Indian Navy and the impending issue of AIP import for Project 75 (I) subs

The DRDO’s Fuel cell-based AIP, which uses hydrogen and oxygen to generate electricity on board and has almost no moving parts, produces minimal waste. With the Chinese presence growing in the Indian Ocean Region, the AIP on the Indian submarines is needed on an urgent basis.

India is one of the few amongst the leading submarine operating navies in the world without an Air Independent Propulsion (AIP) system on its submarines. In the Indo-Pacific itself, Japan, South Korea, China, Singapore, and Pakistan are operating AIP fitted submarines. “This is a serious vulnerability which severely restricts the deployability of Indian Navy (IN) submarines in the contemporary littoral maritime battlespace that prevails in the region,” opines Commodore Anil Jai Singh, former submariner, Indian Navy.

Why is AIP needed?

Commodore Anil Jai Singh, who is also Vice President of the Indian Maritime Foundation, tells Financial Express Online, “In operations and during the war, this will be even more so when the submarines will be expected to go in harm’s way in a dense Anti-Submarine warfare environment. AIP was first introduced on Swedish submarines from 1989 onwards and has since then become almost a standard fitment on modern diesel-electric submarines. India’s bête noire Pakistan too has an AIP installed on each of its three Agosta 90B submarines and is being equipped by eight AIP fitted Type 039 submarines from China, commencing in the second part of this decade.”

“The majority of Indian Naval submarines are from the pre-AIP era but even the recent Scorpene-class submarines, three of which have been commissioned and the remaining three are at an advanced stage of build do not have an AIP on board. This is surprising since the contract for these had been signed in 2005 by which time AIP was an accepted technology on board and it is hoped that those in the decision-making loop had sound reasons for it. Ironically, Pakistan’s first AIP submarine built by the same foreign OEM, Naval Group of France was entering service at the time,” he says.

It is also understood that the next submarine building program, Project 75 (I) which was recently approved by the Defence Acquisition Council (DAC) and is awaiting the issue of an RFP is not likely to insist on the indigenously developed AIP. “This may be a sensible decision since DRDO has often flattered to deceive and its insistence has often compromised combat capability. On the contrary, perhaps the best solution would be to ensure that each of the foreign OEMs in the fray offers a proven AIP with the option of switching to the indigenous AIP provided it is contemporary and performs satisfactorily on the Kalvari class submarines,” the former submariner states.

In his view, “the P75(I) submarines are unlikely to enter service before the early 2030s, by which time technology would have advanced even further and the AIP-lead acid battery combination would have been superseded by the AIP-lithium ion battery combination which would provide additional capability to the submarines. The irony however is that while the DRDO system may not be the preferred choice perhaps because it isn’t yet proven, three of the five foreign OEMs in the fray for P75(I) also do not have a proven fuel cell-based system either.”

In fact, only TKMS (ThyssenKrupp Marine Systems), Germany, and Daewoo South Korea have a proven fuel cell system, with the latter having been derived from the former.

India’s own AIP still far away

For many years since no serious attempt was made to develop an AIP capability till DRDO began work on an indigenous fuel cell-based AIP system. It is understood that this indigenous system will be installed on the Kalvari class submarines as and when they commence their first major refit. “However, this system is still at a development stage on a testbed and could be some distance away from operationalization,” Commodore Anil Jai Singh observes.

AIP for Indian Navy

With the Chinese presence growing in the Indian Ocean Region, the AIP on the Indian submarines is needed on an urgent basis. “Whether India will have to buy from an OEM only time will tell as indigenous AIP is going to take a long time before it can be fitted on any of the submarines,” according to a naval officer.


In March this year, the Defence Research and Development Organisation (DRDO) had issued a media statement announcing the successful testing of the Fuel Cell-based Air Independent Propulsion (AIP) System. It is still in the Lab stage.

The statement had mentioned that the system which has been developed by the Naval Materials Research Laboratory (NMRL) of DRDO, as per the user requirements, was operated in endurance mode and max power mode.

The DRDO’s Fuel cell-based AIP, which uses hydrogen and oxygen to generate electricity onboard and has almost no moving parts, produces minimal waste.

Source: Financial Express


  • Dr. Biplab Rath

    A Forensic Medicine and Toxicology expert from AIIMS Bhubhaneswar. He takes keen interest in ballistics, CBRN warfare and related subjects. He has been associated with the IADN since very initial time.

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