep dive to more than 90 m (300 ft) on the wreck of the RMS Lusitania off south Ireland, followed by a shallower dive to 60 metres (200 ft) in the English Channel in 1937 after which, due to lack of interest, the Tritonia suit was retired. The development in atmospheric pressure suits stagnated in the 1940s through 1960s, as efforts were concentrated on solving the problems of deep diving by dealing with the physiological problems of ambient pressure diving instead of avoiding them by isolating the diver from the pressure. Although the advances in ambient pressure diving (in particular, with scuba gear) were significant, the limitations brought renewed interest to the development of the ADS in the late 1960s.[85] The JIM suitThe Tritonia suit spent about 30 years in an engineering company's warehouse in Glasgow, where it was discovered, with Peress' help, by two partners in the British firm Underwater Marine Equipment, Mike Humphrey and Mike Borrow, in the mid-1960s.[85][87][88] UMEL would later classify Peress' suit as the "A.D.S Type I", a designation system that would be continued by the company for later models. In 1969, Peress was asked to become a consultant to the new company created to develop the JIM suit, named in honour of the diver Jim Jarret.[89] A JIM suit on display at the Royal Navy Submarine Museum, GosportThe Tritonia suit was upgraded into the first JIM suit, completed in November 1971. This suit underwent trials aboard HMS Reclaim in early 1972, and in 1976, the JIM suit set a record for the longest working dive below 490 feet (150 m), lasting five hours and 59 minutes at a depth of 905 feet (276 m).[90][81] The first JIM suit was completed in November 1971 and underwent trials aboard HMS Reclaim in early 1972. In 1976, the JIM suit set a record for the longest working dive below 490 feet (150 m), lasting five hours and 59 minutes at a depth of 905 feet (276 m). The first JIM suits were constructed from cast magnesium for its high strength-to-weight ratio and weighed approximately 1,100 pounds (498.95 kg) in air including the diver. They were 6 ft 6 inches (1.98 m) in height and had a maximum operating depth of 1,500 feet (457 m). The suit had a positive buoyancy of 15 to 50 pounds (6.8 to 22.7 kg). Ballast was attached to the suit's front and could be jettisoned from within, allowing the operator to ascend to the surface at approximately 100 feet (30 m) per minute.[91] The suit also incorporated a communication link and a jettisonable umbilical connection. The original JIM suit had eight annular oil-supported universal joints, one in each shoulder and lower arm, and one at each hip and knee. The JIM operator received air through an oral/nasal mask that attached to a lung-powered scrubber that had a life-support duration of approximately 72 hours, although actual survival for this time would have been unlikely due to thermal transfer through the magnesium body.[92] As technology improved and operational knowledge grew, Oceaneering upgraded their fleet of JIMs. The magnesium construction was replaced with glass-reinforced plastic (GRP) and the single joints with segmented ones, each allowing seven degrees of motion, and when added together giving the operator a very great range of motion. In addition, the four-port domed top of the suit was replaced by a transparent acrylic one that was taken from Wasp, this allowed the operator a much-improved field of vision. Trials were also carried out by the Ministry of Defence on a flying Jim suit powered from the surface through an umbilical cable. This resulted in a hybrid suit with the ability of working on the sea bed as well as mid water.[93] Later developmentsIn addition to upgrades to the JIM design, other variations of the original suit were constructed. The first, named the SAM Suit (Designated A.D.S III), was a completely aluminium model. A smaller and lighter suit, it was more anthropomorphic than the original JIMs and was depth-rated to 1,000 feet (300 m). Attempts were made to limit corrosion by the use of a chromic anodizing coating applied to the arm and leg joints, which gave them an unusual green color. The SAM suit stood at 6 feet 3 inches (1.91 m) in height, and had a life-support duration of 20 hours. Only three SAM suits would be produced by UMEL before the design was shelved. The second, named the JAM suit (Designated A.D.S IV), was constructed of glass-reinforced plastic (GRP) and was depth-rated for around 2,000 feet (610 m).[94] US Navy ADS 2000 on launch and recovery platform after a certification dive in August 2006.In 1987, the "Newtsuit" was developed by the Canadian engineer Phil Nuytten.[91] The Newtsuit is constructed to function like a "submarine you can wear", allowing the diver to work at normal atmospheric pressure even at depths of over 1,000 feet (300 m). Made of wrought aluminium, it had fully articulated joints so the diver can move more easily underwater. The life-support system provides 6–8 hours of air, with an emergency back-up supply of an additional 48 hours. The Newtsuit was used to salvage the bell from the wreck of the SS Edmund Fitzgerald in 1995. A more recent design by Nuytten is the Exosuit, a relatively lightweight suit intended for marine research.[95] It was first used in 2014 at the Bluewater and Antikythera underwater research expeditions.[81][96] The ADS 2000 was developed jointly with OceanWorks International and the US Navy in 1997,[97] as an evolution of the Newtsuit to meet US Navy requirements. The ADS2000 provides increased depth capability for the US Navy's Submarine Rescue Program. Manufactured from forged T6061 aluminum alloy it uses an advanced articulating joint design based on the Newtsuit joints. Capable of operating in up to 2,000 feet (610 m) of seawater for a normal mission of up to six hours it has a self-contained, automatic life support system.[98] Additionally, the integrated dual thruster system allows the pilot to navigate easily underwater. It became fully operational and certified by the US Navy off southern California on 1 August 2006, when Chief Navy Diver Daniel Jackson submerged to 2,000 feet (610 m).