sentences:  According to some Soviet sources, "K-33" underwent an overhaul at a Soviet Northern Fleet base from 25 October 1962 through 29 December 1964 and therefore could not have been involved in the collision, and at the time the Soviets claimed that the submarine involved was not a nuclear submarine, although "Finnclipper"s crew had identified "K-33" clearly.A 1996 Russian article says "K-33" was en route to a patrol in the North Atlantic Ocean when she collided with "Finnclipper".