DRDO Seeks Aging Kilo-Class Submarine to Test Project-76's Next-Gen Technologies, Particularly AIP and Electric Propulsion Motor

In a move aimed at bolstering India's naval capabilities, the Defence Research and Development Organisation (DRDO) has formally requested the Indian Navy to transfer a decommissioned Kilo-class submarine.

This vessel will serve as a crucial test platform for advanced technologies being developed under the ambitious Project-76, which seeks to introduce a new generation of indigenous submarines.

Project-76 represents a significant step in India's pursuit of self-reliance in submarine manufacturing. The project's primary focus is the development of cutting-edge, air-independent propulsion (AIP)-equipped diesel-electric attack submarines.

The Kilo-class submarines, known in India as the Sindhughosh class, have formed a vital part of the Indian Navy's underwater fleet. These Soviet-era vessels, while approaching the end of their service life, provide a reliable and well-understood platform for testing new technologies. Their established design makes them ideal candidates for experimentation, mitigating the risks associated with using newer, untested platforms.

Furthermore, repurposing an existing submarine for testing is considerably more cost-effective than constructing a dedicated test vessel. The Indian Navy's extensive operational experience with these submarines offers valuable insights that can be leveraged during the development process.

The DRDO's plan involves integrating a range of advanced technologies onto the selected Kilo-class submarine for evaluation and refinement. These technologies are intended for incorporation into the Project-76 submarines and include Air Independent Propulsion (AIP) systems, Lithium-ion batteries, indigenous weapon control systems, advanced sensor and communication suites, and an electric propulsion motor.

AIP technology, in particular, is crucial as it allows submarines to operate submerged for extended periods without needing to surface, significantly enhancing their stealth and operational range.

The conversion of the Kilo-class submarine into a research vessel will not only directly support the goals of Project-76 but will also contribute to the broader advancement of naval technology within India.

The knowledge and experience gained from this endeavour can be applied to refine existing technologies for potential retrofitting into the current fleet, as well as inform the design and development of future naval projects, ensuring India maintains a technologically advanced and robust maritime defence posture.

 

[PKPRS]

It’s good to have a real working submarine for testing.

 

[sanket]

Unlike the test bed for the Kaveri engine, this should be handed over quickly to expedite the development of technologies.

 

[obiwankenubi jedi]

Then why did we transfer a kilo class subs to Myanmar - INS Sindhuvir?

 

[RG]

Such moves should be happening without constraints, Armed forces must be proactive and encourage such collaboration. As it is they have been donating Kilos to other nations and DRDO has to wait, it is one of these shameful things that delays development.

 

[Ayush raj]

I hope the navy agrees to give a Kilo-class submarine as a testbed, unlike the IAD where the GTRE demanded a MiG-29 UPG for a testbed, but they denied it. How do they expect to get advanced tech if they are not proactive in such collaborations?

 

[Anant]

Fairly reasonable request, all things considered. The Kilo-class are roughly the size of the Project 76 boats, are not upgradable further as the Type 209-1500s are, and are near the end of their lives.

That said, had DRDO made this request a few years earlier, or had the Navy foreseen this, we could have saved the ex-INS Sindhudhvaj for this role. As it so happens, we just retired her, and scrapping of the boat began about seven months back, and is mostly done.

Oh well. Regardless, INS Sindhughosh is coming up for retirement next year. The other older Kilo-class boats have all received life extension refits that have extended their lives to about 45 years, with Sindhughosh and Sindhurashtra presently not having received those refits and being useful for about 40 years. Sindhurashtra is due to head in for the refit later this decade (she is, after all, almost a decade newer than the rest of the class), which leaves Sindhughosh.

I feel this would be a fitting end to Sindhughosh. Who knows, once the work is done, we can even look at preserving Sindhughosh as a monument to India's indigenous submarine efforts.

 

[Anant]

I hope the navy agrees to give a Kilo-class submarine as a testbed, unlike the IAD where the GTRE demanded a MiG-29 UPG for a testbed, but they denied it. How do they expect to get advanced tech if they are not proactive in such collaborations?