[99] Side view of Exosuit Back view of Exosuit Physiological discoveriesMain article: History of decompression research and developmentThe painting "An Experiment on a Bird in an Air Pump" by Joseph Wright of Derby, 1768, showing Robert Boyle performing a decompression experiment in 1660.This painting, An Experiment on a Bird in the Air Pump by Joseph Wright of Derby, 1768, depicts an experiment performed by Robert Boyle in 1660.A change in pressure may have immediate effect on the ears and sinuses, causing pain and leading to congestion, edema, hemorrhaging, and temporary to permanent hearing impairment. These effects have been familiar to breathhold divers since antiquity and are avoided by equalisation techniques. Reduction of ambient pressure during ascent can cause overpressure injury to internal gas spaces if not allowed to freely equalise. Health effects in divers include damage to the joints and bones similar to symptoms attributed to caisson disease in compressed air workers, which was found to be caused by too rapid a decompression to atmospheric pressure after long exposure to a pressurised environment[100] When a diver descends in the water column the ambient pressure rises. Breathing gas is supplied at the same pressure as the surrounding water, and some of this gas dissolves into the diver's blood and other tissues. Inert gas continues to be taken up until the gas dissolved in the diver is in a state of equilibrium with the breathing gas in the diver's lungs, (see: "Saturation diving"), or the diver moves up in the water column and reduces the ambient pressure of the breathing gas until the inert gases dissolved in the tissues are at a higher concentration than the equilibrium state, and start diffusing out again. Dissolved inert gases such as nitrogen or helium can form bubbles in the blood and tissues of the diver if the partial pressures of the dissolved gases in the diver gets too high when compared to the ambient pressure. These bubbles, and products of injury caused by the bubbles, can cause damage to tissues known as decompression sickness or the bends. The immediate goal of controlled decompression is to avoid development of symptoms of bubble formation in the tissues of the diver, and the long-term goal is to also avoid complications due to sub-clinical decompression injury. The symptoms of decompression sickness are known to be caused by damage resulting from the formation and growth of bubbles of inert gas within the tissues and by blockage of arterial blood supply to tissues by gas bubbles and other emboli consequential to bubble formation and tissue damage. The precise mechanisms of bubble formation and the damage they cause has been the subject of medical research for a considerable time and several hypotheses have been advanced and tested. Tables and algorithms for predicting the outcome of decompression schedules for specified hyperbaric exposures have been proposed, tested, and used, and usually found to be of some use but not entirely reliable. Decompression remains a procedure with some risk, but this has been reduced and is generally considered to be acceptable for dives within the well-tested range of commercial, military and recreational diving. The first recorded experimental work related to decompression was conducted by Robert Boyle, who subjected experimental animals to reduced ambient pressure by use of a primitive vacuum pump. In the earliest experiments the subjects died from asphyxiation, but in later experiments, signs of what was later to become known as decompression sickness were observed. Later, when technological advances allowed the use of pressurisation of mines and caissons to exclude water ingress, miners were observed to present symptoms of what would become known as caisson disease, the bends, and decompression sickness. Once it was recognized that the symptoms were caused by gas bubbles, and that recompression could relieve the symptoms, further work showed that it was possible to avoid symptoms by slow decompression, and subsequently various theoretical models have been derived to predict low-risk decompression profiles and treatment of decompression sickness. By the late 19th century, as salvage operations became deeper and longer, an unexplained malady began afflicting the divers; they would suffer breathing difficulties, dizziness, joint pain and paralysis, sometimes leading to death. The problem was already well known among workers building tunnels and bridge footings operating under pressure in caissons and was initially called "caisson disease" but later the "bends" because the joint pain typically caused the sufferer to stoop. Early reports of the disease had been made at the time of Pasley's salvage operation, but scientists were still ignorant of its causes.[101] Early treatment methods involved returning the diver to pressurised conditions by re-immersion in the water.[100] In 1942–43 the UK Government carried out extensive testing for oxygen toxicity in divers.French physiologist Paul Bert was the first to understand it as decompression sickness. His classical work, La Pression barometrique (1878), was a comprehensive investigation into the physiological effects of air-pressure, both above and below the normal.[102] He determined that inhaling pressurized air caused the nitrogen to dissolve into the bloodstream; rapid depressurization would then release the nitrogen into its natural gaseous state, forming bubbles that could block the blood circulation and potentially cause paralysis or death. Central nervous system oxygen toxicity was also first described in this publication and is sometimes referred to as the "Paul Bert effect".[102][103] John Scott Haldane designed a decompression chamber in 1907 to help make deep-sea divers safer and he produced the first decompression tables for the Royal Navy in 1908 after extensive experiments with animals and human subjects.[32][104][105] These tables established a method of decompression in stages - it remains the basis for decompression methods to this day. Following Haldane's recommendation, the maximum safe operating depth for divers was extended to 200 feet (61 m).[50]:1–1 Research on decompression was continued by the US Navy. The C&R tables were published in 1915, and a large number of experimental dives done in the 1930s, which led to the 1937 tables. Surface decompression and oxygen use were also researched in the 1930s, and the US Navy 1957 tables developed to deal with problems found in the 1937 tables.[106] In 1965 Hugh LeMessurier and Brian Hills published their paper, A thermodynamic approach arising from a study on Torres Strait diving techniques, which suggested that decompression by conventional models results in bubble formation which is then eliminated by re-dissolving at the decompression stops which is slower than off-gassing while still in solution. This indicates the importance of minimizing bubble phase for efficient gas elimination.[107][108] M.P. Spencer showed that doppler ultrasonic methods can detect venous bubbles in asymptomatic divers,[109] and Dr Andrew Pilmanis showed that safety stops reduced bubble formation.[106] In 1981 D.E. Yount described the Varying Permeability Model, proposing a mechanism of bubble formation.