The biggest naval disaster, INS Sindhurakshak exploded in the midnight in Mumbai on August14, 2013 when the submarine caught fire.
At least 18 sailors died in the accident. A major loss to the Navy, INS Sindhurakshak was said to be one of the 10 Kilo-class submarines bought from Russia between 1986 and 2000.
Armed with Russian Club-S cruise missile system, radar and electronics, the submarine was to be the backbone of the Indian Navy.
The submarine had undergone up gradation before the accident. The Russian shipyard that upgraded the submarine under a 2010 contract had claimed it had installed advanced weapons and systems to enhance the boat's combat capability.
