The Soviet, later Russian IDA71 military and naval rebreather is an oxygen

rebreather A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's breathing, exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. ...

intended for use by naval and military divers including

Russian commando frogmen The Russian commando frogmen (russian: Морской спецназ, Morskoy spetsnaz), informally called "frogmen" in civilian media, are a Russian Naval Spetsnaz unit under operational subordination to the Main Intelligence Directorate (GRU). ...

. 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 Nitrox refers to any breathing gas, gas mixture composed (excepting trace gases) of nitrogen and oxygen. This includes atmospheric air, which is approximately 78% nitrogen, 21% oxygen, and 1% other gases, primarily argon. In the usual applicatio ...

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. Here, "up", "back", etc. refer to a man wearing the set standing on land. The casing is thinner towards the lower end, to reduce drag. On the front of the harness of the navy frogman version there is a projecting metal plate intended to carry a limpet mine. The front of the harness is a tough rubber "apron". The loop of each breathing tube can be strapped down to the shoulder to keep it under control to stop it from catching on things or being easily grabbed from behind. On each side of the casing is a small clip to fasten a parachute to.

Operating modes

The IDA-71 can be used as an oxygen rebreather, or with the addition of an external cylinder, as a nitrox rebreather, which converts between nitrox and oxygen automatically by a pressure activated valve on the nitrox attachment. It can run as an ordinary

diving rebreather A Diving rebreather is an underwater breathing apparatus that absorbs the carbon dioxide of a diver's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of ea ...

. Or it can be run with one of its two absorbent canisters filled with

potassium superoxide Potassium superoxide is an inorganic compound with the formula KO2. It is a yellow paramagnetic solid that decomposes in moist air. It is a rare example of a stable salt of the superoxide anion. It is used as a scrubber, dehumidifier, and ge ...

, which gives off oxygen as it absorbs carbon dioxide: 4KO₂ + 2CO₂ = 2K₂CO₃ + 3O₂; in this mode the oxygen cylinder is a bailout, or to fill and flush the circuit at the start of the dive. This mode gives the set more duration underwater, but is dangerous and not to be risked by civilians because of the explosively hot reaction that happens if water gets on the potassium superoxide; whereas ordinary modern diver's rebreather absorbents have been designed to avoid producing a caustic solution (commonly called "cocktail") if they get wet. Tests at the

United States Navy Experimental Diving Unit The United States Navy Experimental Diving Unit (NEDU or NAVXDIVINGU) is the primary source of diving and hyperbaric operational guidance for the US Navy. It is located within the Naval Support Activity Panama City in Panama City Beach, Bay Count ...

Panama City, Florida Panama City is a city in and the county seat of Bay County, Florida, United States. Located along U.S. Highway 98 (US 98), it is the largest city between Tallahassee and Pensacola. It is the more populated city of the Panama City–Lynn ...

showed that the IDA71 could give significantly longer dive time with superoxide in one of the canisters than without. For many years the IDA71 and similar have been a standard Russian frogman's and naval work diver's breathing set. The "71" in its name may be the year that it was designed, like with the numbers in the names of the AK series of Russian rifles. The name IDA comes from russian: Изолирующий дыхательный аппарат ( translit. izoliruyushchiy dykhatel'nyy apparat, literally ''Insulating/Isolating Breathing Apparatus''). Other name is ''Individual Breathing Apparatus'' (russian: Индивидуальний дыхательный аппарат, translit. Individualniy Dykhatelniy Apparat). In its original Russian mode as an oxygen rebreather, its dive duration is said to be 4 hours. Filling both canisters with

soda lime Soda lime is a mixture of NaOH and CaO chemicals, used in granular form in closed breathing environments, such as general anaesthesia, submarines, rebreathers and recompression chambers, to remove carbon dioxide from breathing gases to prevent ...

and putting a second oxygen cylinder in the empty space at the bottom, might increase its dive duration to 8 hours. A number of IDA71's have found their way out of the ex-USSR to Europe and America, where recreational divers have added a wing buoyancy compensator an
converted them
into manually controlled closed circuit rebreathers.