[110] Several other bubble models followed.[106][111][112] Pre-industrialAncient 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.[1]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.[2][3][4][5][6][7]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."[8]1300 or earlier: Persian divers were using diving goggles with windows made of the polished outer layer of tortoiseshell.[6]15th century: Konrad Kyeser, illustrated his manual of military technology Bellifortis with a diving suit fitted with a hose to the surface. The drawing is also visible in Ms.Thott.290.2º[clarification needed] attributed to Hans Talhoffer, which reproduces sections of Bellifortis.[citation needed]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.[9]1535: Guglielmo de Lorena and Francesco de Marchi dived on a Roman vessel in Lake Nemi using a one-man diving bell invented by Guglielmo.[10]1616: Franz Kessler built an improved diving bell.[11]Around 1620: Cornelius Drebbel may have made a crude rebreather: see Rebreather#History of rebreathers.[11]1650: Otto von Guericke built the first air pump.[11]1715:the chevalier (sir) Pierre Rémy de Beauve, a French aristocrat who served as garde de la marine in Brest, built one of the oldest known diving dresses. De Beauve's dress was equipped with a metal helmet and two hoses, one of them air-supplied from the surface by a bellows and the other one for evacuation of the exhaled air.[12][13]the Englishman John Lethbridge, a wool merchant, invented a diving barrel and successfully salvaged valuables from wrecks.[11]Industrial eraStart of modern diving1772: 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,[14] although Fréminet later put it on his back.[15] 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.[16][17]1774: John Day became the first person known to have died in an underwater accident while testing a "diving chamber" in Plymouth Sound.[18][19]1776: David Bushnell invented the Turtle, first submarine to attack another ship. It was used in the American Revolution.[20]1797: Karl Heinrich Klingert designed a full diving dress in 1797. This design consisted of a large metal helmet and similarly large metal belt connected by leather jacket and pants.[21]1798: in June F. W. Joachim, employed by Klingert, successfully completed the first practical tests of Klingert's armor.[citation needed]1800: Captain Peter Kreeft of Germany dived several times with his helmet diving equipment to show it to king Gustav IV Adolf of Sweden.[citation needed]1800: Robert Fulton built a submarine, the "Nautilus"[22]1837: Captain William H. Taylor demonstrated his "submarine dress" at the annual American Institute Fair at Niblo's Garden, New York City.[citation needed]1839: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".[23]W.H.Thornthwaite of Hoxton in London patented an inflatable lifting jacket for divers.[24]Around 1842: The Frenchman Joseph-Martin Cabirol (1799–1874) settled a company in Paris and starts making standard diving dresses.[citation needed]1843: Based on lessons learned from the Royal George salvage, the first diving school is set up by the Royal Navy.[citation needed]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.[citation needed]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).[25]1860: Giovanni Luppis, a retired engineer of the Austro-Hungarian navy, demonstrated a design for a self-propelled torpedo to emperor Franz Joseph.[citation needed]1864: H.L. Hunley became the first submarine to sink a ship, the USS Housatonic, during the American Civil War.[26]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.[citation needed]1882: Brothers Alphonse and Théodore Carmagnolle of Marseille, France, patented the first properly anthropomorphic design of ADS (atmospheric diving suit). Featuring 22 rolling convolute joints that were never entirely waterproof and a helmet that possessed 25 2-inch (51 mm) glass viewing ports,[27] it weighed 380 kilograms (840 lb) and was never put in service.[28]RebreathersMain article: Rebreather § History1808: on June 17, Sieur Pierre-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.[29] Touboulic called his invention Ichtioandre (Greek for 'fish-man').[30]1849: Pierre-Aimable de Saint Simon Sicard (a chemist) made the first practical oxygen rebreather. It was demonstrated in London in 1854.[24]1853: Professor T. Schwann designed a rebreather in Belgium; he exhibited it in Paris in 1878.[31] 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.[32]Diving helmets improved and in common use1808: Brizé-Fradin designed a small bell-like helmet connected to a low-pressure backpack air container.[24]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.[24]1825: William H. James designed a self-contained diving suit that had compressed air in an iron container worn around the waist.[citation needed]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.[24]1829: (1828?)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".[33] 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.[33]E.K.Gauzen, a Russian naval technician of Kronshtadt naval base (a district of Saint Petersburg), offered a "diving machine". His invention was an air-pumped metallic helmet strapped to a leather suit (an overall). The bottom of the helmet was open. The helmet is strapped to the leather suit by metallic tape. Gauzen's diving suit and its further modifications were used by the Russian Navy until 1880. The modified diving suit of the Russian Navy, based on Gauzen's invention, was known as "three-bolt equipment".[citation needed]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.[34] 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).[33]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.[33]1843: The Royal Navy establishes the first diving school.[33]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.[35]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.[36] 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.[37] 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.[38][39][40]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.[citation needed]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;[41] 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.[citation needed]1865: on August the 28th the French Navy Minister ordered the first Rouquayrol-Denayrouze diving apparatus and large scale production started.[29]Gas and air cylinders appearLate 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.[citation needed]Underwater photography The oceanographer and biologist Emil Racoviță, here equipped with a standard diving dress. An underwater photograph taken by Louis Boutan (Banyuls-sur-Mer, south of France, 1899).1893: Louis Boutan invented the first underwater camera and made the first underwater photographs.