(SS66: dp. 520.6 (surf. n.), 629 (subm.); l 1724; b. 18 ¼; dr. 145; s. 14 k. (surf.), 10.5 k. (subm.); cpl. 29; a. 1 3, 4 18 tt.; cl. O1).
O5, a submarine laid down 8 December 1916, was built in 1917 by Fore River Shipbuilding Co., Quincy, Mass.; launched 11 November 1917; and commissioned 8 June 1918, Lt. G. A. Trever in command.
During the final months of World War I, O5 operated along the Atlantic coast and patrolled from Cape Cod to Key West. She departed Newport 3 November with a 20-sub contingent bound for European waters; however hostilities had ceased before the vessels reached the Azores.
After the Armistice, O5 operated out of the Submarine School at New London, Conn. until 1923. O5 then sailed to Coco Solo, C.Z. for a brief tour. On 28 October 1923, as O5 entered Limon Bay, preparatory to transiting the Canal, she was rammed by United Fruit steamer Abangarez and sank in less than a minute, with the loss of 3 men.
Struck from the Navy Register 28 April 1924, she was sold as a hulk to R. K. Morris, Balboa, C.Z. 12 December 1924.