A flurry of activities by Chinese and Pakistani ships and submarines in the Indian Ocean Regions (IOR), have been picked up by the Indian Navy which has been focussed on COVID operations in Malacca Straits, the Gulf of Aden and the Red Sea. During these missions, P-8I Anti-submarine multi-mission maritime patrol aircrafts also participated for ISR (Intelligence, Surveillance and Reconnaissance). The submarines were both conventional and nuclear types.
A submarine’s Air-independent Propulsion (AIP) system ensures operations of the conventionally powered submarine to operate without the need for outside air. A Kalvari Class submarine when fitted with an AIP system onboard shall be able to run its electric propulsion motor and electrical network with the conventional batteries bypassed. This benefit reduces the need for the submarine to surface often to take in the air for running diesel engines (for battery charging). As has been reported by Financial Express Online earlier, the Kalvari class submarines are powered by conventional diesel-electric propulsion systems, and as per the original plans, the last two submarines were to be equipped with an indigenously developed AIP technology. This state of the art Fuel-cell based AIP is to be indigenously designed by DRDO since such technology from abroad is expensive.
Despite the commissioning of the first two submarines, DRDO has been unable to meet the timelines of the AIP development, which is still at a land-based laboratory. The rest of the four P75 submarines are scheduled for commissioning by 2022. Presently, the indigenous AIP system is planned to be a retrofit onboard first submarine, as and when it enters a major Refit.