X-1, the Navy's only midget submarine, was laid down on 8 June 1954 at Deer Park, Long Island, N.Y., by the Engine Division of Fairchild Engine and Airplane Corp.; launched on 7 September 1955 at Oyster Bay, Long Island, by Jakobson's Shipyard; delivered to the Navy on 6 October at New London, Conn.; and placed in service on 7 October 1955, Lt. K. Hanlon in command.
X-1 served in a research capacity in rigorous and extensive tests to assist the Navy to evaluate its ability to defend harbors against very small submarines. Further tests conducted with the X-1 helped to determine the offensive capabilities and limitations of this type of submersible.
Originally powered by a hydrogen peroxide/diesel engine and battery system, an explosion of her hydrogen peroxide supply on 20 May 1957 resulted in the craft's modification to diesel-electric drive. On 2 December 1957, X-1 was taken out of service and inactivated at Philadelphia, Pa.
Towed to Annapolis in December 1960, X-1 was reactivated and attached to Submarine Squadron 6 and based at the Small Craft Facility of the Severn River Command for experimental duties in Chesapeake Bay. In tests conducted under the auspices of the Naval Research Laboratory, X-1 performed for scientists who observed her operations from a platform suspended beneath the Bay Bridge, to learn more about the properties and actions of sea water.
Remaining in an active, in service, status through January 1973, X-1 was again taken out of service on 16 February 1973 and, on 26 April, was transferred to the Naval Ship Research and Development Center, Annapolis. On 9 July 1974, the submersible was slated for use as a historical exhibit; and she was subsequently placed on display on the grounds of the Naval Station complex, North Severn, near Annapolis.