The Indian Navy intends to acquire the next set of conventionally powered six diesel-electric submarines under Project-75I, a follow-on of Project 75 Kalvari-class submarines. Larsen and Toubro (L&T) and another private shipyard Reliance Defence turned out trumps, beating three public sector shipyards to become eligible to participate in the P-75I programme. Business Line caught up with Jayant Patil, Head of Defence and Aerospace, and Member of Shipbuilding and Heavy Engineering Board at L&T, to understand how the Indian shipyard is set to take the lead in responding to the tender, effectively ending the 70-year public sector monopoly. Patil also enumerated on the company's quest for greater submerged endurance with the crucial Air Independent Propulsion (AIP) system, a home-grown technology and an enormous challenge for Indian companies, which is aimed at increasing endurance and stealth capability of the submarine. Excerpts:

Has the request for proposal (RFP) been announced as yet? Can you explain the process?

No, we await receipt of the RFP for P75I. Having approved the Strategic Partner (SP) policy, the defence ministry (MoD) will first issue an expression of interest (EoI) to probable companies and evaluate eligible private sector Indian yards for construction of the P75I submarines. This will be done by a MoD-appointed specialist committee that will short-list yards that meet the Strategic Partnership criterion, leading to selection of Potential SP. Concurrently, the MoD willl evaluate foreign OEMs through a EoI process and short-list those complying with the requirements of P75I.

Could you give us an idea about L&T's capabilities in stealth submarines.

Larsen & Toubro has been associated with India’s strategic submarine programme for decades. It was formally announced when INS Arihant was launched in 2009. Our work centres specialise in the construction of submarine hulls with an entire range of in-house developed capabilities that are key to the submarine construction value chain - from detailed design and engineering in digital domain to hull construction using IT-enabled automation.

We have also developed technologies and matured them to do 3D-assisted outfitting, system integration, to system level qualification tests and trials as proven on classified underwater programmes. These have been developed indigenously given the nature of the programmes and the National endeavour we have been associated with.

How is the company placed with regard to other Indian competitors in facilitating the P75I contract?

L&T is the only shipyard in India which has a track record in the construction and integration of the most critical and complex bow, aft and other pressure tight structures, which needs to be imported by other yards. Our indigenous knowledge and technologies are amply proven across underwater programmes.

L&T is also the System Integrator for DRDO’s Air Independent Propulsion (AIP) system programme. L&T also has a track record in the development of significant platform specific systems such as propulsion systems, engineering systems, control systems and weapon systems for Naval underwater programmes. These capabilities places L&T in a unique position.

Does the company have the wherewithal to undertake and help with the AIP-related technology for the submarines, which is a major prerequisite of this tender?

L&T is currently partnering with the DRDO as Lead System Integrator for the indigenous development of the fuel cell based AIP system. This is engineered as a modular package that can be plugged into a platform of choice. This technological solution holds promise to be among the latest and safest evolutions in propulsion technology for conventional submarines for enhanced indiscretion rates.

(The indiscretion rate refers to the percentage of time a submarine spends when it comes up for air, which also makes it the time when it is the most vulnerable)

It enhances the endurance of conventional diesel-electric submarines to remain underwater many-folds, thus converting it into a more potent weapon platform with higher indiscretion rate.