Over an hour into the test depth trial, the submarine rescue ship USS Skylark’s commanding officer received yet another garbling message from the USS Thresher, barely making out the words: “a ship breaking up . . . like a compartment collapsing.

Unknowingly, it would be among the last time the world would hear about the atomic submarine, which sank deep into the Atlantic Ocean more than 8,000 feet, and with it, its 129 crew on board—forever lost at sea.

The sinking of the Thresher sixty years ago remains one of the most significant tragedies in the history of the US Navy, with the loss of all its crew serving as a sobering reminder of the dangers inherent in submarine operations. But it wasn’t all in vain, leading to significant safety procedures and training changes. Today, the memory of the Thresher and its crew lives on as a statement of their bravery and sacrifice in service of their country.

USS Thresher: First of Its Kind

The lead vessel, the first of its kind, the USS Thresher (SSN-593), is a nuclear-powered submarine developed by Portsmouth Naval Shipyard in the 1950s and early 1960s with a design that combines the attributes of an “attack” and a specialized “hunter-killer” underwater craft. The US Navy initiated the program amid the Cold War era in response to the Soviet Union’s development of advanced submarine technology, which posed a significant threat to American naval dominance.