[citation needed]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.[citation needed]Decompression sickness recognised as a problem1841: 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.[11]1870: Bauer[who?] published outcomes of 25 paralyzed caisson workers.[citation needed]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.[11]1871: The St Louis Eads 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.[42]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.[citation needed]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.[42] 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.[citation needed]1878: Paul Bert published La Pression barométrique, providing the first systematic understanding of the causes of DCS.[43] 1900: John P. Holland built the first submarine to be formally commissioned by the U.S. Navy, Holland (also called A-1).[44]Leonard Hill used a frog model to prove that decompression causes bubbles and that recompression resolves them.[11]1903: Siebe Gorman started to make a submarine escape set in England; in the years afterwards it was improved, and later was called the Davis Escape Set or Davis Submerged Escape Apparatus.[32]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.[45]1905: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.[33]The first rebreather with metering valves to control the supply of oxygen was made.[citation needed]1907: Draeger of Lübeck made a rebreather called the U-Boot-Retter. (submarine rescuer).[citation needed]1908:Arthur Boycott, Guybon Damant, and John Haldane published "The Prevention of Compressed-Air Illness", detailed studies on the cause and symptoms of decompression sickness, and proposed a table of decompression stops to avoid the effects.[11][46]The Admiralty Deep Diving Committee adopted the Haldane tables for the Royal Navy, and published Haldane's diving tables to the general public.[11]1910: the British Robert Davis invented his own submarine rescuer rebreather, the Davis Submerged Escape Apparatus, for the Royal Navy submarine crews.[citation needed]1912:US Navy adopted the decompression tables published by Haldane, Boycott and Damant. Driven by Chief Gunner George Stillson, the navy set up a program to test tables and staged decompression based on the work of Haldane.[47]Maurice Fernez introduced a simple lightweight underwater breathing apparatus as an alternative to helmet diving suits.[citation needed]Draeger started the commercialization of his rebreather in both configuration types, mouthpiece and helmet.[48]1913: The US Navy began developing the future MK V, influenced by Schrader and Morse designs.[47][33]1914: Modern swimfins were invented by the Frenchman Louis de Corlieu, capitaine de corvette (Lieutenant Commander) in the French Navy. In 1914 De Corlieu made a practical demonstration of his first prototype for a group of navy officers.[49]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.[33]1916: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.[33]The Draeger model DM 2 became standard equipment of the German Navy.[citation needed]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.[33]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.[50][51]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.[52]1924:De Corlieu left the French Navy to fully devote himself to his invention.[53]Experimental dives using helium-oxygen mixtures sponsored by the US Navy and Bureau of Mines.[33]1925:Maurice Fernez introduced a new model of his underwater surface-supplied apparatus at the Grand Palais. Yves le Prieur, an assistant at the exhibition, decided to meet Fernez in person and asked him to transform the equipment into a manually-controlled constant flow self-contained underwater breathing apparatus.[54]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.[33]1926:Fernez-Le Prieur self-contained underwater breathing apparatus was demonstrated to the public in Paris, and adopted by the French Navy.[citation needed]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.[citation needed]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.[33]1928: Davis invented the Submersible Decompression Chamber (SDC) diving bell.[33]1929: Lieutenant C.B."Swede" Momsen, a submariner and diver, developed and tested the submarine escape apparatus named the Momsen Lung.[33]The 1930s:In France, Guy Gilpatric started swim diving with waterproof goggles, derived from the swimming goggles which were invented by Maurice Fernez in 1920.[citation needed]Sport spearfishing became common in the Mediterranean, and spearfishers gradually developed the diving mask, fins and snorkel, with Georges Beuchat in Marseille, France, who created the speargun. Italian sport spearfishers started using oxygen rebreathers. This practice came to the attention of the Italian Navy, which developed its frogman unit Decima Flottiglia MAS.[citation needed]1933: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").[49]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.[55] 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.[citation needed]1934:In France, Beuchat established the oldest scuba diving and spearfishing equipment manufacturing company in the world,[citation needed]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".)[citation needed]Otis Barton and William Beebe dived to 3028 feet using a bathysphere.[citation needed]1935: The French Navy adopted the Le Prieur breathing set.[56]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.[57]1937: US Navy published its revised diving tables based on the work of O.D. Yarbrough.[47]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.[citation needed]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).[citation needed]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.[citation needed]1941: The Italian Navy's Decima Flottiglia MAS using oxygen rebreathers and manned torpedoes, attacked the British fleet in Alexandria harbor.[citation needed]1944: American UDT and British COPP frogmen (COPP: Combined Operations Pilotage Parties) used the "Churchill fins" during all prior underwater deminings, allowing this way in 1944 the Normandy landings. During years after World War II had ended, De Corlieu spent time and efforts struggling into civil procedures, demanding others for patent infringement.[58]The demand regulator reappears1934: 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.[citation needed]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.[citation needed]World War II1939: Georges Commeinhes offered his breathing set to the French Navy, which could not continue developing uses for it because of WWII.