Why India Still Cannot Build Conventional Submarines On Its Own: A Chronicle Of Avoidable Failure

Manohar Parrikar was never one to sugarcoat problems, and in November 2016 he made it clear that India’s submarine programme was faltering. India’s submarine plan, he said, needed a complete rethink. The 30-year roadmap approved in 1999, which confidently promised 24 cutting-edge conventional submarines, was already obsolete.

“We need to reassess our real requirement,” he warned, almost exasperated that the country still spoke of submarines as though they were occasional purchases rather than a continuous industrial lifeline. "We also need to ensure that the skilled manpower and expertise we have developed are retained. To retain it, we need to have more construction of submarines," Parrikar said.

It was classic Parrikar. Blunt, almost impatient, but undeniably correct. He pointed to the numbers with a kind of controlled frustration. Only six submarines had been ordered in the past 16 years, a tiny fraction of what the Navy needed. He urged the Navy to plan all the way to 2050 and to picture an India that did not buy submarines in isolated bursts but built them continuously, one after another, without letting the production line go cold.

Nearly a decade later, in December 2025, his words read less like a policy remark and more like a prophecy of failure. Despite all the talk, all the committees, and all the PowerPoints about indigenisation, India has added exactly zero new submarines to its conventional pipeline since Parrikar sounded the alarm. The only boats the Navy has received in these nine years are the Scorpenes. These vessels were already under construction, funded, negotiated, and locked in long before his intervention.

Forget the rethink Parrikar demanded in 2016, even the 1999 plan has been allowed to collapse, and is now more than a decade behind schedule. The follow-on plan meant to restore the rhythm of submarine building and salvage the 1999 roadmap, Project 75I (P75I), has spent these ten years drifting from one bureaucratic sandbank to another. Not a single steel plate has been cut and not a single contract has been sealed. 

The 1999 plan wasn’t India’s first attempt to set up an indigenous conventional submarine-building base. In the early 1980s, Howaldtswerke‑Deutsche Werft (HDW) of West Germany was tapped by the Indian Navy to help build India’s first serious modern conventional submarines under a licensing and technology-transfer framework.

In 1981, India signed a contract with HDW for four Type‑1500 diesel-electric attack submarines, a heavier India-specific version of the German Type‑209 design. Under this agreement, HDW would build the first two in Germany. The plan also envisaged that two further boats would be assembled at Mazagon Dock Shipbuilders Limited (MDL), Mumbai, giving Indian shipbuilders a chance to master submarine construction.

Between 1986 and 1994, the first two boats, commissioned as part of what would become the Shishumar-class submarine, came from Germany. The next two were built at MDL and commissioned in 1992 and 1994.

In theory, this should have been the foundation of an indigenous submarine-building capability, a test run if you will. HDW was expected not only to supply fully built submarines but also to transfer design, construction, and maintenance know-how, train Indian designers and dockyard workers, and help build logistics support infrastructure for subsequent boats. The limited infrastructure and skills developed during this phase were to be sustained by further orders, possibly with modifications to the design.

But, as is tradition in Indian defence procurement, things predictably went off the rails.

The HDW deal got tangled in scandal. Allegations had surfaced as early as 1987 that HDW had paid kickbacks to Indian middlemen to win the contract for the programme. The scandal prompted the blacklisting of HDW in India.

Moreover, between 1980 and 1992, the Deutsche Mark strengthened more than fivefold against the rupee, and Germany also raised the submarines’ base price. This resulted in the cost of the next two boats ballooning to over six times the original estimate. With India simultaneously procuring Kilo-class boats from Russia, the German boats became prohibitively expensive, and the follow-on option was quietly abandoned.

The HDW episode is especially disappointing when one looks at what South Korea managed to achieve with a broadly similar starting point. By the time India commissioned its fourth HDW-assisted submarine, INS Shankul, South Korea had already unveiled a three-stage submarine roadmap stretching from the mid-1990s to 2029, a plan that mirrored almost exactly what India would later outline in its own 1999 plan.

Like India in the 1980s, South Korea had almost no indigenous submarine capability and turned to Germany to kickstart its conventional submarine programme. Unlike India, however, Seoul used the deal deliberately, in stages, to build real, lasting capacity.

The country signed a licensing and technology-transfer agreement with HDW for Type‑209 submarines, much like India had, but the terms were better and the context more favourable. South Korea was closely aligned with the West and had access to technology.

South Korea began by importing a boat for immediate operational use while simultaneously training engineers and dockyard workers in domestic shipyards. Over the next decade, it built eight more Type‑209s locally, mastering construction and maintenance in the process. This is exactly the stage at which India had faltered. 

