PS, slap me silly and call me Bertha, but does anyone have the link to the story about what happened??
It looks like the sub crashed against an uncharted undersea mountain.
Here are a bunch of link stories:
http://news.google.com/news?q=711%20San%20francisco%20sub&hl=en&lr=&sa=N&tab=wn
The entire story is found at this link - copy it and paste it into your browser...
http://www.submarineresearch.com/bull39.html