The Centre has set the ball rolling for the production of six conventional submarines even as its fleet is a fraction of what is operated by China. For a country with wide maritime interests and big power ambitions, submarines are an indispensable asset. But India is seen as having lagged in this area. While the country pursues the production of submarines on priority, here’s what you need to know about these vessels and the advantage they bring.

How Many Submarines Does India Have?

The Indian Navy is said to have a total of 18 operational submarines, of which 16 are of the diesel-electric type. Of the remaining two, one is an indigenously-made ballistic missile nuclear submarine (SSBN) while the other is a nuclear-powered submarine (SSN) that has been leased from Russia. If you’re wondering what the abbreviations stand for, they are submersible ship ballistic nuclear, and submersible ship nuclear, respectively. Diesel-electric submarines are also called SSK, the ‘K’ standing for ‘killer’.

Compare this with China’s reported fleet size of between 70-80 submarines, of which at least six are SSN with the People’s Liberation Army Navy (PLAN) also said to have four SSBN and at least 50 SSK.

Last month, it was reported that the Akula class SSN leased from Russia, which was christened INS Chakra while in Indian service, had been returned to the parent country. It was the second SSN that India had leased from Russia; the first, also called INS Chakra, had reportedly been taken from the erstwhile USSR in 1988 under a three-year lease.

India signed another deal with Russia in 2019 to lease an SSN for a third time for a period of 10 years. Under the $3 billion deal, Russia is expected to deliver an Akula class submarine, to be known as Chakra III, by 2025.

What Is The Difference Between The Various Kinds of Submarines?

According to the Carnegie Science Centre (CSC), the first recorded use of a submarine in combat was in 1776, when the “small human-powered ‘Turtle'” was used by the American colonists in an unsuccessful attempt to sink a British ship. Submarines have, of course, come a long way since then although the ones most commonly used — the diesel-electric vessel — were introduced in the “later part of the 19th century”.

“Diesel electric drive permitted submarines to make long-range voyages… Endurance in undersea vessels increased to over 6,000 miles. As their range increased, so did the size of the submarines,” CSC says, adding that “the greatest advance in submarine technology occurred on January 21, 1954, with the launch of the USS Nautilus, the first nuclear-powered vessel”.

Nuclear-powered submarines can stay underwater for indefinite periods and need to surface only for food and crew requirements. According to the US Naval Institute (USIN), “the performance advantages of nuclear submarines over conventional, diesel-electric submarines are considerable”.

Experts say that compared to SSNs, diesel-electric submarines are really more like ‘submersibles’. The latter have to ‘snorkel’, that is, expose themselves over water, frequently to clear the exhaust from their diesel generators and charge their batteries. Also, they must slow down while snorkeling. But with SSNs, there is no need to snorkel and they can stay completely submerged.

There is also the difference of speed. USIN says that SSNs can have “a sustained submerged speed of more than 30 knots (55 kmph), considerably greater than any contemporary diesel submarine”.

What Is The Difference Between SSNs And SSBNs?

While both are nuclear-powered, the key difference between these two classes of submarines is tactical. An SSBN plays a deterrent role. Armed with nuclear weapons, it is part of what is known as the nuclear triad for countries that have nuclear weapons, the other two components being aircraft and land-based missiles. It is considered to be the concealed part of the triad, designed to strike even if the other two components are destroyed. Hence, they are not to be used in normal warfare.

SSNs on the other hand, are attack submarines and are armed with conventional weapons and missiles and can be deployed against enemy targets.

India has indigenously built two SSBNs with two more under construction at the Ship Building Centre in Visakhapatnam. The INS Arihant, the first of the SSBNs, was commissioned in 2016 while the second, INS Arighat, was launched in 2017 and is in the process of being commissioned.

India is also reportedly pursuing the construction of its own SSNs with the Navy said to have told the government that plans to induct six such vessels would take precedence over the project to build a third aircraft carrier.

What Are The Submarines For Which Proposal Has Been Sought?

The request for proposal (RFP) issued by the Defence Ministry is for six conventional, diesel-electric submarines that are to be manufactured under the ‘Make in India’ initiative. The Centre has identified five foreign-based makers — Naval Group of France, TKMS of Germany, JSC ROE of Russia, Daewoo Shipbuilding and Marine Engineering Co Ltd of South Korea and Navantia of Spain — for the project and the Indian partners (Mazagon Dock Shipbuilders Ltd and Larsen & Toubro) will have to partner any one each of these companies to submit bids.

India’s diesel-electric submarine fleet includes the Kalvari class vessel, which is based on the French Scorpene-class submarine while the Sindhughosh-class submarines are built under a contract with Russia. There is also the Shishumar-class of vessels that were developed by Germany.