I had the pleasure of serving on board two nuclear submarines, the USS Tunny (SSN-682) and the USS Helena (SSN-725), both stationed at Pearl Harbor, Hawaii. I was a quartermaster second class qualified in submarines. Quartermasters in the Navy are navigators, not supply clerks as in the Army. As such, I was responsible for determining the vessel's position. I worked closely with other members of the control room team to make sure every evolution was executed safely and according to procedure.
The sinking of the Ehime Maru is a tragedy. The press is speculating that the civilian visitors may have distracted the crew from their duties or that the commanding officer was negligent. There has even been a retired submarine skipper, Captain Jim Bush, on more than one television news program, volunteering his opinion that the accident was caused by "human error." It is not that simple.