Rs 43,000-crore tender to build six state-of-the-art submarines cleared

The SP model, which is detailed in the DAP 2020, is intended to involve private Indian firms in the building of four categories of defence equipment: Submarines, fighter aircraft, helicopters, and armoured vehicles
The Defence Acquisition Council (DAC), the Ministry of Defence’s (MoD’s) apex procurement body, on Friday gave the go-ahead for the purchase of six conventional submarines under Project 75 (I).

The DAC cleared the issue of a request for proposals (RFP), which “envisages indigenous construction of six conventional submarines equipped with the state-of-the-art air independent propulsion (AIP) system at an estimated cost of Rs 43,000 crore”, stated an MoD release on Friday.

“This is a landmark approval, being the first case processed under the strategic partnership (SP) model,” said the ministry.

The SP model, which is detailed in the Defence Acquisition Policy of 2020 (DAP 2020), is intended to involve private Indian firms in the building of four categories of defence equipment: Submarines, fighter aircraft, helicopters, and armoured vehicles.

In February 2020, Larsen & Toubro and Mazagon Dock Ltd (MDL) were short-listed as SPs for Project 75 (I). There is grumbling from the private industry about MDL’s inclusion, since it is a defence public sector undertaking.

According to the DAP 2020, “It is acknowledged that in the Indian private sector currently there is limited experience in defence manufacturing… (Therefore)… potential SPs will be identified primarily based on their experience and competence in integration of multi-disciplinary functional system of systems, engineering and manufacturing.”


The SP procedure also mandates that, in order to hand-hold the chosen Indian SPs and to access advanced technologies, “the SP will need to enter into relevant tie-ups with foreign Original Equipment Manufacturers (OEMs)”.

“The MoD’s clearance of the RFP for the first strategic partnership model acquisition is welcome. For the first time the private sector has been allowed to participate in a mega programme for a front-line combat platform,” said Jayant Patil, who heads L&T’s defence vertical.

Meanwhile, the MoD has also short-listed five foreign submarine builders for Project 75 (I): Russian export agency Rosoboronexport; Naval Group (France); ThyssenKrupp Marine Systems (TKMS) of Germany; Navantia (Spain); and Daewoo (South Korea).

With the issue of an RFP, the chosen SPs – L&T and MDL – will be required to formulate technical and commercial proposals for building six submarines, in partnership with their chosen OEMs. Each SP is permitted to submit multiple proposals, i.e. partnering more than one OEM.

“Naval Group is in discussion with both SPs and look forward to contributing to  "Aatmanirhbar Bharat" and to reinforcing our historical Indo-French bilateral ties,” said Alain Guillou, who heads international development for Naval Group.

The most complex challenge in Project 75(I) is expected to be the integration of AIP systems into the six submarines. An AIP system increases the submarines’ underwater endurance and, therefore, its combat capability.

Conventional diesel-electric submarines, such as India’s Kilo-class and Scorpene submarines, are powered by large banks of electric batteries, which drive electric motors that turn the submarine’s propellers. Since the batteries get discharged, the submarine must surface every day or two to recharge them by running diesel generators (which require atmospheric air). However, surfaced submarines are visible to radar and, therefore, vulnerable to attack.


Nuclear submarines bypass this vulnerability, since nuclear propulsion requires no oxygen. Nuclear submarines can remain submerged almost indefinitely, but designing a small-enough reactor poses technology challenges. The navy is processing a Rs 90,000 crore project to build six 6,000-tonne, nuclear-powered, attack submarines.

Until nuclear-powered submarines join the fleet, AIP provides an interim propulsion solution. Since it does not have conventional batteries that require generator charging, submarines with AIP can remain underwater for 10-14 days, reducing its vulnerability to detection.

AIP systems such as “fuel cell technology” generate power through the reverse electrolysis of oxygen and hydrogen. The two elements, carried on board the submarine, chemically combine to generate electricity. This charges the submarine’s batteries, doing away with the need for a diesel generator.

Separately, the Defence R&D Organisation (DRDO) is developing an indigenous AIP system that relies on Phosphoric Acid Fuel Cell technology. This is more rugged, tolerant of fuel impurities, and offers longer life and efficiency, which makes it cost-effective.


However, this is unlikely to be operationally available for Project 75(I). So far, the DRDO has demonstrated a land-based AIP prototype, which can generate power, independent of air, for up to two weeks. The challenge now is to “marinise” it, fit into an actual submarine and operate underwater in live conditions. DRDO sources say this will take another 3-4 years.

The AIP systems that go into Project 75(I) must, therefore, be provided by the foreign OEMs. The DRDO’s AIP system will, from 2024-25 onwards, be “retrofitted” into the six Scorpene submarines when they come up for long refit.

The sanction to Project 75(I) is a major step towards implementing the navy’s “30-year Submarine Construction Programme”, which the Union Cabinet sanctioned in 1999. This involves building 12 conventional submarines in India, in partnership with foreign OEMs. Thereafter, Indian shipyards would be expected to have the expertise and experience to design and build 12 indigenous submarines in the country.

“This project under the SP Model provides a unique long-term opportunity and planning certainty for the industry to invest and support submarine construction. It will also infuse the latest technology and weaponry for submarines in India through strategic tie up between Indian Industry and leading foreign OEMs,” said the MoD.



Business Standard is now on Telegram.
For insightful reports and views on business, markets, politics and other issues, subscribe to our official Telegram channel