Indian Navy

Navigating the Depths: Unveiling the India’s Submarine Arsenal

Indian Ocean is an area that holds significance in terms of national security, defense, and geopolitical interests for our country. Beneath the vast expanse of the Indian Ocean, a silent Submarine patrols the depths, safeguarding national interests and maritime borders. In the complex geopolitics of the 21st century, submarines have emerged as indispensable assets, offering unparalleled stealth and versatility in naval operations.

As the Indian Navy charts its course amidst shifting tides of global security dynamics, the spotlight turns to its submarine arm—a cornerstone of maritime defense and power projection. In this comprehensive exploration, we will look into the depths of India’s submarine capability, tracing its evolution from nascent aspirations to formidable prowess on the high seas.

From ambitious plans for indigenous production to strategic collaborations with international partners, I will be taking you on the road walk that has shaped the trajectory of India’s submarine fleet.

Project 2030

The project, initially known as “Project For Series of Construction Of Submarines For Indian Navy And Acquisition Of National Competence In Submarine Building,” was approved by the Cabinet Committee on Security in July 1999. It aimed to construct two parallel lines, each building six submarines, with involvement from different OEMs. Additionally, the plan included the construction of another 12 submarines, leveraging the knowledge gained from the initial phase. This was termed Project 75.

Negotiations with France commenced in 2001, leading to the signing of a contract in 2005 to build six Kalvari class submarines, valued at $3.75 billion, with assistance from the French Naval Group. Originally slated for completion by 2012 with a three-year buffer, the project faced significant delays, with the first submarine commissioned in 2017 and the last expected to enter service this year, resulting in a nearly 12-year delay. Project 75I, intended to run parallel, has yet to conclude. Currently, the plan has been revised to include the induction of 18 conventional submarines and six nuclear attack submarines.


The delays in the Project 75I program, with a program cost of almost 40,000 crores to build six conventional submarines, can be attributed to several factors. These include technical challenges such as developing advanced submarine technology, supply chain issues in procuring specialized components, financial constraints affecting budget allocations, regulatory compliance complexities, delays in negotiation processes with international partners, and potential impacts from political factors. Additionally, the Naval Staff Qualitative Requirement (NSQR) demanding a “proven AIP System” has led to most contenders withdrawing from the contest, leaving only Germany’s TKMS and Spain’s Navantia in the running. Despite shortlisting two Indian shipyards, MDL and L&T, in January 2020 and issuing a Request for Proposal (RFP), the project has stalled due to issues such as liability clauses and stringent requirements, contributing to the ongoing delays in the Project 75I program.

According to recent news, the Spanish Navantia group said it is ready for complete ToT of their fuel cell AIP system and claimed that their submarine cost less than the Germans. On the other hand, Germany is pushing for Government to Government deal but it remains to be seen how the deal progresses.

Efforts To Indigenously Build Submarines

Picture Credit: Naval News

The efforts to acquire the capability and capacity to design and build submarines indigenously have been ongoing since the 1980s. In 1981, an agreement was signed with Germany for two Type 209 submarines, which included the training of Indian personnel and the subsequent building of two submarines in India through technology transfer. The first two submarines, Shishumar and Shankush, were commissioned in 1986, followed by the commissioning of the remaining two, Shalki and Shankul, in 1992 and 1994, respectively. There was an option for constructing another two submarines by MDL, but allegations against HDW, the company that sold the submarines, led to the cancellation of the remaining two submarines, and the firm was blacklisted due to suspicions of paying commissions to secure contracts. Consequently, to maintain force levels, the Navy acquired INS Sindhurakshak and INS Sindhurashtra. With no further orders, MDL lost all its highly skilled and trained manpower, thus losing the capability to produce its submarines. Also, the envisioned plan to manufacture 12 submarines indigenously after P75 and P75I did not materialize as per the plan.

Also Read, How India’s Defence Sector Empowering Smaller Economies ?

Current Strength Of Submarine Fleet

The current submarine fleet of the Indian Navy comprises four Shishumar Class submarines, seven Sindhughosh Class submarines, and five Kalvari Class submarines, with one more in line to join the service. To address the existing gap, three additional Kalvari Class submarines have been ordered. However, even with the conclusion of the deal for six more submarines under Project 75I in the coming years, the first submarine under Project 75I is not expected to enter service before 2030. Considering the aging of the Shishumar and Sindhughosh Class submarines, which were inducted almost thirty years ago, and assuming they will remain in service for the next ten years, there is a pressing need to expedite the acquisition process to ensure the timely induction of new submarines. This effort is essential to maintain and enhance the existing submarine capability of the Indian Navy.

