The Grayback-class submarine was a class of two guided missile-carrying submarines of the United States Navy. They carried the Regulus I and Regulus II nuclear cruise missiles, deployed 1957–64, that were rapidly phased out by Polaris Submarine Launched Ballistic Missiles (SLBMs). They and USS Halibut were the sole submarines designed specifically to carry Regulus missiles, and the only submarines capable of carrying Regulus II. However, USS Tunny and USS Barbero were modified earlier to carry two Regulus I missiles per boat.
Grayback preparing to launch a Regulus II missile, c. 1960
Regulus missile submarines
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.
USS Grayback, one of the five submarines that operated Regulus missiles
JB-2 Loon missile ready for launching from Cusk
Tunny launching a Regulus missile - the cylindrical installation is the missile hangar
A Regulus II missile being prepared for launch from Grayback