Gallery

File:IDA-71 mask, DSV and breathing hoses P5167748.JPG, IDA-71 mask, DSV and breathing hoses File:IDA-71 DSV P5167749.JPG, IDA-71 dive/surface valve File:IDA-71 full face mask and DSV P5167752.JPG, IDA-71 full face mask and DSV File:IDA-71 full face mask P5167753.JPG, IDA-71 full face mask File:IDA-71 transport bag P5167755.JPG, IDA-71 transport bag File:IDA-71 transport bag P5167756.JPG, IDA-71 transport bag File:IDA-71 external Nitrox set P5167759.JPG, IDA-71 external nitrox cylinder with regulator hoses and changeover valve File:IDA-71 external Nitrox set P5167760.JPG, IDA-71 external nitrox cylinder with regulator hoses and changeover valve File:IDA-71 Integrated cylinder valve and regulator of external nitrox set P5167762.JPG, IDA-71 Integrated cylinder valve and regulator of external nitrox set File:IDA 71 rebreather and harness P5167763.JPG, IDA 71 rebreather and harness File:IDA-71 front view P5167767.JPG, IDA-71 rebreather top/front end showing ADV in the middle File:IDA-71 front view P5167768.JPG, Front end of IDA-71 File:IDA-71 in casing P5167769.JPG, Top/back view of IDA 71 in its casing File:IDA-71 with breathing hoses and FFM P5167770.JPG, IDA-71 rebreather with breathing hoses and full face mask fitted. top view. File:IDA-71 with breathing hoses and FFM P5167772.JPG, IDA-71 rebreather with breathing hoses and full face mask fitted File:IDA-71 with breathing hoses and FFM P5167774.JPG, IDA-71 rebreather with breathing hoses and full face mask fitted File:IDA-71 with lid of casing opened showing interior P5167775.JPG, IDA-71 with lid of casing opened showing interior with counterlung, scrubber canisters and oxygen supply cylinder and regulator File:IDA-71 with lid of casing opened showing interior P5167777.JPG, IDA-71 with lid of casing opened showing interior with counterlung, scrubber canisters and oxygen supply cylinder and regulator File:IDA-71 with lid of casing opened showing interior P5167779.JPG, IDA-71 with lid of casing opened showing interior with counterlung, scrubber canisters and oxygen supply cylinder and regulator File:IDA-71 oxygen cylinderP5167780.JPG, Close up of oxygen supply cylinder and regulator in an IDA-71 rebreather File:IDA-71 oxygen regulator P5167781.JPG, Close up of oxygen supply regulator in an IDA-71 rebreather File:IDA-71 external Nitrox connection point P5167783.JPG, IDA-71 external Nitrox connection point File:IDA-71 with lid of casing opened showing interior P5167785.JPG, IDA-71 with lid of casing opened showing interior with counterlung, scrubber canisters and oxygen supply cylinder and regulator, and external nitrox supply plugged in File:IDA-71 nitrox changeover valve P5167789.JPG, Closeup of the pressure activated nitrox changeover valve mounted on the external nitrox supply cylinder for an IDA-71 rebreather File:IDA-71 scrubber canister filling port P5167787.JPG, Detail of the scrubber canister of an IDA-71 showing the filling port for absorbent medium File:AA_IDA71 fullfacemask.jpg, Another type of fullface mask sometimes supplied with an IDA71 rebreather

References

External links

*http://www.therebreathersite.nl/Zuurstofrebreathers/Russian/ida-71.htm information & links *http://www.therebreathersite.nl/Zuurstofrebreathers/Russian/photos_ida-71.htm pictures & links *https://web.archive.org/web/20120314061648/http://www.smrebreathers.ru/rebreathers/rebreather/time_before_time/boets2.jpg Frogman with IDA71 and APS underwater rifle

:: Russian frogman displaying on quayside at

Sevastopol Sevastopol (; uk, Севасто́поль, Sevastópolʹ, ; gkm, Σεβαστούπολις, Sevastoúpolis, ; crh, Акъя́р, Aqyár, ), sometimes written Sebastopol, is the largest city in Crimea, and a major port on the Black Sea ...

on Russian Navy Day with IDA71's with fullface masks with oval windows like an ordinary diving mask's, and AK47's or similar.
Images of Russian frogmen on land
*http://sport.freepage.de/rsdas/ Swiss technical Info about IDA71 with pictures *http://www.bleilatschen.de/idamania7.htm German Information, use of the device, field report Russian website about rebreathers
-> {{Underwater diving, divequ IDA71 Military equipment of the Soviet Union