The ''Nilgiri''-class frigates, formally classified as the Project-17 Alpha frigates (P-17A), are a series of stealth guided-missile frigates currently being built by

Mazagon Dock Shipbuilders Mazagon Dock Shipbuilders Limited (MDL) (IAST: ''Majhagānv Dawk Limiṭeḍ''), formerly called Mazagon Dock Limited, is a shipyard situated in Mazagaon, Mumbai. It manufactures warships and submarines for the Indian Navy and offshore pla ...

(MDL) and

Garden Reach Shipbuilders & Engineers Garden Reach Shipbuilders & Engineers Ltd, abbreviated as GRSE, is one of India's leading shipyards, located in Kolkata. It builds and repairs commercial and naval vessels. GRSE also builds export ships. Founded in 1884 as a small privately-o ...

(GRSE), for the

Indian Navy The Indian Navy is the maritime branch of the Indian Armed Forces. The President of India is the Supreme Commander of the Indian Navy. The Chief of Naval Staff, a four-star admiral, commands the navy. As a blue-water navy, it operates sig ...

Design

Development

The

frigate A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed and ...

s were designed by the Warship Design Bureau ( formerly Directorate of Naval Design ) – an internal establishment within the

responsible for designing

warship A warship or combatant ship is a naval ship that is built and primarily intended for naval warfare. Usually they belong to the armed forces of a state. As well as being armed, warships are designed to withstand damage and are usually faster a ...

s; the organisation is also distinguished for having contributed to the designing of numerous Indian warships, including – India's first indigenously-designed

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a ...

, the s – India's first indigenously-designed nuclear-powered ballistic missile submarines and the s – India's first indigenously designed frigates equipped with

stealth technology Stealth technology, also termed low observable technology (LO technology), is a sub-discipline of military tactics and passive and active electronic countermeasures, which covers a range of methods used to make personnel, aircraft, ships, subm ...

. The class' design was finalised by the DND in 2013; it was later unveiled to the public in April 2018 – when MDL displayed a scale model of the frigate at the "DEXEXPO 2018" defense exhibition, held at

Chennai Chennai (, ), formerly known as Madras ( the official name until 1996), is the capital city of Tamil Nadu, the southernmost Indian state. The largest city of the state in area and population, Chennai is located on the Coromandel Coast of th ...

Tamil Nadu Tamil Nadu (; , TN) is a States and union territories of India, state in southern India. It is the List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of India ...

, India.

Features

Stealth

The frigate's design incorporates a significant degree of stealth and low radar-observability – through the utility of composite materials, radar-absorbent coatings and low-observable/radar-transparent technologies; the usage of the aforementioned materials assists the vessel in maintaining a low

radar cross-section Radar cross-section (RCS), also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected. An object reflects a limited amount of radar energy back to the source. ...

(RCS). The vessel's physical profile also features a substantial level of stealth through the application of different physical forms – including an enclosed mooring deck,

flush deck Flush deck is a term in naval architecture. It can refer to any deck of a ship which is continuous from stem to stern. History The flush deck design originated with rice ships built in Bengal Subah, Mughal India (modern Bangladesh), resulting i ...

-mounted weapon systems and a reduced number of antennae. The frigate's

infrared signature Infrared signature, as used by defense scientists and the military, is the appearance of objects to infrared sensors. An infrared signature depends on many factors, including the shape and size of the object, temperature, and emissivity, reflection ...

, most specifically emissions from its propulsion exhaust and power generation machinery, are reduced through the application of

Venturi effect The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The Venturi effect is named after its discoverer, the 18th century Italian physicist, Giovanni Battista V ...

and fluid injection, which helps to reduce the plume and hot metal temperatures of exhaust. To maintain acoustic silence, the frigate is equipped with

propellers A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

designed to have onset of cavitation at higher speeds to reduce hydrodynamic noise. In addition to the propellers, the vessel's hull also features special acoustic enclosures for some of the machinery to reduce the emission air-borne noise.

