INS Vagir, fifth Scorpene submarine, commissioned

Subject : Science and Technology

Defence

Concept :

INS Vagir, which is the fifth Scorpene-class conventional submarine, was commissioned into the Indian Navy.
Also, INS Kalvari, the first Scorpene-class submarine built for the Indian Navy, will be fitted with an indigenous Air Independent Propulsion (AIP) system developed by the Defence Research and Development Organisation (DRDO), the Ministry of Defence (MoD) has said in a statement.
Six conventional diesel-electric Scorpene-class submarines are being built at the Mazagon Dockyards Limited in Mumbai under Project 75.
With the inclusion of INS Vagir, the Indian Navy now has 16 conventional and one nuclear submarine in service which includes:
- Seven Russian Kilo-class submarines
- Four German HDW submarines
- Five Scorpene class submarines
- INS Arihant which is indigenous nuclear ballistic missile submarine
Further the sixth and the last of the French-origin Scorpene-class submarines, INS Vagsheer, being built in India under technology transfer is currently undergoing sea trials and will be delivered to the Navy in 2024.

Kalvari-class submarine

Vagir is a Kalvari-class submarine, which includes vessels, such as the INS Kalvari, INS Khanderi, INS Karanj, INS Vela, INS Vagir and INS Vagsheer.
In April, 2022 INS Vagsheer was launched and would be commissioned by 2023.
In maritime parlance, a class of ships is a group of vessels which have the same make, purpose and displacement.
The class is generally named after the first vessel in the category.
This class of submarines have Diesel Electric transmission systems and these are primarily attack submarines or ‘hunter-killer’ types.
This means they are designed to target and sink adversary naval vessels.
These submarines are around 220 feet long and have a height of 40 feet.
It can reach the highest speeds of 11 knots (20 km/h) when surfaced and 20 knots (37 km/h) when submerged.

Technical features

Vagir is capable of undertaking diverse missions including anti-surface warfare, anti-submarine warfare, intelligence gathering, mine laying and surveillance missions.
It has advanced stealth features and is also equipped with both long-range guided torpedoes and anti-ship missiles.

Air Independence Propulsion Systems (AIP)

AIP system gives a submarine the ability to remain submerged underwater, away from enemy sensors, for a long time without surfacing.
A diesel-electric boat not equipped with an AIP has to snorkel frequently to recharge its batteries which power its propellers and other equipment.
The process of snorkeling involves travelling just below the surface of the water with the submarine’s periscope and generator exhaust pipe above the surface.
Submarines have to rise to periscope depth and extend the snort mast above the water line — every day or two in some cases — so as to ingest air needed for running noisy diesel generators (which require atmospheric air) to charge their batteries.
This significantly increases the risk of detection.

Significance of AIP

Radars on modern anti-submarine warfare platforms can easily detect periscope and exhaust pipes, taking away the element of surprise critical for submarines.
An AIP system reduces the need for snorkeling by enabling it to generate electricity for charging its batteries while completely submerged.
As a result, it improves a submarine’s ability to remain undetected.
Most AIP systems installed on submarines use liquid or compressed oxygen or hydrogen fuel cells to reduce the need for external sources.
DRDO’s AIP is based on Phosphoric Acid Fuel Cell technology, which offers relatively longer life and more efficiency, which makes it cost-effective.