Analysis Kolkata Class stealth guided missile destroyers

The Kolkata class destroyers  (Project 15A) are the 3rd most powerful surface combat ships of the Indian Navy after the aircraft carriers and Visakhapatnam class destroyer. The class is made of 3 ships: INS Kolkata, INS Kochi & INS Chennai.

The Project 15A Destroyers are the follow-on ships of the legendary Project 15 ‘Delhi’ class Destroyers which entered service in the late 1990s.

Conceived and designed by the Indian Navy’s Directorate of Naval Design, the P15A ships have been christened after major port cities of India: Kolkata, Kochi and Chennai.

Status and delivery

The Indian Government ordered three Kolkata-class destroyers in May 2000. The ships were built by Mazagon Dock Limited (MDL) at their Mumbai shipyard.

Idian Navy INS kolkata and INS Chennai next to INS Vikramaditya  aircraft carrier
Idian Navy INS kolkata and INS Chennai next to INS Vikramaditya aircraft carrier

INS Kolkata was the first of the class. The ship was laid in September 2003, was launched in March 2006, and delivered to the Indian Navy in July 2014. The vessel was commissioned in August 2014. INS Kolkata took 11 years to build. Program delays were blamed by Defense Minister A. K. Antony on the delay in supply of warship-grade steel by Russia, which forced India to develop its own steel manufacturing capability.

The second of class, INS Kochi, was laid on 25 Oct 2005, and launched on 18 Sep 2009 and commissioned in September 2015. It took 10 years to build.

The last ship in the class, INS Chennai, was laid in February 2006. It was launched in April 2010 and was commissioned in Nov 21, 2016. It took almost 11 years to complete.

Each Kolkata class destroyer had a cost of about $950 million (₹3,887 crore).


Conceptualised by the Indian Navy, the detailed design phase for the class was completed by MDL. Kolkata-class is a follow-on model of the Delhi-class and is fitted with modern weapons and sensor systems. The propulsion system of the Delhi-class was also retained with minor upgrades. Most of the systems integrated in the ships are designed and built in India.

The destroyers are also equipped with an action information system and an atmospheric control system. The modern stealth destroyers demonstrate superior anti-surface warfare (ASuW) capabilities. The vessel has an overall length of 163m, a beam of 17.4m and a draft of 6.5m. The full load displacement of the ship is 7,400 t (7,300 long tons; 8,200 short tons) full load.

Speed 30 knots (56 km/h)
Range 6,000 nmi (11,000 km) at 18 kn (33 km/h)
Complement 50 officers and 250 ratings

Kolkata Class destroyer Propulsion

The Kolkata propulsion is COGAG (Two combined gas turbines). It includes 2 Zorya M36E gas turbines, 4 DT-59 reversible gas turbines & 2 KVM-diesel engines. It also has MWE Wartsila WCM-1000 & Kirloskar 1 MV AC electrical generators.

DT-59 reversible gas turbine
DT-59 reversible gas turbine

Ukrainian Zorya Production Association M36E gas turbine systems, producing more than 64,000 HP. The M36 gas turbine system compromises four DT-59 reversible gas turbine grouped in two pairs, driving two propellers through two RG-54 gearboxes. There will be 4 separate Russia-made gas turbine electrical generators, two in each engine room. Fresh air for the turbine will be drawn through two large stacks, one after the bridge superstructure and one aft.

The two KVM diesel motors are provided by Bergen and Garden Reach. Four Wartsila WCM-1000 generators and Kirloskar AC generators supply onboard electricity. The propulsion system provides a maximum speed of 30kt.

The intricate power supply management is done using APMS, and remote control and monitoring of machinery is achieved through the ACS.

While Machinery Control Rooms (MCR) of previous warships featured manual controls and analogue dials, the MCR onboard the Kochi is completely automated. Officers here monitor firefighting systems, propulsion and auxiliary systems, power generation, the ship’s stabilizers, her air conditioners and four large Reverse Osmosis Plants that provide the ship and her crew with abundant fresh water. The data provided by the MCR’s systems are part of the Ship’s Data Network (SDM), the backbone of what is an information highway onboard the ship.


