Maarg Manthan · Topic 16.22

Indian Submarines and Naval Ships: Project 75, INS Kalvari, INS Kolkata, INS Kiltan

Science & Technology › Defence Technology and Missile Systems · Topic 16.22

The Indian Navy's submarine force includes conventional diesel-electric boats and nuclear submarines. Project 75 is a programme to build six Scorpene class submarines at Mazagon Dock in Mumbai with French Naval Group, called the Kalvari class; INS Kalvari was commissioned on 14 December 2017, followed by Khanderi, Karanj, Vela, Vagir and Vagsheer, the last in January 2025. Project 75I will add six submarines with air independent propulsion. India's nuclear submarines are INS Arihant, commissioned in 2016, and INS Arighaat, commissioned in August 2024. INS Kolkata is the lead destroyer of Project 15A, commissioned in 2014, and INS Kiltan, commissioned in October 2017, is an anti-submarine warfare corvette of the Kamorta class built by Garden Reach in Kolkata.

5 min read · UPSC Prelims · Science & Technology · Defence Technology and Missile Systems

At a Glance

Project 75 Six Scorpene submarines
First boat INS Kalvari, December 2017
SSBNs Arihant 2016, Arighaat 2024
Destroyer INS Kolkata, 2014
Corvette INS Kiltan, 2017
Exam link UPSC Prelims, Science & Technology: Defence Technology and Missile Systems

Where Does It Fit?

This topic follows the account of Indian surface ships. It covers the underwater arm and two more named ships, and leads to the next topics on cruise missiles and submarine propulsion. Previous topic: Frigates, Destroyers and Aircraft Carriers of the Indian Navy. Next topic: Nirbhay Subsonic Cruise Missile.

What Are the Main Indian Submarine Programmes?

Programme or boat	Details
Project 75	Six Kalvari class submarines, a version of the French Scorpene, built by Mazagon Dock Shipbuilders in Mumbai with Naval Group. About 1,775 tonnes, diesel-electric, with torpedoes and anti-ship missiles
The six boats	Kalvari (December 2017), Khanderi (September 2019), Karanj (March 2021), Vela (November 2021), Vagir (January 2023) and Vagsheer (January 2025)
Project 75 (India)	A follow-up of three more Scorpene submarines was discussed but is not finalised
Project 75I	Six advanced conventional submarines with air independent propulsion, to be built in India with a foreign partner. A German-Indian partnership of Thyssenkrupp Marine Systems and Mazagon Dock was selected for negotiation, valued at around Rs 70,000 crore; check the status
Sindhughosh class	Russian Kilo class submarines bought from 1986, being phased out
Shishumar class	German Type 209 submarines
Nuclear submarines	INS Chakra, an Akula class SSN leased from Russia, and indigenous SSBNs

What About the Nuclear Submarines, INS Kolkata and INS Kiltan?

INS Arihant: India’s first indigenous SSBN under the Advanced Technology Vessel project, launched in 2009 and commissioned in August 2016, with 83 MW reactor and K-15 missiles
INS Arighaat: second SSBN, commissioned on 29 August 2024, carrying K-15 and K-4 missiles
S4 and later: a third boat reported to be commissioned afterwards, and larger S5 class are planned. The reports should be checked
Nuclear triad: Arihant completed the land, air and sea delivery triad
Planned SSNs: the Government approved the building of two nuclear attack submarines in 2024
INS Kolkata: lead ship of Project 15A, built at Mazagon Dock and commissioned on 16 August 2014. About 7,400 tonnes, stealth guided missile destroyer with BrahMos and Barak-8
INS Kiltan: anti-submarine warfare stealth corvette of the Kamorta class (Project 28), built by Garden Reach Shipbuilders and Engineers and commissioned on 16 October 2017. Named after an island in Lakshadweep, with a hull built of indigenous carbon fibre composite
Kamorta class: INS Kamorta, Kadmatt, Kiltan and Kavaratti, commissioned from 2014 to 2020

What Else Should You Remember?

