Thresher-class (SSN-593)
Summary
| Origin country | 🇺🇸 United States |
| Category | Submarine |
| Subtype | Nuclear submarine |
| Manufacturer | Portsmouth Naval Shipyard |
| Year commissioned | 1961 |
| Units | USS Thresher, USS Permit, USS Plunger, USS Barb, USS Pollack, USS Haddo, USS Jack, USS Tinosa, USS Dace, USS Guardfish, USS Flasher, USS Greenling, USS Gato, USS Haddock |
Operators
Technical specifications
| Displacement | 3810 tons |
| Displacement submerged | 4369 tons |
| Range | Unlimited, except by food supplies |
| Crew | 112 members |
| Width | 9.63 m (31.6 ft) |
| Length | 84.86 m (278.4 ft) |
| Max. depth | 400 m (1312.3 ft) |
| Propulsion | 1 S5W PWR, 2 steam turbines, 15,000 shp (11 MW), 1 shaft |
| Armament |
|
| Maximum speed | 15 knots |
| Max. speed submerged | 28 knots |
Description
The Thresher class (later designated the Permit class) was a series of 14 nuclear-powered fast attack submarines for the United States Navy. The design originated from the 1956 "Project Nobska" study commissioned by Chief of Naval Operations Admiral Arleigh Burke. Managed under project SCB 188, the class was intended as a successor to the Skipjack class. Construction occurred between 1958 and 1967 at Portsmouth, Mare Island, Ingalls, New York Shipbuilding, and General Dynamics Electric Boat.
The design utilized the S5W reactor plant but introduced changes to submarine architecture. To accommodate a large BQQ-2 sonar sphere in the bow, the four torpedo tubes were relocated amidships and angled outboard. The pressure hull, constructed of HY-80 steel, featured a design that increased the test depth to 1,300 feet. For acoustic quieting, engineering components were placed on isolation mounts, or "rafts," to reduce noise transmission to the hull.
While the lead ship, USS Thresher, featured a small sail and a five-bladed screw, subsequent vessels underwent modifications. Most ships in the class utilized seven-bladed skewback screws to mitigate blade-rate noise. USS Jack served as a testbed for counter-rotating propellers and a direct-drive propulsion system. Later units, including Flasher, Greenling, and Gato, were built to the SCB 188M standard, featuring a longer hull and a larger sail to house additional masts and electronics.
The class entered commission in 1961. On April 10, 1963, USS Thresher was lost with all personnel during sea trials. This event led to the establishment of the SUBSAFE program, which implemented manufacturing standards and quality control for systems subject to sea pressure. Following the loss, the class was renamed after the second ship, USS Permit.
During the 1970s and 1980s, the submarines received mid-life upgrades. These included the installation of the BQQ-5 sonar suite, the Mk 117 fire control system, and the integration of Harpoon anti-ship missiles and Mark 48 torpedoes. The vessels remained in service through the Cold War, with the final unit decommissioned in 1996. The Thresher class was succeeded by the Sturgeon and Los Angeles classes.