15. USS Thresher changed US Navy submarine operations
In April 1963 USS Thresher, as part of its testing operations following a shipyard overhaul, was engaged in diving operations, escorted by the rescue ship Skylark. On April 10, after the submarine had remained submerged for the night, Thresher began a deep dive test, gradually working its way down to its test depth in a series of steps. The submarine followed a circular path beneath Skylark as it worked its way down. It never resurfaced, and after receiving some garbled communications Skylark realized that the submarine had been sunk. It was the first loss of a nuclear-powered submarine, and 129 members of its crew and shipyard personnel were killed in the disaster.
Subsequent to the loss and following the investigations into its cause, the US Navy instituted a program of safety procedures and equipment known as SUBSAFE. SUBSAFE was the creation of strictly adhered-to inspections, safety procedures, and redundancy of design to protect submarines and the personnel involved in their construction, maintenance, and operation. Since the implementation of SUBSAFE only one American submarine has been lost, USS Scorpion, and that vessel had not yet been SUBSAFE certified. The wreck of Thresher was mapped and photographed in color by Dr. Robert Ballard in the 1980s (as was that of Scorpion), funded by the Navy and screened by his successful search for the wreck of Titanic.
