Cochin Shipyard Ltd (CSL) delivered Mangrol, the third Anti-Submarine Warfare Shallow Water Craft (ASW SWC) of the Mahe class, to the Indian Navy on 21 August 2026 in Kochi. With more than 80 percent indigenous content, the 78-metre corvette is built to hunt submarines in shallow coastal waters where larger destroyers and frigates cannot operate effectively. Its induction strengthens India’s coastal surveillance, mine warfare and low-intensity maritime operations at a time when underwater threats in the Indian Ocean are steadily increasing.
What Is Mangrol and Why Is It Important?
Mangrol is the third ship of the eight Mahe-class Anti-Submarine Warfare Shallow Water Craft (ASW SWC) being built by Cochin Shipyard Ltd (CSL) in Kochi for the Indian Navy. It was delivered on 21 August 2026 after the first two ships of the class, INS Mahe (P80) and INS Malwan (P81), which were launched together with Mangrol on 30 November 2023. Mahe was delivered on 23 October 2025 and commissioned on 24 November 2025 in Mumbai, while Malwan was delivered on 31 March 2026 and commissioned at Karwar in July 2026.
The vessel is named after the coastal town and fishing harbour of Mangrol in Junagadh district, Gujarat, on the Arabian Sea coast. The name continues the legacy of the earlier INS Mangrol, a minesweeper that served the Navy until its decommissioning in 2004. As a shallow water craft, Mangrol is designed to operate within 200 nautical miles of the coast, in shallow and confined waters where conventional large warships have limited manoeuvrability and sonar performance is degraded by noise, temperature layers and seabed interference.
Its core mandate is Anti-Submarine Warfare (ASW), which is the branch of naval warfare that finds, tracks and destroys enemy submarines using ships, aircraft and other submarines. Mangrol adds a much needed layer of close-to-coast ASW capability. It performs full scale underwater surveillance, detects and prosecutes subsurface targets, and coordinates its operations with naval aircraft such as P-8I maritime patrol aircraft and helicopters. In its secondary roles, it conducts Low-Intensity Maritime Operations (LIMO), mine laying, search and rescue, coastal patrol and interception of intruding craft.
The 16-Ship Shallow Water Programme: Mahe Class and Arnala Class
The ASW SWC programme was conceived to replace the ageing Abhay-class corvettes, which were customised variants of the Soviet Pauk class commissioned between 1989 and 1991. These older ships had become inadequate for modern shallow water surveillance needs. In December 2013, the Defence Acquisition Council (DAC), the main acquisition body of the Ministry of Defence chaired by the Defence Minister, cleared the procurement of 16 ASW Shallow Water Craft at an estimated cost of ₹13,440 crore.
After a tender issued in June 2014 under the Buy and Make India category, Cochin Shipyard Ltd (CSL) and Garden Reach Shipbuilders and Engineers (GRSE), Kolkata emerged as the lowest bidders. On 29 April 2019, the Ministry of Defence signed a contract worth ₹6,311.32 crore with GRSE and on 30 April 2019 a similar contract worth ₹6,311.32 crore with CSL, for eight ships each. The total programme cost of ₹12,622 crore works out to about ₹789 crore per ship in 2020 prices. Both contracts required delivery of the first ship within 42 months and the remaining ships at a rate of two per year, with completion within 84 months.
The 16 ships are being built in two subclasses with minor design differences but a common operational philosophy:
| Feature | Mahe Class (CSL, Kochi) | Arnala Class (GRSE and L&T Kattupalli) |
|---|---|---|
| Number of ships | 8 | 8 |
| Fleet assignment | Western Naval Command | Eastern Naval Command |
| Gross tonnage and displacement | About 900 to 1,100 tonnes, 78 metres long | About 900 tonnes, 77.6 metres long |
| Lead ship | INS Mahe (P80), commissioned 24 Nov 2025 | INS Arnala (P68), commissioned 18 June 2025 |
| Design partners | Smart Engineering and Design Solutions (SEDS), Kochi and Surma, Finland for signature management | GRSE with Larsen and Toubro Kattupalli partnership |
| Classification | Built to Det Norske Veritas (DNV) rules | Built to Indian Register of Shipping (IRS) Naval Rules 2015 |
Steel cutting for the CSL ships began on 1 December 2020 for yard number BY 523 (Mahe), with keel laying of Mahe on 30 August 2022. The first three CSL ships Mahe, Malwan and Mangrol were launched together on 30 November 2023, followed by Malpe and Mulki in December 2023 and later vessels Magdala, Machilipatnam and P87. For GRSE, the lead ship Arnala was launched on 20 December 2022 and has already been commissioned, while Androth and Agray have also entered service. With Mangrol’s delivery, seven of the 16 shallow water craft have now been handed over across both yards, marking the most productive phase of the programme. All 16 ships are planned to be in service by 2028.
