ISS–67: dp. 520.6 (surf. n.), 629 (subm.); l 172’4”; b. 18’ ¼”; dr. 14’5”; s. 14 k. (surf.), 10.5 k. (subm.); cpl. 29; a. 1 3”, 4 18” tt.; cl. O–1).
O-6, 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, O-6 operated out of Philadelphia, on coastal patrol against U-boats, cruising from Cape Cod to Key West. A British merchantman fired 6 shots at O-6 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, O-6 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. O-6 recommissioned at Philadelphia 4 February 1941 and then returned to New London to train students at the sub school. On 19 June 1941, O-6 made a trial run to Portsmouth, N.H.; the next day O-9 went down 15 miles off Portsmouth. O-6 joined O-10, Triton, and other vessels in the search for the lost sub, but to no avail.
Remaining in the Portsmouth area, O-6 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.