The story of the Halibut submarine, protagonist of many cold war mysteries

(To Andrea Mucedola)

Among the most secretive nuclear submarines of the US Navy, the USS Halibut it is certainly one of those who can boast a decidedly unique operational life.

Originating as a nuclear-powered missile submarine, it was transformed into a special operating platform and later redesigned as an attack submarine with an SSN-587 optical badge.

THEHalibut, belonging to the class of submarines Gato, was the first boat designed and built to carry and launch five missiles Regulus II from a hangar integrated into the hull.

Curiously, the program Regulus II was finished 17 days before the commissioning of theHalibut for which he was sent to sea trials in the South Pacific embarking the missiles Regulus of the first series. 

A long operational history

Set up at the Mare Island shipyard in Vallejo, California on April 11, 1957, she was launched on January 9, 1959, and delivered to the US Navy on January 4, 1960 under the command of Lieutenant Captain Walter Dedrick.

The boat was born with a diesel-electric propulsion which was then transformed into nuclear to increase its autonomy in immersion.

Intended to carry nuclear warhead cruise missiles Regulus I e Regulus II, its main deck was high above the waterline to provide a dry "flight deck".

The missile system was fully automated, with hydraulic machines controlled from a central control station.

Halibut she set out on her Pacific campaign on March 11, 1960. On March 25, en route to Australia, she became the first nuclear-powered submarine to successfully launch a guided missile. She returned to the Mare Island shipyard on June 18, 1960, and after brief training outings she sailed on November 7 to Pearl Harbor to join the Pacific Fleet.

During its first deployment it successfully launched its seventh Regulus I missile during a large joint exercise with the Southeast Asian Treaty Organization. Returned to Pearl Harbor on April 9, 1961, Halibut began its second deployment in May.

USSN Halibut it deployed for the third time in the western Pacific in late 1961, establishing a pattern of training and readiness operations that were perpetuated until 1964.

The 4 May 1964 Halibut left Pearl Harbor for the last missile activity Regulus * which was to be carried out from a submarine in the Pacific.

In total, between February 1961 and July 1964, he made a total of seven displacements before being replaced in the Pacific by submarines equipped with Polaris of the class George Washington.

Actually the weak point of the Regulusdespite their supersonic capabilities, it was that they had to be launched by emerging to the surface.

A significant operational limitation that led to a re-use of these submarines for special operations, using the ex-hangars for missiles Regulus for SEAL underwater raiders.

For all intents and purposes, the missiles Polaris they surpassed the SSGNs and modified the use of nuclear submarines both from a tactical and strategic point of view.

Operational use

According to the program Regulus, the main objective ofHalibut, in the event of a nuclear attack, it would have been to eliminate the Soviet naval base in Petropavlovsk-Kamchatsky. The operational displacements of the submarine therefore had an important deterrent function during the Cold War, when the two blocks and their members lived with bated breath in fear of a nuclear attack on one side or the other.

For the youngest, who did not even partially experience that period, during the Cold War there was sometimes very close to a clash between the two blocs which, everyone knew, would have no winners..

In February 1965 Halibut entered the Pearl Harbor shipyard for a major overhaul and on August 15 was redesigned as an attack submarine, receiving a new hull classification, SSN-587.

Halibut then began anti-submarine combat operations (ASW) in the area, continuing until August 1968 when he moved to Mare Island for the overhaul and installation of side thrusters, a hangar section, anchor winches with front and rear anchors, a saturation diving habitat, a side sounder as well as video and photographic equipment. These were only the first variants to transform the boat into an oceanographic submarine and for intelligence missions. Missions covert who made history.

Eventually, she returned to Pearl Harbor in 1970 and operated with the Pacific Fleet until her decommissioning in 1976.

But what was so special about Halibut?

After his disarmament, information about his operations began to circulate covert made during the cold war. Among the best known are the clandestine listening to a Soviet submarine communication line, from the Kamchatka peninsula to the Soviet mainland in the Sea of ​​Okhotsk (Operation Ivy Bells) and the search for the Soviet submarine K-129 in August 1968. :

Operation Ivy Bells

During the Cold War, the United States wanted to learn more about Soviet submarine and missile technology, especially ICBM (acronym for Intercontinental Ballistic Missile) testing and nuclear strike capability. In the early 70s, the US government learned of the existence of a submarine communications cable in the Sea of ​​Okhotsk, which connected the main naval base of the Soviet Pacific Fleet in Petropavlovsk (Kamchatka Peninsula) with the headquarters General of the Pacific Fleet in Vladivostok.

At the time, the Sea of ​​Okhotsk was claimed by the Soviet Union as territorial waters and was strictly off-limits to foreign ships. In addition, the Soviet Navy had installed a network of acoustic sensing devices (passive sonars) on the sea floor to detect intruders and carried out continuous air and naval exercises in the area.

Despite these obstacles, the United States sent the USS submarine in October 1971 Halibut (SSGN-587) in the Sea of ​​Okhotsk. The divers who worked on theHalibut they found the cable at a depth of 120 meters and installed a 6,1 meter long device (photo), around the cable without piercing its casing, a system that allowed all communications to be recorded.

K 129

This last secret mission is recounted in the 1996 book, Spy Sub - A Top Secret Mission to the Bottom of the Pacific, by Dr. Roger C. Dunham, under an assumed name. For reasons of secrecy the author substituted the name of the boat with USS Viperfish, among other things assigning it a fictitious side number, SSN-655, to be able to overcome the security restrictions of the Department of Defense for its publication.

Once in the areaHalibut he used a wire-guided underwater vehicle, equipped with sonar and cameras and, after a few weeks, he found the wreck of the Soviet submarine. The K-129 was lying on the starboard side at a depth of about 5000 meters. The boat had a gash behind the turret, possibly caused by an explosion, and two of the three nuclear missiles appeared badly damaged.

Halibut in three weeks he collected over 20000 close-up images of the Soviet submarine. Later his recovery was assigned to billionaire Howard Hughes who had a large ship built, the Hughes Glomar Explorer (HGE), to recover the submarine in the highest secrecy. The story is told in more detail in one of ours article about the history of the unfortunate K129.

THEHalibut was placed in reserve on June 30, 1976 and transferred to Keyport / Bangor Trident Base, Washington in 1976, but was struck off the ship register nearly ten years later on April 30, 1986. In 1994, he was transferred for his final trip to the shipyard. Naval Puget Sound, Bremerton, Washington, for its scrapping.


The SSM-N-8A Regulus o Regulus I was a second-generation turbojet nuclear-capable cruise missile. It was developed at Naval Air Station Point Mugu in California based on the German V-1 missile design. Despite supersonic performance and an attempt at development with a later model, Regulus II, the program was abandoned having come into conflict with the sub launched ballistic missile program Polaris with which he clearly lost the comparison. The submarines made for its use ended their days as carriers of other weapons and their hangars were used to house special underwater vehicles.


various articles on Wikipedia
"Halibut". Fitzsimons, Bernard, ed. (1978) from the XNUMXth Century Encyclopedia of Weapons and Warfare. II, London. 
US Adcock Ballistic Missile Submarines, Alii (1993). ISBN 978-0-89747-293-7.
"Secret subtitles - USS Halibut". Hidden shores. January 2, 2015.
“Spy Sub - hardcover - by Roger C. Dunham”.
American Naval Fighting Ships. Combat ships around the world from 1947 to 1995. Robert, Gardiner, ed. (1995 London: Conway Maritime Press, Ltd. p. 610.

Photo: NavSource Naval History

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