Navy’s SSN Program

Under Project 75 Alpha, the Indian government approved the construction of six SSNs (nuclear-powered attack submarines) in February 2015, with a program cost totaling $18 billion. These submarines are to be designed by the Navy’s Directorate of Naval Design, leveraging the experience gained from building the Arihant class submarines. India is also considering the possibility of partnering with France, which operates the Barracuda class SSNs. Currently Navy operate Russian Akula SSN’s after reported extension of lease contract till 2025 and another lease agreement has also been signed with Russia for leasing Akula SSN from 2025 for almost $3 Billion.

Since India’s responsibilities have increased due to its participation in the Quad alliance, the growing presence of Chinese submarines in the Indian Ocean region, and its role as a net security provider. These factors have led to the necessity of having nuclear submarines for long-range patrols to safeguard its maritime interests effectively.

SSBN For Navy

Picture Credit: Naval News

In 1971 War United States dispatched its aircraft carrier USS Enterprise to support Pakistan and in response to that Soviet Union deploying submarines armed with nuclear missiles, the conflict highlighted the critical role of maritime capabilities in modern warfare. For India, this demonstration of power projection capabilities by nuclear-armed submarines served as a stark realization of the need to bolster its naval arsenal to safeguard national security interests. In response, India started on a path of developing its indigenous SSBN program, recognizing the importance of possessing a credible nuclear deterrent capability to ensure strategic stability in the region.

The initiation of a technical feasibility study for an indigenous nuclear propulsion system, known as Project 932, marked the first step in India’s quest for self-reliance in the development of nuclear propulsion. Led by the Director of Marine Engineering (DME) at Naval Headquarters, this ambitious undertaking aimed to explore the viability and potential of developing a nuclear propulsion system domestically. In the 1990s, the Indian Navy initiated the Advanced Technology Vessel project to develop a nuclear submarine. Originally focused on nuclear-powered fast attack submarines, the project shifted its focus to ballistic missile submarines following India’s nuclear tests in 1998. This realignment aimed to complete India’s nuclear triad capability.

S4 Class

The first boat INS Arihant of the Advanced Technology Vessel project was laid down in 2004 and commissioned in 2016. It is speculated that the 2nd boat INS Arighat is already commissioned but there are no confirmed reports. Both boats have a displacement of 6000 tons but the next-in-line submarines are expected to have higher displacements of 7000 tons and can carry twice payload as the first two boats.

SubmarineNuclear Ballistic Missiles
INS Arihant(S2)4 K-4 and 12 K-15
INS Arighat(S3)4 K-4 and 12 K-15
S48 K-4 and 24 K-15
S4*8 K-4 and 24 K-15

S5 Class

The S5-class submarines, planned as successors to the Arihant class in the Indian Navy, are designated to weigh around 13,500 tonnes, which is twice the displacement of the Arihant class submarines.

SubmarineNuclear Ballistic Missiles
S5 Class12 K6 MIRV Missile

SSBNs are extremely important for India to maintain credible deterrence, specially when you have two nuclear neighbors, with one possessing a nuclear triad is of paramount importance for maintaining a credible second-strike capability and ensuring national security. The triad, consisting of land-based intercontinental ballistic missiles (ICBMs), sea-based submarine-launched ballistic missiles (SLBMs), and air-delivered nuclear weapons, provides redundancy, survivability, and flexibility in response options. It deters potential adversaries from launching a first strike by ensuring that even if one leg of the triad is compromised, the ability to retaliate with devastating nuclear force remains intact. This enhances strategic stability, reduces the risk of miscalculation or accidental escalation, and fosters responsible behavior among nuclear-armed states, ultimately promoting regional peace and security.

To conclude, India must reform its acquisition and planning processes to effectively address evolving threats and ensure the maintenance of a robust and credible defense posture. By streamlining procurement procedures, encouraging indigenous innovation, and enhancing coordination between defense agencies, India can optimize its resources and capabilities to meet present and future challenges. Moreover, maintaining adequate force levels corresponding with the prevailing threat environment is essential for safeguarding national security interests. As regional dynamics evolve with China making inroads into IOR and geopolitical tensions persisting with IOR becoming an arena for great power competition, India being at the heart in the region must remain proactive in modernizing its armed forces to effectively deter potential adversaries and uphold peace and stability and rules-based order in the region.

As you guys wrap up this read, have you got something on your mind?, any questions, thoughts on how we(Government/Navy) should move forward regarding the above topic, or is there anything that you want to know more, feel free to share in the comments.


Bheemanagouda M Patil

Hi, I'm Bheemanagouda Patil, currently I'm pursuing Mechanical Engineering (3rd year) from Dayanand Sagar College Of Engineering. I write on topics related defence and geopolitics.

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