USS O'Brien (Destroyer No. 51/DD-51) was the lead ship of s built for the United States Navy prior to the American entry into World War I. The ship was the second US Navy vessel named in honor of Jeremiah O'Brien and his five brothers Gideon, John, William, Dennis, and Joseph who, together on the sloop Unity, captured a British warship during the American Revolutionary War. O'Brien was laid down by William Cramp & Sons of Philadelphia in September 1913 and launched in July 1914. After her May 1915 commissioning, O'Brien sailed off the east coast and in the Caribbean. She was one of seventeen destroyers sent out to rescue survivors from five victims of German submarine off the Lightship Nantucket in October 1916. After the United States entered World War I in April 1917, O'Brien was sent overseas to patrol the Irish Sea out of Queenstown, Ireland. After returning to the United States in January 1919, O'Brien revisited European waters in May to serve as one of the picket ships for the NC-type seaplanes in the first aerial crossing of the Atlantic. O'Brien was decommissioned at Philadelphia in June 1922. She was struck from the Naval Vessel Register in March 1935 and sold for scrapping in April. Design and construction O'Brien was authorized in March 1913 as the lead ship of the , which was an improved version of the s authorized in 1911. Construction of the vessel was awarded to William Cramp & Sons of Philadelphia which laid down her keel on 8 September 1913. On 20 July 1914, O'Brien was launched by sponsor Miss Marcia Bradbury Campbell, great-great-granddaughter of Gideon O'Brien, one of the ship's namesakes. Gideon and his four brothers—John, William, Dennis, and Joseph—were crewmen aboard sloop Unity, under the command of their brother Jeremiah O'Brien, when that vessel captured on 12 June 1775 during the American Revolutionary War; the destroyer O'Brien was named after all six brothers, and was the second US Navy vessel named in their honor. As built, the destroyer was in length, abeam, and drew . The ship had a standard displacement of and displaced when fully loaded. O'Brien had two Zoelly steam turbines that drove her two screw propellers, and an additional pair triple-expansion steam engines, each connected to one of the propeller shafts, for cruising purposes. Four oil-burning White-Forster boilers powered the engines, which could generate , moving the ship at