ON MARCH 31, 1958, the U.S. Navy established the world’s first Atomic Submarine Division. Its inception had been announced to the press earlier in the month and reported in the New York Times. Three atomic submarines, Nautilus, Sea Wolf, and Skate, joined three diesel-powered submarines, Hardhead, Bang, and Halfbreak to make up the unit. The latter were replaced as more atomic submarines were commissioned, beginning with the launch of the Skipjack in May of 1958. For the first three months, Atomic Submarine Division 102 was under the command of Comdr. Roger G. Black, a WWII submarine veteran. In July, command was passed to Capt. Eugene P. Wilkinson (first skipper of the Nautilus -- the world's first atomic submarine) after he completed his studies at the Naval War College.
In the years during and after WWII, Chelsea continued to live up to its reputation as Timekeeper of the Sea, manufacturing thousands of clocks for the United States Armed Forces for use on Liberty ships, destroyers, submarines, battleships, cruisers, and aircraft carriers.