See also
- Rebreather – Portable apparatus to recycle breathing gas
The Lambertsen Amphibious Respiratory Unit (LARU) is an early model of closed circuit oxygen rebreather used by military frogmen. Christian J. Lambertsen designed a series of them in the US in 1940 (patent filing date: 16 Dec 1940) and in 1944 (issue date: 2 May 1944). [1]
The LARU is what the initials SCUBA (Self-Contained Underwater Breathing Apparatus) originally meant; Lambertsen changed his invention's name to SCUBA in 1952; [2] but later "SCUBA", gradually changing to "scuba", came to mean (first in the USA) any self-contained underwater breathing apparatus. (Modern diving regulator technology was invented by Émile Gagnan and Jacques-Yves Cousteau in 1943 and was not related to rebreathers; nowadays the word SCUBA is largely used to mean Gagnan's and Cousteau's invention and its derivatives.)
Lambertsen designed the LARU while a medical student and demonstrated the LARU to the Office of Strategic Services (OSS) (after already being rejected by the U.S. Navy) in a pool at the Shoreham Hotel in Washington D.C. in 1942 [3] [4] The OSS "Operational Swimmer Group" was formed and Lambertsen's responsibilities included training and developing methods of combining self-contained diving and swimmer delivery including the LARU. [5] [6]
Many diving rebreathers are descended from it. However, there were earlier underwater uses of rebreathers:
A scuba set, originally just scuba, is any breathing apparatus that is entirely carried by an underwater diver and provides the diver with breathing gas at the ambient pressure. Scuba is an anacronym for self-contained underwater breathing apparatus. Although strictly speaking the scuba set is only the diving equipment that is required for providing breathing gas to the diver, general usage includes the harness or rigging by which it is carried and those accessories which are integral parts of the harness and breathing apparatus assembly, such as a jacket or wing style buoyancy compensator and instruments mounted in a combined housing with the pressure gauge. In the looser sense, scuba set has been used to refer to all the diving equipment used by the scuba diver, though this would more commonly and accurately be termed scuba equipment or scuba gear. Scuba is overwhelmingly the most common underwater breathing system used by recreational divers and is also used in professional diving when it provides advantages, usually of mobility and range, over surface-supplied diving systems and is allowed by the relevant legislation and code of practice.
The timeline of underwater diving technology is a chronological list of notable events in the history of the development of underwater diving equipment. With the partial exception of breath-hold diving, the development of underwater diving capacity, scope, and popularity, has been closely linked to available technology, and the physiological constraints of the underwater environment.
Aqua-Lung was the first open-circuit, self-contained underwater breathing apparatus to achieve worldwide popularity and commercial success. This class of equipment is now commonly referred to as a twin-hose diving regulator, or demand valve. The Aqua-Lung was invented in France during the winter of 1942–1943 by two Frenchmen: engineer Émile Gagnan and Jacques Cousteau, who was a Naval Lieutenant. It allowed Cousteau and Gagnan to film and explore underwater more easily.
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from open-circuit breathing apparatus, where the exhaled gas is discharged directly into the environment. The purpose is to extend the breathing endurance of a limited gas supply, while also eliminating the bubbles otherwise produced by an open circuit system. The latter advantage over other systems is useful for covert military operations by frogmen, as well as for undisturbed observation of underwater wildlife. A rebreather is generally understood to be a portable apparatus carried by the user. The same technology on a vehicle or non-mobile installation is more likely to be referred to as a life-support system.
A frogman is someone who is trained in scuba diving or swimming underwater in a tactical capacity that includes military, and in some European countries, police work. Such personnel are also known by the more formal names of combat diver, combatant diver, or combat swimmer. The word frogman first arose in the stage name the "Fearless Frogman" of Paul Boyton in the 1870s and later was claimed by John Spence, an enlisted member of the U.S. Navy and member of the OSS Maritime Unit, to have been applied to him while he was training in a green waterproof suit.
The Soviet, later Russian IDA71 military and naval rebreather is an oxygen rebreather intended for use by naval and military divers including Russian commando frogmen. As supplied it is in a plain backpack harness with no buoyancy aid. The casing is pressed aluminium with a hinged cover. It has a small optional nitrox cylinder which can be clipped on its outside to convert it to nitrox mode. It contains one oxygen cylinder and two absorbent canisters. In the bottom of its casing is an empty space which is intended for an underwater communications set.
The Clearance Divers Breathing Apparatus (CDBA) is a type of rebreather made by Siebe Gorman in England.