Scorpene: a French design of conventional submarines also built for Chile, Malaysia and Brazil
Submarine rescue: India has deep submergence rescue vessels
Sonar: underwater sensors that detect submarines
Torpedoes: Varunastra is an indigenous heavy torpedo
Sub-surface launched missiles: anti-ship and land attack missiles that can be fired from torpedo tubes
Submarine Rescue: rescue units help crews in distress
Naval Group delays: the Scorpene project was delayed by several years from the original schedule
Air independent propulsion: an add-on that DRDO is developing for the Kalvari class, as in Air Independent Propulsion Technology for Submarines
Southern Naval Command: Kochi trains submarine crews
Project 75 Alpha: a nuclear attack submarine programme
Hunter-killer: submarines designed to hunt other submarines and ships
Submarine strength: the Navy has about 16 conventional submarines, which is below the needed number
Chinese submarine presence: Chinese submarines have visited Indian Ocean ports
Quiet running: silence is the main protection for submarines
Link: ship classes are in Frigates, Destroyers and Aircraft Carriers of the Indian Navy
Link to nuclear power: reactor technology is in Department of Atomic Energy and Bhabha Atomic Research Centre (BARC)
Arihant name: means destroyer of enemies
Crew training: submarine crews train at special schools and simulators, because the work is dangerous and complex

Why Does It Matter for the Exam?

Project 75: six Scorpene, Mazagon Dock
Dates: Kalvari 2017, Arihant 2016, Arighaat 2024
Ships: Kolkata P15A, Kiltan P28
Current affairs link: Project 75I and SSN approval
Common errors: saying INS Kiltan is a destroyer or Kalvari is nuclear powered

As an analytical point, India needs more submarines to guard the Indian Ocean, and a continuous production line with technology partners is the answer. The nuclear fleet gives a secure second strike, while conventional boats guard sea lanes.

Why Is This Topic Important?

Conventional Kalvari class
Nuclear Arihant class
Ships Kolkata, Kiltan

What Came Next?

The next topic covers the Nirbhay subsonic cruise missile. Next topic: Nirbhay Subsonic Cruise Missile.

Key People and Terms

P75 Project 75
P75I Project 75 India
ATV Advanced Technology Vessel
Kamorta class ASW corvettes
SSN Nuclear attack submarine
SSK Conventional submarine

Exam Corner

Points to Remember

INS Kalvari commissioned 14 December 2017.
INS Arihant: August 2016.
INS Arighaat: August 2024.
INS Kolkata: August 2014.
INS Kiltan: October 2017.

Do Not Confuse With

Project 75 and 75I Scorpene boats versus AIP boats
Kalvari and Arihant Conventional versus nuclear
Kolkata and Kiltan Destroyer versus corvette

Memory Hook

Six Scorpenes from Mumbai, Arihant and Arighaat in the deep, Kolkata destroys, Kiltan hunts subs.

Mains Angle

Questions ask for names, dates and types. These points help.

Fleet Conventional and nuclear
Gaps Numbers
Plan P75I, SSN

A Question You May Face

An original practice question, not a past paper question.

“Examine the status of India’s submarine programmes and their significance for maritime security.”

How to Answer

Conventional Project 75.
Nuclear Arihant class.
Gaps Numbers.
Plans P75I.

GS Relevance

Prelims: Kalvari class, Project 75I, SSBNs, Kolkata, Kiltan. GS Paper 3: defence, maritime security.

Frequently Asked Questions

What is Project 75?

Project 75 is an Indian Navy programme to build six Scorpene class diesel-electric submarines, known as the Kalvari class, at Mazagon Dock in Mumbai in partnership with France's Naval Group. The first, INS Kalvari, was commissioned in December 2017 and the sixth, INS Vagsheer, in January 2025.

What is Project 75I?

Project 75I is a planned programme to build six more advanced conventional submarines in India with air independent propulsion, which lets them stay under water for longer. A foreign partner would transfer technology, and a German design with Mazagon Dock was being negotiated, but the contract status should be checked.

What is INS Arihant?

INS Arihant is India's first indigenously built nuclear-powered ballistic missile submarine, commissioned in August 2016 under the secret Advanced Technology Vessel project. It completed the nuclear triad for India. A second boat, INS Arighaat, was commissioned in August 2024.

What is INS Kolkata?

INS Kolkata is the lead ship of the Kolkata class, Project 15A, of stealth guided missile destroyers. Built at Mazagon Dock in Mumbai, it was commissioned on 16 August 2014 and carries BrahMos and Barak-8 missiles. Kochi and Chennai are the other two ships of this class.

What is INS Kiltan?

INS Kiltan is an anti-submarine warfare stealth corvette of the Kamorta class, or Project 28, built by Garden Reach Shipbuilders and Engineers in Kolkata and commissioned in October 2017. Its hull has an indigenous carbon fibre composite superstructure, and it is named after an island in Lakshadweep.

PYQ Practice — Statement Analysis

1 INS Kalvari is a Scorpene class submarine.

True

Built in Mumbai.

2 INS Kiltan is a nuclear submarine.

False

It is an ASW corvette.

3 INS Arihant was commissioned in 2016.