How 3 more Kalvari submarines will boost Indian Navy's underwater strength

Talks for acquiring additional Kalvari-class Scorpene submarines have reportedly seen progress, with MDL in advanced discussions for a potential Rs 35,000-cr deal for three stealthy vessels

State-owned Mazagon Dock Shipbuilders Limited (MDL) is in advanced talks for a potential Rs 35,000-crore deal, under which the Indian Navy will acquire three additional Kalvari-class submarines that will be larger and more advanced than the six vessels of the same class that India had previously acquired, the Economic Times reported on Monday.

A contract for six French Scorpene (Kalvari-class) conventional submarines was signed in 2005. The first of the Kalvari-class submarines, built at MDL, was inducted in 2017. While the sixth submarine is slated for induction this year, approval was given for three additional conventional vessels in 2023.

An export derivative of the French-origin Scorpene-class submarine, the Kalvari-class vessels are diesel-electric attack submarines operated by the Indian Navy. They have been built by a syndicate of French and Indian shipyards -- the Naval Group and MDL, respectively. The Scorpene-class vessels were originally designed by the Naval Group.

 

What's the latest update on India's Kalvari-class subs? 

According to the ET report, MDL has submitted a detailed techno-commercial bid for the contract for three additional Kalvari-class submarines to the Ministry of Defence (MoD). 

Under its bid, MDL has reportedly promised at least 60 per cent indigenous content in the new submarines, with a large share of the work going to Indian suppliers and micro, small and medium enterprises in the country. For this reason, MDL and its suppliers are reportedly expected to receive significant technology transfer while building these three additional boats. The ET report says that this will pave the way for future submarines of the same class to be fully designed, developed and manufactured within India.

A major part of the contract value of the three vessels will reportedly remain within the Indian ecosystem.

The final pricing of the three submarines will be determined after tough negotiations between MDL and the MoD, but the deal is likely to be valued at around Rs 35,000 crore, said the ET report, citing unnamed sources. The report added that this deal value would be in line with international pricing for new submarines of the class.

Under Project 75, MDL has also built the previous tranche of Kalvari class submarines with French assistance. MDL's proposal reportedly says that the three additional submarines can be delivered within six years.

How will the new subs be different from past Kalvari boats?

The three additional Kalvari-class submarines will be larger than their predecessors and equipped with more modern electronics, the ET report said, while citing sources.

They will also have longer endurance, with the report saying that advances in propulsion technology will also be incorporated into the new vessels.

According to the ET report, the three new submarines will be capable of travelling greater distances than their predecessors, which already possess the ability to reach as far as Australia during operational deployments.

While the ET report did not say that the three new submarines would be equipped with an air-independent propulsion (AIP) system, previous reports had suggested that this was a possibility. However, the ET report's mention of these boats being equipped with advanced propulsion technology could be a reference to an AIP system, which will allow them to stay underwater for longer.

According to a July 2023 report by ThePrint, Naval Group France and the Defence Research and Development Organisation (DRDO) had signed an agreement in January that year to install an indigenous AIP system onboard the Kalvari-class submarines.

The report added that the three new Kalvari-class submarines would have an indigenous AIP system fitted on board.

While all six previous Kalvari-class submarines were reportedly meant to undergo a refit to install AIP systems in the due course of time, that project has been delayed. In fact, according to the original plan, the fifth and sixth Kalvari-class submarines were meant to have an indigenous AIP system on board, but that did not come through.

What is an AIP submarine propulsion system?

An AIP system refers to any means of marine propulsion that enables a conventional, non-nuclear-powered submarine to operate for extended periods of time without surfacing or using a snorkel, which is needed for access to atmospheric oxygen.

Most diesel-electric submarines are forced to surface to recharge their batteries after a specific period, which makes them vulnerable to enemy sensors. Meanwhile, an AIP-equipped submarine is stealthier in comparison, since it possesses a greater underwater endurance.

Why are the new Kalvari-class submarines important?

India's Project-75 (I) programme, under which six conventional submarines are to be built within the country with AIP systems, is still under the works. In the meantime, these three new submarines will help the Indian Navy boost its underwater strength.

At present, the Indian Navy operates 16 conventional submarines, including seven Russian Sindhughosh-class, five Indo-French Kalvari-class, and four German Shishumar-class submarines.

The Navy also has two nuclear-powered ballistic missile-carrying submarines belonging to the Arihant class.

However, its conventional submarine arm is getting long in the tooth and beginning to face competition from Pakistan.

In April, China launched the first of the eight advanced Hangor-class stealth submarines it is building for the Pakistan Navy. These submarines will reportedly be equipped with weapons to strike targets at standoff ranges. Also a diesel-electric attack submarine, the Hangor-class vessel will also be reportedly equipped with an AIP system.

At present, the Pakistan Navy operates three Agosta 90B submarines equipped with AIP systems and two Agosta 70 diesel-electric vessels.

Launching ceremony of first HANGOR-class submarine constructed for Pakistan Navy held at Shuangliu Base in Wuhan, China, on April 26, 2024. Image credit: Pakistan Navy