Modular profile

The P-17A frigates are the first major class of Indian-designed warships to be built using the methodology of integrated modular construction – a manufacturing process in which multiple modules (or "blocks") of a vessel's hull are pre-assembled/pre-outfitted independently, before being aggregated for final assembly. In December 2015, MDL contracted Fincantieri S.p.A. to provide technical assistance and essential expertise in the construction of the seven frigates using the "modular construction" methodology.

Naming

The P-17A frigates were christened after the former-s, which served in the Indian Navy between 1972 and 2013; the first six ships of the series were allotted the names utilised by the older class, namely – , , ''Taragiri'', , ''Dunagiri'', and ''Vindhyagiri''. The seventh and final vessel of the P-17A series, which did not have a namesake from the older class, was given the new name of ''Mahendragiri''.

Instrumentation

Armament

Anti-surface warfare

As part of its

anti-surface warfare Anti-surface warfare (ASuW or ASUW) is the branch of naval warfare concerned with the suppression of surface combatants. More generally, it is any weapons, sensors, or operations intended to attack or limit the effectiveness of an adversary's su ...

(ASuW) capabilities, the class features eight

BrahMos The BrahMos (also designated as PJ-10)anti-ship

cruise missiles A cruise missile is a guided missile used against terrestrial or naval targets that remains in the atmosphere and flies the major portion of its flight path at approximately constant speed. Cruise missiles are designed to deliver a large warhead ...

, capable of speeds of up to Mach 3. The BrahMos is widely regarded as one of the most formidable anti-ship missiles currently in service, given the missile's extreme versatility and manoeuvrability. The vessels are equipped with one

OTO Melara 76 mm The OTO Melara 76 mm gun is a naval gun built and designed by the Italian defence company OTO Melara. It is based on the OTO Melara 76/62C and evolved toward 76/62 SR and 76/62 Strales. The system is compact enough to be installed on rel ...

naval gun Naval artillery is artillery mounted on a warship, originally used only for naval warfare and then subsequently used for naval gunfire support, shore bombardment and anti-aircraft roles. The term generally refers to tube-launched projectile-firi ...

. Originally, the Indian Navy had planned to install the Mk 45 naval gun, manufactured by

BAE BAE Systems plc (BAE) is a British multinational arms, security, and aerospace company based in London, England. It is the largest defence contractor in Europe, and ranked the seventh-largest in the world based on applicable 2021 revenues. ...

; however, this plan was later scrapped in 2021 on account of financial constraints.

Anti-air warfare

As part of its anti-air warfare (AAW) capabilities, the class features thirty-two

Barak 8 Barak 8 ( he, בָּרָק, lit. "Lightning"), also known as LR-SAM or as MR-SAM, is an Indo-Israeli jointly developed surface-to-air missile (SAM) system, designed to defend against any type of airborne threat including aircraft, helicopters, ant ...

surface-to-air missile A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground to destroy aircraft or other missiles. It is one type of anti-aircraft syst ...

s, with sixteen missiles present in four "2 x 4" VLS configurations – with two placed at the bow and two placed aft. The Barak 8ER, also classified as the LR-SAM, is an "extended-range" variant of the original Barak 8 – designed to neutralize various aerial threats, including fighter aircraft, helicopters, anti-ship missiles, cruise missiles, ballistic missiles and

unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...

s (UAV); the new variant is expected to feature a range of about .

Anti-submarine warfare

As part of its

anti-submarine warfare Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are t ...

(ASW) capabilities, the class features two triple-tube lightweight torpedo launchers for firing ASW torpedoes. The class also features two

RBU-6000 The RBU-6000 Smerch-2 (Реактивно-Бомбовая Установка, ''Reaktivno-Bombovaja Ustanovka''; reaction engine-bomb installation & Смерч; waterspout) is a 213 mm caliber Soviet Union, Soviet anti-submarine weapon, a ...

(RPK-8) anti-submarine rocket launchers, capable of firing ASW projectiles to depths of up to .

Decoys

During the class' unveiling in 2018, the frigate's design was noted to possess two anti-torpedo decoy systems and four decoy launchers – which presumably may be the NSTL Maareech torpedo-countermeasure system and the Kavach anti-missile decoy launchers, respectively.