The missile systems include 32 Barak 8 (LR-SAM) air defense missiles & 16 Brahmos anti ship missiles with extra space available for future add ons. Other weapon systems include a 76mm main gun, 4 AK-630M 30mm guns, 2 RBU-6000 ASW rocket launchers and 2 twin 533mm torpedo launchers.

The 16-cell universal vertical launcher module (UVLM) fitted on the ship can launch BrahMos missiles. There are two vertical launching systems (VLS) for Barak SAM (surface-to-air missile). The ships seems to have space for future installation of more VLS systems for new missiles such as Hypersonic Brahmos, Barak 8 ER, Nirbhay, etc.

BrahMos anti-ship missile

BrahMos is an anti ship, sea-skimming, supersonic cruise missile, whose high speed of up to mach 3 makes it very difficult to intercept.. In addition to making it difficult to intercept, this speed also imparts a greater strike power. In addition, the BrahMos is equipped with stealth technology designed to make it less visible to radar and other detection methods. It has an inertial navigation system (INS) for use against ship targets, and an INS/Global Positioning System for use against land targets. Terminal guidance is achieved through an active/passive radar.

brahmos missile
Brahmos missile fired from Kolkata class destroyer

BrahMos is a two-stage missile with a solid propellant booster engine as its first stage which brings it to supersonic speed and then gets separated. The liquid ramjet or the second stage then takes the missile closer to Mach 3 speed in cruise phase. In addition to making it difficult to intercept, the high speed also imparts a greater destructive power due to large kinetic energy on impact.

The missile has a flight range of up to 450 km with supersonic speed all throughout the flight, leading to shorter flight time, consequently ensuring lower dispersion of targets, quicker engagement time and non-interception by any known weapon system in the world.

It operates on the ‘Fire and Forget Principle’, adopting varieties of flights on its way to the target. Its cruising altitude could be up to 15 km and terminal altitude is as low as 4–5 meters. It carries a conventional warhead weighing 200 Kg.

BrahMos can be launched in single or in a salvo from a ship towards single or different types of targets within an interval of 2–2.5 seconds in various trajectories.

BrahMos is equipped with stealth technology designed to make it less visible to radar and other detection methods.

Barak-8 (LR-SAM) Air Defense missiles

The ship’s main air-defence armament is composed of two 4×8-cell vertical launching systems (VLS) allowing for up to 32 Barak 8 (medium-long range) air-defence missiles.

Barak-8 MR-SAM launch from INS Chennai
Barak-8 MR-SAM launch from INS Chennai

Barak 8 is an Indian-Israeli surface-to-air missile (SAM), designed to defend against any type of airborne threat including aircraft, helicopters, anti-ship missiles, hypersonic missiles., ballistic missiles, and UAVs as well as cruise missiles and having an amazing minimum engagement range of just 300 m and a maximum of 90 km. Barak 8 is “an advanced, long-range missile defense and air defense system” with its main features being

Engine Two stage, smokeless pulsed rocket motor
Wingspan 0.94 m (3 ft 1 in)
0.3–100 km
Flight ceiling 16 and 30 km (9.9 and 18.6 mi)
Maximum speed Mach 3 (1030 m/s)
  • Two way data link
  • Active RF/IIR seeker[

Oto Melara 76 mm naval gun

The 76mm Oto Melara is one of the most popular naval guns ever produced, in service with 60 navies around the world. There are two versions of the gun, the Compact and the Super Rapid (SR). Kolkata class carries the Super Rapid Gun Mount (SRGM). The gun is manufactured in India under license.

Indian Navy Kolkata Class Destroyers | by China_SCS_Info | Indo-Pacific  Geomill | Medium

The gun’s high rate of fire and wide range of ammunition make it effective for short-range anti-missile point defense, anti-aircraft, anti-surface, and ground support. Ammunition includes armor piercing, incendiary, directed fragmentation effects.

The Firing rate can be selected from single shot to 120 rds/min. In operational conditions the tactical time is less than 3 seconds and the standard deviation at firing is less than 0.3 mrad, thus providing excellent accuracy.