Inside Mangrol: Design, Sensors and Weapons
Mangrol is classified as a corvette, which is a small warship larger than a patrol vessel but smaller than a frigate, optimized for coastal operations. It reflects the Make in India and Aatmanirbhar Bharat (Self-Reliant India) thrust, with indigenous systems contributing the bulk of its capability.
Hull, Propulsion and Stealth Features
The ship measures 78 metres in length, 11.26 metres in beam and has a very shallow draught of 2.7 metres, which allows it to patrol close to the coastline, enter harbours and navigate channels that are inaccessible to deeper draught vessels. Its full load displacement is between 896 and 1,100 tonnes and it carries a complement of 57 personnel, including 7 officers and 50 sailors. The hull is built to classification rules of Det Norske Veritas (DNV), an international standards body headquartered in Norway, and is designed with a low radar cross section, low acoustic signature and low infrared signature.
Mangrol is the largest warship of the Indian Navy propelled by a diesel engine-waterjet combination. It is fitted with three marine diesel engines, each coupled to a waterjet, together developing about 6 MW of power. Waterjet propulsion, where water is drawn in and expelled at high pressure to push the ship, makes it particularly suitable for shallow waters because it has no exposed propellers, gives high manoeuvrability, quick acceleration and deceleration, tight turning radius and reduced underwater noise. The ship reaches a maximum speed of 25 knots (about 46 km per hour), has a range of 1,800 nautical miles at a cruising speed of 14 knots, and an endurance of 14 days with distributed automation systems managing propulsion, power and damage control.
Stealth and survivability features were shaped with input from Smart Engineering and Design Solutions (SEDS), a Kochi-based firm that created the basic design and thereby became the first private Indian firm to design warships for the Navy, and Finland-based Surma, which supplied signature management software and combat survivability inputs.
Surveillance Systems and Weapon Suite
For its primary underwater role, Mangrol integrates a network of sensors tied together by a Combat Management System (CMS) and the Integrated Anti-Submarine Warfare Defence Suite (IADS).
Its sonar package includes the Abhay compact Hull-Mounted Sonar (HMS), developed by the Naval Physical and Oceanographic Laboratory (NPOL) in Kochi, a laboratory of the Defence Research and Development Organisation (DRDO) established in 1958, and manufactured by Bharat Electronics Limited (BEL). Abhay is an active-cum-passive system that can detect, classify and track sub-surface and surface targets and is designed specifically for small warships, replacing legacy Russian sonars earlier limited to frigates and destroyers. It is complemented by a Low Frequency Variable Depth Sonar (LFVDS) obtained through a joint venture of CFF Fluid Control Ltd, India and German firm Atlas Elektronik, a division of ThyssenKrupp Marine Systems, which can be lowered to different depths to overcome temperature and salinity layers in shallow waters. An Underwater Acoustic Communication System (UWACS) and a towed LFVDS further improve detection in complex littoral acoustics. For surface surveillance it carries a multi-function radar, Electronic Support Measures (ESM) and Electronic Intelligence (ELINT) for intercepting enemy emissions, together with satellite communication, Integrated Platform Management System, Automatic Power Management System and Battle Damage Control System.
