This weekend marks the 50th Anniversary of the loss of the US submarine, the USS Thresher.
http://www.ctpost.com/local/article/Thresher-sinking-remembered-a-half-century-later-4415345.php (http://www.ctpost.com/local/article/Thresher-sinking-remembered-a-half-century-later-4415345.php)
The USS Thresher was an advanced nuclear powered submarine that was on post rehab trials off the coast of Cape Cod.
(http://upload.wikimedia.org/wikipedia/commons/thumb/3/38/USS_Thresher%3B0859306.jpg/300px-USS_Thresher%3B0859306.jpg)
Due to what was believed to be poor welds and brazing, a water leak formed in the back of the sub. A short due to the water was believed to have caused a reactor shutdown. Attempts to blow air into the ballast revealed a flaw where strainers in the valve assembly would be clogged with ice during an emergency blow.
This ship sank past its crush depth and imploded with loss of all life. Studies show that at their depth the implosion took a mere .005 seconds. Studies continue to measure any/all radioactivity emanating from the crash site.
Due to the Thesher incident, the US Navy was forced to start the SAFESUB initiative. Unfortunately, due to financial, political and operational delays, the USS Scorpion, which never got its SAFESUB certification was sunk of the coast of the Azores just few years later.
http://en.wikipedia.org/wiki/USS_Thresher_%28SSN-593%29 (http://en.wikipedia.org/wiki/USS_Thresher_%28SSN-593%29)