Aviation facilities

As part of its aviation facilities, the class is equipped with a flight-deck and an enclosed aviation hangar, capable of accommodating a single naval helicopter – most likely the ALH Dhruv MK-III maritime-reconnaissance helicopters, or the Westland Sea King Mk. 42B ASW/ASuW helicopters – both of which are operated by the

Indian Naval Air Arm The Indian Naval Air Arm is the aviation branch and a fighting arm of the Indian Navy which is tasked to provide an aircraft carrier based strike capability, fleet air defence, maritime reconnaissance, and anti-submarine warfare. The Flag Off ...

Sensors

Radar

The class features the EL/M-2248 MF-STAR

active electronically scanned array An active electronically scanned array (AESA) is a type of phased array antenna, which is a computer-controlled array antenna in which the beam of radio waves can be electronically steered to point in different directions without moving the an ...

(AESA) radar as its primary radar suite. The EL/M-2248 is a multi-function, phased-array radar system featuring an azimuth of 360^o, with the capability to track both aerial and surface targets, at a range of over . The class also features the Indra LTR-25 'Lanza' surface-search radar, as its

secondary radar Secondary surveillance radar (SSR)''Secondary Surveillance Radar'', Stevens M.C. Artech House, is a radar system used in air traffic control (ATC), that unlike primary radar systems that measure the bearing and distance of targets using the d ...

suite. The LTR-25 is a solid-state, three-dimensional (3D), long-range radar capable of operating in a dense electronic environment and features a range of over , with the capability to track various aerial targets – including

fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

and

ballistic missile A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are guided only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles stay within the ...

s. The frigates are also equipped with an advanced combat management system, classified as "CMS-17A", which is reportedly equipped with sophisticated

data link A data link is the means of connecting one location to another for the purpose of transmitting and receiving digital information (data communication). It can also refer to a set of electronics assemblies, consisting of a transmitter and a recei ...

s for high, efficient interoperability with other naval vessels.

Sonar

The class is equipped with the BEL HUMSA-NG

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigation, navigate, measure distances (ranging), communicate with or detect o ...

, developed by the

DRDO The Defence Research and Development Organisation (DRDO) (IAST: ''Raksā Anūsandhān Evam Vikās Sangaṭhan'') is the premier agency under the Department of Defence Research and Development in Ministry of Defence of the Government of India, ...

. The HUMSA-NG is a hull mounted "active cum passive" integrated sonar system capable of detecting, localizing, classifying and tracking sub-surface targets in both active and passive modes.

Electronic warfare

The frigates feature the ''Shakti''

electronic warfare Electronic warfare (EW) is any action involving the use of the electromagnetic spectrum (EM spectrum) or directed energy to control the spectrum, attack an enemy, or impede enemy assaults. The purpose of electronic warfare is to deny the opponen ...

(EW) suite – developed by the Defence Electronics Research Laboratory (DLRL), for defense against anti-ship missiles and for the interception, detection, classification, identification and jamming of conventional radars. ''Shakti'' is equipped with wide-band electronic-support measures (ESM), electronic countermeasures (ECM), an integrated "Radar Finger Printing System (RFPS)" and a data-recording replay feature for "post-mission analysis".

Propulsion

At the time of the order, HAL had already delivered eleven LM2500 turbines to the Indian Navy; the turbines are specifically used on multiple Indian warships, most notably on the ''Shivalik''-class frigates. Each frigate features two

General Electric LM2500 The General Electric LM2500 is an industrial and marine gas turbine produced by GE Aviation. The LM2500 is a derivative of the General Electric CF6 aircraft engine. As of 2004, the U.S. Navy and at least 29 other navies had used a total of mor ...

gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...

s – manufactured by

GE Aviation GE Aviation, a subsidiary of General Electric, is headquartered in Evendale, Ohio, outside Cincinnati. GE Aviation is among the top aircraft engine suppliers, and offers engines for the majority of commercial aircraft. GE Aviation is part of the ...

and two

MAN A man is an adult male human. Prior to adulthood, a male human is referred to as a boy (a male child or adolescent). Like most other male mammals, a man's genome usually inherits an X chromosome from the mother and a Y chromo ...

