India deploys silent warships to prowl the seas. Why this is a gamechanger

As China and Pakistan expand their maritime capabilities in the region, the Indian Navy is accelerating its own buildup. The Navy recently took the delivery of INS Mahendragiri, a new Nilgiri-class stealth frigate. The Navy vessel, when commissioned into the fleet, would enhance its multi-mission capabilities. The delivery of INS Mahendragiri comes just a month after the Indian Navy got the delivery of a frontline warship, the INS Dunagiri. Earlier in April, the INS Taragiri, which has multi-mission capabilities, was commissioned into the Indian Navy.

All three are guided-missile warships, designed with advanced stealth features to reduce detectability by enemy radars and sensors. The induction of these warships, which comes within a month of the commissioning of INS Aridhaman, the country's third nuclear-powered ballistic missile submarine, is a marker of the Indian Navy's rapid progress in surface and underwater platforms.

The INS Mahendragiri was delivered to the Indian Navy on April 30, at Mazagon Dock Shipbuilders Limited (MDSL) in Mumbai. The INS Dunagiri was delivered on March 30, at Garden Reach Shipbuilders and Engineers Ltd (GRSE) in Kolkata.

All three Nilgiri-class stealth warships — INS Taragiri, INS Dunagiri, and INS Mahendragiri — fall under the Indian Navy's Project 17A. For the uninitiated, Project 17A, also known as the Nilgiri-class, comprises the development and deployment seven stealth guided-missile frigates developed as a follow-on to the Shivalik-class (Project 17).

The Shivalik-class frigates — three in total — were India's first indigenously designed stealth warships, entering service between 2010 and 2012. The succeeding Project 17A project builds on this foundation with improved stealth, larger size (about 6,670 tonnes displacement, 149 metres long), modular construction techniques, and a more advanced weapon-sensor suite.

These versatile multi-mission platforms are engineered to tackle current and emerging threats in the maritime domain, including anti-surface warfare against enemy ships, anti-air defence against aircraft and missiles, and anti-submarine operations against underwater threats.

They support blue-water operations, sea-lane protection, and power projection in regions like the Indian Ocean. Blue-water operations means a navy's ability to operate far from its home coast, across deep oceans, for long periods.

Here's a quick look at the latest warships that have been inducted into the Indian Navy.

WHAT'S SPECIAL ABOUT INS MAHENDRAGIRI?

Mahendragiri (Yard 12654) is the sixth ship of the Nilgiri-class (Project 17A) and the fourth built by Mazagon Dock Shipbuilders Limited (MDSL) in Mumbai. "Yard 12654" is the shipyard's internal construction or hull number assigned during building at MDSL. Earlier Nilgiri-class ships from the same yard include Nilgiri (Yard 12651), Udaygiri, and Taragiri.

It must be noted that Project 17A frigates feature about 75% indigenous content, with design by the Warship Design Bureau (WDB) of the Indian Navy and oversight by the Warship Overseeing Team, Mumbai.

INS Mahendragiri shows the growing capability of India to build sophisticated warships domestically rather than relying heavily on imports.

The broader Indian Navy fleet now includes a high proportion of indigenously built vessels, with recent inductions pushing towards over 100 indigenous warships, driven by policies emphasising local design, materials, and systems.

The project has involved over 200 micro, small and medium enterprises (MSMEs) and generated approximately 4,000 direct and more than 10,000 indirect jobs.

INS Mahendragiri is a state-of-the-art frigate with not just stealth features but also has firepower, automation, and survivability.

NOT JUST INS MAHENDRAGIRI, INDIAN NAVY HAS AN INS DUNAGIRI TOO

Months before the delivery of the INS Mahendragiri on April 30, the Indian Navy also got the delivery of INS Dunagiri in March.

Dunagiri (Yard 3023), is the fifth ship of the Nilgiri-class (Project 17A) and the second of the class built at Garden Reach Shipbuilders and Engineers Ltd (GRSE) in Kolkata. The first GRSE-built P17A ship is Himgiri.

