Archive for April 10th, 2008

On April 10, 1963, the USS Thresher was performing some deep-water testing in the Atlantic.  As the lead ship of the Thresher class, she signified the latest iteration of the U.S. Navy’s nuclear-powered attack submarines.

Now “deep-water” was something of a misnomer since, relatively speaking, submarines at that time didn’t go beyond 1,500 feet below the surface.  It was simply too dangerous.  Any mechanical or structural failure could lead to a death dive, in which sailors could only wait for the implosion that would end their lives in less than a tenth of a second.  So, having completed two years of testing and refurbishing, the USS Thresher began her dive and, at about 8:30 in the morning, levelled off at 1,000 feet.  One hour later, her escort ship heard the distinctive sounds of a submarine implosion and the USS Thresher was gone, with 129 sailors and crew.

What had gone wrong?!?  Investigations on a submarine under more than 8,000 feet of water are difficult, but the best conclusions were that, about 40 minutes after reaching depth, a failure in the piping system had caused a leak.  The leak may have shorted out some electronics which then led to a shutdown of the nuclear powerplant.  With power being lost and water being added, it’s possible the sub commander gave the order to blow the ballast tanks, which meant forcing compressed air through a valve into the water tanks to add buoyancy.  But the compressed air coming through the valve cooled as it expanded, freezing enough of the water to clog the valve and prevent the ballast from blowing, dragging the sub down.  In all likelihood, the USS Thresher began her ascent, only to stall and slide backwards to her end, just 10 minutes after trouble first struck.

In response to the accident, the U.S. Navy began a significant overhaul of its testing and safety procedures.  Flood-control systems were improved, engine room layout and design was reconsidered, and more formal and rigorous documentation had to be kept in shipyards during construction.

Recommended Reading: Blind Man’s Bluff – The Untold Story of American Submarine Espionage – Easily one of the most fascinating books I’ve read.  It is cloak-and-dagger Cold-War fiction at its absolute best…and it’s NOT fiction.

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