'Sir, We Lost a Submarine': How a Russian-Built 'Black Hole' Sub Was Lost 3,000 Feet Down

Summary and Key Points: Since the Cold War, India has relied on Soviet and Russian military hardware, including 10 Kilo-class submarines like the INS Sindhurakshak. This submarine, respected for its stealth capabilities, sometimes called the 'black hole' submarine, had a troubled service life with multiple incidents, including a 2010 fire.

-In August 2013, it suffered a catastrophic explosion in Mumbai's naval dockyard, killing 18 crew members.

-An investigation revealed lapses in standard procedures during torpedo loading.