Cochin Shipyard Ltd launched the Machilipatnam (BY 529), the seventh of eight Mahe class Anti-Submarine Warfare Shallow Water Craft for the Indian Navy, on July 29, 2026 at its Kochi facility. The vessel has over 80% indigenous content and is named after the historic port city of Machilipatnam in Andhra Pradesh. It is equipped for underwater surveillance, anti-submarine warfare operations, low intensity maritime operations, and mine warfare.
The ASW SWC Project: Strengthening India’s Littoral Defence
The Anti-Submarine Warfare Shallow Water Craft (ASW SWC) programme is one of the Indian Navy’s most significant indigenous warship building efforts. In April 2019, the Ministry of Defence signed two contracts worth a combined ₹12,622 crore with Cochin Shipyard Ltd (CSL) and Garden Reach Shipbuilders and Engineers (GRSE) for the construction of 16 warships, eight each. The vessels are designed to replace the Abhay class corvettes, which were commissioned between 1989 and 1991 and have served at the end of their operational lives.
The ships built by CSL are designated as the Mahe class, while those built by GRSE are called the Arnala class. While both classes share comparable specifications, they differ in design details such as the placement of the 30 mm gun deck, the main mast, funnel, and torpedo launcher arrangements. The GRSE vessels were designed in-house by GRSE’s own team, while the Mahe class ships were designed by Kochi-based Smart Engineering and Design Solutions (SEDS) making it the first private Indian firm to design warships for the Navy. Finland-based Surma provided signature management software and design inputs for combat survivability.
The Arnala class ships (built by GRSE in partnership with Larsen and Toubro at Kattupalli, Chennai) are ahead in deliveries. The first ship of that class, INS Arnala, was commissioned in June 2025, followed by INS Androth in October 2025, INS Anjadip in February 2026, and INS Agray in June 2026. Four more Arnala class vessels are at various stages of construction.
On the CSL side, INS Mahe was commissioned in November 2025, and INS Malvan was commissioned in July 2026 at Karwar Naval Base. Machilipatnam (BY 529) is the seventh of the eight CSL vessels. The keel for this vessel was laid on January 29, 2025. The eighth and final vessel (BY 530) had its keel laid in May 2025 and is expected to be delivered by June 2028.
Mahe Class: Specifications and Capabilities
The Mahe class vessels are corvettes designed for operations in littoral (coastal) waters within 200 nautical miles of the coastline. Each ship measures 78 metres in length with a beam of 11.36 metres and a draught of just 2.7 metres, allowing it to operate in shallow waters where larger warships cannot venture.
The ships displace about 900 to 1,100 tonnes and can reach a maximum speed of 25 knots with an endurance of 1,800 nautical miles at 14 knots. They are powered by three marine diesel engines coupled with waterjet propulsion, making them the largest Indian warships to use a diesel engine waterjet combination. This propulsion system allows them to sprint quickly in short bursts to track detected submarines. Each vessel carries a complement of 57 personnel, including 7 officers.
The class is designed and constructed as per the Classification Rules of Det Norske Veritas (DNV), a Norwegian classification society.
Armament and Sensor Suite
The warships pack a powerful anti-submarine punch. Their weapons include a RBU-6000 anti-submarine rocket launcher mounted forward, two triple 324 mm lightweight torpedo launchers that fire DRDO’s Advanced Light Weight Torpedo (ALWT), and mine laying rails for deploying anti-submarine mines on the seabed. For surface defence, they carry a 30 mm naval surface gun and two 12.7 mm Stabilised Remote Controlled Guns made by Ordnance Factory Tiruchirappalli in collaboration with Elbit Systems.
On the sensor side, the ships are equipped with the Abhay hull mounted sonar (HMS) developed by DRDO’s Naval Physical and Oceanographic Laboratory (NPOL) and manufactured by Bharat Electronics Limited (BEL). They also carry a Low Frequency Variable Depth Sonar (LFVDS) sourced from a joint venture between Indian firm CFF Fluid Control and German company Atlas Elektronik. The combination of these sonars allows the vessel to detect, track, and classify submarines in both shallow and deep waters. The ships also feature Electronic Support Measures (ESM), Electronics Intelligence (ELINT), and an Integrated ASW Complex for fire control solutions.
