INS Kalvari: All you need to know about navy’s first Scorpene-class submarine

INS Kalvari (S50) is the first of the Indian Navy’s six Kalvari-class submarines being built in India. It is a diesel-electric attack submarine which is designed by DCNS (French naval defence and energy company) and being manufactured at Mazagon Dock Limited in Mumbai.
Kalvari, the first of six Scorpene-class submarines handed over to the Indian Navy by shipbuilder Mazagon Dock limited, will be commissioned this month, a top Navy official said.

“Kalvari is likely to be commissioned this month after extensive sea trials,” Vice Admiral Girish Luthra, Flag Officer Commanding of the Western Naval Command, told reporters.

The Kalvari was built with a special kind of high-tensile steel that is capable of withstanding high yield stress. This feature allows it to withstand pressure exerted by water, hydrostatic force, while diving deeper to enhance stealth.

It is also capable of carrying weapons that can be easily reloaded at sea.

The submarine was undocked on pontoon on 6 April 2015. After completing the important milestones of vacuum test and battery loading, the submarine was launched at the Naval Dockyard on 28 October 2015 and thereafter brought back to Mazagon Dock Limited for completion of the Basin trials and Harbour Acceptance trials phase. After conquering numerous challenges faced during the ‘Setting to Work’ phase and undergoing rigorous Harbour tests & trials to the complete satisfaction of the customer, the submarine commenced sea trials on 1 May 2016. On 27 May 2017, it was reported that Kalvari had successfully fired a torpedo.


Kalvari has a superior stealth technology compared to previous diesel-electric submarines. She can also launch attacks through precision guided weapons including torpedoes or tube launched anti-ship missiles. Other activities include mine laying, area surveillance, anti-submarine warfare and intelligence gathering.

These attack submarines are also equipped with diesel propulsion and extra air independent propulsion. The new diesel electronic Scorpene submarines will be named as per the old Foxtrot-class submarines decommissioned around 10 years ago; these were the first submarines of the Navy. INS Kalvari is one of a set of six submarines which will undergo test and trials for one and a half years rigorously at harbour and on sea whether on the surface or underwater. Mechanisms on this submarine have been designed to optimize safety; DRDO is in the process of establishing a system for carrying out structured health monitoring of under development nuclear submarines as well as future conventional Naval submarines.

Kalvari and other submarines in this class are also equipped with WLT/Weapons Launching tubes and these can carry weapons on board which can effectively be reloaded at sea.

The submarine is equipped with 6 x 533-mm torpedo tubes for 18 whitehead Alenia Sustemi Subacquei Black Shark heavyweight torpedoes or SM.39 Exocet Anti-ship missiles and 30 mines in place of torpedoes.

Kalvari class Submarines

The Kalvari class is a class of submarines based on the Scorpène-class submarine being built for the Indian Navy. It is a class of diesel-electric attack submarine which is designed by French naval defence and energy company DCNS and being manufactured by Mazagon Dock Limited in Mumbai.

About Project 75

In 2005, India chose the Scorpène design; purchasing six submarines for US$3 billion ($500 million per boat) under Project 75 (P75). The project was necessitated by the dwindling number of submarines in the Indian Navy. Indian Navy needed replacement for the older Sindhughosh (Kilo) and Shishumar (U209) class of submarines. The Scorpène design won the deal, defeating the rival U214 because of the capability to fire Exocet anti-ship missiles and an agreement on the air-independent propulsion (AIP). The submarines are to be manufactured under a technology transfer agreement by the state-owned Mazagon Docks in Mumbai.

Class overview
Name: Kalvari class
Builders: Mazagon Dock Limited
Operators:  Indian Navy
Succeeded by: Project 75I-class submarine
In commission: Mid-2017
Building: 4
Planned: 6
Completed: 2
General characteristics
Type: Attack submarine
Displacement: 1,870 tonnes (2,060 short tons) (AM-2000)
Length: 61.7 m (202 ft) (AM-2000)
Beam: 6.2 m (20 ft)
Draught: 5.8 m (19 ft)
Propulsion: Diesel-electric, batteries, and AIP
  • 20 knots (37 km/h) (submerged)
  • 12 kn (22 km/h) (surfaced)
  • 6,500 nmi (12,000 km) at 8 kn (15 km/h) (surfaced)
  • 550 nmi (1,020 km) at 5 kn (9.3 km/h) (submerged)
  • 40 days (compact)
  • 50 days (normal)
  • 50+21 days (AIP)
Test depth: 350 metres (1,150 ft) 
Complement: 31
Armament: 6 x 533 mm (21 in) torpedo tubes for 18 heavyweight torpedoes/Varunastra torpedo or SM.39 Exocet antiship missiles, 30 mines in place of torpedoes

Ships of the class

The hull fabrication of all six submarines is now complete. The first Scorpène submarine was delivered in September 2016, delivery of successive boats have been compressed to nine months and the project is expected to be completed by 2020.

Name Pennant Builder Launched Commissioned Status
INS Kalvari S50 Mazagon Dock Limited 28 October 2015 Late 2017  Awaiting commissioning. 
INS Khanderi S51 12 January 2017 March 2018 (expected) In sea trials
INS Karanj S52 October 2017 (expected) December 2018 (presumed) Under-construction
S53 S53 Under-construction
S54 S54 Under-construction
S55 S55 Under-construction

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