NEW DELHI: In a major step towards building a formidable blue-water Navy for the future, the Modi government has cleared the indigenous construction of seven stealth frigates and six nuclear-powered attack submarines, which together will cost well upwards of Rs 1 lakh crore.The Cabinet committee on security (CCS) took these decisions in tune with the “critical necessity” for India to bolster its “overall deterrence capability” in the entire Indian Ocean Region (IOR), especially its primary area of strategic interest stretching from the Persian Gulf to Malacca Strait.Under the over Rs 50,000 crore ‘ Project-17A ’ for stealth frigates, four will be constructed at Mazagon Docks in Mumbai and three in Garden Reach Shipbuilders and Engineers in Kolkata. “The contract will be inked with MDL and GRSE this month itself, with an initial payment of Rs 4,000 crore,” said a source.Both the defence shipyards are already geared up for the project because it’s a “follow-on” to the three 6,100-tonne stealth frigates built by MDL, INS Shivalik, INS Satpura and INS Sahyadari, which were inducted in 2010-2012.The new multi-mission frigates will be larger, faster and stealthier than the Shivaliks as well as packed with more weapons and sensors to operate in “a multi-threat environment”. But it could well take a decade, if not more, to build all the seven frigates.The complex project for the nuclear-powered submarines (SSNs) will take longer. After the CCS approval, technical parameters or naval staff qualitative requirements (NSQRs) will now be drafted for the over 6,000-tonne submarines.The SSNs are likely to be constructed at the secretive ship-building centre (SBC) in Vizag, where India’s first three SSBNs (nuclear-powered submarines with nuclear ballistic missiles) are being built to complete the country’s nuclear weapons triad.The government has basically “reworked” the 30-year diesel-electric submarine-building plan, approved by the CCS in 1999, which envisaged induction of 12 new conventional submarines by 2012, followed by another dozen by 2030. But with no new submarine inducted till now, the government has decided to go in for six SSNs and 18 conventional vessels, said sources.Nuclear-powered submarines are much deadlier than diesel-electric submarines since they do not need to surface every few days to get oxygen to recharge their batteries. “SSNs, which usually carry only conventional missiles, can swiftly and quietly undertake long-range patrols. They can run at high speeds like 30 knots for much longer distances, hunting for targets and gathering intelligence,” said an expert.INS Chakra, the nuclear-powered Akula-II class SSN taken on a 10-year lease from Russia, may not be armed with long-range missiles due to international treaties, but has bolstered India’s depleting underwater combat arm that is currently grappling with just 13 ageing conventional diesel-electric submarines.Armed with 300km range Klub-S land-attack cruise missiles and advanced torpedoes, INS Chakra can be a potent ‘hunter-killer’ of enemy submarines and warships as well as provide effective protection to a fleet at sea.