NEW DELHI: In a major indigenisation step towards integrating the niche air-independent propulsion (AIP) system, the plans are to equip the second submarine of the INS Kalvari-class by the middle of the next year. Sources in the defence and establishment said AIP is likely to be fitted on INS Khanderi in July 2026.
INS Khanderi is scheduled to go for refitting in mid-2026. The work on AIP is being carried out by the Defence Research and Development Organisation (DRDO) which "The prototype of the AIP system will be ready by December this year."
The integration will be completed in another year. "If everything goes as per the plan, the first sailing would begin in March-April 2027 and the refitting process will be concluded by July 2027." The trials will take around one year to get the AIP fitted in the submarine before going for trials.
The AIP system has been developed with the support of industry partners L&T and Thermax, and it was supposed to be fitted with INS Kalvari, the first of the six Kalvari-class of diesel-electric submarines of the Indian Navy. With its integration into the submarines, India will join an elite club of nations that have indigenously developed fuel cell-based submarine Air Independent Propulsion technology.
This technology is a green one since the by-product of the reaction is non-polluted water, which can be released into the oceans. A submarine is a military vessel that can travel both on the surface and in a submerged state and is deployed to execute offensive or defensive operations. Giving details about the technology, The New Indian Express reported earlier that the niche technology being developed will enhance the submerged endurance of the submarine several-fold.
An AIP system gives a submarine the ability to remain submerged underwater, away from enemy sensors, for a long time without surfacing. As per DRDO, the AIP has a "force multiplier effect on lethality of a diesel-electric submarine."
The plan, sources said, is to equip all new submarines with the indigenous AIP system. L&T is the recipient of the Transfer of Technology (ToT) for this DRDO developed AIP System. The Transfer of Technology documents for the same were handed over during Aero India 2021 in Bangalore.
The technology of this indigenous AIP system is a unique one that generates hydrogen on demand, thereby obviating the need for carrying hydrogen onboard, which is a major safety concern for a submarine.