The limitations of the SS-N-1 missile were clear by 1965 and the Soviet Navy decided to convert the ships to a more general purpose / ASW role. These ships were called the Kanin class by NATO. This involved providing the destroyers with a new bow sonar, MG-332 Titan-2 that controlled two quintuple torpedo tubes and three RBU-6000s. To clear the bow sonar also required that the bow be extended . A helicopter pad was installed aft that allowed the ships to operate a Kamov Ka-25 helicopter.