page_title: Regulus missile submarines
section_title: Regulus submarines as nuclear deterrent
hierarchical_section_title: Regulus missile submarines / History / Regulus submarines as nuclear deterrent
context_page_description: The Regulus missile submarines were a group of submarines operated by the United States Navy capable of carrying the Regulus cruise missile. Between 1959 and 1964, a total of five boats were used to undertake the first submarine-based nuclear deterrent patrols by the United States. Regulus submarines were used for this task until 1964, when sufficient ballistic missile submarines carrying the Polaris ballistic missile became available.
context_section_description: In 1956, while the test program was still under way, the US Navy instituted a policy of keeping one of its then existing cruise missile submarines in each ocean. Tunny was deployed to the Pacific Fleet at Pearl Harbor, while Barbero was sent to the Atlantic Fleet home-ported at Norfolk. As part of the testing phase, both boats undertook the first submarine based nuclear deterrent patrols. Subsequently, with the ramping up of the nuclear arms race between the United States and the Soviet Union that came following both superpowers successfully launching SLBMs, in 1958 Barbero was moved back to the Pacific to join Tunny, and the newly commissioned Grayback and Growler, to form Submarine Squadron One. Both Cusk and Carbonero were also retained as part of the Regulus programme and transferred to Pearl Harbor, as they had retained the guidance equipment to control the missile, despite having the launching equipment removed. This formed a major part of the US Navy's contribution to the nation's overall strategic deterrent, with the policy to continually have a minimum of four Regulus missiles at sea in the Western Pacific at all times. 
  Following the constitution of Squadron 1, Tunny departed on the first operational deterrent patrol on 23 October 1959. Halibut meanwhile joined the Pacific Fleet in November 1960, becoming the fifth and final Regulus submarine to serve in the US Navy. The policy of keeping four missiles at sea at all times meant that Grayback, Growler and Halibut could undertake Western Pacific cruises alone, while Tunny and Barbero, both only capable of accommodating a pair of missiles, had to be at sea simultaneously. The system was found to have significant limitations, not just concerning those inherent in the Regulus missile itself. In order to launch a missile, the submarine was forced to surface and have a missile removed from the hangar to be loaded onto the launcher. This operation was undertaken manually on the two smallest boats, was partly automated on the second two, and fully automated on Halibut, but still took approximately 15 minutes to complete, during which time the submarine was on the surface and potentially vulnerable to air and sea attack. Once the missile was launched, the submarine was able to dive, but had to remain at periscope depth in order for the remote control system to operate and guide the missile to its target. Additionally, although the nuclear-powered Halibut was able to maintain station constantly for the duration of her cruise, the four diesel-powered boats needed to make refuelling stopovers during the periods that they were at sea, in order to maximise their time on station - these stops would usually take place either in Adak in Alaska, or at Midway Island. Nevertheless, between October 1959 and July 1964, when Halibut returned to Hawaii following its final patrol, the Regulus force had maintained at least one submarine constantly on station in the Western Pacific in the strategic deterrent role.
  Regulus II had been cancelled as the limitations of using cruise missiles became more apparent. The US Navy had therefore elected to alter the thinking behind the deployment of submarine-based nuclear weapons to ballistic missiles. The Navy's ballistic missile program had begun in 1955 when it was instructed to develop the Jupiter IRBM for use at sea. However, at a conference on nuclear weapons development in 1956, it was announced that the technology to create a lightweight thermonuclear warhead would be available by the end of the 1950s, which led to the eventual development of the SLBM in the form of Polaris. In 1957, the attack submarine USS Scorpion, then under construction, was selected for conversion to the US Navy's first ballistic missile submarine. This was accomplished by inserting an additional 130 ft (40 m) section containing a compartment capable of holding up to 16 Polaris missiles. The new boat, renamed as USS George Washington, entered service in December 1959 as part of the Atlantic Fleet, and departed on her first deterrent patrol in November 1960. The Regulus
caption: Halibut with a Regulus missile on the launcher
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