Mumbai, Oct 29 (IANS): INS Kalvari, the first of the six Scorpene diesel-electric attack submarines (SSK) of the Indian Navy, was set afloat on Thursday for pre-commissioning sea trial for 10 months at the Mazagaon Docks here.

The 66-metre vessel, part of a $3.6 billion contract signed in 2005 with DCNS, France, for delivery of six Scorpene submarines, is scheduled for commissioning in September 2016.

The deal envisages building six SSKs here under the India's Project 75 submarine construction programme, with transfer of technology licence from DCNS.

While four would be conventional submarines, the last two would be equipped with air independent propulsion system that enables vessels to stay underwater for longer duration.

According to the defence ministry, after INS Kalvari, the remaining five vessels under Project 75 will be delivered to the navy every nine months, by 2020, and would form the core of the Indian Navy's submarine arm for the next two decades.

Steeped in the glorious tradition of its illustrious predecessor, the erstwhile Russian 'Foxtrot' class submarine, INS Kalvari would lend enormous fillip to the Indian Navy's underwater capabilities.

"The Scorpene submarines would pack a potent punch. These would be equipped with anti-ship missiles and long-range guided torpedoes along with modern sensor suites," an official said.

Mazagaon Docks Ltd. chairman and managing director Rear Admiral R.K. Shrawat termed the development "a historic milestone" in line with the Indian Navy's credo of 'Glorious Wake, Vibrant Future'.