The weapons package is tailored for shallow water kills. At the bow it carries a RBU-6000 anti-submarine rocket launcher, a Soviet-origin system now manufactured in India for rapid firing of depth rockets. On the port and starboard sides it has two triple 324 mm lightweight torpedo tubes firing the Advanced Light Weight Torpedo (ALWT) or Torpedo Advanced Light (TAL), an electrically propelled self-homing torpedo developed by Naval Science and Technological Laboratory (NSTL), Visakhapatnam, weighing about 220 kg with operating depth up to 450 metres and manufactured by Bharat Dynamics Limited. Behind the torpedo tubes are two Mahindra Defence Systems supplied torpedo decoy launching systems that form part of the decoy suite. The stern is fitted with mine laying rails for deploying anti-submarine mines to deny access to harbour approaches and sea lanes. For self defence the ship uses one 30 mm Naval Surface Gun (NSG) developed by GRSE and integrated with an electro-optical fire control system, and two 12.7 mm M2 Stabilized Remote Controlled Guns (SRCG) made by Ordnance Factory Tiruchirappalli in collaboration with Elbit Systems for close range surface and aerial threats.
Navigation aids, integrated bridge system, expandable bathythermograph, automatic identification system, echo sounder and rigid inflatable boats for boarding and search and rescue complete the outfit.
Why Shallow Water Anti-Submarine Warfare Matters for India
India has a coastline of about 7,516 km, expanding to 11,098 km when island territories are counted, and more than 200 major and minor ports that handle over 90 percent of trade by volume. Much of the threat from conventional diesel-electric submarines, midget submarines and unmanned underwater vehicles occurs in the littoral zone close to shore, near naval bases, commercial harbours and narrow channels. In these shallow waters, the acoustic conditions are noisy, sound bends due to temperature layers, and large ocean-going warships with deep hulls and large propellers cannot operate effectively or risk detection.
Small, quiet, waterjet-propelled ships like Mangrol fill this gap. Their low draught and low noise let them conduct subsurface surveillance of coastal waters, maintain search and attack unit missions, and work alongside aircraft to create a multi-layered coastal defence net. Together with Kamorta-class corvettes for open ocean ASW, P-8I aircraft for long range detection and the upcoming Next Generation Missile Vessels, the ASW SWC grid protects sea lines of communication, offshore assets, and the approaches to both eastern and western seaboards.
Low-Intensity Maritime Operations and Mine Warfare Explained
Low-Intensity Maritime Operations (LIMO) refers to operations short of full scale war, often against asymmetric threats. These include countering terrorism, piracy, gun and drug smuggling, preventing infiltration, protecting ports and offshore installations, and prosecution of intruding small craft. Mangrol can rapidly interdict such vessels, provide naval presence, and support constabulary roles that do not require a destroyer.
Mine warfare is another critical secondary role. A naval mine is an explosive device laid on or below the sea surface to deny access to an area. Mines can be laid by ships, submarines or aircraft and anchored or left to drift, and modern influence mines detonate when they sense changes in magnetic field, sound or pressure from a passing ship. A single mine can cost a few thousand dollars, but clearing it can cost ten to twenty times more and requires specialised ships, sonars and remotely operated vehicles. Even the suspicion of mines can close a harbour for days.
India has had no dedicated mine countermeasure vessel since the last Pondicherry-class minesweeper, a Soviet-era Natya class vessel INS Kozhikode, was decommissioned in 2019. The Navy currently depends on clip-on mine countermeasure suites fitted on other platforms, which are considered interim solutions. To close this gap, the Defence Acquisition Council cleared the acquisition of 12 Mine Counter Measure Vessels (MCMVs) in July 2025 for about ₹44,000 to ₹45,000 crore under the Buy (Indian-IDDM) category, meaning they must be designed, developed and manufactured in India. Mangrol does not replace a full minesweeper, but its mine laying rails allow it to lay defensive minefields quickly, adding a layer of sea denial capability for protecting harbours and choke points until dedicated MCMVs arrive.