12V28/33D STC four-stroke engines – manufactured by

MAN Diesel & Turbo MAN Energy Solutions SE is a German multinational company based in Augsburg that produces large-bore gas and diesel engines and also turbomachinery for marine, rail and stationary applications, as locomotive and marine propulsion systems, power ...

, arranged in a

combined diesel and gas Combined diesel and gas (CODAG) is a type of propulsion system for ships that need a maximum speed that is considerably faster than their cruise speed, particularly warships like modern frigates or corvettes. Pioneered by Germany with the , a ...

(CODAG) propulsion configuration. In May 2016, the Indian Navy contracted MAN Diesel & Turbo to supply fourteen MAN 12V28/33D STC four-stroke engines for the seven frigates; under the deal, the requisite parts needed for the engines were sourced from India, while the engines' final assembly and testing were conducted at MAN's facility in

Aurangabad Aurangabad ( is a city in the Indian state of Maharashtra. It is the administrative headquarters of Aurangabad district and is the largest city in the Marathwada region. Located on a hilly upland terrain in the Deccan Traps, Aurangabad is th ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

. In December 2016, the Indian Navy contracted GE Aviation to supply fourteen LM2500 gas turbines for the seven frigates, which were license-assembled in India by the Industrial & Marine Gas Turbine Division (IMGT) of

Hindustan Aeronautics Limited Hindustan Aeronautics Limited (HAL) is an Indian state-owned aerospace and defence (military), defence company, headquartered in Bangalore, India. Established on 23 December 1940, HAL is one of the oldest and largest aerospace and defence manuf ...

(HAL). Under the deal, HAL was additionally sanctioned to provide comprehensive services – including the supply of spare parts, maintenance inspections and equipment overhauls. In February 2019, MDL contracted GE to supply an assortment of auxiliary equipment to the Indian Navy to support the fourteen engines; under the agreement, GE also handled the design work of the frigate's auxiliary system and its fuel supply system.

History

Background

In June 2009, the Defence Acquisition Council (DAC) – the main acquisition panel subordinate to India's

Ministry of Defence {{unsourced, date=February 2021 A ministry of defence or defense (see spelling differences), also known as a department of defence or defense, is an often-used name for the part of a government responsible for matters of defence, found in states ...

(MoD), cleared a proposal for the procurement of seven stealth frigates at a cost of ₹45,000 crore – classified as "Project 17A" – on the lines of the Indian Navy's initiative of establishing a 160-ship fleet. In September 2012, the

Cabinet Committee on Security The Cabinet Committee on Security (CCS) of the Government of India discusses, debates and is the final decision-making body on senior appointments in the national security apparatus, defence policy and expenditure, and generally all matters of Ind ...

(CCS) – India's top decision-making institution on matters related to defense and national security, green-lighted the proposal for the "development cum construction" of the seven frigates. Initially, the Indian Navy favoured a proposal of building the first two frigates at a foreign shipyard – seeking to minimize the project's overall construction timeline; however, this suggestion was overruled by India's

(MoD) – which favoured indigenous production of the frigates. The seven frigates were envisioned as a "follow-on series" to the ''Shivalik''-class frigates (Project 17), which were also being built for the Indian Navy at the time, but equipped with more sophisticated capabilities. The designing-process of the seven frigates was completed in mid-2013. The project – consisting of the construction of the seven designated frigates over a span of five years – was formally approved by the CCS in February 2015.

Construction

The seven frigates are to be jointly constructed by two public-sector shipyards, namely,

Mazagon Dock Shipbuilders Limited Mazagon Dock Shipbuilders Limited (MDL) ( IAST: ''Majhagānv Dawk Limiṭeḍ''), formerly called Mazagon Dock Limited, is a shipyard situated in Mazagaon, Mumbai. It manufactures warships and submarines for the Indian Navy and offshore pl ...

(MDL) and

Garden Reach Shipbuilders and Engineers Garden Reach Shipbuilders & Engineers Ltd, abbreviated as GRSE, is one of India's leading shipyards, located in Kolkata. It builds and repairs commercial and naval vessels. GRSE also builds export ships. Founded in 1884 as a small privately ...

