In a message to employees Monday, April 10, Newport News Shipbuilding President Jennifer Boykin marked the solemn 60th anniversary of the loss of submarine USS Thresher (SSN 593).

On April 10, 1963, Thresher began a dive to test depth off the coast of New England as part of her sea trials. After the crew initially reported minor difficulties, communications with the submarine were lost and all on board perished.

The congressional board of inquiry concluded that the loss of Thresher was most likely the result of a failed piping joint, a failure that began a series of events ultimately resulting in the ship’s inability to maintain propulsion or to effectively blow seawater from her ballast tanks and return to the surface.

“Although Thresher was not built at Newport News Shipbuilding, it is a story that every shipbuilder needs to know, share and hold in their hearts,” Boykin wrote.

NNS sounded the shipyard whistle at 9:15 a.m. to mark the anniversary. View a slideshow featuring shipbuilders and their thoughts about safety.