USS Thresher (SSN-593)

USS Thresher (SSN-593) was the lead ship of her class of nuclear-powered attack submarines in the United States Navy. Commissioned in 1961, she represented a significant leap in submarine design, speed, and quieting technology. Her tragic loss during deep-diving tests in 1963, with 129 lives lost, remains one of the worst peacetime disasters in U.S. Navy history and led to profound changes in submarine safety and construction programs.

Construction and commissioning

The contract for the construction of the new submarine was awarded to the Portsmouth Naval Shipyard in Kittery, Maine, on 15 January 1958. Her keel was laid down on 28 May 1958, and she was launched on 9 July 1960, sponsored by Mrs. Frederick B. Warder, wife of a prominent submarine officer. The vessel was commissioned on 3 August 1961, under the command of Commander Dean L. Axene. Following her commissioning, *Thresher* conducted extensive shakedown and training operations along the East Coast of the United States and in the Caribbean Sea, preparing for her role as the Navy's most advanced hunter-killer submarine.

Design and specifications

As the lead ship of the *Thresher*-class, later known as the *Permit*-class, she introduced numerous innovations. Her design emphasized deep-diving capability and acoustic quieting to better pursue Soviet Navy submarines. Key features included an advanced S5W reactor plant, a new AN/BQQ-2 sonar system housed in a distinctive bow dome, and a HY-80 high-strength steel hull. She displaced approximately 3,700 tons submerged, measured 279 feet in length, and could achieve speeds in excess of 30 knots. Her armament consisted of Mark 37 torpedoes and later, Subroc anti-submarine missiles, fired from four torpedo tubes amidships.

Loss and investigation

On 10 April 1963, during post-overhaul deep-diving tests approximately 220 miles east of Cape Cod, *Thresher* was lost with all 129 crew and civilian personnel aboard. The submarine, accompanied by the submarine rescue ship USS Skylark (ASR-20), was conducting tests near her design depth when communications ceased. A subsequent search located wreckage on the seafloor at a depth of over 8,400 feet. The Court of Inquiry and the comprehensive investigation led by retired Admiral Hyman G. Rickover concluded the likely cause was a piping failure in the engine room, leading to flooding, a loss of power, and an uncontrolled descent that exceeded the hull's crush depth. The official report cited deficiencies in both construction quality and submarine design.

Aftermath and legacy

The disaster prompted an immediate and sweeping review of the entire U.S. Navy submarine fleet. This led to the creation of the rigorous SUBSAFE program, a quality assurance initiative governing the design, construction, and maintenance of all U.S. nuclear-powered submarines. The program mandated stricter welding standards, improved systems integrity, and enhanced emergency recovery capabilities. No SUBSAFE-certified submarine has ever been lost. The tragedy also accelerated the development of deep-sea search and recovery capabilities, influencing projects like those undertaken by the Woods Hole Oceanographic Institution and the vessel RV Alvin.

Memorials and tributes

Numerous memorials honor the crew of *Thresher*. A dedicated memorial featuring a sail from a later submarine stands at the Portsmouth Naval Shipyard. The Thresher Memorial in Kittery, Maine, lists the names of all who perished. Annual remembrance ceremonies are held by the United States Submarine Veterans organization. The disaster is commemorated within the U.S. Navy every 10 April, and a memorial park exists in Albuquerque, New Mexico. The loss profoundly affected communities like Charleston, South Carolina, home to many crew families, and remains a somber chapter in the history of American naval.

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