(GRSE), with four of the frigates allotted to MDL and the remaining three allotted to GRSE.

Garden Reach Shipbuilders & Engineers

In February 2015, the Indian Navy contracted Garden Reach Shipbuilders & Engineers (GRSE), a

Kolkata Kolkata (, or , ; also known as Calcutta , the official name until 2001) is the capital of the Indian state of West Bengal, on the eastern bank of the Hooghly River west of the border with Bangladesh. It is the primary business, comme ...

-based public-sector shipyard, to build three P-17A frigates at an estimated cost of ₹19,294 crore. According to the terms of the contract, GRSE is slated to deliver the three frigates in 2023, 2024 and 2025, respectively. In preparation for the order, GRSE re-augmented its infrastructure by establishing newer "modular" shipyards along with a Goliath gantry crane, meant for enabling the construction of the frigates in a short time frame. A significant proportion of the hull's blocks needed for the vessel's construction was procured from smaller shipyards and metal fabrication shops in and around Kolkata, while the construction/fabrication of additional infrastructure was done at GRSE's

Rajabagan Rajabagan is a neighbourhood located in the south-western part of Kolkata city, in the state of West Bengal, India. It is located on the eastern bank of Hooghly river and is situated between Metiabruz (east) and Badartala (west). Geography Po ...

shipyard. The construction of the first frigate began in November 2018, while work on the second and third frigates began in January 2020 and March 2021, respectively. The first of the three frigates, ''Himgiri'', was launched on 14 December 2020, with its delivery slated to occur for August 2023. The second frigate, ''Dunagiri'', was launched on 15 June 2022, with its delivery slated to occur in 2024.

Mazagon Dock Shipbuilders Limited

INS Nilgiri in Mumbai on September 28, 2019

In February 2015, the Indian Navy contracted Mazagon Dock Shipbuilders Limited (MDL), a

Mumbai Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second- ...

-based public-sector shipyard, to build four P-17A frigates at an estimated cost of over ₹21,000 crore. According to the terms of the contract, MDL is to deliver the four frigates in 2022, 2023, 2024 and 2025, respectively. The four frigates were built at different locations, namely, at MDL's main shipbuilding facility in Mumbai, at MDL's subordinate facility in

Nhava Jawaharlal Nehru Port Trust (JNPT) or JLN Port, also known as Nhava Sheva Port, is the second largest container port in India after Mundra Port. Located in Navi Mumbai's Raigad district, this port on the Arabian Sea is accessed via Thane Creek ...

, at a smaller shipbuilding facility also operated by MDL in Mumbai, at an MSE shipyard in

Gujarat Gujarat (, ) is a state along the western coast of India. Its coastline of about is the longest in the country, most of which lies on the Kathiawar peninsula. Gujarat is the fifth-largest Indian state by area, covering some ; and the ninth ...

and at another shipyard in

Goa Goa () is a state on the southwestern coast of India within the Konkan region, geographically separated from the Deccan highlands by the Western Ghats. It is located between the Indian states of Maharashtra to the north and Karnataka to the ...

. Similarly to GRSE, MDL also upgraded its existing infrastructure; the shipyard augmenting its existing facilities with newer equipment, including a "Goliath" gantry crane, a module workshop, a wet basin and a "cradle assembly" shop, meant to facilitate modular construction. The construction of the first frigate began in December 2017, while work on the second, third and fourth frigates began in May 2019, September 2020 and June 2022, respectively. The first of the four frigates, ''Nilgiri'', was launched on 28 September 2019, with its delivery slated to occur in August 2022. The second frigate of the four frigates, ''Udaygiri'', was launched on 17 May 2022, in a ceremony coinciding with the launch of , a . The third frigate, ''Taragiri'', was launched on 11 September 2022, and is scheduled to be delivered in 2025.

Ships in the class

References

External links

Project 17A frigate at Bharat-rakshak.com
{{Frigates of the Indian Navy Frigates of the Indian Navy Frigate classes Proposed ships