[citation needed]1940-1944: Christian J. Lambertsen of the United States designed a rebreather 'Breathing apparatus' for the U.S. military.[citation needed]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.[citation needed]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.[59]1943: after fixing some technical problems, Cousteau and Gagnan patented the first modern demand regulator.[citation needed]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.[60]In July Commeinhes reached 53 metres (about 174 feet) using his GC42 breathing set off the coast of Marseille.[61]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.[62]1944: Commeinhes died in the liberation of Strasbourg in Alsace. His invention was overtaken by Cousteau's invention.[citation needed]Various nations use frogmen equipped with rebreathers for war actions: see Human torpedo.[citation needed]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.[citation needed]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.[63] 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.[citation needed]1944: Cousteau's first aqualung was destroyed by a stray artillery shell in an Allied landing on the French Riviera: that leaves two.[citation needed]PostwarThe public first heard about frogmen.[citation needed]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).[64] 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.[65]1946: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".[citation needed]Henri Broussard founded the first post-WWII scuba diving club, the Club Alpin Sous-Marin. Broussard was one of the first men who Cousteau trained in the GRS.[66]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.[citation needed]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.[citation needed]The Cave Diving Group (CDG) is formed in Britain.[citation needed]1947: Maurice Fargues became the first diver to die using an aqualung while attempting a new depth record with Cousteau's Undersea Research Group near Toulon.[19]1948:Auguste Piccard sent the first bathyscaphe, FNRS-2, on unmanned dives.[citation needed]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.[67] 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".[citation needed]Ted Eldred in Australia started developing the first open-circuit single-hose scuba set known: see Porpoise (make of scuba gear).[citation needed]Georges Beuchat in France created the first surface buoy.[citation needed]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.[citation needed]1949: William Beebe and Otis Barton made a record dive to 4,500 feet in the Benthoscope.[citation needed]1950: a British naval diving manual printed soon after this said that the aqualung is to be used for walking on the bottom with a heavy diving suit and weighted boots, and did not mention Cousteau.[citation needed]A report to Cousteau said that only 10 aqualung sets had been sent to the USA because the market there was saturated.[citation needed]The first camera housing called Tarzan is released by Georges Beuchat,[citation needed]1951: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.[citation needed]The US Navy started to develop wetsuits, but not known to the public.[47][68][69]In December 1951 the first issue of Skin Diver Magazine (USA) appeared. The magazine ran until November 2002.[citation needed]Cousteau-type aqualungs went on sale in Canada.[citation needed]1952:UC Berkeley and subsequent UC San Diego Scripps Institution of Oceanography physicist Hugh Bradner, invented the modern wetsuit.[70]Cousteau-type aqualungs went on sale in the USA.[citation needed]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.[citation needed]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.[citation needed]Public interest in scuba diving takes off1953: 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.[citation needed]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.[citation needed]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.[citation needed]Captain Trevor Hampton founded the British Underwater Centre at Dartmouth in Devon in England.[citation needed]False Bay Underwater Club founded in Cape Town, South Africa (1950).[citation needed]Rene's Sporting Goods shop (now owned by La Spirotechnique) became U.S. Divers, now a leading maker of diving equipment.[citation needed]15 October 1953: The British Sub-Aqua Club (BSAC) was founded.[71][72]1954: USS Nautilus, the first nuclear-powered submarine, was launched.[citation needed]The first manned dives in the bathyscaphe FNRS-2 were made.[citation needed]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.[73]In the USA, MSA advertised (in Popular Mechanics magazine) a two-cylinder aqualung-like open-circuit diving set using the MSA regulator.[63]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.[citation needed]1955: In Britain, "Practical Mechanics" magazine published an article on "Making an Aqualung".[74]Jacques-Yves Cousteau and assistant director Louis Malle, a young film maker of 23, shot The Silent World, one of the first films to use underwater cinematography to show the ocean depths in color.[citation needed]Fédération Française d'Études et de Sports Sous-Marins (FFESSM) was formed.[citation needed]1956:Wetsuits became available to the public.[citation needed]US Navy published decompression tables that allowed for repetitive diving.[75]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.)[citation needed]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.[citation needed][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.[citation needed]The Silent World received an Academy Award for Best Documentary Feature, and the Palme d'Or award at the Cannes Film Festival.[citation needed]1958:The U.S. television series Sea Hunt began. It introduced scuba diving to the television audience. It ran until 1961.[76]USS Nautilus completed the first ever voyage under the polar ice to the North Pole and back.[citation needed]The Confédération Mondiale des Activités Subaquatiques (CMAS) (World Underwater Federation) was founded in Brussels.[citation needed]August 1959: YMCA SCUBA Program was founded.[77]1959: National Association of Underwater Instructors (NAUI) was founded by Albert Tillman and Neal Hess.[citation needed] Norwegian diving pioneer Odd Henrik Johnsen with 1960's diving equipment.1960: Jacques Piccard and Lieutenant Don Walsh, USN, descended to the bottom of the Challenger Deep, the deepest known point in the ocean (about 10900 m or 35802 ft, or 6.78 miles) in the bathyscaphe Trieste.[78]USS Triton completes the first ever underwater circumnavigation of the world.[citation needed]In Italy, sport diving oxygen rebreathers continued to be made well into the 1960s.