Naval Systems and Maritime Technology

Why a warship is a harder indigenisation problem than an aircraft

A modern warship is not one system but dozens layered together: hull, propulsion, radar, weapons, sonar, and command systems, each sourced or built and then integrated into one platform that has to work as a whole for decades at sea. That is why naval indigenisation is treated as a distinct achievement from indigenising a single aircraft or missile, and why the specific platforms below are each treated as milestones.

INS Vikrant: the aircraft carrier

INS Vikrant is India's first indigenously designed and built aircraft carrier, designed by the Indian Navy's own Warship Design Bureau and constructed at Cochin Shipyard Limited. Its significance is less about any single piece of technology and more about what building a carrier at home demonstrates: an aircraft carrier draws on the most demanding parts of shipbuilding, metallurgy, propulsion and systems integration at once, so a country that can build one credibly has a mature domestic shipbuilding base across all of those fields simultaneously.

Project 17A: the frigates

Project 17A produces the Nilgiri-class frigates, a major advance over the earlier Shivalik class, incorporating stealth features that reduce the ship's radar cross-section, the same concept covered for aircraft elsewhere on this site. The class carries roughly 75% indigenous content and has drawn on more than 200 Indian MSMEs in its supply chain, which is the point worth remembering: indigenisation here is measured not just in the finished ship but in how much of its supply chain is domestic.

P-75(I): the submarines

P-75(I) is the Ministry of Defence's programme for constructing six new submarines for the Indian Navy, procured as a Strategic Partnership project, meaning an Indian shipyard builds them in partnership with a foreign original equipment manufacturer that transfers the underlying technology. This model, building at home with transferred technology rather than importing complete platforms, is itself a distinct indigenisation strategy worth telling apart from the fully domestic design-and-build approach used for INS Vikrant.

Sonar: radar's underwater equivalent, with one crucial difference

Radar does not work underwater, because radio waves are absorbed by seawater within a short distance. Sonar (Sound Navigation and Ranging) solves the same detection problem using sound instead, and the same active-versus-passive split that governs radar detection reappears here, with a twist that matters specifically for submarines.

Active sonar transmits an acoustic pulse and listens for the echo, exactly like radar, which lets it measure range and bearing directly. The problem is that transmitting reveals the transmitter's own position. Active sonar is therefore used by fast, already-visible platforms such as aircraft, helicopters and surface ships, but a submarine, whose entire value lies in staying hidden, uses it only rarely.

Passive sonar emits nothing. It only listens, for the engine noise, propeller cavitation and other sounds a target vessel inevitably makes. This is what lets a submarine hunt while remaining silent and undetected itself, at the cost of being unable to measure range from a single listening point.

India's indigenous sonar programme is led by DRDO's Naval Physical and Oceanographic Laboratory (NPOL) in Kochi, with production by Bharat Electronics Limited. HUMSA (Hull-Mounted Sonar Array) is its indigenous medium-range sonar, operating in both active and passive modes across dual frequency bands, optimised for both shallow and deep water.

The pace, as a single fact worth holding

Since 2014, Indian shipyards have delivered more than 40 indigenous warships and submarines to the Navy, averaging roughly one new platform every 40 days. That figure is a cleaner way to demonstrate the scale of naval indigenisation than any single ship, and it is exactly the kind of aggregate statistic a Prelims question likes to test.

Quick revision points

• A warship integrates dozens of separate systems, hull, propulsion, radar, weapons, sonar, at once, which is why naval indigenisation is treated as a harder and more significant achievement than a single aircraft or missile.
• INS Vikrant: India's first indigenously designed and built aircraft carrier, designed by the Navy's own Warship Design Bureau, built at Cochin Shipyard Limited.
• Project 17A / Nilgiri-class frigates: stealth features reducing radar cross-section, roughly 75% indigenous content, over 200 MSMEs in the supply chain.
• P-75(I): six submarines under a Strategic Partnership model, built in India with technology transferred from a foreign OEM, distinct from the fully domestic design-build approach.
• Since 2014, over 40 indigenous warships and submarines delivered, averaging one new platform roughly every 40 days.
• Sonar is radar's underwater equivalent, needed because radio waves do not travel far in seawater. Active sonar (transmit and listen for the echo) gives range and bearing but reveals the transmitter, so it is used by ships and aircraft, rarely by submarines. Passive sonar (listen only) lets a submarine hunt while staying silent, at the cost of not directly measuring range. India's HUMSA, from DRDO's NPOL, Kochi, operates in both modes.