USS Thresher Sinking – 1963

In the early 1960s the pride of the US Navy’s submarine fleet was SSN-593, the second sub to bear the proud name USS Thresher (the first served throughout World War D). The reborn Thresher was lead boat in a new class of nuclear-powered attack submarines.

Commissioned in 1961, she undertook extensive sea trials to test advanced technological systems. There were minor setbacks, as when her generator Med in port while the reactor was shut down, necessitating partial evacuation as temperature within the hull rose sharply. She was also hit by a tug in a separate incident, requiring repairs followed by a thorough overhaul.

In early April 1963, Thresher began more trials. First came deep-diving tests, some 350 km (220 mi) off Cape Cod, Massachusetts. Accompanied by the submarine support ship USS Skylark, she embarked on the first of a series of deep fives. As Thresher neared maximum test depth, a distorted message reached Skylark through the underwater telephone system suggesting that the crew was experiencing minor difficulties. It was the last communication ever received from the doomed submarine and gradually the awful realization that she had sunk with all hands dawned on those at the surface.

The subsequent enquiry concluded that a joint in the sub’s salt-water piping system had failed, the leak creating a short-circuit that caused the reactor to shut down. With propulsion lost, Thresher was unable to ‘drive’ back to the surface or even blow her tanks successfully (the valves froze). She simply sank to the depth where she imploded under intense water pressure. The shocking loss of Thresher led the US Navy to accelerate SUBSAFE, a rigorous quality-control program applied to the construction of nuclear submarines whereby hulls are built to maximum possible strength and systems within can function in the event of unexpected flooding.

When was the USS Thresher Sinking: April 10 1963

Where was the USS Thresher Sinking: North Atlantic Ocean

What was the USS Thresher Sinking death toll: 139 US Navy personnel and civilian technicians died.

You should know: The joint American-French expedition aboard the RV Knorr that located the wreck of Titanic in September 1985 was secretly funded by the US Navy, on condition that the oceanographers first found and photographed the sunken USS Thresher and the US Navy’s other missing nuclear sub, USS scorpion, lost in 1967. This was duly done before the dramatic discovery of Titanic’s long-lost remains was achieved.