What is Project 17A and how is INS Dunagiri related to it?

Project 17A is India's programme to build seven next-generation stealth guided-missile frigates with improved stealth features, advanced weapons, and sensors. INS Dunagiri (F36) is the fifth ship under this programme, built by GRSE Kolkata. The earlier INS Talaiyvar, INS Nilgiri, INS Himgiri, and INS Vindhyagiri were also commissioned under Project 17A.

What is the role of INS Sanshodhak?

INS Sanshodhak is a Survey Vessel Large (SVL) and the fourth ship of the Sandhayak class. Its mission is to map the seabed, measure water depths, study coastal and deep-water oceanographic features, and collect geophysical data. It uses Autonomous Underwater Vehicles (AUVs), Remotely Operated Vehicles (ROVs), and multi-beam echo sounders to build accurate charts of India's maritime domain.

What is Anti-Submarine Warfare Shallow Water Craft (ASW-SWC)?

An ASW-SWC is a small, agile warship designed to detect and destroy enemy submarines operating in shallow coastal waters — areas where traditional deep-water ASW frigates are less effective due to clutter from fishing boats, merchant ships, and the seafloor. INS Agray (P36) of the Arnala class is India's newest ASW-SWC, equipped with lightweight torpedoes, indigenous rocket launchers, and coastal sonar systems.

What does 75% indigenous content mean for these ships?

75% indigenous content means that at least three-quarters of the materials, components, weapons systems, sensors, and equipment used in building these ships were manufactured within India. This is a major benchmark under the Atmanirbhar Bharat (self-reliant India) initiative for defence, involving over 200 MSMEs across the country.

What is a Blue Water Navy and does India now have one?

A Blue Water Navy refers to a naval force capable of sustained, independent operations across deep open oceans, far from the home country's shores. India is progressively building blue water capabilities through INS Vikrant (aircraft carrier), nuclear submarines like INS Arihant, and Project 17A frigates like INS Dunagiri. The triple commissioning of June 2026 signals India is building naval power in layers — blue water, survey, and coastal ASW.

Three Ships, Three Roles: India's Naval Triple Commissioning

On June 21, 2026, Prime Minister Narendra Modi presided over a landmark triple naval commissioning ceremony at Kolkata — inducting INS Dunagiri, INS Sanshodhak, and INS Agray into the Indian Navy simultaneously. All three vessels were built by Garden Reach Shipbuilders & Engineers (GRSE), carry over 75% indigenous content, and involve more than 200 MSMEs across India. Together they represent a layered naval power projection strategy that is deeply relevant for UPSC GS Paper III (Defence Technology) and GS Paper II (India's Strategic Interests).

3Ships Commissioned in One Day

75%+Indigenous Content by Value

200+MSMEs Involved Nationwide

GRSEBuilder — Kolkata Shipyard

UPSC pen-paper notes: 3 Ships 3 Roles quick reference — Quick UPSC Notes — INS Dunagiri, Sanshodhak & Agray at a glance

Meet the Three Ships

Each vessel fills a distinct tactical and strategic niche — together forming a complete layered naval ecosystem. Explore each one below:

Stealth Guided-Missile Frigate

INS Dunagiri

F36

Blue Water Operations

The most heavily armed of the three, Dunagiri is a destroyer-sized frigate under Project 17A — India's programme to build seven next-generation stealth frigates. It operates far from shore in deep open ocean.

BrahMos surface-to-surface supersonic cruise missiles
MRSAM (Medium Range Surface-to-Air Missile) system
MFSTAR multi-function surveillance radar
Anti-submarine warfare torpedo launchers
Electronic warfare suites & stealth hull design

Survey Vessel Large (SVL)

INS Sanshodhak

J24

Ocean Intelligence

The fourth and final ship of the Sandhayak class, Sanshodhak is India's ocean intelligence platform — mapping seabeds, approach channels, and building the navigational databases that enable safe fleet operations.

Multi-beam echo sounders for seabed mapping
Autonomous Underwater Vehicles (AUVs)
Remotely Operated Vehicles (ROVs)
Oceanographic & geophysical data collection
Supports port approach & disaster relief operations

ASW Shallow Water Craft

INS Agray

P36

Coastal Sub-Hunting

The smallest but most specialised — Agray is the fourth vessel of the Arnala class, built purely for hunting submarines in India's shallow coastal waters, ports, and near naval bases where larger frigates cannot operate effectively.

Lightweight torpedoes for shallow-water engagements
Indigenous anti-submarine rocket launchers
Coastal shallow-water sonar systems
Agile hull for littoral zone operations
Designed for India's western and eastern seaboard patrol

India's Layered Naval Doctrine

The simultaneous commissioning is not a coincidence — it reflects a deliberate three-tier maritime strategy that the Indian Navy has been building towards:

Tier 1 — Blue Water Projection

Deep ocean, far from home shores. Power projection across the Indian Ocean Region (IOR), countering naval threats from peer competitors. Long-range cruise missiles, air defence, ASW.