[citation needed]1962:Robert Sténuit lives aboard a tiny one-man cylinder at 200 feet for over 24 hours off Villefranche-sur-Mer on the French Riviera, becoming the world's first aquanaut.[19][79][80]Swiss diver Hannes Keller reaches over 1,000 feet (300 m) depth off California.[33]Edward A. Link’s Man-in-the-Sea program had one man breathing helium-oxygen at 200 fsw for 24 hours in the first practical saturation dive.[33]1964:In France, Georges Beuchat creates the Jetfins, first vented fins.[citation needed]The U.S. Navy's Sealab 1 underwater habitat project directed by Captain George F. Bond, keeps four divers in saturation underwater at an average depth of 193 feet for 11 days.[33]1965:Robert D. Workman of the U.S. Navy Experimental Diving Unit (NEDU) publishes an algorithm for computing decompression requirements suitable for implementing in a dive computer, rather than a pre-computed table.[81]Bob Kirby and Bev Morgan formed Kirby-Morgan.[33]Three teams of ten men each spent 15 days under saturation at 205 fsw in Sealab II. Astronaut Scott Carpenter stayed for 30 days.[33]The film version of James Bond in Thunderball (using both sorts of open-circuit scuba)[clarification needed] was released and helps to make scuba diving popular.[citation needed]1966: Professional Association of Diving Instructors (PADI) was founded by John Cronin and Ralph Erickson.[82]1968: An excursion dive to 1025 fsw was made from a saturation depth of 825 fsw at NEDU.[33]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.[83]1971: Scubapro introduced the Stabilization Jacket, commonly called stab jacketin England, and Buoyancy Control (or Compensation) Device (BC or BCD) elsewhere.[citation needed]1972: Scubapro introduced the decompression meter (the first analog dive computer).[citation needed]1976: Professor Albert A. Bühlmann published his work extending the formulae to apply to diving at altitude and with complex gas mixes.[84]1983: The Orca Edge (the first commercially viable electronic dive computer) was introduced.[85][86]1985:The wreck of RMS Titanic was found. Air India Flight 182, a Boeing 747 aircraft, was found and salvaged off Cork, Ireland during the first large scale deep water (6,200 feet) air crash investigation.[citation needed]International Association of Nitrox and Technical Divers (IANTD) was founded[87][citation needed]1986 Apeks Marine Equipment introduced the first dry sealed 1st Stage developed by engineering designer Alan Clarke, later to house a patented electronic pressure sensor named STATUS.[citation needed]1989: The film The Abyss (including an as-yet-fictional deep-sea liquid-breathing set) helped to make scuba diving popular.[citation needed]The Communist Bloc fell apart and the Cold War ended (see Fall of Communism and dissolution of the Soviet Union), and with it the risk of future attack by Communist Bloc forces including by their combat divers. After that, the world's armed forces had less reason to requisition rebreather patents submitted by civilians, and sport diving automatic and semi-automatic mixture rebreathers start to appear.[citation needed]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.[88]1994:Divex and Kirby-Morgan developed the Divex UltraJewel 601 gas-reclaim system in response to rising helium costs.[33]Technical Diving International was founded to focus on training beyond the contemporary scope of recreational diving.[89][dead link][citation needed]1995: BSAC allowed nitrox diving and introduced nitrox training.[72][90]1996: PADI introduced its Enriched Air Diver Course.[91]1997: The film Titanic helped to make underwater trips onboard MIR submersible vehicles popular.[citation needed]1998 August: Dives on RMS Titanic were made using a Remotely Operated Vehicle controlled from the surface (Magellan 725), and the first live video broadcast was made from the Titanic.[citation needed]1999 July: The Liberty Bell 7 Mercury spacecraft was recovered from 16,043 feet (4,890 m) of water in the Atlantic Ocean during the deepest commercial search and recovery operation to date.[citation needed] 2001 December: The BSAC allowed rebreathers to be used in BSAC dives.[72]2006 August 1: A US Navy diver in an ADS 2000 atmospheric suit established a new depth record of 2,000 feet (610 metres).[92]2009 June: NAUI approved the first Standard Diving Dress recreational diving course. The course is offered in Australia.[citation needed]2012 March: Canadian film director James Cameron piloted the Deepsea Challenger 10,898.4 metres (35,756 feet) to the bottom of the Challenger Deep, the deepest known point in the ocean.[93][94]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.[95][96][clarification needed]See alsounderwater diving portalTimeline of atmospheric diving suits HistoryEarly designs John Lethbridge's diving dress, the first enclosed diving suit, built in the 1710s.In 1715, British inventor John Lethbridge constructed a "diving suit". Essentially a wooden barrel about 6 feet (1.8 m) in length with two holes for the diver's arms sealed with leather cuffs, and a 4-inch (100 mm) viewport of thick glass. It was reportedly used to dive as deep as 60 feet (18 m), and was used to salvage substantial quantities of silver from the wreck of the East Indiaman Vansittart, which sank in 1719 off the Cape Verde islands.[2] The first armored suit with real joints, designed as leather pieces with rings in the shape of a spring (also known as accordion joints), was designed by Englishman W. H. Taylor in 1838. The diver's hands and feet were covered with leather. Taylor also devised a ballast tank attached to the suit that could be filled with water to attain negative buoyancy. While it was patented, the suit was never actually produced. It is considered that its weight and bulk would have rendered it nearly immobile underwater.[2] Lodner D. Phillips designed the first completely enclosed ADS in 1856. His design comprised a barrel-shaped upper torso with domed ends and included ball and socket joints in the articulated arms and legs. The arms had joints at shoulder and elbow, and the legs at knee and hip. The suit included a ballast tank, a viewing port, entrance through a manhole cover on top, a hand-cranked propeller, and rudimentary manipulators at the ends of the arms. Air was to be supplied from the surface via hose. There is no indication, however, Phillips' suit was ever constructed.