Akula - class submarine Project 971 Щука - Б ( " Shchuka - B " , ' Shchuka ' meaning pike , NATO reporting name " Akula " ) , is a nuclear - powered attack submarine ( SSN ) first deployed by the Soviet Navy in 1986 . The class is also known under the name Bars ( eng . snow leopard ) . There are four sub - classes or flights of Shchuka , consisting of the original seven " Akula I " submarines which were commissioned between 1984 and 1990 , six " Improved Akula " submarines commissioned between 1991 and 2009 , one " Akula II " submarine commissioned in 1995 and one Akula III commissioned in 2001 . The Russians call all of the submarines Schuka - B , regardless of modifications . The name " Akula " ( " Акула " meaning " " shark " " in Russian ) is the Soviet designation of the ballistic missile submarine class designated by NATO as the Typhoon class submarine . The name " Akula " was used as the NATO designation of the " Projekt 971 " because the first of the class was the K - 284 christened " Akula " . Construction . The Akula incorporates a double hull system composed of an inner pressure hull and an outer " light " hull . This allows more freedom in the design of the exterior hull shape , resulting in a submarine with more reserve buoyancy than its western analogs . This design requires more power than single - hull submarines because of the greater wetted surface area , which increases drag . The distinctive " bulb " or " can " seen on top of the Akula ' s rudder houses its towed sonar array , when retracted . Most Akulas have the SOCKS hydrodynamic sensors , which detect changes in temperature and salinity . They are located on the leading edge of the sail , on the outer hull casing in front of the sail and on the bottom of the hull forward of the sail . All Akulas have two T - shaped doors on the aft bottom of the hull , on either side . These are where the OK - 300 auxiliary propulsion devices are located , which can propel the submarine at up to . All Akulas are armed with four 533 mm torpedo tubes which can use Type 53 torpedo es or the SS - N - 15 Starfish missile , and four 650 mm torpedo tubes which can use Type 65 torpedo es or the SS - N - 16 Stallion missile . These torpedo tubes are arranged in two rows of four tubes each . Improved Akulas , Akula IIs have an additional six 533 mm torpedo tubes mounted externally , capable of launching possibly up to 6 decoys each . The external tubes are mounted outside the pressure hull in one row , above the torpedo tubes , and can only be reloaded in port or with the assistance of a submarine tender . The 650 mm tubes can be fitted with liners to use the 533 mm weaponry . The submarine is also able to use its torpedo tubes to deploy mines . Current status . As with many Soviet / Russian craft , information on the status of the Akula Class submarines is sparse , at best . Information provided by sources varies widely . Akula - I ( project 971 ) . Of the seven original Akula - I submarines , only three are known to still be in service . These boats are equipped with MGK - 500 Skat sonar system ( with NATO reporting name Shark Gill ) . The lead boat of the class , K - 284 ' Akula ' was decommissioned in 2001 , apparently to help save money in the cash - strapped Russian Navy . K - 322 ' Kashalot ' and K - 480 ' Bars ' [ Currently Ak Bars ] are in reserve . K - 480 ' Bars ' was put into reserve in 1998 , and is being dismantled in February 2010 . ' Pantera ' returned to service in January 2008 after a comprehensive overhaul . All were retrofitted with the SOCKS hydrodynamic sensors except " Volk " . All submarines before K - 391 " Bratsk " have reactor coolant scoops that are similar to the ones of the Typhoon class SSBNs , long and tubular . " Bratsk " and subsequent submarines have reactor coolant scoops similar to the ones on the Oscar IIs , short and ( the Typhoon , Akula and Oscar classes use the similar OK - 650 reactor ) . Akula - I Improved ( project 971 and 971I ) . The six Akulas of this class are all thought to be in service . They are quieter than the original MGK - 500 Skat sonar system on Akula - I is upgraded to the MGK - 501 Skat - MS . Sources also disagree as to whether construction of this class has been suspended , or if there are a further two units planned . Improved Akula - I Hulls : K - 328 " Leopard " , K - 461 " Volk " , K - 154 " Tigr " , K - 419 " Kuzbass , K - 295 " Samara " and K - 152 " Nerpa " . " These submarines are much quieter than early Akula class submarines and all have the SOCKS hydrodynamic sensors except " Leopard " . The Akula - I Improved submarines have 6 533 mm decoy launching tubes , as do subsequent submarines . They have a different arrangement of limber holes on the outer hull than Akula Is . Nerpa and Iribis ( not completed ) have a different rescue chamber in the sail . I can be distinguished by the large dome on the top surface . " Akula - II ( project 971U ) . K - 157 " Vepr " is the only completed Akula II . The Akula II is some meters longer and displaces about 700 tons ( submerged displacement ) more than the Akula I . The added space was used for additional quieting measures . The MGK - 501 Skat sonar system on Akula - I is replaced to a new MGK - 540 Skat - 3 sonar system . K - 157 " Vepr " became the first Soviet submarine that was quieter than the latest U . S . attack submarines of that time , which was the Improved " Los Angeles " class ( SSN 751 and later ) . Two of these submarines were used to build the Borei class SSBNs . Akula - III ( project 971M ) . K - 335 " Gepard " is the only completed Akula III ( see table for others ) ( There is no AKULA III NATO classification ) . It is longer and has a larger displacement compared to the Akula II . Also , it has an enlarged sail and a different towed - array dispenser on the vertical fin . Again , more noise reduction methods were employed . The " Gepard " is the most advanced Russian submarine before the submarines of the Severodvinsk and Borei classes are commissioned . One of this class was used to complete the Borei SSBNs . The Soviet advances in sound quieting were of considerable concern to the West , for acoustics was long considered the most significant advantage in U . S . submarine technology compared to the Soviets . In 1983 – 1984 the Japanese firm Toshiba sold sophisticated , nine axis milling equipment to the Soviets along with the computer control systems , which were developed by Norwegian firm Kongsberg Vaapenfabrik . U . S Navy officials and Congressmen announced that this technology enabled the Soviet submarine builders to produce more accurate and quieter propellers . Due to the breakup of the Soviet Union in 1991 , production of all Akulas slowed . The 1999 – 2000 edition of " Jane ' s Fighting Ships " incorrectly listed the first Akula - II as " Viper " ( the actual name is " Vepr " , " wild boar " in Russian ) , commissioned November 25 , 1995 , " Gepard " ( Cheetah ) , launched 1999 and commissioned December 5 , 2001 , and " Nerpa " , laid down in 1993 began sea trials in October , 2008 and was commissioned by the Indian Navy as INS Chakra II in April 2012 . Units . Lease to India . Three hundred Indian Navy personnel are being trained in Russia for the operation of the Akula II submarine " Nerpa " . India has finalized a deal with Russia , in which at the end of the lease of these submarines , it has an option to buy them . The submarine will be named INS " Chakra " as was the previous India - leased Soviet Charlie - I SSGN . INS Chakra was officially inducted into the Indian Navy on April 4 , 2012 . Whereas the Russian Navy ' s Akula - II could be equipped with 28 nuclear - capable cruise missiles with a striking range of , the Indian version was reportedly expected to be armed with the - range 3M - 54 Klub nuclear - capable missiles . Missiles with ranges greater than cannot be exported due to arms control restrictions , since Russia is a signatory to the MTCR treaty . Nerpa 2008 accident . On 27 October 2008 , it was reported that K - 152 " Nerpa " of the Russian Pacific Fleet had begun her sea trials in the Sea of Japan before handover under a lease agreement to the Indian Navy . On 8 November 2008 , while conducting one of these trials , an accidental activation of the halon - based fire - extinguishing system took place in the fore section of the vessel . Within seconds the halon gas had displaced all breathable air from the compartment . As a result , 20 people ( 17 civilians and 3 seamen ) were killed by asphyxiation . Dozens of others suffered freon - related injuries and were evacuated to an unknown port in Primorsky Krai . This was the worst accident in the Russian navy since the loss of the submarine K - 141 " Kursk " in 2000 . The submarine itself did not sustain any serious damage and there was no release of radiation . Recent overseas deployments . In August 2009 , the news media reported that two " Akula " - class submarines operated off the East Coast of the United States , with one of the submarines being identified as a Project 971 Shchuka - B type . U . S . military sources noted that this was the first known Russian submarine deployment to the western Atlantic since the end of the Cold War , raising concerns within U . S . military and intelligence communities . The U . S . Northern Command confirmed that this 2009 " Akula " - class submarine deployment did occur . In August 2012 , the news media reported that another " Akula " - class submarine operated in the Gulf of Mexico purportedly undetected for over a month , sparking controversy within U . S . military and political circles , with U . S . Senator John Cornyn of the Senate Armed Services Committee demanding details of this deployment from Admiral Jonathan W . Greenert , the Chief of Naval Operations .