Established in 1800, Charlestown Navy Yard served the fleet with distinction--especially proving its worth in each of the nation's wars--until its closing in 1974. The men and women of its workforce built more than 200 warships and maintained and repaired thousands. From its inception the yard was in the forefront of shipyard technology, from building the Navy's only ropewalk to making itself a center of missile and electronics conversions. In its 174-year history, Charlestown Navy Yard played an important role in the birth, growth, and continued effectiveness of the U.S. Navy. When the Charlestown Navy Yard closed in 1974 after nearly 175 years of serving the fleet, 30 acres became part of Boston National Historical Park. The National Park Service now maintains an important part of the ship yard, and as part of the Park Service's interpretive program, USS Constitution, in connection with the United States Navy, and USS Cassin Young are preserved as representatives of the kinds of vessels built in this yard. Together they represent a 200-year-old tradition of building fine ships for the Navy. - NPS