The Foxtrot class was the NATO reporting name of a class of diesel-electric patrol submarines that were built in the Soviet Union. The Soviet designation of this class was Project 641. The Foxtrot class was designed to replace the earlier Zulu class, which suffered from structural weaknesses and harmonic vibration problems that limited its operational depth and submerged speed. The first Foxtrot keel was laid down in 1957 and commissioned in 1958 and the last was completed in 1983. A total of 58 were built for the Soviet Navy at the Sudomekh division of the Admiralty Shipyard, Saint Petersburg. Additional hulls were built for other countries.
The Scorpène-class submarines are a class of diesel-electric attack submarines jointly developed by the French Naval Group and the Spanish company Navantia. It features diesel propulsion and an additional air-independent propulsion (AIP). It is now marketed as the Scorpène 2000.
Mazagon Dock Shipbuilders Limited (MDL), formerly called Mazagon Dock Limited, is a shipyard situated in Mazagaon, Mumbai. It manufactures warships and submarines for the Indian Navy and offshore platforms and associated support vessels for offshore oil drilling. It also builds tankers, cargo bulk carriers, passenger ships and ferries.
Nerpa is a 8,140-tonne (8,010-long-ton) Project 971 nuclear-powered attack submarine. The construction of the submarine was started in Russia in 1993, but was suspended due to lack of funding. India then sponsored further construction and sea trials of the submarine provided it was leased to the Indian Navy for 10 years. It was launched as K-152 Nerpa in October 2008 and entered service with the Russian Navy in late 2009. The submarine was leased to the Indian Navy in 2011 after extensive trials, and was formally commissioned into service as INS Chakra with the Eastern Naval Command at a ceremony in Visakhapatnam on 4 April 2012. In June 2021 Chakra was spotted on the surface escorted by Indian and Russian warships in the Singapore Strait while presumably heading towards the Russian naval base in Vladivostok; some media speculated that she was returning to Russia before the expiry of the lease term.
The Kalvari-class submarines, formally classified as the Project-75 submarines (P-75), is a class of diesel-electric attack submarines operated by the Indian Navy (IN). Currently being constructed by a syndicate of French and Indian shipyards, namely, Naval Group and Mazagon Dock Limited (MDL) respectively, the class is an export derivative of the French-origin Scorpène-class submarine, originally designed by Naval Group.
Vela-class submarines of the Indian Navy were variants of the later Soviet Foxtrot-class submarines. The last of the class was decommissioned from the Indian Navy in December 2010. The submarines formed the 8th Submarine Squadron and were based at INS Virbahu.
INS Kalvari (S23) was the lead vessel of the Kalvari class of diesel-electric submarines of the Indian Navy. It was the first ever submarine inducted into service by the Indian Navy. The submarine was laid down on 27 December 1966 as Foxtrot-class submarine B-51 of the Soviet Navy by Novo-Admiralty at Galerniy Island, Leningrad.
INS Khanderi (S22) was a Kalvari-class diesel-electric submarine of the Indian Navy.
INS Karanj (S21) was a Kalvari-class diesel-electric submarine of the Indian Navy.
INS Kursura (S20) was a Kalvari-class diesel-electric submarine of the Indian Navy. It was India's fourth submarine. Kursura was commissioned on 18 December 1969 and was decommissioned on 27 February 2001 after 31 years of service. It participated in the Indo-Pakistani War of 1971, where it played a key role in patrol missions. It later participated in naval exercises with other nations and made many goodwill visits to other countries.
Soviet submarine B-402 may refer to one of the following submarines of the Soviet Navy:
Panchendriya is a sonar suite that has been developed by the Defence Research and Development Organisation, India for the submarines of the Indian Navy. It has been described as India's "first indigenously developed sonar system for submarines".
INS Kalvari (S21) is the first of the six indigenous Scorpène-class submarines currently in service with the Indian Navy. It is a diesel-electric attack submarine which is designed by DCNS and was manufactured at Mazagon Dock Limited in Mumbai.
INS Satavahana is the premier Submarine Training Base of the Indian Navy and is located at Visakhapatnam, Andhra Pradesh. Training is carried out by the Submarine School (SMS) and the Escape Training School (ETS) and the School of Advanced Undersea Warfare (SAUW).
INS Karanj (S21) is the third submarine of the first batch of six Kalvari-class submarines for the Indian Navy. It is a diesel-electric attack submarine based on the Scorpène class, designed by French naval defence and energy group DCNS and manufactured by Mazagon Dock Limited, an Indian shipyard in Mumbai. The submarine was launched on 31 January 2018, delivered to Indian Navy on 15 February 2021, commissioned on 10 March 2021 in Mumbai in presence of Chief of Naval Staff Admiral Karambir Singh and Admiral (Retired) VS Shekhawat.
Kalvari-class submarine may refer to:
Rear Admiral Arun Auditto, AVSM, NM was a Flag Officer in the Indian Navy. He was decorated with a gallantry award during the Liberation of Goa. A pioneer submariner in the Indian Navy, he was the commissioning Commanding Officer of the Kalvari-class submarine INS Kursura (S20), which he commanded during the Indo-Pakistani War of 1971. He later commanded the submarine base INS Virbahu and the Whitby-class frigate INS Trishul (F143). After promotion to flag rank, he served as the Fortress Commander, Andaman and Nicobar Islands (FORTAN) and as the first Flag Officer Submarines, before retiring in 1988.
The Commodore Commanding Submarines (East) is an operational appointment in the Indian Navy. The COMCOS (E) is the commander of the all submarines and allied units of Eastern Naval Command. Based in Visakhapatnam, Andhra Pradesh, the COMCOS is also the Commanding Officer of the submarine base INS Virbahu. Currently, there are two COMCOS in the Indian Navy, COMCOS (East) and COMCOS (West). The COMCOS (E) is a one star officer holding the rank of Commodore. The current COMCOS (E) is Commodore K. Venkatraman, VSM who took over on 20 February 2020.
The Commodore Commanding Submarines (West) is an operational appointment in the Indian Navy. The COMCOS (W) is the commander of the all submarines and allied units of Western Naval Command. Based in Mumbai, Maharashtra, the COMCOS is also the Commanding Officer of the submarine base INS Vajrabahu. Currently, there are two COMCOS in the Indian Navy, COMCOS (East) and COMCOS (West). The COMCOS (W) is a one star officer holding the rank of Commodore. The current COMCOS (W) is Commodore Anurag Srivastava.
Indian Navy 
