The O'Brien class of destroyers was a class of six ships designed by and built for the United States Navy shortly before the United States entered World War I. The O'Brien class was the third of five classes of destroyers that were known as the "thousand tonners", because they were the first U.S. destroyers over displacement. The design of what became the O'Brien class was the result of discussions between the General Board of the United States Navy and the U.S. Navy's Bureau of Ordnance. What resulted was a design that was an incremental development of the , which itself was similar to the first of the thousand tonners, the (which displaced about a third more than the preceding ). The key difference in the O'Brien class was the increase in torpedo size, going up to from the preceding classes' torpedoes. The ships had a median displacement of , were just over in length, and had a beam of about . All of the ships had two direct-drive steam turbines and a combination of other engines for cruising at speeds less than . All of the ships were designed for a maximum speed of . As built, they were armed with four guns and had four twin 21 inch (533 mm) torpedo tubes with a load of eight torpedoes, but all were later equipped with depth charges. The ships were built by four private American shipyards—Bath Iron Works, Fore River Shipbuilding Company, New York Shipbuilding Corporation, and William Cramp & Sons—and were laid down between September and November 1913; launched between April 1914 and February 1915; and commissioned into the U.S. Navy between June 1914 and August 1915. All six ships operated in the Atlantic or Caribbean until the U.S. entrance into World War I in April 1917, when all six were sent overseas to Queenstown, Ireland, for convoy escort duties. Several of the ships rescued passengers and crew from ships sunk by U-boats, and several had encounters with U-boats themselves; helped sink in November 1917, the first U-boat sunk by the U.S. Navy. All six members of the class had returned to the United States in January 1919 and were decommissioned by June 1922. In 1924, two of the six— and —were commissioned into the United States Coast Guard to help enforce Prohibition as a part of the "Rum Patrol". They were returned to U.S. Navy custody in 1932