The gun interfaces with the ship’s Combat Management System and fire control system for a fully remote operation and automated use.

Caliber: 3 inches / 76,2 mm
Shell: 76 x 900 mm / 12,34 kilograms
Elevation: – 15° to + 85°
Traverse: 360°
Rate of fire: Compact: 85 rpm / Super Rapid: selectable from single shot up to 120 rpm
Muzzle Velocity: 925 m/s (1100 m/s – DART)
Magazine: Compact: 80 rounds / SR: 85 rounds
Range: 16 kilometers with standard ammunition, 20 km with extended range ammunition up to 40 km with VULCANO ammunition

AK-630M 30mm CIWS

Four AK-630M close-in weapon systems (CIWS) are used for air defense against incoming anti-ship missiles & other guided weapons.

AK-630M 30mm CIWS
AK-630M 30mm CIWS in action

The AK-630M is a Soviet era fully automatic 30mm, six-barreled, AO-18Gatling gun used to protect ships from incoming anti ship missiles. The gun fires high velocity HE-FRAG incendiaries or fragmentation tracer projectiles.

The system’s primary purpose is defense against anti-ship missiles and other precision guided weapons, but it can also be used against fixed or rotary wing aircraft, ships and other small craft, coastal targets, and floating mines.

  • Caliber: 30×165mm AO-18Shell: HEI-Frag, Frag-T
  • Action: Gas-operated rotary cannon
  • Rate of fire: 4,000–5,000 rounds/min (AK-630M) 10,000 rounds/min (AK-630M1-2)
  • Muzzle velocit: y880–900 m/s (2,900–3,000 ft/s)
  • Effective firing range: 5,000 m (16,000 ft) (maritime)

RBU-6000 ASW rocket launchers

Kolkata class has two RBU-6000 ASW rocket launchers at the front of the ship. The rockets can be launched against submarines & torpedoes up to a 5+ km range & can also be used as an anti-frogman system against combat divers who try to sabotage a ship. The RBU-6000 is basically a naval mortar that fires unguided depth charges. The system can also be used for shore bombardment.

Two RBU-6000 ASW rocket launchers on the Kolkata destroyer’s deck
Two RBU-6000 ASW rocket launchers on the Kolkata destroyer’s deck

The RBU-6000 ASW (also known as Smerch in Russia) rocket launchers are now designated as IRL (Indigenous Rocket Launchers) and is made by Larsen & Toubro Limited. Each launcher has 12 barrels and is automatically reloaded by the 60UP loading system from a below deck magazine. The magazine is either 72 or 96 rounds per launcher. They are used because of their hard kill ability and immunity against countermeasures. The RBU-6000 system is remotely directed by the Burya fire control system of the ship. The weight of a RBU-6000 launcher is 3500 Kg.


For ASW warfare, there is a twin-tube launcher on each side of the ship with 533mm torpedoes. Kolkata class currently uses the Russian Type 53K-65KE torpedoes and will later also use the domestic Varunastra torpedoes developed by DRDO. There are also two RBU-6000 ASW rocket launchers and the Maareech Advanced Torpedo Defence System (ATDS) countermeasure launchers.

Domestic 533mm Twin Tube Torpedo Launcher (ITTL)
Domestic 533mm Twin Tube Torpedo Launcher (ITTL)

The Indigenous Twin Tube Torpedo Launcher (ITTL) is a Heavy Weight Torpedo (HWT) Launching system made by Larsen & Toubro Limited. It has a provision to accept firing commands to launch Anti-Ship and Anti-Submarine torpedoes.

Type-53K-65KE Torpedo

The Type-53K-65KE torpedo its used exclusively to attack surface ships, has a range of about 19 km & speed of 45 kt (48km/h cruise speed that increases to 74 km/h in the final stage), it has a sonar seeker. Its a wake-homing torpedo that follows the wake of the ship, this being a feature that has no countermeasures to it. Its the only wake-homing torpedo in existence. It weights 2.2 tons and carries a 200 Kg warhead.

