With peace came the end of Charlestown’s brief period as a major shipbuilding center. But the war-seasoned yard did not simply revert to what it had been before. Charlestown found a new postwar role as a place where old vessels were remade from the inside out, transformed into modern warships. Old did not necessarily mean long in years. In the 1950s, ships that had performed admirably in the late war were being left behind in a world of accelerating technological change. Charlestown extended their careers, installing state-of-the-art electronics. When advances in missile technology opened a new era in naval weapons and strategy, Charlestown played a leading role in the changeover. The life of the crowded and aging yard itself was extended by such activities, enabling Charlestown to render another three decades of service to the country.
In the months after war’s end, the level of activity naturally fell off, but the yard remained busy converting transports to bring home the troops, inactivating ships, and completing the last few LSTs, barracks ships, and subs laid down in 1945. Charlestown also carved a niche for itself in sonar, a technology dating to the World War I period and considered standard equipment since the 1930s. Beginning in 1948 the yard became a center for the repair of sonar equipment, establishing a sonar laboratory and developing techniques adopted by other electronics repair centers throughout the Navy.
Radar, developed in the 1930s, had come into widespread use during the war. The yard undertook a major conversion program in 1950 when it began upgrading radar and sonar systems on a number of destroyers and destroyer escorts, converting them to radar picket and antisubmarine warfare (ASW) roles. Charlestown also planned and designed all alterations, wherever they were performed, to cruisers, destroyers, escort carriers, LSTs, and several auxiliary vessel types.
While the yard accepted a variety of vessels, including aircraft carriers, it continued its traditional specialization in destroyers and destroyer escorts. In 1955 the yard converted the 10-year-old _Gyatt_ into the world’s first guided missile destroyer.
That year the yard laid down the keel of its only postwar vessel and the last one it built: the LST _Suffolk County_, first of a larger and faster class of LSTs. Charlestown also served as the design yard for the other six LSTs, built in private yards.