"Why are we behind South Korea? Because they stuck with a single manufacturer. They first built their Type-209 equivalents, then the Type-214-based KSS-II, and over the course of producing 18 or so boats they accumulated the shipbuilding skills and absorbed enough German technology to move on to their own KSS-III," the officer quoted above said.

"If you look at the KSS-III, it still has a broadly German design philosophy, but the internals are substantially different. They’ve added a vertical launch system and made multiple independent modifications. We, meanwhile, remain limited by whatever the foreign OEM is willing to let us change," he added.

By 2007, Korean shipbuilders had graduated to producing nine AIP-equipped Type‑214 submarines, and soon after they began designing and building an entirely indigenous class, the KSS‑III Dosan Ahn Chang‑ho. Nearly 30 years later, the South Korean Navy operates 21 submarines across three classes, with plans for 27, and Korean shipbuilders have even entered the submarine export market.

“When I visited Daewoo and Hyundai in 1997, one submarine was being built, one was about to be launched, one was fitting out, and a fourth was already operational. That kind of pipeline is what creates mastery," Vice Admiral Arun Kumar Singh, who retired as Commander-in-Chief of the Navy's Eastern Naval Command in 2007, recalled in his conversation with Swarajya.

"All these guys who build submarines have to be kept continuously busy. If a welder is not in touch for more than three months, he has to be recertified, at least for submarines, because your survival depends on good welding of the pressure hull," he said, adding, "All the people who build submarines have to be kept continuously busy. That’s something the Navy has managed with surface ships simply because of the volume. At any given time, every shipyard has some kind of ship under construction."

India’s own submarine roadmap of 1999 was supposed to achieve what the German partnership ended up delivering for South Korea.

The programme was ambitious, but not unrealistic. It envisioned two parallel production lines to build 24 submarines by 2030, with each successive batch incorporating more indigenous content. One line would absorb foreign technology through licensed construction, much like South Korea’s Type-209 phase, and the second line would take India toward an advanced, AIP-equipped, semi-indigenous design.

Had the plan been executed properly, it would have hardwired into the system the very point Parrikar kept hammering — that submarine building must be relentless and uninterrupted.

"The Navy’s early thinking was to maintain one Western submarine production line and one Russian line. But that approach was soon reconsidered. Rather than locking itself into predetermined partners, the Navy argued for flexibility. The plan was reframed as simply establishing two parallel production lines, with the choice of platform left open. If the Soviet design proved superior, it would be adopted. If a Western option emerged stronger, the Navy would retain the freedom to pursue that instead," a retired Indian Navy officer who served at the Directorates of Naval Plans and Submarine Acquisition when the 1999 plan was envisaged told Swarajya.

"The decision was taken to set up two production lines on which, simultaneously, we would build, or would have built, six submarines each," he added.

The first line, eventually known as Project 75, was meant to absorb foreign technology through licensed construction, much like South Korea’s Type-209 phase.

The second line, Project 75I, would push India further by incorporating higher levels of indigenisation and, crucially, by building the domestic capability to design an advanced submarine class. Together, these two lines were supposed to create the infrastructure, workforce, and design culture needed for the final stage.

In that third phase, India was to design and build 12 fully indigenous submarines, drawing directly from the experience accumulated in the first two. With orders placed consecutively and the assembly line never allowed to fall silent, the roadmap imagined India progressing steadily from licensed production to a genuinely homegrown conventional submarine fleet in the 2030s.

Caught On The Scorpene’s Barb

The Scorpene deal was meant to kickstart the first of the two production lines. Signed in October 2005 with France’s Naval Group, it was to deliver six diesel-electric submarines at a cost of $3.75 billion.

At this stage, the expectation was that the P75 submarines would field Air Independent Propulsion (AIP) and updated torpedo-missile suites. The difficulty was that the French partner did not have the AIP configuration India required.

Rather than reopen negotiations or delay the programme indefinitely, the government opted to proceed and retrofit a DRDO-developed AIP system during the boats’ medium refit. The first submarine, INS Kalvari, was to delivered by 2012, with all six boats to be built at MDL under technology-transfer. The plan included progressively increasing Indian content as MDL absorbed know-how from the French.

In reality, however, the first of the class, INS Kalvari, was commissioned only in December 2017, five years behind schedule. The remaining five were inducted intermittently over the next eight years, with the last commissioned in 2025.

Yet the delays were hardly the most consequential problem in the Scorpene story.

The deal, according to another Navy veteran who spent three decades as a submariner, involved “no real transfer of technology”.

"What I know is that even if a design drawing was with MDL and even if a line had to be modified by a centimetre, it had to go back to the French and come back again. That was the sort of control they kept on the design."

