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X-1 / SSX-1

X-1 - the Navy's first and only midget submarine - the US Navy's midget submarine design, was built in 1955 to test U.S. defenses against enemy counterparts. Originally powered by an experimental hydrogen-peroxide propulsion system, X-1 was converted to conventional propulsion after a 1957 explosion destroyed much of her original bow.

X-1 was laid down on 8 June 1954 at Deer Park, Long Island, NY, 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-l 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-l helped to determine the offensive capabilities and limitations of this type of submersible.

In the early 1930s the brilliant German engineer, Dr. Helmuth Walter (ca. 1900-1980) of Kiel's Germaniawerft, proposed a radical new submarine propulsion plant based on the use of high-purity hydrogen peroxide (H2O2) as an oxidant. In Walter's system, hydrogen peroxide from an onboard supply was decomposed using a permanganate catalyst to yield high temperature steam and free oxygen. Into the reaction chamber was injected diesel fuel, which combusted with the oxygen to yield a mixture of steam and hot gas that drove a high-speed turbine. The exhaust and condensed steam were then expelled overboard. Walter's primary design goal was high underwater speed, rather than long endurance, and indeed, his first submarine prototype, the experimental V80, reached 28.1 knots submerged in its 1940 trials - at a time when conventional submarines were limited to 10 knots or less. Thus, V80, only 76 tons and 22 meters long, also served as an early test bed for studying the dynamics and control of high-speed underwater vehicles.

After the conflict, several nations sought to exploit Dr. Walter's revolutionary propulsion concepts. As war prizes, the United States and Britain received the scuttled Type XVIIBs, U-1406 and U-1407, respectively.

In September 1955, the U.S. Navy's first midget submarine, the one-of-a-kind X-1 (SSX-1), was launched on Long Island with a closed-cycle hydrogen peroxide/diesel plant! Inspired by the success of the British "X-craft" of World War II, X-1 was intended for shallow-water commando operations. Displacing 36 tons submerged on a length of some 50 feet, X-1 was powered by a heavily modified commercial diesel engine with a small battery-powered electric motor as a backup. On the surface, the ambient atmosphere charged the engine, but underwater, the oxygen required for combustion was derived from the catalytic decomposition of hydrogen peroxide in a reaction chamber. Both engine exhaust and water condensate were compressed and discharged overboard. Four hundred gallons of peroxide could be stored in a flexible polyvinyl-chloride bag forward, and the craft could accommodate four crewmembers.

After several engine failures and subsequent design modifications, X-1 finally achieved acceptable performance in February 1957 and undertook a series of operational trials based at the Portsmouth Naval Shipyard. Unfortunately, on 20 May 1957, an explosion in the hydrogen peroxide storage system blew off the whole bow section, and although no one was injured, X-1's closed-cycle capability was never replaced. On 2 December 1957, X-l was taken out of service and inactivated at Philadelphia, Pa. forthe craft's modification to diesel-electric drive

The boat was rebuilt with a small, conventional diesel-electric/battery plant, and after being laid up for three years, it was reactivated in late 1960 and subsequently used until 1973 for a variety of research studies in the Chesapeake Bay. Towed to Annapolis in December 1960, X-l 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-l 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.

In a typical experiment, on November 5, 6, 7, and 8, 1962, operations with the SSX-1 submarine were conducted off Kent Island in the Chesapeake Bay. The purpose was to test further the changes in pigment, turbidity, and surface tension caused by the passage of a submarine. These were the properties of the water which showed the greatest changes during a previous field trip to Block Island, RI. Consequently, water samples were collected in and out of the wake and tested a short time later for pigment, turbidity, and surface tension. Also, bacteria were measured on some samples. These tests were made at a temporary laboratory set up on Kent Island.

The purpose of this problem was to investigate the mechanisms involved in environmental effects caused bythe presence of a submarine in order to develop devicesthat will further Navy capability in local detectionand classification of a submarine target. Some of the possible mechanisms investigated, that would couple a submarine's energy to the sea surface or near surface, are hydrodynamic and sonic. In the hydrodynamic case the submarine could push small quantities of water from its operating depth into the surface layers. In the sonic case organisms located in ornear the sea surface appear to act as backscatterersand absorbers of the acoustic energy emitted by asubmarine.

Remaining in an active, in service, status through January 1973, X-l 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. Later, X-1 was put on static display at the Nautilus Museum in Groton, Connecticut. Significantly, her former Officer-in-Charge later wrote, "The most important lesson learned from this experimental program was. that high concentration unstabilized hydrogen peroxide has no place on a fighting ship."

displacement 36.3 (subm.), 31.5 (surf.);
length 49'7"
beam 7'0"
draft 6'2" (mean)
complement 10

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Page last modified: 07-07-2011 12:55:26 ZULU