Explainer: Growing submarine activity in Indian Ocean and India’s counter capability

The Indian Navy is scheduled to commission its first indigenously developed Anti-Submarine Warfare Shallow Water Craft (ASW-SWC) on June 18, giving a fillip to its capability to counter underwater threats as the Indian Ocean Region (IOR) witnesses increasing naval sub-surface operations by a host of friendly as well as hostile countries.

Christened INS Arnala after the historic Arnala Fort near Vasai in Maharashtra, the ship is designed to have a formidable presence at sea and withstand the challenges of the maritime domain amidst emerging threats.

As many as 16 ships of the Arnala-class are being constructed by Garden Reach Shipbuilders and Engineers, Kolkata, in a public-private partnership with L&T Shipbuilders. These will replace the Navy’s ageing Abhay-class corvettes, inducted in 1989.

The IOR is no stranger to submarines which have traversed its waters since the Second World War era, During the Cold War, NATO and Soviet submarines routinely deployed to this area as part of their strategic deterrence and nuclear strike capability and of late more countries have acquired submarines.

While western submarines, including those equipped with ballistic missiles, continue to patrol the Indian Ocean or traverse it for various missions, there have been growing forays by Chinese submarines.

China has a fleet of seven nuclear-powered ballistic missile submarines, nine nuclear-powered attack submarines and 45 conventional submarines, and like other surface assets, these are used for power projection and intelligence gathering. While there have been reports in the past of Chinese submarines docking in Pakistan and Sri Lanka, most under-water missions would have remained under wraps.

Pakistan, with whom India had a limited military confrontation in May that included strikes on its territory by the Indian Navy, currently operates five French Agosta Class submarines and three Italian origin midget submarines. Eight Hangor Class submarines from China are expected to be commissioned between 2025-28.

In India’s immediate neighborhood, Bangladesh and Myanmar have two submarines each. Iran, Indonesia, Malaysia, Australia and South Africa are among other submarine operating nations along the Indian Ocean Rim.

While every submarine operating in the Indian Ocean may not be hostile, effective surveillance of naval activity is strategically important to develop a holistic picture of the maritime environment, identify friend and foe and coordinate operations.

Modern submarines run silent and deep, making detecting difficult. Anti-submarine warfare involves different tactics and employs surface warships, aircraft, submarines as well as underwater sensors and mines to deter, detect, track and destroy them.

Besides visual contact, sonar, radar, sonobuoys, signal intercept and magnetic anomaly detection are ways to detect the presence of a submarine. Operating these require a high level of training and skill. Different weapons like rockets, guided missiles, torpedoes, mortars and depth charges are used to disable or destroy them.

While the Indian Navy operates dedicated anti-submarine platforms like the Kamorta Class corvettes, all its major surface combatants like destroyers and frigates possess significant anti-submarine capabilities, such as torpedoes and rockets, in addition to their anti-surface and anti-air roles. Helicopters integral to these ships are also equipped with anti-submarine measures.

In addition to the air wings of India’s two aircraft carriers and shore-based assets like the Boeing P-8 and Dornier 228 aircraft, and drones, the Navy has a combat fleet of 17 attack submarines, 13 destroyers, 15 frigates and 19 corvettes.

Platforms such as INS Arnala are primarily meant for operations closer to the shore and in shallow waters which are not suitable for operations by heavier vessels like frigates. Designed for a range of anti-submarine operations, Arnala is equipped for sub-surface surveillance, search and rescue, mine laying and low-intensity maritime operations.

Besides a range of sensors and advanced combat management system enabling it to operate in a multi-dimensional network centric environment, its armament includes torpedoes, anti-submarine rockets and guns.

The 77.6 metres-long warship has a gross tonnage of about 1,500 tonnes, and is the largest Indian naval warship to use a diesel engine—waterjet combination. In comparison, INS Surat and INS Nilgiri, the latest Indian destroyer and frigate, have a displacement of 7,400 tonnes and 6,670 tonnes, respectively, and are 163 meters and 149 meters long.

Arnala is also another feather in India’s well established military ship-building ecosystem that has manufactured vessels from small unarmed support ships to giant aircraft carriers.

The warship incorporates more than 80 per cent indigenous content, and integrates advanced systems from Indian firms including Bharat Electronics Limited, Larsen and Toubro, Mahindra Defence and MEIL. The project has also engaged over 55 micro, small, and medium enterprises (MSMEs), promoting domestic industry and generating related economic activity.