Machilipatnam: A Historic Port City
The vessel draws its name from Machilipatnam, a historic port city located in the Krishna district of Andhra Pradesh at the mouth of the Krishna River on the Bay of Bengal. Known historically as Masulipatnam or Masula, the city was a thriving maritime trade hub as early as the 1st century AD and reached its peak of prominence between the 16th and 18th centuries under the Vijayanagara Empire.
Machilipatnam was the first British trading settlement on the Bay of Bengal, established in 1611 by the East India Company. Later, the Dutch and the French also set up trading posts here, recognising its strategic location along India’s eastern seaboard. The city is also famous for Kalamkari, a traditional hand-painted or block-printed cotton textile art form that flourished under the patronage of international traders.
Today, a greenfield deep sea port is under development at Manginapudi near Machilipatnam, with operations expected to commence by the end of 2026. The port is expected to handle coal, pharma products, cement, fertilisers, and container traffic, boosting connectivity for the landlocked regions of Andhra Pradesh.
Significance for India’s Maritime Security
The induction of ASW SWC vessels addresses a critical gap in India’s coastal defence architecture. The Indian Ocean Region has seen a steady build-up of submarine capabilities among neighbouring nations, including conventional submarines, midget submarines, and uncrewed underwater vessels. In this context, the shallow water craft act as a dedicated anti-submarine screen for India’s coastline, naval bases, and commercial ports.
These vessels are designed to operate in the littoral zone, the shallow waters close to the shore where larger frigates and destroyers cannot manoeuvre effectively. Their primary mission is search and attack unit (SAU) operations: detecting hostile submarines and engaging them with torpedoes and rocket launchers before they can threaten Indian assets. They can also coordinate with maritime patrol aircraft such as the P-8I Poseidon for wide area anti-submarine coverage.
Beyond ASW, the ships can perform Low Intensity Maritime Operations (LIMO) such as anti-piracy patrols, search and rescue missions, and mine warfare including laying mines to protect vital approaches to harbours.
Aatmanirbhar Bharat in Defence Shipbuilding
With over 80% indigenous content, the Machilipatnam and other Mahe class vessels showcase the growing maturity of India’s private defence shipbuilding ecosystem. Key indigenous suppliers include Bharat Electronics Limited (sonars and combat systems), Mahindra Defence (torpedo decoy launchers), Larsen and Toubro (torpedo launchers and ASW rocket launchers), and the Ordnance Factory Board (gun systems). The design itself was provided by a Kochi-based private firm.
Cochin Shipyard Ltd, India’s largest shipbuilding and maintenance facility, was incorporated on April 29, 1972 and is headquartered in Kochi, Kerala. It is a Miniratna central public sector enterprise under the Ministry of Ports, Shipping and Waterways. CSL built India’s first indigenous aircraft carrier, INS Vikrant, which was commissioned in September 2022. In April 2024, it signed a Master Ship Repair Agreement (MSRA) with the US Navy for repairs of its Military Sealift Command vessels, becoming the third Indian shipyard to do so.
Key Takeaways
- Machilipatnam (BY 529), the seventh of eight Mahe class ASW SWC vessels, was launched at Cochin Shipyard Ltd on July 29, 2026.
- The vessel has over 80% indigenous content and is equipped for underwater surveillance, anti-submarine warfare, LIMO, and mine warfare.
- The ASW SWC programme involves 16 warships (8 by CSL, 8 by GRSE) under contracts worth ₹12,622 crore signed in April 2019.
- The Mahe class vessels are 78 metres long, displace 900-1,100 tonnes, reach 25 knots, and carry a crew of 57.
- The ships carry RBU-6000 rockets, 324 mm lightweight torpedoes, Abhay hull mounted sonar by DRDO/BEL, and a Low Frequency Variable Depth Sonar.
- Cochin Shipyard Ltd, established in 1972 and headquartered in Kochi, is India’s largest shipbuilding and maintenance facility and built the indigenous aircraft carrier INS Vikrant.