"In certain areas they said, ‘This can only be French equipment, it can’t be anybody else’s. You don’t have the option to choose. We are telling you this is what has to go here.’ So there was no real technology transfer," he said.

"It was screwdriver TOT. They give you a drawing and say, ‘Okay, build the submarine'."

India, he insisted, did not have any better options at the time.

"Remember, HDW was still blacklisted in 2005 when this contract was signed. There was nobody else to go to. It was only the French, and we also had this suddenly new-found French strategic friendship with India after the Pokhran tests. So they started with an advantage and there was no real competition. The ban on HDW was lifted only after the Scorpene contract was signed,” the retired officer added.

This was not the only time India had engineered such a trap for itself by eliminating competition and then discovering, far too late, that it had boxed itself into a corner. While there are many other examples, there's one concerning the submarine arm itself.

In the mid-2010s, the Navy found its brand-new Scorpene fleet sailing without heavyweight torpedoes after the government blacklisted Italian conglomerate Finmeccanica and, by extension, its subsidiary Whitehead Alenia Sistemi Subacquei, the maker of the Black Shark torpedo originally selected for the class.

With the vendor suddenly off-limits and no alternative procured in time, India effectively commissioned frontline submarines that were forced to rely on outdated SUT torpedoes from the 1980s, weapons that were never meant for the new boats.

That episode, however damaging, paled in comparison to the fundamental problem that had always sat at the heart of the Scorpene deal.

Even Mazagon Dock’s own leadership has publicly acknowledged that the Scorpene “technology transfer” was never the kind India actually needed.

When MDL was completing the last of the six submarines in 2022, its Chairman and Managing Director, Vice Admiral Narayan Prasad (Retd), said the French approach kept India permanently downstream of the real design and development ecosystem.

Prasad made it clear that Mazagon Dock had mastered the nuts-and-bolts of building Scorpenes. “After the second submarine, I did not need any assistance. The remaining four we made ourselves,” he said. But he also underlined the larger, structural flaw in the arrangement.

“If I have to build a submarine all by myself, designed by me, then there is a problem because certain components of empirical data, which they have evolved over a period of time, are not shared with us,” he said.

India, in short, had learned to assemble what the French had designed, but not to design, test and certify the next boat on its own.

Prasad backed the point with an example that ought to have embarrassed everyone involved.

Before a submarine was delivered, it had to successfully complete a missile-firing trial, a test in which every aspect of the firing was measured against technical reference data. MDL engineers were not given access to this data held by the Naval Group.

"One of my submarines is right now at sea for missile firing to demonstrate to our customer, during which the entire range is tracked for compliance purposes. When these things come, the reference is all given by them [the French], something which they have not shared with us [MDL]. They will come with their own laptops and do it very quickly, the moment you are close to them they will shut it [laptops] down, so that does not get shared with us," Prasad had recalled back then.

Prasad said the MDL had told the Indian Navy that now, with four submarines built, the firing parameters and all related decisions should be determined jointly by the Indian Navy, MDL, and the relevant DRDO laboratory, with the goal of eventually dispensing with the foreign technology partner.

"Now, you can take some bold steps, but it is fraught with its own difficulties. Who will give guarantee and warranty, [besides concerns over] this is not there, that is not there? So, you can take a couple of bold steps, and this is what I offered to the government," he said. 

Prasad’s admission was hardly a revelation, even if it offered a more granular look at the problem. Back in 2016, well before the first Scorpene-class boat entered service, Parrikar had already flagged the poor level of technology transfer, noting that indigenisation, which he said was "not up to the mark", hovered at barely 30 to 40 per cent, pointing to the contrast with India’s secretive nuclear-submarine project, the Advanced Technology Vessel programme that built the Arihant-class SSBNs, where indigenisation exceeds 70 per cent.

Even the modest consolation prize, the promise of retrofitting DRDO’s indigenous fuel-cell AIP during the Scorpene medium refits, is now off the track.

The plan to insert an AIP module during the submarines’ medium refits was intended to significantly extend underwater endurance and enhance stealth.

Developed by DRDO, the system was expected to allow the boats to remain submerged for up to two weeks without snorkelling, a process where a submarine comes close to the surface to draw in air for its diesel engines, which increases the risk of detection by radar, sonar, or satellites. By reducing the need to snorkel, the AIP would have made the boats far harder to track, partially offsetting the limitations of conventional diesel-electric operation.

Yet the project has been plagued by repeated delays. The first boat, INS Kalvari, undergoing its maintenance refit without receiving the AIP, and sources now suggest that the first installation may not occur until 2026, possibly on the second boat, INS Khanderi. 

The AIP system, approved in 2014 and originally expected to be operational by 2017, has been held up by persistent certification and integration issues. And the delays have affected more than just the Scorpene-class submarines. More on that later.

