Kalvari-class submarine (1967)

Kalvari-class submarines were the first submarines inducted into the Indian Navy. They were variants of the early Soviet Foxtrot-class submarines. Four of the class served in the Indian Navy. Four additional variants of the later Foxtrot class were inducted as the Vela-class submarine.

INS Kursura (S20) has been preserved as a museum on Ramakrishna Mission Beach in Visakhapatnam. The sail of the lead vessel, INS Kalvari (S23) is also on display at the Visakhapatnam city museum.