Thresher Disaster
The Thresher Disaster refers to the tragic sinking of the USS Thresher, a nuclear-powered submarine, on April 10, 1963, during a test dive off the coast of Cape Cod, Massachusetts. As the first of a new class of "hunter-killer" submarines, the Thresher was designed to counter potential threats from Soviet ballistic missile submarines. During its dive to a depth of 1,000 feet, the crew encountered difficulties, and communication was abruptly lost shortly after they reported a "minor problem." An extensive search confirmed the submarine's loss, with all 126 crew members on board presumed dead.
A subsequent court inquiry suggested that a cracked fitting or faulty seal in a cooling pipe likely caused flooding that disabled the ship's electrical systems, ultimately leading to the Thresher's sinking. The disaster highlighted deficiencies in shipbuilding practices and prompted improvements in quality control at naval shipyards. It also led to the development of new deep-sea rescue capabilities to better address similar emergencies in the future. Concerns regarding the safety of the submarine's nuclear reactor were addressed by Navy officials, who assured the public that there was no risk of contamination. The Thresher remains a somber chapter in naval history and serves as a reminder of the inherent risks associated with underwater operations.
Thresher Disaster
Date: April 10, 1963
The worst submarine disaster in the history of the U.S. Navy. The loss of the nation’s most modern and powerful nuclear submarine heralded reform in the service.
Origins and History
The Thresher was the first of a new class of nuclear submarines known as “hunter-killers.” The construction of nuclear ballistic missile submarines, particularly by the Soviet Union, required a warship to hunt and destroy these vessels in the event of a threat of an undersea nuclear weapons launch. The Thresher was laid down at Portsmouth Naval Shipyard in New Hampshire on May 28, 1958, and launched on July 9, 1960. At a cost of forty-five million dollars, with a length of 278 feet, a beam of 31 feet, and a displacement of 3,732 tons while surfaced, this ship amply fulfilled the requirements. Equipped with a nuclear reactor and the most advanced sonar system available, this ship was capable of diving to a depth of 1,000 feet and was the most powerful submarine in the service.
The Loss of the Thresher
As the prototype of the hunter-killer submarines, the Thresher was subjected to numerous sea trials. The U.S. Navy ordered the Thresher, under the command of Lieutenant Commander John W. Harvey, to cruise 220 miles east of Cape Cod, Massachusetts, beyond the continental shelf, where the water was 8,400 feet deep. The Thresher was to submerge to 1,000 feet to test its performance at maximum depth. The submarine rescue ship Skylark, skippered by Commander Stanley W. Hecker,monitored the submarine’s progress and stood ready in case of emergency. The Thresher began the dive at 7:49 a.m. on April 10. All seemed well until 9:13 a.m. when the Skylark received a message from Harvey that the ship was experiencing a “minor problem” and was attempting to surface. Hecker lost communication for the next four minutes. Finally at 9:17 a.m., the Skylark received the Thresher’s last message, unintelligible except for the phrase “test depth.” The crew of the Skylark assumed that the full message was “exceeding test depth.” Hecker then heard a dull, muffled thud, a sound that the ship might make if it were breaking up. He reported the Thresher missing following an exhaustive search. The Navy confirmed the loss of the submarine at dusk after a rescue vessel spotted an oil slick and debris on the surface. The entire crew of 126 died.
Impact
The disaster resulted in a court of inquiry into the loss of the submarine. It concluded that the probable cause was a cracked fitting or a faulty seal in a cooling pipe. The court concluded that flooding disabled the ship’s electrical system, which shut down the nuclear reactor. The Thresher consequently lost propulsion and sank beneath its test depth. The inquiry also uncovered poor shipbuilding practices in the construction of the Thresher that may have contributed to its loss. The result was an improved quality-control system in naval shipyards and the development of new, deep-sea rescue submersibles to respond to future disasters at sea. Many Americans were worried that the nuclear reactor on the submarine might leak and contaminate the ocean, but U.S. Navy officials assured the public that there was no danger of leakage.
Additional Information
John Bentley wrote a detailed work on the disaster and the events following it entitled The “Thresher” Disaster: The Most Tragic Dive in Submarine History (1965).