India's Russian-built submarine the INS Sindhurakshak arrived at its home port Mumbai after an overhaul including structural hull upgrades at the Zvezdochka shipyard.
The Sindhurakshak -- a Russian Type 877EKM submarine, Sindhughosh class for the Indian navy -- was constructed in Admiralteiskie Verfi shipyard in St. Petersburg in 1997.
It's one of 10 Kilo class submarines constructed in Russia's shipyards for the Indian navy from 1985-2000, a report by TV-Novosti said in January.
Zvezdochka shipyard, in Severodvinsk, near Archangel on Russia's western Arctic Ocean coast, signed the retrofit deal in June 2010 and the submarine arrived the following August.
The overhaul and retrofit for the 2,300-ton vessel reportedly cost around $80 million, TV-Novosti said.
Work included overhaul of hull structures, installation of upgraded electronic warfare and weapons control systems, the mounting of Indian-made sonar USHUS and installation of CCS-MK radio communication systems.
The submarine was handed over to the Indian navy in Severodvinsk Jan. 26 -- India's Republic Day -- and immediately left for Mumbai, a report by Russia and Indian Report said.
The Sindhurakshak is armed with the latest export variant of the Russian-made submarine-specific Club-S multi-role cruise missile system capable of hitting targets more than 150 miles away, the RIR report said.
The Club-S, which has an 880-pound warhead, has improved effectiveness because of its active radar seeker system, the Args 14e designed by Radar MMS of St. Petersburg, a technical report by Defense Update said in 2006.
The Args system radar system kicks in around 12 miles from the missile's target to improve accuracy.
A Club-S can be launched from standard torpedo tubes at a depth of up to 130 feet, Defense Update said. It cruises towards the target initially at 70 feet above seal level and drops down to around 25 feet on final approach.
The Kilo class vessels can travel at around a maximum 20 mph at a depth of around 900 feet.
Zvezdochka also has modernized India's Kilo class submarines Sinduvir, Sindhuratna, Sindugosh and Sinduvijay submarines since 1997.
The shipyard expects to receive its next retrofit contract from India in 2014 or 2015, RIR said. It also will repair and upgrade the Sindukirti Kilo class submarine at the vessel's base in Visakhapatnam in the Indian state of Andhra Pradesh.
Meanwhile, India's Scorpene submarine project could face an 18-month delivery delay after the pullout of consultants from Spanish shipbuilding partner Navantia.
Mazagon Dock Ltd., the government shipbuilder in Mumbai where the vessels are being made, informed the navy that the project would be delayed by another 18 months to the end of 2016, a report by India's Times News Network said last month.
Delivery was expected sometime in 2015.
The Scorpene is a diesel-electric attack submarine with additional air-independent propulsion jointly developed by the French shipbuilder DCN -- now DCNS -- and Spain's Navantia.
The submarines were ordered in 2005 under a technology transfer agreement.