page_title: History of scuba diving
section_title: Military diving
hierarchical_section_title: History of scuba diving / History of specific fields of application for scuba diving / Military diving
caption_attribution_description: English: Atlantic Ocean (May 5, 2005) - A member of SEAL Delivery Vehicle Team Two (SDVT-2) climbs aboard one of the team's SEAL Delivery Vehicles (SDV) before launching from the back of the Los Angeles-class attack submarine USS Philadelphia (SSN 690) on a training exercise. The SDVs are used to carry Navy SEALs from a submerged submarine to enemy targets while staying underwater and undetected. SDVT-2 is stationed at Naval Amphibious Base Little Creek, Va., and conducts operations throughout the Atlantic, Southern, and European command areas of responsibility. U.S. Navy photo by Chief Photographer's Mate Andrew McKaskle (RELEASED)
context_page_description: The history of scuba diving is closely linked with the history of scuba 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.
context_section_description: The first modern military scuba divers were the World War II Italian commando frogmen, of Decima Flottiglia MAS (now "ComSubIn": Comando Raggruppamento Subacquei e Incursori Teseo Tesei) which formed in 1938 and was first in action in 1940. Originally these divers were called "Uomini Gamma" because they were members of the top secret special unit called "Gruppo Gamma", which originated from the kind of Pirelli rubber skin-suit nicknamed muta gamma used by these divers. Later they were nicknamed "Uomini Rana", Italian for "frog men" This special corps used an early oxygen rebreather scuba set, the Auto Respiratore ad Ossigeno (A.R.O), a development of the Dräger oxygen self-contained breathing apparatus designed for the mining industry and of the Davis Submerged Escape Apparatus made by Siebe, Gorman & Co and by Bergomi, designed for escaping from sunken submarines. The Italian frogmen trained in La Spezia, Liguria, using swimfins, rubber dry suit, and the new A.R.O. scuba unit. After Italy declared war, the Decima Flottiglia MAS (Xª MAS) attempted several attacks on British naval bases in the Mediterranean between June 1940 and July 1941, but none was successful, because of equipment failure or early detection by British forces. On September 10, 1941, eight Xª MAS frogmen were inserted by submarine close to the British harbour at Gibraltar, where using human torpedoes to penetrate the defences, sank three merchant ships with limpet mines before escaping through neutral Spain. An even more successful attack, the Raid on Alexandria, was mounted on 19 December on the harbour at Alexandria, again using human torpedoes. The raid resulted in disabling the battleships HMS Queen Elizabeth and HMS Valiant together with a destroyer and an oil tanker, but all six frogmen were captured.
  The British Royal Navy had captured an Italian human torpedo during a failed attack on Malta; they developed a copy called the Chariot and formed a unit called the Experimental Submarine Flotilla, which later merged with the Special Boat Service. A number of Chariot operations were attempted, most notably Operation Title in October 1942, an attack on the German battleship Tirpitz, which had to be abandoned when a storm hit the fishing boat which was towing the Chariots into position. The last and most successful British operation resulted in sinking two liners in Phuket harbour in Thailand in October 1944.
  An oxygen rebreather set  called the Lambertsen Amphibious Respirator Unit (LARU) was invented in the United States 1939 by Christian Lambertsen, and was patented in 1940. Lambertsen 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 it to the Office of Strategic Services (OSS) after being rejected by the U.S. Navy  OSS not only bought into the concept, they hired Dr. Lambertsen to lead the program and build-up the dive element of their maritime unit.  The OSS was the predecessor of the Central Intelligence Agency and the maritime element still exists inside their Special Activities Division.
  The Shayetet 13 commandos of the Israeli Navy have carried out a number of underwater raids on harbors. They were initially trained by veterans of Xª MAS and used Italian equipment. As part of Operation Raviv in 1969, eight frogmen used two human torpedoes to enter Ras Sadat naval base near Suez, where they destroyed two motor torpedo boats with mines.
  During the 1982 Falklands War, the Argentinian Naval Intelligence Service planned an attack on British warships at Gibraltar. Code named Operation Algeciras, three frogmen, recruited from a former anti-government insurgent group, were to plant mines on the ships' hulls. The operation was abandoned when the divers were arrested by Spanish police and deported.
  In 1985, the French nuclear weapons tests at Moruroa in the Pacific Ocean was being contested by environmental protesters led by the Greenpeace campaign ship, Rainbow Warrior. 
caption: A SEAL Delivery Team member climbs aboard a delivery vehicle before launching from the back of the submarine USS Philadelphia.
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