Permit-class submarine

Permit-class submarine
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Name	Permit class
Caption	The lead boat, USS Permit (SSN-594), underway.
Builders	Mare Island Naval Shipyard, Portsmouth Naval Shipyard, General Dynamics Electric Boat, Ingalls Shipbuilding
Operators	United States Navy
Built range	1958–1967
In commission range	1961–1996
Total ships built	14
Type	Nuclear-powered attack submarine
Displacement	Surfaced: 3,750 tons, Submerged: 4,300 tons
Length	278 ft 5 in (84.9 m)
Beam	31 ft 8 in (9.7 m)
Draft	28 ft 5 in (8.7 m)
Propulsion	1 × S5W reactor
Speed	20+ knots (submerged)
Complement	112 (13 officers, 99 enlisted)
Armament	4 × 21-inch (533 mm) torpedo tubes amidships

Permit-class submarine. The Permit class, originally designated the Thresher class, was a class of nuclear-powered attack submarines in service with the United States Navy from the early 1960s. They represented a significant leap in submarine design, incorporating the advanced AN/BQQ-2 sonar suite and a new, quieter S5W reactor plant. The class is most infamously remembered for the loss of its namesake, USS Thresher (SSN-593), which led to major safety reforms under the SUBSAFE program.

Design and development

The design and development of the class was driven by the need for a true hunter-killer submarine to counter the growing threat of Soviet Navy ballistic missile submarines. Key innovations included the adoption of the teardrop hull form, pioneered on the USS Albacore (AGSS-569), for superior underwater speed and maneuverability. The submarines were constructed with HY-80 steel, allowing greater operating depths, and featured a novel arrangement with four torpedo tubes positioned amidships to streamline the bow for the large, spherical AN/BQQ-2 sonar array. The design process involved extensive work at the David Taylor Model Basin and lessons from earlier classes like the Skipjack-class submarine.

Service history

The service history of the Permit class was dominated by the tragic loss of USS Thresher (SSN-593) during deep-diving tests southeast of Cape Cod in April 1963. This disaster, which claimed all 129 crew and shipyard personnel, led to the immediate creation of the rigorous SUBSAFE certification program. The remaining submarines, including USS Permit (SSN-594), USS Plunger (SSN-595), and USS Barb (SSN-596), underwent extensive modifications and served as front-line assets throughout the Cold War. They conducted vital intelligence, surveillance, and reconnaissance missions against the Soviet Union, monitored Warsaw Pact naval exercises, and participated in major fleet exercises like Ocean Safari.

Specifications

The specifications of the Permit class underscored its role as a deep-diving, high-endurance attack platform. Each submarine was powered by a single Westinghouse Electric Corporation S5W reactor, driving two steam turbines and a single propeller shaft. The class had a test depth of approximately 1,300 feet, though operational depths were classified. Armament was launched from four 21-inch torpedo tubes, which could fire the Mark 37 torpedo, Mark 48 torpedo, SUBROC anti-submarine rocket, and later, the Harpoon (missile). The ships were equipped with the AN/BPS-12 radar and the AN/BQR-7 passive sonar as part of the integrated AN/BQQ-2 combat system.

Variants

The primary variant within the class was the unique USS Jack (SSN-605), which was fitted with experimental contra-rotating propellers to study acoustic and hydrodynamic performance. Another notable variant was the USS Tullibee (SSN-597), originally conceived as a separate, quiet hunter design but often grouped with the Permits; it featured a direct-drive S2C reactor and an oversized bow array for its AN/BQQ-1 sonar. The later Sturgeon-class submarine was a direct, enlarged evolution of the Permit design, incorporating SUBSAFE features from the outset and an extended sail for under-ice operations.

Operators

The sole operator of the Permit class was the United States Navy. The submarines were assigned to various fleets, including the United States Pacific Fleet and the United States Atlantic Fleet, operating from bases like Naval Submarine Base New London, Naval Station Pearl Harbor, and Naval Base Kitsap. Key operational commands included Submarine Development Squadron 12 and Submarine Squadron 3. The last of the class, USS Gurnard (SSN-662), was decommissioned in 1996, with several hulls serving as moored training ships at Naval Nuclear Power Training Unit sites before final disposal through the Ship-Submarine Recycling Program.

Category:Submarine classes Category:Cold War submarines of the United States