All Rigmarole, No Rhythm

Project 75I was never meant to be a distant sequel to the Scorpene programme. It was designed to run almost alongside P75, so the skills, workforce, suppliers and production infrastructure built up during Scorpene construction would flow seamlessly into the next class of submarines. That continuity was the entire logic of the 1999 plan, to avoid the HDW-era mistake of letting the line go cold and losing hard-won capability.

Instead, the exact scenario Parrikar warned against has unfolded. Three years after the last Kalvari-class boat entered service, India still has no signed contract for P75I, a programme that should've begun soon after the P75.

"P-75I should have begun far earlier, ideally around 2008–09. The first Acceptance of Necessity came in 2010, but the project kept drifting for various reasons," the first of the two officers quoted earlier in the report said.

But the P75I agreement, sources say, will be materially different from the Scorpene deal.

"What will come now is not only the final P-75I drawings being transferred to MDL for construction, but a complete transfer of design that will enable India to build its future submarines without needing a foreign partner again. This means that what is being spoken of as P-76 will be a fully independent Indian design," he added.

"Based on the design knowledge they already have, this transfer will involve TKMS training Indian designers. When they hand over the design, it won’t just be a bundle of a thousand drawings, there will be workshops, exposure visits, and hands-on instruction. Designers will be taken to the yards, shown the processes, and given guidance in areas where they need more experience or deeper understanding.”

"We’re at that cusp. We just need that final tipping point of knowledge to be able to design on our own. There will always be a few niche areas we can’t handle right now, but if P75I gives us that push, we’ll be well placed to design future submarines and even modify those designs ourselves," the other officer said.

"The submarine design group in the Warship Design Bureau is already working intensely toward this [Project 76]. I know that for a fact. So from a design perspective, the next class of submarines will likely emerge by the mid-2030s," he added.

One of the major sticking points in the P75I programme over the past few years was the Navy’s insistence on a sea-proven AIP system. And when the field finally narrowed after almost a decade of drift to just two serious contenders, Germany’s ThyssenKrupp Marine Systems, which bid with MDL, and Spain’s Navantia, which tied up with Larsen & Toubro, even they could not fully satisfy that benchmark.

In demanding a proven AIP, the Navy wanted to sidestep years of integration and certification delays by selecting a platform built around a system that had already demonstrated its reliability at sea. The Navy also reportedly wanted to prevent any last-minute push from the DRDO for its under-development indigenous AIP, which had already missed timelines for integration into the Scorpene-class.

However, when both TKMS and Navantia entered their systems for field evaluation trials, neither had an AIP that fully met the Navy’s specifications.

Navantia’s AIP, based on Bio-Ethanol Stealth Technology, was the closest fit. It uses bioethanol fuel, avoids the need for stored hydrogen onboard, and is easily refuelled at any port. The Spanish Navy had cleared it for integration on the third boat of its S-80 class, and it had reportedly undergone over 50,000 hours of testing. But it was not yet installed on an operational submarine.

A revealing detail here is that India was told from the outset that the first S-80 submarine with Navantia’s new AIP would only enter service with the Spanish Navy in 2026.

TKMS faced a different issue. Its fuel-cell-based AIP, proven on the smaller Type 214 submarines, was undersized for Indian requirements. To meet the Navy’s demand, TKMS would need to scale up its system and revalidate battery performance with new fuel-cell components offered specifically for the Indian bid.

In effect, Germany would be developing a new variant based on a smaller baseline, one not previously demonstrated at sea.

It was only this year that the TKMS–MDL bid finally crawled past the last bureaucratic checkpoint at the Ministry of Defence. A formal contract, if nothing else derails the process, will be signed only in 2026. The first submarine would then arrive no earlier than 2032 or 2033, with the rest trickling in at best one per year in the most optimistic scenario.

The first of the class will start with around 45 per cent indigenous content, inching up to 60 per cent in later units, though the actual level of indigenisation will also become clear when the boats begin to enter service.

With the deal now expected to cost about Rs 90,000 crore, nearly twice the Rs 45,000 crore earmarked for P75I in 2019, it is hard to see the government clearing another conventional submarine line for an indigenous design anytime soon.

The recent approval for the construction of two nuclear-powered attack submarines (SSNs) will stretch resources even further, making any parallel green-lighting of a second conventional line even more unlikely.

The third and final phase of the 1999 plan, the stage where India was supposed to build 12 fully indigenous submarines using the expertise accumulated from the first two phases, will now have to wait. This was the phase that would have finally given India the steady, uninterrupted rhythm of submarine construction that Parrikar kept insisting was essential. That momentum has again slipped out of reach.