Prime Minister Narendra Modi on Sunday presided over commissioning of three versatile and strategically diverse Indian Naval Ships at Kolkata, including one that can fight far out at sea, one that can map the sea, and one that can hunt submarines close to the coast.In the last yearp-and-a-half, the Indian Navy has seen a steady run of new inductions with over a dozen seagoing platforms having been commissioned since January 2025 — from destroyers and frigates to submarines, survey ships, anti-submarine craft and varied specialist support vessels.The three vessels — Brahmos-armed stealth frigate INS Dunagiri, deep water survey vessel INS Sanshodhak, and submarine hunter Arnala-class Anti-Submarine Warfare Shallow Water Craft (ASW SWC) INS Agray — have been built by Garden Reach Shipbuilders & Engineers (GRSE) in Kolkata. The Ministry of Defence has said that the three together have more than 75 per cent indigenous content and involve over 200 MSMEs.Here is a closer look at why this ‘tri-commissioning’ — as the navy has called it — is significant and why these three platforms are crucial.INS Dunagiri: The largest and most heavily armed of the three is INS Dunagiri. It is a frigate, which is a medium-to-large warship. In simple terms, a frigate is smaller than a destroyer but large enough to operate far from the coast, escort bigger ships, launch missiles, defend itself against adversary aircraft and missiles and hunt submarines. Dunagiri is about 149 metres long, roughly one-and-a-half football fields, and displaces about 6,670 tonnes. It can sail at about 28 knots, or nearly 52 kilometers per hour. It is part of the Navy’s Project 17A — the Nilgiri-class stealth frigates.Project 17A is the Navy’s programme to build a new generation of stealth guided-missile frigates in India. The ‘stealth’ here does not connote complete invisibility, but means that it is harder to detect on radar and other sensors. This guided-missile ship carries modern missiles that can be directed towards targets at sea or in the air. Dunagiri carries weapons such as BrahMos surface-to-surface missiles and a medium-range surface-to-air missile (MRSAM) system, along with sensors including Multi-Function Surveillance, Track And Guidance Radar (MFSTAR), sonar, electronic warfare systems and anti-submarine weapons.Project 17A is a follow-on of the Shivalik class or Project 17 frigates active in service. “At the strategic level, these multi-mission frigates are capable of operating in a ‘blue water’ environment — deep sea far from shore — dealing with both conventional and non-conventional threats.” A serving Navy officer said. The newly designed class of ships are also being built using ‘integrated construction’ philosophy, which involves extensive pre-outfitting at the block stages to reduce the overall building periods. These ships can play a crucial role in anti surface warfare, anti-air warfare and anti submarine warfare, with their versatile weapons and capabilities. Other vessels in the class are INS Nigiri, Himgiri, Taragiri, Udaygiri and Vindhyagiri.Story continues below this adINS Sanshodhak: The second vessel being commissioned, INS Sanshodhak, is not meant to fight in the same way. It is a Survey Vessel — Large (SVL). Its job is to measure and map the sea: the depth of waters, seabed features, approach channels to ports, navigational routes, and oceanographic data. Sanshodhak is about 110 metres long, roughly the length of a football field, and has a displacement of around 3,300 tonnes. It has a top speed of about 18 knots, or around 33 kmph. It is equipped with systems such as autonomous underwater vehicles, remotely operated vehicles and multi-beam echo sounders. These help the ship collect data from the surface and underwater.A survey ship may appear less dramatic than a missile-armed frigate, but it performs a foundational military role. “Warships and submarines do not operate in an empty blue space. They move through waters shaped by depth, seabed features, currents, reefs, channels, ports, underwater slopes and coastal clutter. Knowing this environment helps ships move safely, submarines plan routes, ports update charts, and forces prepare for operations. It also supports civilian needs such as safe shipping, disaster relief, ocean research and coastal development.” said a Navy officer who has served on survey ships.Sanshodhak is the last ship of the Sandhayak-class of SVLs. The contract for four Survey Vessel (Large) ships was signed in October 2018. The previous ships of the same class are INS Sandhayak, INS Nirdeshak and INS Ikshak were commissioned in Feb 2024, Dec 2024 and Nov 2025.INS Agray: The third vessel, INS Agray, is the smallest of the three but has a highly specialised role. It is an Anti-Submarine Warfare Shallow Water Craft. Put simply, it is a submarine-hunter designed for coastal waters.Story continues below this adAgray belongs to the Arnala-class. This is a class of smaller warships built specifically to detect and attack submarines in shallow waters near the coast, ports, naval bases and important sea approaches. Agray is about 77 metres long, displaces around 900 tonnes, and can reach about 25 knots, or roughly 46 kilometers per hour. It carries lightweight torpedoes, indigenous anti-submarine rocket launchers and sonar systems. Interestingly these are the largest Indian Naval warships propelled by waterjets.The word often used for coastal waters is littoral. It simply means the waters close to the shore. “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-SWCc such as Agray come in. They are smaller, faster, and designed for coastal anti-submarine work. Their job is to protect approaches to ports, naval bases and coastal routes from underwater threats.” said an officer. This matters because submarines are among the most difficult military platforms to detect. A Navy that wants to secure its coastline cannot rely only on large destroyers and frigates. It also needs smaller, specialised hunters for near-shore waters. In December 2013, the Defence Acquisition Council (DAC) gave a nod for the procurement of sixteen ASW SWC vessels at a cost of over Rs 13 thousand crores.What is the larger message behind commissioning them together?The importance of Sunday’s ceremony is that the three ships add three different capabilities at once. In simpler terms, the ceremony brings together a frontline fighter, a sea-mapping ship, and a specialised submarine hunter. “Together, they reflect the Navy’s balanced approach to capability development, strengthening blue-water operations, enhancing maritime domain awareness, and securing coastal waters against evolving threats.” The Navy has said.The Indian Ocean is becoming more crowded and contested. China has increased its naval presence, Pakistan continues to operate various platforms including submarines, and India’s own maritime responsibilities now stretch across the Arabian Sea, Bay of Bengal, island territories and more importantly the wider Indian Ocean and the Indo Pacific. “Triple commissioning should not be seen merely as three more ships joining the fleet. It is a sign of how the Navy is building capability in layers: big warships for distant operations, survey ships to understand the sea, and smaller submarine-hunters to guard coastal waters.” said an officer.Story continues below this adIt is also an industrial signal. That three different kinds of ships, with different missions and technologies, can be built domestically and commissioned together shows the growing maturity of India’s naval shipbuilding ecosystem. The moment, therefore, is not just about Dunagiri, Sanshodhak and Agray individually. It is about what they represent together: a Navy that wants to fight better, see better, and defend its near seas better.