Design conservatism and economic realities forced Portsmouth to continue to use riveting in the construction of the inner and outer hulls, although non-critical areas like the superstructure, piping brackets, support framing, and interior tankage were actually welded.

[6] After shakedown, further construction, tests, and overhaul, Cachalot sailed for San Diego, California, where on 17 October 1934 she joined the Submarine Force, U.S. Fleet.

Operating until 1937 principally on the West Coast, she engaged in fleet problems, torpedo practice, and antisubmarine, tactical, and sonar training exercises.

Returning to Pearl Harbor on 26 July, she cleared on her final war patrol on 23 September, penetrating the frigid waters of the Bering Sea in support of the Aleutian Islands operations.

Over-age and lacking endurance for strenuous war patrols, Cachalot still had a key role to play, acting as training ship for the Submarine School at New London.