Cassin Young
The US Coast Guard has a base in Boston, and the sail frigate USS Constitution ("Old Ironsides") is berthed at the former Charlestown Navy Yard, now part of the Boston National Historical Park. The park is also home to the USS Cassin Young, a World War II-era Fletcher-class destroyer and now a museum ship. The park's Drydock Number 1 was completed in 1833 and first used by the "Constitution." It is now used to overhaul historic ships, including "Constitution" in 1992 and "Cassin Young" in 2007. Two other pre-World War II-era dry docks in the harbor are still operational (as of 2014), including Dry Dock Number 3 — one of the largest dry docks on the U.S. East Coast — which regularly repairs ships for the Military Sealift Command. These are located at the former South Boston Naval Annex.