I have a feeling the Navy might not have too much of an issue. INS Sindhughosh is coming up for retirement next year, and has not received a second life extension refit like her sisters.

That said, had there been a bit more planning to this, we could have used the old submarine INS Sindhudhvaj instead. We decommissioned her in 2022 after 35 years of service, and she was sold for scrap just a few months back (in the second half of 2024), with the ship pretty much gone by now.

 

[Anant]

Such moves should be happening without constraints, Armed forces must be proactive and encourage such collaboration. As it is they have been donating Kilos to other nations and DRDO has to wait, it is one of these shameful things that delays development.

Well, had DRDO asked for a submarine earlier, I am fairly certain the Navy would have transferred either the Sindhuvir (the boat we donated to Myanmar) or the Sindhudhvaj (the boat we decommissioned in 2022 and scrapped in 2024).

Regardless, the Sindhughosh is coming up for retirement next year, so this request shouldn't be too difficult to accommodate most likely.

 

[Anant]

It’s good to have a real working submarine for testing.

I have a feeling the Sindhughosh is going to be retired as scheduled in 2026 and transferred. The other boats, of course, have a few more years thanks to the LIFEX refits.

 

[PKPRS]

I have a feeling the Sindhughosh is going to be retired as scheduled in 2026 and transferred. The other boats, of course, have a few more years thanks to the LIFEX refits.

I think Sindhughosh is currently going through refit.

 

[Hawk]

People think P76 will be based on P75I or Scorpenes but most probably it will be based on Kilo class.

 

[Hawk]

Then why did we transfer a kilo class subs to Myanmar - INS Sindhuvir?

If we did not give them one, China would have. Better to have an ex Indian sub where Myanmar will be depended on India for maintenance, training etc rather than China. Moreover, we lack long term planning.

 

[Anant]

I think Sindhughosh is currently going through refit.

Are you, perchance, referring to the Sindhukirti, which is currently under refit?

Sindhughosh was planned to receive a refit starting in 2020, but as far as I can find, that refit was postponed due to Covid, and eventually cancelled due to the limited effect it would have.

 

[Anant]

People think P76 will be based on P75I or Scorpenes but most probably it will be based on Kilo class.

Fairly unlikely. The Kilo-class is a fairly old design, and a lot of the design elements on the Kilo-class are outdated by modern standards.

Project 76 will most likely take lessons from Project 75, 75I, and maybe the Arihant-class. Granted, the Arihant-class does borrow design elements from the Kilo-class, but this influence would be very limited on Project 76.

 

[Anant]

If we did not give them one, China would have. Better to have an ex Indian sub where Myanmar will be depended on India for maintenance, training etc rather than China. Moreover, we lack long term planning.

Well, it was India giving them a submarine that prompted China to gift them a submarine too.

 

[Sandeep]

The kilo submarine are very old now and the technology is outdated despite being heavily upgraded several times. The problem is that modern submarine technology, equipment, software, weapons, systems etc can’t be tested properly in real life world conditions at sea on the Kilo. We can test some equipment or technology but not a lot really.

 

[R. Singh]

DRDO+ Directorate of Naval design jointly develop P-76 SSKs taking best from Kilo,Kalavari & TKMS SSKs to make 4500+ ton displacement SSKs keeping in mind of crew comfort, AIP, Pump jet propulsion, vertical missile launch tubes etc !

 

[Anant]

Then why did we transfer a kilo class subs to Myanmar - INS Sindhuvir?

While I do agree that donating Sindhuvir to Myanmar eventually ended up not going well for us, back when we did donate her, there was an actual democratic government sitting in the nation.

It was becoming evident China wanted to make major inroads in terms of defence cooperation with Myanmar (think Bhikaristan but slightly richer and more geopolitically significant), and so Sindhuvir was to be the first step in a new era of Indian defence cooperation.

Of course, China did end up gifting them a submarine too, and the subsequent coup put an end to things. Now, China has sided with the junta in the civil war, which means that if the various rebel factions do win the renewed civil war, China would have to start paying off a few sympathetic ears in the rebels to their side.