(This story originally appeared in on Dec 17, 2014)

NEW DELHI: India is on course to acquire a second nuclear-powered submarine on lease from Russia to bolster its depleted underwater combat arm as well as train its sailors in the complex art of operating such vessels.Defence minister Manohar Parrikar indicated this possibility on Tuesday on being asked whether India was planning to acquire another Akula-II class nuclear submarine from Russia after President Vladimir Putin's visit here last week.India had inducted the first Akula-II submarine, christened INS Chakra , on a 10-year lease from Russia in April 2012, under a secret around $1 billion deal inked way back in January 2004.India and Russia have been holding talks on leasing another mothballed Akula-II submarine named "Irbis'', the full construction of which also could not be completed due to financial problems after the USSR broke up in the early-1990s, as earlier reported by TOI."It's an open secret. We are discussing the possibility of extending the current lease or of taking another submarine on lease. This will help us in training," said Parrikar, after paying homage at Amar Jawan Jyoti on Vijay Diwas.This comes a day after India's first indigenous nuclear submarine INS Arihant began its sea-trials off Visakhapatnam. It will take "10-12 months" for the 6,000-tonne INS Arihant to be ready for induction, said Parrikar.The difference between INS Arihant and these 8,000-tonne Akula submarines is that the latter are not armed with nuclear-tipped or long-range missiles due to international treaties. INS Arihant, during its long-drawn sea trials, will also have to test-fire its nuclear-tipped K-15 ballistic missiles before it can become fully-operational.While not meant for "nuclear deterrent patrols", INS Chakra can be "a potent hunter-killer'' of enemy submarines and warships as well as undertake swift intelligence-gathering operations, apart from being equipped with land-attack conventional cruise missiles. In this, the leased submarine has added some much-needed muscle to India's depleting fleet of 13 ageing diesel-electric submarines, only half of them which are currently operational.INS Chakra also serves as a training platform for INS Arihant and its two follow-on sister SSBNs (nuclear-powered submarines armed with ballistic missiles) being built at the shipbuilding centre at Vizag.The next SSBN, INS Aridhaman, is also now ready for "launch" into water, while the third called S-4 is at an advanced fabrication stage in the building blocks. The Navy is also pursuing the proposed project to build six SSNs (nuclear-powered attack submarines without ballistic missiles) at Vizag, as earlier reported by TOI.Nuclear submarines can operate at high speeds for long distances, and do not have to surface or "snorkel" every few days to get oxygen to recharge their batteries like diesel-electric submarines.