What are the three ships with three different strategic roles that Navy inducted today

The Indian Navy inducted three warships — INS Dunagiri (stealth frigate), INS Sanshodhak (survey vessel), and INS Agray (anti-submarine warfare craft) — in a...

What Happened

The Indian Navy inducted three warships — INS Dunagiri (stealth frigate), INS Sanshodhak (survey vessel), and INS Agray (anti-submarine warfare craft) — in a single ceremony in Kolkata on June 21, 2026.
The three ships serve fundamentally different strategic roles: blue-water power projection (Dunagiri), maritime domain awareness through hydrographic survey (Sanshodhak), and coastal/littoral zone submarine detection (Agray).
All three were built by Garden Reach Shipbuilders and Engineers (GRSE), Kolkata — a public sector Navratna enterprise — representing the same shipyard's capacity to simultaneously build vessels across different mission profiles.
This is part of India's largest-ever naval expansion cycle: 45 warships are under construction, with 19 planned for induction in 2026 alone.

Static Topic Bridges

Stealth Technology in Naval Vessels

Stealth in naval warships refers to reducing the vessel's detectability across multiple signatures: radar cross-section (RCS), infrared (heat) signature, acoustic (noise) signature, and magnetic signature. Project 17A frigates like INS Dunagiri employ a suite of signature management technologies.

Radar: Flush-deck (tumblehome hull) layout with no protruding superstructures; angled surfaces deflect rather than return radar waves
Infrared: Venturi effect and fluid injection applied to exhaust funnels cool hot gases before emission, masking the heat plume
Acoustic: Low-cavitation propellers (onset of cavitation at higher RPM reduces noise); acoustic enclosures around machinery; vibration isolation mounts for engines
Magnetic: Degaussing coils run through hull to neutralise the vessel's magnetic field (reduces vulnerability to magnetic mines and magnetic anomaly detectors)
AESA (Active Electronically Scanned Array) radar allows simultaneous tracking of multiple air/surface/subsurface targets while minimising radar emissions

Connection to this news: INS Dunagiri's stealth suite makes it difficult to detect, track, or target — enabling it to approach adversary vessels or launch BrahMos strikes from stand-off ranges without detection.

Hydrographic Surveys and Maritime Domain Awareness

Hydrography is the science of measuring and describing the physical features of bodies of water and adjacent coastal areas. Naval hydrographic surveys serve dual purposes: safe navigation for all vessels and intelligence gathering for submarine and mine warfare operations.

Side-scan sonar: towed behind the vessel, creates acoustic images of the seabed — identifies wrecks, cables, anomalies, and mine-like objects
Autonomous Underwater Vehicles (AUVs): pre-programmed unmanned submersibles that conduct deep surveys without risking crew
Remotely Operated Vehicles (ROVs): tethered to the surface ship, operated in real time for visual inspection and sampling
Oceanographic data (temperature, salinity, current profiles, thermocline depth) determines sonar performance — critical for both attacking submarines and defending against them
India's National Hydrographic Office (NHO) publishes charts based on data collected by survey ships

Connection to this news: INS Sanshodhak completes the four-ship Sandhayak-class SVL programme, giving India a modern hydrographic survey capability that covers both the Arabian Sea and Bay of Bengal theatres.

Littoral Combat and ASW Shallow Water Operations

Littoral warfare refers to military operations in coastal waters — the zone extending roughly 200 nautical miles from shore. Shallow-water ASW is considered the hardest anti-submarine problem because complex bathymetry, shipping noise, and temperature layers make sonar performance highly degraded compared to deep-ocean environments.

Waterjet propulsion (used in INS Agray): provides high speed in shallow water, better manoeuvrability at low speeds, and reduced acoustic signature compared to conventional propeller shafts
Shallow-water SONAR: hull-mounted and towed array sonar tuned for high reverberation coastal environments
Lightweight torpedoes (Mark 54 equivalent class): air-launchable or ship-launched, designed for shallow-water engagements where heavyweight torpedoes cannot operate safely
Indigenous rocket launchers: provide a stand-off attack option against snorkelling or surfaced submarines
India's coastal ASW mission includes protecting submarine bases (Visakhapatnam, Karwar), nuclear-armed SSBNs leaving/entering port, and critical undersea infrastructure

Connection to this news: INS Agray is the fourth of eight ASW SWC being built — a dedicated coastal ASW fleet that did not exist a decade ago, addressing the growing submarine threat in India's immediate maritime neighbourhood.

GRSE — Garden Reach Shipbuilders and Engineers

GRSE is a Government of India undertaking under the Ministry of Defence, headquartered in Kolkata. It is one of India's three major defence shipyards and the only one on the eastern coast of India.

Navratna Public Sector Undertaking (PSU) under MoD
Has built over 100 vessels for the Indian Navy and Coast Guard
Holds the record for building the largest number of warships for the Indian Navy among all Indian shipyards
Specialises across classes: frigates (Project 17A), survey vessels (Sandhayak class), ASW craft, patrol vessels, and fast attack craft
GRSE is also pursuing export orders, having supplied vessels to Bangladesh and Mauritius

Connection to this news: The fact that all three ships in the triple commissioning — a frigate, a survey vessel, and an ASW craft — were built by a single shipyard (GRSE) demonstrates its range and production throughput, a key enabler of India's accelerated naval expansion.

Key Facts & Data

INS Dunagiri (5th Nilgiri-class / Project 17A): 149 m, 6,670 tonnes, BrahMos + AESA radar, CODAG propulsion, ~75% indigenous content
INS Sanshodhak (4th Sandhayak-class SVL): 110 m, ~3,300 tonnes, equipped with AUVs, ROVs, digital side-scan sonar
INS Agray (4th of 8 ASW SWC): ~77 m, waterjet propulsion, lightweight torpedoes, indigenous rocket launchers, shallow-water SONAR
Builder: Garden Reach Shipbuilders and Engineers (GRSE), Kolkata — Navratna PSU under MoD
June 2026 is India's largest single-month naval induction: five indigenous warships inducted in the same month
45 warships currently under construction in India; 19 planned for commissioning in 2026
BrahMos cruise missile: Mach 3 speed; up to 500 km range; jointly developed by India and Russia (BrahMos Aerospace)
India's indigenisation: 90% in Float (hull), 60% in Move (propulsion), 50% in Fight (weapons/sensors) categories