Cochin Shipyard and the Push for Indigenous Shipbuilding
Cochin Shipyard Ltd (CSL) was incorporated on 29 March 1972 as a fully owned Government of India company under the Ministry of Ports, Shipping and Waterways, with its yard at Kochi in Kerala. It was conceived in 1969 after a nationwide location survey and was built with technical collaboration from Mitsubishi Heavy Industries, Japan. Construction of the yard’s first phase was completed by 1982, with shipbuilding operations commencing in 1978 and ship repair in 1982. It was granted Category I Miniratna status in July 2008, completed its Initial Public Offer (IPO) in August 2017 and is listed on the BSE and NSE. The Government of India currently holds about 72 to 75 percent of its equity.
Starting from bulk carriers, CSL evolved to build highly sophisticated vessels including Platform Supply Vessels, Anchor Handling Tug Supply Vessels, double hull Aframax tankers of 95,000 DWT, and has exported more than 47 vessels to clients in Norway, Netherlands, Germany, the United States and the Middle East. Its most prestigious achievement remains the construction of INS Vikrant, India’s first indigenous aircraft carrier, delivered in 2022 and commissioned on 2 September 2022 by Prime Minister Narendra Modi. With that delivery, India joined the select group of nations capable of designing and building an aircraft carrier indigenously. The yard is also building Next Generation Missile Vessels (NGMV) and has handled refits of aircraft carriers like INS Vikramaditya and INS Viraat.
Mangrol underscores this indigenous trajectory. More than 80 percent of its content is sourced within India from firms such as Bharat Electronics Limited, Mahindra Defence and Larsen and Toubro. CSL is certified under ISO 9001, ISO 14001, ISO 45001 and ISO 27001. The ASW SWC project has also strengthened domestic design capacity, with SEDS providing the basic design and the yard handling detailed design and integration.
The Way Forward
With seven of 16 shallow water craft now delivered between CSL and GRSE, the programme is in its most productive delivery stage after initial delays caused by supply chain disruptions for engines and sonars. The remaining Mahe-class ships, Malpe, Mulki, Magdala, Machilipatnam and P87, are at various stages of launch, fitting out and construction, with CSL scheduled to complete its eight ships by June 2028. GRSE’s remaining vessels are on a parallel timeline toward the same target year of 2028.
For the Navy, Mangrol will undergo harbour and sea trials, weapons and sensor integration checks, and crew work-up before formal commissioning and assignment to the Western Fleet based in Mumbai. Once all eight Mahe-class ships are operational alongside the eight Arnala-class ships of the Eastern Fleet, the Navy will have continuous shallow water coverage on both coasts. The class will also provide interim mine laying capacity while the larger 12-ship MCMV programme progresses through the request for proposal stage.
In the longer term, the success of the ASW SWC programme demonstrates a shift to distributed littoral combat power, where small, stealthy, heavily automated ships complement larger fleet units. It also validates the public-private design partnership model that the Navy intends to replicate for future small combatants.
Key Takeaways
- INS Mangrol, the third Mahe-class ASW Shallow Water Craft, was delivered by Cochin Shipyard Ltd to the Indian Navy on 21 August 2026 in Kochi.
- The ASW SWC programme comprises 16 ships, with 8 Mahe-class ships built by CSL for the Western Fleet and 8 Arnala-class ships built by GRSE for the Eastern Fleet, under contracts signed on 29 and 30 April 2019 worth ₹6,311.32 crore each.
- Designed to replace the Abhay-class corvettes (1989 to 1991), the 78-metre, 896 to 1,100 tonnes corvettes have a shallow draught of 2.7 metres, speed of 25 knots, range of 1,800 nautical miles and crew of 57.
- Mangrol carries over 80 percent indigenous content and is fitted with Abhay hull-mounted sonar, Low Frequency Variable Depth Sonar, RBU-6000 rockets, triple lightweight torpedo tubes with Advanced Light Weight Torpedo, and mine laying rails.
- The ship is equipped for underwater surveillance, coastal ASW operations and Low-Intensity Maritime Operations (LIMO) including mine warfare, search and rescue and interception of intruding craft.
- Cochin Shipyard Ltd, incorporated on 29 March 1972 and granted Category I Miniratna status in 2008, also built INS Vikrant, India’s first indigenous aircraft carrier commissioned on 2 September 2022.
