INS Vela that Mumbai's Mazagon Dock launched on Monday is the fourth of Indian Navy's six Scorpene-class submarines that will be crucial to the country defence against China's power projection in the Indian Ocean Region. Named after the Soviet-built underwater warship of the same name that served Indian Navy from 1973 to 2010, INS Vela will now undergo fitting and trials and is expected to be commissioned in 2020.

The Scorpene-class submarine is a diesel-electric attack submarine developed jointly by the French Direction des Constructions Navales (DCN) and the Spanish company Navantia, which is now known as the Naval Group. The submarine is lethal as an attack submarine with its powerful diesel propulsion and additional air-independent propulsion (AIP). The later versions of the Scorpene-class submarine that India builds will feature PAFC fuel cell developed by India's Defence Research and Development Organization (DRDO).

The submarines of the class with a displacement of 1,565 tonnes are about 70 metres long and hit 37 km per hour (kmph) underwater and 22 kmph on the surface. The submarine's endurance of 50 days with an additional 21 days on AIP is important for patrolling India's vast exclusive economic zone (EEZ) that extends from Gujarat coast in the west to Kerala and Tamil Nadu coasts in the south to Bengal coast in the east. Indian warships need to be going as far out as the Andaman Islands and the Minicoy Islands in the Indian Ocean.

People Liberation Army Navy's (PLAN) well-known strategy of encircling India with a string of strategically located naval bases in the Indian Ocean Region, known as the String of Pearls, has made it necessary that India has a navy that is fast and stealthy. Chinese presence in Myanmar, Sri Lanka, Pakistan and the African coast has forced the Indian Navy to redraw its defence strategy with enough strategic reach and depth.

INS Kalvari, the first Scorpene-class submarine, was commissioned in December 2107 and the second, INS Khanderi, launched in January 2017, is almost ready for delivery, according to Ajay Kumar, secretary of defence production. INS Karanj, the third submarine, was launched in January last year and has successfully completed its deep-diving trials. It is expected to be commissioned later this year. The keel for the fifth Scorpene-class submarine named INS Vagir is yet to be laid but is tentatively expected to be commissioned in 2021. The expected commissioning date of the sixth submarine of the class to be named INS Vagsheer is 2022.

The state-owned Mazagon Dock Shipbuilders Limited with annual revenue of Rs 4,500 crore has a deal with French collaborator Naval Group (formerly DCNS) for construction and transfer of technology of six Scorpene-class submarines.