INS Dunagiri

Tier 2 — Ocean Domain Awareness

Mapping, intelligence, navigational accuracy. Survey vessels provide the foundational knowledge layer that enables warships, submarines, and aircraft to operate safely. Critical for fleet planning and disaster relief.

INS Sanshodhak

III

Tier 3 — Littoral / Coastal Defence

Shallow coastal waters, ports, and near-shore zones. Protecting against submarine incursions in areas too cluttered for blue-water platforms. India's coastline of over 7,500 km demands dedicated ASW-SWC platforms.

INS Agray

Why Shallow Water ASW Matters

Shallow coastal waters are among the most difficult environments for submarine detection. The noise from fishing boats, merchant vessels, underwater geological features, and thermal layers creates a dense acoustic clutter that confuses sonar systems.

"Coastal waters are difficult places to find submarines. They are noisy, busy and cluttered. Fishing boats, merchant ships, seabed features and coastal activity can make submarine detection harder than in the open ocean. That is where ASW-SWCs such as Agray come in." — Senior Indian Navy Officer

This is precisely why the Arnala-class vessels like INS Agray are purpose-built with shallow-water sonar profiles and manoeuvrable hulls — they can operate in the very zones where Pakistan's Navy and potential adversaries may try to deploy diesel-electric submarines covertly near Indian ports and naval installations.

The Atmanirbhar Bharat Signal

The triple commissioning carries a powerful industrial policy message. All three ships:

Were built at a single Indian shipyard — GRSE, Kolkata
Carry over 75% indigenous content by value
Involve 200+ MSMEs in their supply chains — from electronics to propulsion components
Feature Indian-developed systems including the BrahMos missile (Indo-Russian joint venture), indigenous torpedoes, and sonar systems developed by DRDO

This represents a significant departure from India's historically import-heavy defence procurement — where over 60% of equipment was sourced from Russia, Israel, France, and the USA — towards a model of indigenous production with export potential.

UPSC Angle (GS-III / GS-II): The triple commissioning is a case study in defence indigenisation — linking Atmanirbhar Bharat policy to strategic autonomy. An examiner may ask: how does domestic defence production reduce strategic dependence? The answer involves supply chain security, avoiding export controls from foreign governments during conflict, and building a defence-industrial base that creates skilled jobs and technology spillovers.

Project 17A — India's Stealth Frigate Family

Ship Name	Pennant	Builder	Status
INS Nilgiri	F33	MDL, Mumbai	Commissioned 2024
INS Himgiri	F34	MDL, Mumbai	Commissioned 2024
INS Udaygiri	F35	MDL, Mumbai	Commissioned 2025
INS Taragiri	F34	GRSE, Kolkata	Commissioned 2025
INS Dunagiri	F36	GRSE, Kolkata	June 21, 2026 — Latest
INS Vindhyagiri	F37	GRSE, Kolkata	Under fitting out
INS Mahendragiri	F38	MDL, Mumbai	Under construction

The Geostrategic Context: Why Now?

The timing of this commissioning is deeply significant. India's maritime environment in 2026 is defined by:

Chinese naval expansion — the PLA Navy is the world's largest by vessel count and has increased submarine patrols in the Indian Ocean, necessitating India's ASW capability build-up.
Strait of Hormuz tensions — India imports nearly 85% of its crude oil through the IOR; survey vessels that map approach routes and frigates that escort trade are both strategically essential.
Pakistan's submarine force — Pakistan operates Agosta-class submarines (French design, now produced indigenously) that could threaten India's western ports; INS Agray's ASW-SWC role directly counters this threat.
HADR missions — Survey vessels like Sanshodhak provide oceanographic data used in disaster relief operations following cyclones, tsunamis, and flooding along India's coast.

UPSC Mains Angle

PYQ-Style Question: "India's maritime security is a function of its naval depth across three domains: open ocean, intelligence, and littoral. Analyse in the context of India's recent naval acquisitions."

A well-rounded answer should cover:

Blue Water vs. Brown Water Navy — distinction and India's evolving position
Project 17A — significance of stealth frigates in India's power projection
Ocean Domain Awareness (ODA) — role of survey vessels in maritime intelligence
ASW-SWC doctrine — why shallow water sub-hunting is the next frontier
Atmanirbhar Bharat in Defence — GRSE as a case study in indigenous shipbuilding; DPP 2020 and positive indigenisation lists
Indian Ocean Region (IOR) strategy — SAGAR doctrine, QUAD, bilateral naval agreements

Conclusion

The commissioning of INS Dunagiri, INS Sanshodhak, and INS Agray on a single day is far more than a ceremonial milestone. It is a strategic statement about where India's naval posture is heading — outward into the deep ocean with blue-water frigates, downward into the seabed with ocean intelligence platforms, and inward toward its coastline with specialised sub-hunters. Together, these three ships represent the most comprehensive single-day expansion of India's naval capability in decades — and a powerful signal of the country's defence-industrial maturity.