Sindhughosh-class submarine


Sindhughosh-class submarines are diesel-electric submarines in active service with the Indian Navy. Their names are in Sanskrit, but in their Roman-alphabet forms sometimes a final short -a is dropped.
The Sindhughosh submarines, designated 877EKM, were designed as part of Project 877, and built under a contract between Rosvooruzhenie and the Ministry of Defence (India).
The submarines have a displacement of 3,000 tonnes, a maximum diving depth of 300 meters, top speed of 18 knots, and are able to operate solo for 45 days with a crew of 53. The final unit was the first to be equipped with the 3M-54 Klub antiship cruise missiles with a range of 220 km.
As of 2024, three of the submarines based at INS Vajrabahu, Mumbai, form 12th Submarine Squadron while four of the submarines based at INS Virbahu, Mumbai, form 11th Submarine Squadron.

Life extension and refit

INS Sindhuvijay has been upgraded with the hydro acoustical USHUS complex and the CCS-MK radio communications system. On 29 August 2014, the Defence Acquisition Council cleared the long-awaited mid-life upgrade of the four Kilo-class submarines, which would be carried out in Indian shipyards and is likely to cost. On 5 November 2014 official sources at HSL said more than 90% of the work has been completed on the seventh submarine of the Sindhughosh class INS Sindhukirti. Scheduled to re-join the fleet on 31 March 2015, she re-entered service on 23 May.
The Indian Navy signed a contract with the Russian shipbuilder Sevmash to refit and upgrade the existing submarines and to extend their operational life by 35 years. The first submarine, INS Sindhukesari, will be sent for refit starting June 2016. The extensive refit, the value for which is pegged at for a total of four submarines, will not only extend the life of the boats but will also upgrade their combat potential and fitted with Klub land attack cruise missile.
In December 2015, L&T was chosen by the Russian shipbuilder Sevmash to be its Indian partner in the refit project. While the first of the four Kilo class subs will go to the Russian Zvezdochka shipyard for inspection and refit, the remaining three are likely to be modernized at the Kattupalli shipyard. The first of the submarines to be modernized at private yard, a first for India, will go in by 2017. An order for 2-3 more submarines could also be commissioned, depending on ongoing acquisition plans of the Indian Navy.
As reported on 3 September 2025, INS Sindhuvijay is expected to undergo a refit at the Hindustan Shipyard. While the Navy has acquired the Acceptance of Necessity from the Defence Acquisition Council of the Ministry of Defence, the contract finalisation is expected to be completed within two or three weeks. Given that all the procedures are completed on schedule, the submarine is expected to begin its refit by the end of the year. The refits will include hull repair, equipment overhauling, upgrading sensors and weaponry, extending the submarine's life as well as enhancing combat readiness of the vessel.

Service history

In 2015, the naval exercise Malabar, between the navies of India and the United States, involved and hunting each other. India Today reported that Sindhudhvaj managed to track Corpus Christi and score a simulated kill without being detected.
It was reported in April 2023 that India would be purchasing over 20 Klub anti-ship cruise missiles worth $120 million. On 4 February 2025, it was reported that the deal has been concluded for cruise missiles for Sindhughosh-class submarines in the presence of the Defence Secretary Rajesh Kumar Singh.
One of the submarine was deployed alongside along with 7 frontline warships and 5 submarines on 7 November 2024. The operations included carrier operations of MiG-29K, missile firing drills, submarine manoeuvres and flypasts by 30 aircraft demonstrated to the President of India Droupadi Murmu who was present on board INS Vikrant.
The lead ship of the class, Sindhughosh, was decommissioned after 40 years of service in Mumbai in the presence of the Western Naval Command chief, Vice Admiral Krishna Swaminathan. The submarine was paid off under the command of Lieutenant Commander Rajat Sharma.

Incidents

  • On 10 January 2008, INS Sindhughosh collided with the cargo ship MV Leeds Castle. The submarine was reported to have sustained superficial damage to its conning tower. As a result, the submarine was out of service for a month. The cargo ship was in restricted shallow waters.
  • On 26 February 2010, a fire on board INS Sindhurakshak killed one sailor and injured two others. The fire was due to a defective battery.
  • On 14 August 2013 an explosion, followed by a fire, was reported to have occurred on Sindhurakshak. Sindhurakshak sank in the dock.
  • On 17 January 2014, Sindhughosh ran aground due to the low tide, while returning to the Naval Dockyard, Mumbai.
  • On 26 February 2014, smoke was detected on board INS Sindhuratna resulting in 7 sailors being rendered unconscious and two dead. Those unconscious were airlifted to hospital.

    Ships of the class