See USS Thresher. "Too far, too fast." and look up the term Scope of
Certification which came into use after that failure.
I remember the Thresher sinking. I was in college then. As best I
understand, the usual practices shipyard practices (brazing, etc) turned
out not be be up to the needs of deep-diving nuclear submarines.
Probably (though I don't really know) the Navy had left the shipyard
work in the hands of those who had always done it, without realizing
that the old ways weren't good enough anymore. [Ironically, it now
appears that the shipyard work wasn't responsible for the sinking after
all - see
