Naval Group India commissioned a Pneumatic Reducer and Actuator Mechanism (RAM) test facility at its technical workshop in Karwar, Karnataka, to support maintenance activities for the Indian Navy’s Kalvari-class submarines. The facility enables local maintenance, repair and overhaul (MRO) of equipment used in the mast-raising systems of the Scorpène-design submarines.
The Pneumatic RAM test facility was inaugurated at the Karwar workshop by Vice Admiral B. Sivakumar, AVSM, VSM, Chief of Materiel of the Indian Navy. Developed in collaboration with an Indian micro, small and medium enterprise (MSME), the installation is intended to strengthen in-country MRO capabilities for the submarine fleet.
The system is designed to support servicing of the Reducer and Actuator Mechanism used in mast-raising systems such as periscopes and antennas installed on the submarines. The presence of a domestic testing and repair facility allows these components to be maintained within India.
The Kalvari-class submarines were built at Mazagon Dock Shipbuilders Limited in collaboration with France’s Naval Group, based on the Scorpène submarine design. The six submarines in the class—INS Kalvari, INS Khanderi, INS Karanj, INS Vela, INS Vagir and INS Vagsheer—have been commissioned and are operational with the Indian Navy.
The final submarine of the class, INS Vagsheer, was commissioned on 15 January 2025. The vessel marked the completion of the six-submarine construction programme undertaken at Mazagon Dock Shipbuilders Limited under the Scorpène design collaboration.
Further upgrades are planned for the fleet through the integration of an air-independent propulsion (AIP) system developed by the Defence Research and Development Organisation’s Naval Materials Research Laboratory in Pune. The retrofit programme involves inserting an additional AIP section into existing submarines during refit, allowing them to generate electricity underwater without combustion.
India’s second Kalvari-class submarine, INS Khanderi, is scheduled to receive the indigenous AIP system before the end of 2026 while undergoing refit. The phosphoric acid fuel cell technology developed by the Naval Materials Research Laboratory generates electricity underwater and produces water as its only by-product.
Naval Group India supports technical maintenance and sustainment activities related to the Kalvari-class submarine programme built at Mazagon Dock Shipbuilders Limited in collaboration with Naval Group of France. The company operates facilities in India that provide technical services and lifecycle support for the submarines in service with the Indian Navy.
