India Commissions INS Arnala to Track Pakistani Submarine Threats in Shallow Seas

Defence affairs

The induction of INS Arnala comes amid growing maritime tensions with Pakistan, whose naval strategy—hampered by limited surface combatant capability—relies heavily on undersea warfare to pose asymmetric threats to India’s sea lines of communication, ports, and offshore infrastructure.

In a decisive move to counter Pakistan’s expanding submarine fleet in the Indian Ocean, the Indian Navy has formally commissioned INS Arnala, its first indigenously developed Anti-Submarine Warfare Shallow Water Craft (ASW-SWC), with a clear mission to dominate and deny adversary access to India’s littoral waters.

Commissioned on June 18 at the Naval Dockyard in Visakhapatnam by Chief of Defence Staff General Anil Chauhan, the 77-metre-long INS Arnala marks a pivotal milestone in India’s coastal defence doctrine, which is increasingly focused on countering submarine threats in complex, shallow-water environments.

With the operational deployment of Agosta-90B submarines, some retrofitted with Air Independent Propulsion (AIP), and the expected induction of eight advanced Hangor-class submarines from China, Islamabad’s undersea fleet represents a growing challenge to India’s maritime dominance, particularly in the Arabian Sea.

Indian intelligence reports indicate that Pakistani submarines may attempt to penetrate shallow coastal zones—some only 50 to 60 metres deep—to acquire torpedo firing positions against high-value Indian targets, including naval bases, commercial ports, and carrier battle groups operating nearshore.

INS Arnala has been designed precisely to counter this form of low-visibility intrusion, boasting a diesel engine-waterjet propulsion system that delivers high speed and unmatched manoeuvrability in confined and shallow maritime spaces.

With a displacement of 1,490 tonnes, Arnala is the largest Indian naval platform to be equipped with this propulsion architecture, giving it a unique edge over conventional propeller-driven ships when operating in tight, nearshore geographies where adversary submarines might lurk.

More importantly, Arnala is equipped with a sophisticated suite of indigenised underwater sensors, including a Variable Depth Sonar (VDS) system jointly developed by India’s CFF Fluid Control Ltd and Germany’s Atlas Elektronik—enabling the vessel to detect submerged targets operating beneath thermal layers that shield them from standard sonar detection.

The platform also integrates advanced Low-Frequency Variable Depth Sonar (LFVDS), Underwater Acoustic Communication Systems (UWACS), and mine-laying capability—allowing it to conduct not only ASW but also low-intensity maritime operations, underwater surveillance, and defensive interdictions in congested coastal zones.

Indian defence planners stress that unlike destroyers and frigates—designed for open-ocean multi-domain warfare—Arnala-class warships are built for defensive ASW operations from the outset, focused on eliminating submarine threats in chokepoints, harbours, and along the 7,500-kilometre-long Indian coastline.