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.
Siebe Gorman & Company Ltd was a British company that developed diving equipment and breathing equipment and worked on commercial diving and marine salvage projects. The company advertised itself as 'Submarine Engineers'. It was founded by Augustus Siebe, a German-born British engineer chiefly known for his contributions to diving equipment.
Porpoise is a tradename for scuba developed by Ted Eldred in Australia and made there from the late 1940s onwards. The first Porpoise was a closed circuit oxygen rebreather, and the following models were all single hose open circuit regulators.
Edward Francis Eldred was a pioneer of scuba diving in Australia. He invented Porpoise scuba gear.
The Davis Submerged Escape Apparatus, was an early type of oxygen rebreather invented in 1910 by Sir Robert Davis, head of Siebe Gorman and Co. Ltd., inspired by the earlier Fleuss system, and adopted by the Royal Navy after further development by Davis in 1927. 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.
The Proto is a type of rebreather that was made by Siebe Gorman. It was an industrial breathing set and not suitable for diving. It was made from 1914 or earlier to the 1960s or later.. Also known as proto suits.
Sir Robert Henry Davis was an English inventor and director of the Siebe Gorman company. His main invention was the Davis Submerged Escape Apparatus, an oxygen rebreather that Davis patented for the first time in 1910, inspired by the rebreathers that Henry Fleuss patented as of 1876. Davis breathing set was destined to allow British submarine crews to escape when their ship started to sink.
Christian James Lambertsen was an American environmental medicine and diving medicine specialist who was principally responsible for developing the United States Navy frogmen's rebreathers in the early 1940s for underwater warfare. Lambertsen designed a series of rebreathers in 1940 and in 1944 and first called his invention breathing apparatus. Later, after the war, he called it Laru and finally, in 1952, he changed his invention's name again to SCUBA. Although diving regulator technology was invented by Émile Gagnan and Jacques-Yves Cousteau in 1943 and was unrelated to rebreathers, the current use of the word SCUBA is largely attributed to the Gagnan-Cousteau invention. The US Navy considers Lambertsen to be "the father of the Frogmen".
Vintage scuba is scuba equipment dating from 1975 and earlier, and the practice of diving using such equipment.
Aqualung Group is a large and well-known firm which makes scuba and other self-contained breathing apparatus, and other diving equipment. It produced the Aqua-Lung line of regulators, like the CG45 (1945) and the Mistral (1955), among others. Until 2016, the company was a division of Air Liquide since its foundation in 1946. The company was sold to Montagu Private Equity in 2016, and subsequently acquired by Barings LLC in 2023.
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.
The history of scuba diving is closely linked with the history of the equipment. By the turn of the twentieth century, two basic architectures for underwater breathing apparatus had been pioneered; open-circuit surface supplied equipment where the diver's exhaled gas is vented directly into the water, and closed-circuit breathing apparatus where the diver's carbon dioxide is filtered from the exhaled breathing gas, which is then recirculated, and more gas added to replenish the oxygen content. Closed circuit equipment was more easily adapted to scuba in the absence of reliable, portable, and economical high pressure gas storage vessels. By the mid-twentieth century, high pressure cylinders were available and two systems for scuba had emerged: open-circuit scuba where the diver's exhaled breath is vented directly into the water, and closed-circuit scuba where the carbon dioxide is removed from the diver's exhaled breath which has oxygen added and is recirculated. Oxygen rebreathers are severely depth limited due to oxygen toxicity risk, which increases with depth, and the available systems for mixed gas rebreathers were fairly bulky and designed for use with diving helmets. The first commercially practical scuba rebreather was designed and built by the diving engineer Henry Fleuss in 1878, while working for Siebe Gorman in London. His self contained breathing apparatus consisted of a rubber mask connected to a breathing bag, with an estimated 50–60% oxygen supplied from a copper tank and carbon dioxide scrubbed by passing it through a bundle of rope yarn soaked in a solution of caustic potash. 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. In the U.S. Major Christian J. Lambertsen invented a free-swimming oxygen rebreather. In 1952 he patented a modification of his apparatus, this time named SCUBA, an acronym for "self-contained underwater breathing apparatus," which became the generic English word for autonomous breathing equipment for diving, and later for the activity using the equipment. 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. The high percentage of oxygen used by these early rebreather systems limited the depth at which they could be used due to the risk of convulsions caused by acute oxygen toxicity.
The following outline is provided as an overview of and topical guide to underwater diving:
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