INS Karanj (S21) was a Kalvari class diesel-electric submarine of the Indian Navy. It was the Indian Naval submarine which tracked and followed the US Naval Aircraft Carrier USS Enterprise during the Indo-Pak war of 1971 as it steamed towards the Bay of Bengal as a policy of show of support by President Nixon towards Pakistan. It was reported that it was in position to fire her torpedoes and sink the aircraft carrier multiple times during the duration of the crisis in case the USS Enterprise actually engaged the Indian Navy.