The USS Thresher was crushed in under a second. π . . . On April 10, 1963, the nuclear sub dove 220 miles off Cape Cod. At around 2,400 feet, the hull collapsed inward at 2,000 mph. All 129 men aboard died before the sound of the alarm could finish. The wreck lies in 6 pieces on the Atlantic floor, still radioactive.
Source
US Navy Court of Inquiry report, 1963, 'Loss of the USS Thresher (SSN-593)'; also Naval History and Heritage Command online article on Thresher
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