Varunastra Torpedo

The Varunastra is a domestic heavyweight torpedo developed by DRDO. The Varunastra was inducted in the Indian Navy on June 2016.

torpedo launch test from Kolkata class destroyer
torpedo launch test from Kolkata class destroyer

Varunastra has conformal array transducer which enables the torpedo to look at wider angles than most common torpedoes. It also has advanced autonomous guidance algorithms with low drift navigational aids, and an insensitive warhead that can operate in a wide variety of combat scenarios. It is the only torpedo in the world to have a GPS-based locating aid.

Specs: Range: 40 km, Speed: 40 Knots, Warhead size: 250 Kg, Size: 7.6m long x 533 mm diameter, Weight: 1.25 tons, Maximum depth: 400 meters, Price: $1.77 million.

Sensors and processing

Indian Navy Kolkata Class Destroyers | by China_SCS_Info | Indo-Pacific  Geomill | Medium

EL/M-2248 MF-STAR multimission radar

Made by Israel Aircraft Industries (IAI), and known as MF-Star, it is literally the eyes of the ship. The MF-STAR (ELM-2248) is a multi-function, solid-state, digital active phased array (AESA), 3D radar. MF-STAR is an acronym of Multi-Function Surveillance, Track And Guidance Radar.

 EL/M-2248 MF-STAR Radar
The antenna set up of the EL/M-2248 MF-STAR Radar

The MF-STAR is capable of tracking both air and surface targets and can track hundreds of targets simultaneously with a very fast refresh rate. The EL/M-2248 MF-STAR detects air targets at more than 250 km & sea skimming subsonic cruise missiles at more than 25 km. It is capable of providing guidance illumination and mid course updates to both active and semi active surface to air missiles and anti ship missiles, with multiple simultaneous engagement capability. It is also capable of automatic splash detection and correction for naval gun support.

It has 4 active arrays in S-Band frequency, each one pointing in a different direction. Overall, the EL/M-2248 performance and appearance is similar to the US Navy’s AEGIS combat system and its AN/SPY-1D radar antenna.


  • Fast threat alert response time
  • Very high tracking update rate and accuracy for priority targets
  • Short search frame/TWS revisit time
  • Mid-course guidance of active/semi-active anti-air missiles
  • Illuminator enslavement for semi-active missiles
  • Automatic splash detection and measurement for gunnery support
  • Instantaneous multi-beam
  • Advanced beam forming techniques for ECCM
  • Lightweight antenna
  • Scalable, modular active solid-state phased array
  • High reliability and high availability

HUMSA-NG Nagin sonar

HUMSA-NG is the third generation indigenous, ship borne, hull mounted, Sonar system designed by DRDO and productions by Bharat Electronics. HUMSA-NG is a state of the art Active cum Passive Integrated Ship Sonar system designed to be installed on a variety of naval surface platforms such as Frigates, Destroyers, ASW Corvettes and other classes of ships.

HUMSA-NG is an advanced version of the existing HUMSA sonar presently fitted on P16, P15, Ranjit and Talwar Class of ships.

The NACS system has been integrated with the HUMSA-NG sonar array and has met the desired operational classifications. NACS or Near-field Acoustic Characterization System, is a performance monitoring system that will be used to determine the in-situ performance of the sonars.

The sonar is capable of simultaneous operation in active and passive modes. It is capable of detecting, localizing, classifying and tracking sub-surface targets in both active and passive modes. The sonar is capable of localization and automatic tracking of up to eight targets in both active and passive modes.

Thales LW-08 Air Search radar

Thales Naval Nederland developed the LW08, a high-powered, coherent D-band radar system for naval vessels.

The Thales LW08 is a D band, 2 Dimension, long range surveillance radar, providing target indication to weapon control systems. The aspect which distinguishes LW08 is its wide range and superb accuracy. LW08 performs with great frequency agility over a wide band, due to its synthesizer-driven TWT transmitter.

Bharat Electronics Ltd. (BEL) manufactured the Thales LW08 radars used in the Kolkata class under a license agreement with Thales, using Thales-supplied components. The BEL designation for this radar is BEL RAWL-02.

