Armed with torpedoes, sonar and rockets: Navy inducts submarine hunter INS Mangrol

INS Mangrol is an Anti-Submarine Warfare Shallow Water Craft, or ASW-SWC. It was built by Cochin Shipyard Limited in Kochi and commissioned at the Naval Dockyard in Mumbai. Its main purpose is to detect and counter submarine threats in coastal and shallow waters. These areas can restrict larger warships.

Commissioning marks the vessel’s formal entry into the Indian Navy. It becomes part of the Navy’s operational fleet, rather than remaining a ship under construction, testing, or delivery. Mangrol carries sonar, torpedoes, rockets, mines, and torpedo decoys for several maritime missions.

Mangrol is the third of eight Mahe-class vessels planned by Cochin Shipyard, after Mahe and Malvan. With more than 80% indigenous content, its induction also demonstrates the growing capability of India’s domestic warship industry. It is named after Mangrol, a coastal town in Gujarat.

Submarines operating near India’s coast can hide, manoeuvre, or approach important ports through confined waters. Larger warships may face operational limits in these areas because of their size and deeper underwater profile. Mangrol is designed specifically for this environment, where close-range surveillance and quick movement matter.

The craft has a draught of only 2.7 metres and uses three diesel engines linked to waterjets. This arrangement gives it high manoeuvrability in shallow water. Its Abhay hull-mounted sonar helps search underwater, while lightweight torpedoes, rockets, mines, and decoys support attack and protection.

The wider Mahe-class mission includes anti-submarine warfare, underwater surveillance, mine warfare, and low-intensity maritime operations. Mangrol can also work with maritime patrol aircraft, helicopters, and other warships. This combination gives the Navy a focused tool for monitoring and responding to underwater threats in the littoral zone.

The Mahe-class craft is compact but capable. The class has a displacement of 896 to 1,100 tonnes, a length of 78 metres, a beam of 11.36 metres, and a draught of 2.7 metres. These dimensions suit its work in coastal and shallow waters, where larger ships may face limits.

Its three diesel engines drive waterjets, allowing a maximum speed of 25 knots, or 46 kilometres per hour. At 14 knots, or 26 kilometres per hour, it has a range of 1,800 nautical miles, equal to about 3,300 kilometres. This gives it useful reach for patrol and surveillance missions.

The class has an endurance of 14 days. That allows a craft to remain deployed for extended coastal operations without returning immediately for replenishment. Its size, speed, range, and endurance balance local manoeuvrability with sustained maritime presence.

Mangrol’s Abhay hull-mounted sonar is the main underwater search tool. Sonar uses sound underwater to detect and track possible submarine contacts. Once a threat is identified, the ship’s weapons provide several response options suited to different situations and distances.

Lightweight torpedoes, fired through triple 324 mm torpedo tubes on each side, can attack submarines. The forward RBU-6000 rocket launcher adds an anti-submarine strike option. Rails for anti-submarine mines support mine warfare and can help shape where underwater vessels move. These systems give the craft both search-and-attack capability and area-control options.

The Maareech Advanced Torpedo Decoy System protects the ship from hostile torpedoes. Decoy launchers supplied by Mahindra Defence Systems form part of an integrated anti-submarine defence suite. Mangrol can coordinate with aircraft, helicopters, and other warships to extend surveillance and combine responses.

A larger warship may carry more equipment, but its size and underwater draught can restrict operations near coasts, ports, and shallow approaches. A smaller craft can enter tighter waters and maintain closer contact with possible underwater threats. That makes it useful for local surveillance and rapid response.

Mangrol’s draught is 2.7 metres, and three diesel engines drive waterjets. The waterjets give the craft high manoeuvrability, while its maximum speed of 25 knots supports quick movement between contacts or patrol areas. Its sonar and anti-submarine weapons can then be used within the shallow-water environment.

The craft also carries a 30 mm naval gun and two 12.7 mm stabilised remote-controlled guns. These provide surface-warship capability and allow independent operations in contested littoral zones. Mangrol is therefore not simply a smaller submarine hunter; it is a flexible coastal platform for surveillance, mine warfare, and low-intensity maritime operations.

The induction of Mangrol expands India’s ability to watch and respond to underwater threats near the coast. Ports, harbours, and maritime approaches are important access points, but they can also contain shallow, confined waters. Specialised ASW craft can patrol these areas and support protection where larger vessels face limits.

The broader programme includes 16 vessels in two classes. Garden Reach Shipbuilders and Engineers is building eight Arnala-class ships, while Cochin Shipyard is building eight Mahe-class ships. They are designed for subsurface surveillance, search-and-attack missions, and coordinated operations with naval aircraft. Their secondary roles include minelaying and search and rescue.

Mangrol can work with maritime patrol aircraft, helicopters, and other warships. This creates a layered response rather than relying on one platform. Domestic suppliers include Bharat Electronics, Mahindra Defence, and Larsen & Toubro. The final hull of the 16-ship project is expected by June 2028, expanding the planned coastal force further.

Sonar means sound navigation and ranging. It is a system for detecting and locating objects underwater, where visibility is often limited. The Abhay hull-mounted sonar on Mangrol is intended to help search for underwater contacts, including possible submarines.

The basic physics is straightforward. A sonar system sends a sound pulse through the water. When the pulse meets an object, some sound reflects back as an echo. By measuring the echo’s travel time, the system can estimate the object’s distance. Changes in the returning sound can also help identify movement or other characteristics.

Sonar can be active or passive. Active sonar sends a pulse and listens for echoes; passive sonar listens to sounds produced by an object. The article identifies Mangrol’s hull-mounted sonar but does not specify its operating mode. In practice, sonar supports the ship’s torpedoes, rockets, mines, and coordinated operations with aircraft and other warships.