ISS67: dp. 520.6 (surf. n.), 629 (subm.); l 1724; b. 18 Ό; dr. 145; s. 14 k. (surf.), 10.5 k. (subm.); cpl. 29; a. 1 3, 4 18 tt.; cl. O1).
O6, was laid down 6 December 1916 by Fore River Shipbuilding Co., Quincy, Mass.; launched 25 November 1917; sponsored by Mrs. Carrol Q. Wright; and commissioned at Boston 12 June 1918, Lt. C. Q. Wright, Jr., in command.
During the final months of World War I, O6 operated out of Philadelphia, on coastal patrol against U-boats, cruising from Cape Cod to Key West. A British merchantman fired 6 shots at O6 on 14 July 1918, but caused no appreciable damage. On 2 November the boat departed Newport in a 20-sub contingent bound for service in European waters, however, the Armistice had been signed before the vessels reached the Azores, and they returned to the United States.
After the war, O6 prolonged her Naval career by operating as a training ship out of New London. Reclassified to a 2nd line submarine 25 July 1924 while stationed at Coco Solo, C.Z., she reverted to 1st line class 6 June 1928 and continued at New London until February 1929, when she steamed to Philadelphia, to decommission there 9 June 1931.
Submarines had proved to be a major weapon in World War I. As U.S. involvement in World War II approached, old subs were taken out of mothballs and prepared to renew training activities. O6 recommissioned at Philadelphia 4 February 1941 and then returned to New London to train students at the sub school. On 19 June 1941, O6 made a trial run to Portsmouth, N.H.; the next day O9 went down 15 miles off Portsmouth. O6 joined O10, Triton, and other vessels in the search for the lost sub, but to no avail.
Remaining in the Portsmouth area, O6 decommissioned there 11 September 1945, was struck from the Navy Register the same day, and was sold to John J. Duane Co., of Quincy, 4 September 1946. The boat was subsequently scrapped in December 1946.