[2] ADS, built by Carmagnolle brothers in 1882, was the first anthropomorphic design.The first properly anthropomorphic design of ADS, built by the Carmagnolle brothers of Marseilles, France in 1882, featured rolling convolute joints consisting of partial sections of concentric spheres formed to create a close fit and kept watertight with a waterproof cloth. The suit had 22 of these joints: four in each leg, six per arm, and two in the body of the suit. The helmet possessed 25 individual 2-inch (50 mm) glass viewing ports spaced at the average distance of the human eyes.[3] Weighing 830 pounds (380 kg), the Carmagnole ADS never worked properly and its joints never were entirely waterproof. It is now on display at the French National Navy Museum in Paris.[4] Another design was patented in 1894 by inventors John Buchanan and Alexander Gordon from Melbourne, Australia. The construction was based on a frame of spiral wires covered with waterproof material. The design was improved by Alexander Gordon by attaching the suit to the helmet and other parts and incorporating jointed radius rods in the limbs. This resulted in a flexible suit which could withstand high pressure. The suit was manufactured by British firm Siebe Gorman and trialed in Scotland in 1898. US Navy 1913 ADS 1913 US Navy ADS at Man in the Sea Museum, Panama City, FL with the lobster claws Close up view of two-jawed grasper and pitch-yaw wrist joint on 1913 US Navy armored diving suitAmerican designer MacDuffy constructed the first suit to use ball bearings to provide joint movement in 1914; it was tested in New York to a depth of 214 feet (65 m), but was not very successful. A year later, Harry L. Bowdoin of Bayonne, New Jersey, made an improved ADS with oil-filled rotary joints. The joints use a small duct to the interior of the joint to allow equalization of pressure. The suit was designed to have four joints in each arm and leg, and one joint in each thumb, for a total of eighteen. Four viewing ports and a chest-mounted lamp were intended to assist underwater vision. Unfortunately there is no evidence that Bowdoin's suit was ever built, or that it would have worked if it had been.[2] Atmospheric diving suits built by German firm Neufeldt and Kuhnke were used during the salvage of gold and silver bullion from the wreck of the British ship SS Egypt, an 8,000 ton P&O liner that sank in May 1922. The suit was relegated to duties as an observation chamber at the wreck's depth, and was successfully used to direct mechanical grabs which opened up the bullion storage. In 1917, Benjamin F. Leavitt of Traverse City, Michigan, dived on the SS Pewabic which sank to a depth of 182 feet (55 m) in Lake Huron in 1865, salvaging 350 tons of copper ore. In 1923, he went on to salvage the wreck of the British schooner Cape Horn which lay in 220 feet (67 m) of water off Pichidangui, Chile, salvaging $600,000 worth of copper. Leavitt's suit was of his own design and construction. The most innovative aspect of Leavitt's suit was the fact that it was completely self-contained and needed no umbilical, the breathing mixture being supplied from a tank mounted on the back of the suit. The breathing apparatus incorporated a scrubber and an oxygen regulator and could last for up to a full hour.[5] In 1924 the Reichsmarine tested the second generation of the Neufeldt and Kuhnke suit to 530 feet (160 m), but limb movement was very difficult and the joints were judged not to be fail-safe, in that if they were to fail, there was a possibility that the suit's integrity would be violated. However, these suits were used by the Germans as armored divers during World War II and were later taken by the Western Allies after the war. In 1952, Alfred A. Mikalow constructed an ADS employing ball and socket joints, specifically for the purpose of locating and salvaging sunken treasure. The suit was reportedly capable of diving to depths of 1,000 feet (300 m) and was used successfully to dive on the sunken vessel SS City of Rio de Janeiro in 328 feet (100 m) of water near Fort Point, San Francisco. Mikalow's suit had various interchangeable instruments which could be mounted on the end of the arms in place of the usual manipulators. It carried seven 90-cubic foot high pressure cylinders to provide breathing gas and control buoyancy. The ballast compartment covered the gas cylinders. For communication, the suit used hydrophones.[6] The modern suitPeress' Tritonia Two divers, one wearing the "Tritonia" ADS and the other standard diving dress, preparing to explore the wreck of the RMS Lusitania, 1935.Although various atmospheric suits had been developed during the Victorian era, none of these suits had been able to overcome the basic design problem of constructing a joint which would remain flexible and watertight at depth without seizing up under pressure. Pioneering British diving engineer, Joseph Salim Peress, invented the first truly usable atmospheric diving suit, the Tritonia, in 1932 and was later involved in the construction of the famous JIM suit. Having a natural talent for engineering design, he challenged himself to construct an ADS that would keep divers dry and at atmospheric pressure, even at great depth. In 1918, Peress began working for WG Tarrant at Byfleet, United Kingdom, where he was given the space and tools to develop his ideas about constructing an ADS. His first attempt was an immensely complex prototype machined from solid stainless steel. In 1923, Peress was asked to design a suit for salvage work on the wreck of SS Egypt which had sunk in the English Channel. He declined, on the grounds that his prototype suit was too heavy for a diver to handle easily, but was encouraged by the request to begin work on a new suit using lighter materials. By 1929 he believed he had solved the weight problem, by using cast magnesium instead of steel, and had also managed to improve the design of the suit's joints by using a trapped cushion of oil to keep the surfaces moving smoothly. The oil, which was virtually non-compressible and readily displaceable, would allow the limb joints to move freely at depths of 200 fathoms (1,200 ft; 370 m), where the pressure was 520 psi (35 atm). Peress claimed that the Tritonia suit could function at 1,200 ft (370 m) although this was never proven.[7] In 1930, Peress revealed the Tritonia suit.[8] By May it had completed trials and was publicly demonstrated in a tank at Byfleet. In September Peress' assistant Jim Jarret dived in the suit to a depth of 123 m (404 ft) in Loch Ness. The suit performed perfectly, the joints proving resistant to pressure and moving freely even at depth. The suit was offered to the Royal Navy which turned it down, stating that Navy divers never needed to descend below 90 m (300 ft). In October 1935 Jarret made a successful deep dive to more than 90 m (300 ft) on the wreck of the RMS Lusitania off south Ireland, followed by a shallower dive to 60 metres (200 ft) in the English Channel in 1937 after which, due to lack of interest, the Tritonia suit was retired. The development in atmospheric pressure suits stagnated in the 1940s through 1960s, as efforts were concentrated on solving the problems of deep diving by dealing with the physiological problems of ambient pressure diving instead of avoiding them by isolating the diver from the pressure. Although the advances in ambient pressure diving (in particular, with scuba gear) were significant, the limitations brought renewed interest to the development of the ADS in the late 1960s.