Dunagiri is a reincarnation of the erstwhile INS Dunagiri, a Leander-class frigate (of British origin) that served the Indian Navy from May 1977 to October 2010, rendering 33 years of service.

The Dunagiri, a new state-of-the-art frigate, has features similar to Mahendragiri, in terms of superior stealth shaping, advanced sensors, and integrated systems that far exceed the capabilities of the older Leander-class vessels.

Dunagiri's weapons and sensors suite comprises BrahMos surface-to-surface missiles, which have the supersonic anti-ship and land-attack capability, the MFSTAR radar and MRSAM (Medium-Range Surface-to-Air Missile, also known as Barak-8) complex for air defence, a 76 mm super rapid gun mount (SRGM) for surface engagements, a combination of 30 mm and 12.7 mm close-in weapon systems for last-ditch defence against incoming threats, and rockets plus torpedoes for anti-submarine warfare.

Two helicopters, such as HAL Dhruv or Sea King, can also be embarked on the Dunagiri for extended reach.

Days after the INS Dunagiri was delivered, the Navy commissioned another multirole stealth frigate, the INS Taragiri. On the same day, Defence Minister Rajnath Singh presided over a brief ceremony to formally commission India's third nuclear submarine, INS Aridhaman, which is the third in the Arihant-class of SSBNs (Submersible Ship Ballistic Nuclear).

WHAT'S SPECIAL ABOUT INDIA'S NEW STEALTH WARSHIPS?

The Indian Navy warships of the P17A class are fitted with an advanced weapon and sensor suite compared to the P17 (Shivalik-class). The Shivalik-class introduced stealth to Indian frigates but used older systems. P17A incorporates next-generation technology such as the MF-STAR active electronically scanned array (AESA) radar for superior multi-target tracking.

These ships are configured with Combined Diesel or Gas (CODOG) propulsion plants.

In simple terms, CODOG allows the ship to switch between efficient diesel engines for cruising (fuel-saving, long-range patrols) and powerful gas turbines for high-speed dashes when needed. Each drives a controllable pitch propeller (CPP) on twin shafts, offering precise speed control. This is modern, proven technology used worldwide.

Many might think that diesel technology is outdated, but diesel engines are highly efficient and reliable. The Integrated Platform Management System (IPMS) further automates engine and system management for reliability and reduced manning.

Another significant feature of these warships is their stealth property. This is an important capability for the Indian Navy to have amid reports of secret Chinese patrol vessels sailing in the Indian Ocean Region. It's also significant to the Navy's capabilities in dealing with emerging naval threats.

HOW WARSHIPS GET STEALTH CAPABILITIES?

So, how do warships go stealth? How do they hide their positions?

Stealth is achieved through a low radar cross-section (RCS) using composite materials, radar-absorbent coatings, radar-transparent technologies, flush deck-mounted weapons, an enclosed mooring deck, and fewer antennae.

Infrared signature is reduced via advanced exhaust systems (Venturi effect and fluid injection to cool plumes), while acoustic stealth comes from specially designed propellers that delay cavitation (bubble formation that creates noise detectable by sonar).

These features make the ship harder to detect and target.

Firepower and sensors are upgraded with a potent suite for anti-surface, anti-air, and anti-submarine warfare. Automation via the state-of-the-art Integrated Platform Management System (IPMS) allows the Indian Navy the luxury of centralised monitoring and control of machinery, reducing crew workload.

The survivability of these ships is enhanced by better damage control and overall design.

Together, these inductions underline the Indian Navy's shift towards self-reliance and adds to its maritime muscle. Platforms are being stacked up on both surface and underwater fronts, and India is clearly preparing for a more contested Indian Ocean. With such multi-role platforms capable of operating independently or in task forces, they would play key roles in securing India's waters for decades.