for Submariners

by Hamilton 1:1 Communications, LLC

JB-2 Loon SSG Conversions

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The JB-2 Loon SSG

In July 1944 a crashed V-1 cruise missile was inspected by the US Army Air Force. In late 1944 a decision was made to manufacture 75,000 American copies as the JB-2. Orders for 12,000 were placed for use against the Japanese home islands. Modifications to the German design included rail launch using a JATO solid rocket motor rather than a catapult. However the planned invasion of Japan became unnecessary after Japan's surrender in August 1945. Further production was cancelled with 1400 JB-2's completed. After the war development of an improved radio-command guidance system for the missile with a 400 m CEP was undertaken. However new turbojet- and ramjet-powered cruise missiles – the Mace, Matador, and Navaho – were in development with much greater performance. JB-2's were used only as test vehicles, the last flying in 1949.

The Navy also tested JB-2's under the Loon name. Consideration was given to equipping submarines and escort carriers with the missiles. Submarines were converted with external Loon shelters and rail launchers. The submarines had to surface to launch the missile, and test launches were conducted from 1946 to 1950. As in the case of the Air Force, no production was undertaken since the Navy was developing a much more capable turbojet-powered cruise missile, the Regulus, for the naval cruise missile role.

Standard warhead: 940 kg (2,070 lb). Maximum range: 240 km (140 mi). Boost Propulsion: Torpedo. Maximum speed: 710 kph (440 mph). Initial Operational Capability: 1947.

USS Cusk (SSG-348) Balao Class

USS Cusk (SSG-348) Loon

The keel for the USS Cusk was laid down, 25 May 1944, at the Electric Boat Co., Groton, CT.; Cusk (SS-348) was launched 28 July 1945 by Electric Boat Co., Groton, Conn., and commissioned 5 February 1946.

Departing New London 24 April 1946, Cusk made an extended cruise through the Caribbean Sea, and arrived at San Diego 6 June 1946. She sailed to Alaska and northern waters between 16 July and 20 August, then carried out local operations out of San Diego. A pioneer in the missile field, Cusk was designated (SSG-348), 20 January 1948 and was the first submarine to launch a guided missile from her own deck, a forerunner of the ballistic missile submarines of the future. She entered Mare Island Naval Shipyard for extensive modernization in 1954, but remained in the missile program because of her special guidance equipment although redesignated (SS-348), 1 July 1954.

Cusk arrived at Pearl Harbor, her new homeport, 13 May 1957. Continuing her missile experiments she operated in Hawaiian waters except for a cruise to San Diego in 1957 and duty in the Far East in 1958 and 1960.

USS Carbonero (SSG-337) Balao Class
Shown with missile sled

USS Carbonero (SSG-337) Loon

The USS Carbonero keel was laid down, 16 December 1943, at the Electric Boat Co., Groton, CT.; launched 19 October 1944 by Electric Boat Co., Groton, Conn., and commissioned 7 February 1945.

Sailing from New London 21 March 1945, Carbonero served with the Fleet Sonar School at Key West, and conducted torpedo exercises at Balboa, C.Z., before arriving at Pearl Harbor 9 May. Her first war patrol, conducted off Formosa from 26 May to 8 July, was devoted to lifeguard duty, standing by for possible rescue of aviators downed in carrier strikes. After refitting at Subic Bay, Carbonero cleared for the Gulf of Siam on 4 August, and cruising off the east coast, of the Malay Peninsula, sank four schooners, two sampans, and two junks, some of the small remnants of the Japanese merchant fleet. This second war patrol ended with the cease fire order on 15 August, and Carbonero put back to Subic Bay.

Carbonero reported at Seattle, Wash., 22 September 1945 for operations on the west coast. Early in 1947, she was assigned to the guided missile program, as a control vessel operating out of San Diego and Port Hueneme, Calif. Fitted to launch missiles in May 1949, and with a snorkel in 1951,

From 1952 to 1957, the submarine performed important service in the evaluation of the "Regulus" missile. Since 13 May 1957, her homeport has been Pearl Harbor. Carbonero received one battle star for service in World War II.

One of her two war patrols was designated as "successful."

Boats Converted:

USS Cusk (SS-348) Balao
USS Carbonero (SS-337) Balao



312' length
27' 4” Beam
1,525 tons Surfaced Displacement
2,400 tons Submerged Displacement
84 crew


6 x 21” TT Bow
4 x 21” TT Stern


Original conversion had just a launching ramp aft and control equipment for use as a control ship. Later, a hangar for two Loons was fitted.