Detection range

  • Small missile : 100 km
  • Fighter aircraft : 230 km
  • Target speed : up to Mach 4
  • Surface targets : radar horizon
  • Minimum range : 2 km
  • Instrumented range : 135/270 km
  • Tracking capacity : 400
Altitude Max: 30480 m
Range Max: 333.4 km Altitude Min: 0 m
Range Min: 5.4 km Generation: Early 198

Radar for Navigation and Fire Control

The BEL APARNA radar is an active and passive radar used for navigation as well as a fire control radar for the ship’s 76mm gun. It’s a modified Russian Garpun-Bal 3TS-25E Fire Control radar, the NATO name is Plank Shave. The name APARNA means: Active and PAssive Radar for Navigation and Attack.

The BEL APARNA radar is designed to detect surface targets, furnish target data to a weapon computer for missile/gun firing at these targets in the autonomous mode from the ship. The radar system has two transmitter–receiver channels. The first or main channel for fire control and a second channel for navigation. The two channels have different transmitter peak power, pulse width etc. identification nationality targets and IFF by means of coupled interrogators equipment

Combat Management System (CMS)

INS Chennai, the last one of the Kolkata class, was fitted with the advanced BEL Electronic Modular Command & Control Applications (EMMCCA Mk 4) combat management system (CMS).

The CMS is the heart of the ship. The CMS is the computer and software system that integrates all of a ship’s weapons, data, sensors and other equipment into a single system. All of the ship’s sensors and weapon systems are connected to the CMS and are controlled from it.

The CMS is the central command and decision-making element of a ship’s combat system. Basically, it allows the crew to counter threats faster and more efficiently, especially during combat operations.

The CMS enables the crew to perform multiple tasks such as data processing, threat evaluation, decision making, control of on-board weapons, and engagement of targets in response to multiple threats.

Electronic warfare & decoys

Kolkata class carries the domestic ELLORA MK I Electronic Warfare Suite which combines Electronic Support Measures (ESM) and active Electronic Counter Measures (ECM). The ELLORA suite is a powerful EW system with active jamming capability against multiple threats.

ELLORA ESM & ECM antennas in Kolkata Class destroyers
Pictures showing the location of the ELLORA ESM & ECM antennas in Kolkata Class destroyers

ELLORA is an offshoot of the Sangraha Electronic Warfare (EW) System — a co-development by the Indian Navy and DRDO’s Electronics Research Laboratory (DLRL) and Bharat Electronics Limited (BEL) which has spawned five different airborne and shipborne EW projects based on a common core technology architecture. The Sangraha family family of EW suites is capable of intercepting, detecting and classifying pulsed, CW, PRF agile, frequency agile and chirp radars.

BEL describes ELLORA as a state of the art EW shipborne system, adding that it can handle multiple threats with a reaction time up to 5 times faster compared to the conventional servo controlled jammers.

ELLORA also has an ESM subsystem with a frequency coverage that goes up to 40 Ghz. Some sources say that the ESM subsystem is in fact the BEL Ajanta MK3 electronic warfare (EW) suite but there is no confirmation.

The ELLORA suite in Kolkata class ships has two primary functions: A) Electronic Support Missions (ESM) to try and detect faint radar emissions from ships or planes in the area and B) Electronic Counter Measures (ECM) to jam the signals of enemy aircraft or incoming anti ship missiles if they were detected.

If incoming enemy missiles are detected, the ELLORA ECM system will try to jam the active radar seeker of the incoming missile while ‘Kavach’ or ELBIT’s Deseaver, will fire aluminum chaff on the path of the missile in order to confuse the missile sensors and make it veer away harmlessly from the ship.

‘Kavach’ chaff decoy system

NS Chennai comes equipped with ‘Kavach’ chaff decoy system. It is also fitted with ‘Mareech’ torpedo decoy system for defence against torpedoes. Both of these decoy systems have been developed indigenously.

The KAVACH MOD-II system is designed to counter the threat of various anti-ship missiles by using chaff decoys. The system provides soft kill defense in a three-layered defense scheme.

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