India is having four more of its ten Kilo class submarines equipped with the Russian 3M54 ("Klub") anti-ship missiles. Only two Indian Kilo boats currently have the Klub, and that was only after some troublesome testing.
Last year, India finally accepted the Russian refurbishment of one of its Russian made Kilo submarines, the INS Sindhuvijay. The year before, India had refused to accept the refurbished Kilo because of repeated failures of the subs Klub missiles it was not equipped with. The Indian sub had test fired six Klubs in late 2007, and all failed. The Russians had no explanation for the failures. That boat had been in Russia for over two years, for $80 million worth of upgrades and repairs. India refused to pay, or take back the sub, until Russia fixed the problems with the missiles. This the Russians eventually did, and there were several successful Klub launches a year ago. India has had four of its Kilo class boats refurbished in Russia.
The Klub missile is a key weapon for the Kilo. Weighing two tons, and fired from a 533mm (21 inch) torpedo tube, the 3M54 has a 440 pound warhead. The anti-ship version has a range of 300 kilometers, and speeds up to 3,000 kilometers an hour during its last minute or so of flight. There is also an air launched and ship launched version. A land attack version does away with the high speed final approach feature, and has an 880 pound warhead.
What makes the 3M54 particularly dangerous against ships is its final approach, which begins when the missile is about 15 kilometers from its target. Up to that point, the missile travels at an altitude of about a hundred feet. This makes the missile more difficult to detect. The "high speed approach" (via the use of additional rockets) means that it covers that last fifteen kilometers in less than twenty seconds. This makes it difficult for current anti-missile weapons to take it down.
The 3M54 is similar to earlier, Cold War era Russian anti-ship missiles, like the 3M80 ("Sunburn"), which has a larger warhead (660 pounds) and shorter range (120 kilometers.) The 3M80 was still in development at the end of the Cold War, and was finally put into service about a decade ago. Even older (it entered service in the 1980s) is the P700 ("Shipwreck"), with a 550 kilometers range and 1,650 pound warhead.
All these missiles are considered "carrier killers," but it's not known how many of them would have to hit a carrier to knock it out of action, much less sink it. Moreover, Russian missiles have little combat experience, and a reputation for erratic performance. Quality control was never a Soviet strength, but the Russians are getting better, at least in the civilian sector. The military manufacturers appear to have been slower to adapt.
India plans to use the Klub against Pakistani, or Chinese, ships in any future conflict.