In Memoriam - USS Thresher (SSN-593) - Lost 10 April 1963

46 years ago, USS Thresher (SSN-593) became the first American nuclear powered submarine to be lost.

Thresher was built at the Portsmouth Naval Shipyard in Kittery, Maine, the same shipyard were Razorback was built. Commissioned in 1961 as the lead ship of her class, she conducted extensive training and trials in 1961 and 1962.

On April 10th, 1963, following an overhaul, Thresher returned to sea. During her deep-diving tests, while near her test depth (in excess of 1,000 feet) Thresher apparently suffered a failure of a pipe fitting somewhere in the Engine Room.

The leak almost certainly caused an automatic shut-down of the nuclear reactor, and a combination of loss of power, flooding and a previously unknown fault in the ballast system caused Thresher to sink below her test depth.

At approximately 2,000 feet below the surface, Thresher's hull imploded, killing all 129 men aboard instantly.

After an extensive underwater search, Thresher's wreckage was positively identified in 8,400 feet of water.

Following a Court of Inquiry, the "SUBSAFE" program was developed to correct the design and construction problems that led to Thresher's loss.

For additional information about USS Thresher, please visit the Naval Historical Center web site.

Photograph courtesy of the U.S. Naval Historical Center.