The Scorpene data leak is bad news not only for the extent of damage it can potentially cause in terms of Indian Navy’s submarine operations but also for the fact that it adds to India’s woes of dealing with an already thin fleet of subs. According to an Indian Express report, to fulfill its mandate of a blue water navy, India should ideally have around 30 submarines. “A force level of 3-5 SSBNs, six SSNs and 20 SSKs is required to fulfill its mandate of a blue water navy,” sources have told the paper. Submarines are basically of two types: nuclear and conventional.
The nuclear submarines, as the name suggests, are powered by a nuclear reactor. The advantage they enjoy is that they can be under water for months in a go. Within nuclear submarines, there are nuclear-powered attack submarines, or SSNs, and those that carry ballistic missiles with nuclear warheads (SSBNs). SSBNs are equipped with better stealth features and are larger compared to SSNs. They are also said to be the “best guarantor” of a second strike capability in a nuclear exchange.
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On the other hand, conventional submarines, or SSKs, make use of a diesel-electric engine and are required to resurface every day in order to get oxygen for fuel combustion. However, if SSKs are fitted with an air-independent propulsion system (as is the case with Indian Navy’s Scorpene submarines), they can stay longer in the water and would require oxygen only once in a week. Each type of submarine, whether SSK, SSN or SSBN, enjoy various advantages that add to the overall combat capability of a Navy. Where conventional subroutines score over nuclear is in littoral waters (regions near the shore). The effectiveness of conventional submarines in relatively shallow water is a critical requirement and benefit. They are optimised for stealth, and their weapons and sensors provide for effective operations close to the shore.

The guiding principle of submarines is that one should patrol, another should be in transit to patrol, and the third should be in the harbour for maintenance. One SSBN should be underwater at any given point of time to ensure adequate strategic deterrence. This implies that the Navy needs a minimum of three SSBNs in the fleet. “The three aircraft carrier battle groups, envisaged for potent force projection and expeditionary capacity, will need two SSNs each,” the newspaper says. Additionally, if one were to assume an operational availability of 60%, 12 out of the 20 SSKs would be there for both the coasts. This is the minimum required for India to maintain a “credible tactical and operational presence” in shallow waters.
Also read: Scorpene data leak: Details that have been leaked may be old
Now for the reality check! India has no SSBN right now and just one SSN, that is the Akula-class submarine from Russia. This submarine has been taken on lease from Russia in 2012 for 10 years. Meanwhile, INS Arihant, India’s indigenous SSBN is currently undergoing sea trials. As for SSKs, the Indian Navy has 4 Shishumar-class (German Type 209) submarines and 9 Sindhughosh-class (Russian Kilo Class) subs. That’s a total of only 13 SSKs! Of the 13 SSKs, 10 of them are actually of the pre-1990 vintage time. Four Sindhughosh and 2 Shishumar subs will undergo refitting to extend their life. But, despite that it is expected that the conventional submarines will suffer from performance degradation during operations.
To put things in better (or worse!) perspective, the Navies in India’s maritime neighbourhood have been boosting their submarine and anti-submarine warfare capabilities. While China has 53 SSKs, 5 SSNs and 4 SSBNs, Pakistan is acquiring 8 submarines from China. Given the scenario, India desperately needs new submarines, and the Scorpene data leak will be a big blow to India’s maritime security plans.