Bengaluru: India’s first Scorpene submarine INS Kalvari, which was commissioned in 2017, will undergo a scheduled normal refit this year but is unlikely to get an Air Independent Propulsion System (AIP) as was planned, ThePrint has learnt.
Sources in the defence and security establishment said the indigenous AIP system, being developed by the Defence Research and Development Organisation (DRDO), is still not functionally ready.
The AIP plug’s advantage is that it allows a boat to remain underwater for about two weeks rather than needing to surface every two-three days to charge its batteries.
Indian private firm Larsen & Toubro and the DRDO in June, 2023 signed a contract for the realisation of two AIP system modules for the Kalvari, the Indian name for the Scorpene.
These modules constitute the core of the fuel cell-based AIP system, indigenously developed by the Naval Materials Research Laboratory with L&T as the prime industry partner.
The energy modules (EMs) comprising fuel cells produce the required power, along with onboard hydrogen generation. The technology of this indigenous AIP system is unique – it generates hydrogen on demand, thereby obviating the need for carrying hydrogen onboard which is a major safety concern for a submarine.
The sources said once the construction was completed, there would be a series of tests before the system was cleared for installation. The installation will require the submarine to be cut and an additional compartment fitted which would make the process longer.
INS Kalvari, according to the sources, will go in for its normal refit in the second half of this year. The work schedule being drawn does not include AIP as of now because of the delay.
According to the original plan, the 5th and 6th Scorpene class submarines were to be fitted with the AIP system while the earlier ones would have got them during the normal refits. But the delay in developing the AIP meant the 5th and 6th boats were also commissioned without the AIP.
The AIP could get installed on the second of the Kalvari class as and when it comes in for its normal refit, the sources said.
Last December, the defence ministry signed a Rs 1,990 crore contract with Mazagon Dock Shipbuilders Limited (MDL) for the construction of the AIP plug and its integration into the Kalvari class of submarines.
Interestingly, the normal refit is likely to be carried out by the Naval Dockyard Mumbai rather than by the MDL, which had manufactured the submarines in conjunction with French firm Naval Group, earlier known as DCNS.
While initially a proposal from the MDL was sought for the normal refit, the Navy is now tilting towards its own dockyard keeping cost in mind. Navy sources said the Naval Dockyard has the experience and capability to carry out the normal refit.
(Edited by Tikli Basu)
Also read: Self-reliance in defence production only achievable with satisfaction of armed forces, says Rajnath