INS Sindhurakshak (Sanskrit, for Protector of the Seas) was a Russian-made Kilo-class 877EKM () diesel-electric submarine of the Indian Navy. Commissioned on 24 December 1997, it was the ninth of the ten Kilo-class submarines in the Indian Navy. On 4 June 2010, the Indian Defence Ministry and Zvezdochka shipyard signed a contract worth US$80 million to upgrade and overhaul the submarine. After the overhaul, it returned to India from Russia between May and June 2013. The submarine suffered a major fire and explosion on 14 August 2013 and sank at Mumbai's naval dockyard with the death of 18 crew members. Construction Sindhurakshak was constructed at the Admiralty Shipyard in Saint Petersburg, Russia. Construction of the submarine began in 1995. It was launched in June 1997 and delivered to India in December 1997. Service history Kargil war (1999) Sindhurakshak was deployed very close to Karachi, Pakistan during the Kargil War in 1999. President Kalam (2006) On 13 February 2006, during the submarine's deployment in Vishakhapatnam under the Eastern Naval Command, the then President of India A. P. J. Abdul Kalam became the first Indian head of state to sail in a submarine. He was given a demonstrative excursion, during which the submarine dived and sailed in the Bay of Bengal for a few hours. He was accompanied by the Chief of Naval Staff Arun Prakash. The submarine was commanded by Commander P S Bisht. Accident (2010) A fire broke out aboard Sindhurakshak while the vessel was in Visakhapatnam in February 2010. One sailor was killed and two others were injured. Navy officials reported that the fire had been caused by an explosion in the submarine's battery compartment, which occurred due to a faulty battery valve that leaked hydrogen gas. Upgrades After the fire damage in 2010, Sindhurakshak was transported to Russia on board a heavy lift ship from Visakhapatnam in June 2010 for refit, overhaul and upgrade which lasted two and a half years. In August 2010, Sindhurakshak arrived at the Zvezdochka shipyard in Russia. The submarine was modernised, repaired and retrofitted under Project 08773, and after the upgrade, the sea trials started in October 2012. The upgrades included improved electronic warfare systems, an integrated weapon control system and a new cooling system, and were expected to extend the service life of the submarine by ten years. The Club-S (3M54E1 anti-ship and 3M14E land attack) missiles, USHUS sonar, СCS-MK-2 radio communication