[Osage Orange]

The fast-attack submarine smashed full speed into the mountain near Guam on Jan. 8, 2005

How could this happen? Human error...or mechanical?

[rednesss]

"How could this happen? Human error...or mechanical?"

Also from Wikipedia

The seamount that the San Francisco struck did not appear on the chart in use at the time of the accident, but other charts available for use indicated an area of 'discolored water', an indication of the presence of a seamount. The Navy determined that information regarding the mount should have been transferred to the charts in use — particularly given the relatively uncharted nature of the ocean area that was being transited — and that the failure to do so represented a breach of proper procedures.

[OA5599]

Subs navigate by charts. The sub's fathometer should match the depth written on the chart by a certain percentage. Outside of that range, the boat should slow down and ascertain whether they are off course or the chart is wrong. Apparently the San Fran just kept going full speed despite the discrepancy because there was so much depth under the keel... which didn't last that long.

At least that's what I read. I actually was on that sub (well before the crash), but I was in the engine room and know little of what they guys in the cone do.