Grayback-class submarine

Grayback preparing to launch a Regulus II missile, c. 1960
Class overview
Name	Grayback
Operators	United States Navy
Preceded by	Tang-class
Built	1954–1958
In commission	1958–1964, 1969–1984
Completed	2
Retired	1
Preserved	1
General characteristics
Type	Submarine
Tonnage	Surfaced: 2712 tonnes (2670 tons) Submerged: 3708 tonnes (3650 tons)
Displacement	2,768 long tons (2,812 t) full
Length	317 ft 7 in (96.80 m)
Beam	27 ft 2 in (8.28 m)
Draft	19 ft (5.8 m)
Propulsion	3 × Fairbanks-Morse Diesel engines (total 4,500 shp (3,400 kW)),[1] 2 × Elliott electric motors (total 5,500 shp (4,100 kW)),[1] 4 × 126-cell GUPPY I batteries,[2] 2 shafts
Speed	15 knots (28 km/h; 17 mph) surfaced, 12 knots (22 km/h; 14 mph) submerged
Test depth	700 ft (210 m)[2]
Complement	84
Armament	2 × Regulus missile hangars (4 × Regulus I missiles or 2 × Regulus II missiles) 8 × 21 inch (533 mm) torpedo tubes (6 bow, 2 stern)

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.