[7] The JIM suitThe Tritonia suit spent about 30 years in an engineering company's warehouse in Glasgow, where it was discovered, with Peress' help, by two partners in the British firm Underwater Marine Equipment, Mike Humphrey and Mike Borrow, in the mid-1960s.[7][9][10] UMEL would later classify Peress' suit as the "A.D.S Type I", a designation system that would be continued by the company for later models. In 1969, Peress was asked to become a consultant to the new company created to develop the JIM suit, named in honour of the diver Jim Jarret.[11] A JIM suit on display at the Royal Navy Submarine Museum, GosportThe first JIM suit was completed in November 1971 and underwent trials aboard HMS Reclaim in early 1972. In 1976, the JIM suit set a record for the longest working dive below 490 feet (150 m), lasting five hours and 59 minutes at a depth of 905 feet (276 m). The first JIM suits were constructed from cast magnesium for its high strength-to-weight ratio and weighed approximately 1,100 pounds (498.95 kg) in air including the diver. They were 6 ft 6 inches (1.98 m) in height and had a maximum operating depth of 1,500 feet (457 m). The suit had a positive buoyancy of 15 to 50 pounds (6.8 to 22.7 kg). Ballast was attached to the suit's front and could be jettisoned from within, allowing the operator to ascend to the surface at approximately 100 feet (30 m) per minute.[12] The suit also incorporated a communication link and a jettisonable umbilical connection. The original JIM suit had eight annular oil-supported universal joints, one in each shoulder and lower arm, and one at each hip and knee. The JIM operator received air through an oral/nasal mask that attached to a lung-powered scrubber that had a life-support duration of approximately 72 hours, although actual survival for this time would have been unlikely due to thermal transfer through the magnesium body.[13] As technology improved and operational knowledge grew, Oceaneering upgraded their fleet of JIMs. The magnesium construction was replaced with glass-reinforced plastic (GRP) and the single joints with segmented ones, each allowing seven degrees of motion, and when added together giving the operator a very great range of motion. In addition, the four-port domed top of the suit was replaced by a transparent acrylic one that was taken from Wasp, this allowed the operator a much-improved field of vision. Trials were also carried out by the Ministry of Defence on a flying Jim suit powered from the surface through an umbilical cable. This resulted in a hybrid suit with the ability of working on the sea bed as well as mid water.[14] In addition to upgrades to the JIM design, other variations of the original suit were constructed. The first, named the SAM Suit (Designated A.D.S III), was a completely aluminium model. A smaller and lighter suit, it was more anthropomorphic than the original JIMs and was depth-rated to 1,000 feet (300 m). Attempts were made to limit corrosion by the use of a chromic anodizing coating applied to the arm and leg joints, which gave them an unusual green color. The SAM suit stood at 6 feet 3 inches (1.91 m) in height, and had a life-support duration of 20 hours. Only three SAM suits would be produced by UMEL before the design was shelved. The second, named the JAM suit (Designated A.D.S IV), was constructed of glass-reinforced plastic (GRP) and was depth-rated for around 2,000 feet (610 m).[15] Current suits US Navy ADS 2000 on launch and recovery platform after a certification dive in August 2006.In 1987, the "Newtsuit" was developed by the Canadian engineer Phil Nuytten, and a version was put into production as the "Hardsuit" by Hardsuits International.[16] The Newtsuit is constructed to function like a 'submarine you can wear', allowing the diver to work at normal atmospheric pressure even at depths of over 1,000 feet (300 m). Made of wrought aluminium, it had fully articulated joints so the diver can move more easily underwater. The life-support system provides 6–8 hours of air, with an emergency back-up supply of an additional 48 hours. The Hardsuit was used to salvage the bell from the wreck of the SS Edmund Fitzgerald in 1995. The latest version of the Hardsuit designed by Oceanworks, the "Quantum 2", uses higher power commercially available ROV thrusters for better reliability and more power as well as an atmospheric monitoring system to monitor the environmental conditions in the cabin. A more recent design by Nuytten is the Exosuit, a relatively lightweight and low powered suit intended for marine research.[17] Atmospheric Diving System (ADS 2000)A diver wearing the Oceanworks ADS 2000 suit with the helmet dome open stands in an indoor test pool and talks to two other naval officersAtmospheric Diving System at the Naval Reserve Deep Submergence Unit Detachment at Naval Air Station North IslandThe ADS 2000 suit is lowered into the sea from the side of a shipAtmospheric Diving System lowered into the water from the salvage ship USNS Grasp (T-ARS-51)The ADS 2000 was developed jointly with OceanWorks International and the US Navy in 1997,[18] as an evolution of the Hardsuit to meet US Navy requirements. The ADS2000 provides increased depth capability for the US Navy's Submarine Rescue Program. Manufactured from forged T6061 aluminum alloy it uses an advanced articulating joint design based on the Hardsuit joints. Capable of operating in up to 2,000 feet (610 m) of seawater for a normal mission of up to six hours it has a self-contained, automatic life support system.[19] Additionally, the integrated dual thruster system allows the pilot to navigate easily underwater. It became fully operational and certified by the US Navy off southern California on August 1, 2006, when Chief Navy Diver Daniel Jackson submerged to 2,000 feet (610 m).[20] From the project's beginning until 2011, the US navy spent $113 million on the ADS.[21] Condition: Very good condition - see description., Maker: Mason, Original/Reproduction: Antique Original, Model/Style: Commercial, Time Period, War: Civil War, Country/Region of Origin: United States

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