Scorpene class submarine Vela, equipped with modern machinery and technology to guard the seas, was launched in Mumbai on Monday, an official said.
It will undergo a number of tests by the Indian Navy before it gets commissioned in the defence fleet, the official added.
It is the fourth submarine to be launched by the state-owned Mazagon Dock Shipbuilders Limited (MDL) after entering into a contract for the construction and transfer of technology for six Scorpene class submarines with French collaborator Ms Naval Group (formerly known as DCNS).
"Today, we are bringing the new Vela with modern machinery and technology to guard the seas," an official from MDL said.
INS Vela was first commissioned on August 31, 1973 in the Indian Naval service and continued to serve for 37 years. It was the oldest submarine of the country when it was decommissioned on June 25, 2010, MDL said in a statement.
The fifth Scorpene class submarine will also be launched soon, he said.
MDL recently reported an annual turnover of Rs 4,500 crore, the official added.