The fourth Scorpene submarine of Project - 75, Yard 11878 was delivered to the Indian Navy on Tuesday.The Project - 75 includes the construction of six submarines of Scorpene design. These submarines are being constructed at Mazagon Dock Shipbuilders Limited (MDL) Mumbai, under collaboration with Naval Group, France.Project-75 envisages construction of six submarines of Scorpene design. Three of them -- Kalvari, Khanderi and Karanj -- have already been delivered to the Navy and commissioned.These submarines are being constructed at Mazagon Dock Shipbuilders Limited (MDL) Mumbai, under collaboration with M/s Naval Group, France. Christened ‘Vela’, the submarine was launched on 06 May 19, and has completed all major harbour and sea trials including weapon and sensor trials despite COVID restrictions. Three of these submarines are already in commission with the Indian Navy.Submarine construction is an intricate activity as the difficulty is compounded when all equipment are required to be miniaturised and are subject to stringent quality requirements. Construction of these submarines in an Indian yard is yet another step towards ‘AatmaNirbhar Bharat’.The submarine would soon be commissioned into the Indian Navy and enhance the Indian Navies capability.The `Acceptance Document' was signed by Vice Admiral Narayan Prasad, Chairman and Managing Director MDL and Rear Admiral K P Arvindan, Chief Staff Officer (Tech), Western Naval Command in the presence of MDL Directors and Navy personnel at MDL, the release said. The fifth submarine `Vagir' was launched on November 12, 2020, and has started her harbour trials, MDL said. It is expected to go for the maiden surface sortie in December whilst the sixth submarine is presently in the advanced stage of outfitting, it added.