Arne:

My data, second hand at best, is that the fishing vessel was adrift and not under power when the incident occurred. I would be inclined to assume they did a 'scope scan because it WAS the drill, and the kinds of civilians who get onto such a ride are not usually the kind who would be impressed by joy-riders messing about with a 100 million dollar piece of Navy equipment (number guessed at, sorry). And the skipper said that he repeated the 'scope scan. But amidst the unusual chatter of their civvy supernumeraries, my "imagined scenario" is that they did the routine hastily under conditions where ordinary attentiveness would have been insufficient.

The civilians at the controls were a nonissue because the only controls involved would have been the blow-valve master control (whatever it is properly called) which initiated the ascent, and the for'ard planes which would have had an unknown and probably unpredictable effect on the net track of ascent. The is because, even if you start a large object like that at an exactly known depth, angle of aspect and known location, your next instant does two things: it unleashes (by blowing the total air out of the tanks and replacing it with sea water) a chaotic condition of pressure, current and variable drag and lift in the immediate boundary between the sub and the surrounding water and (2) it unleashes an uncontrolled, completely over-ruling and unstoppable force on the entire boat, which will not stop no matter what you do until the vessel has broached and relaxed back to a floating posture on thesurface. It could have been Davey Jones at the controls ...once those valcves blow you're a cork in a hurricane. This was not a controlled ascent.

That's why, given the unpredictable components of such a manuver, they do scan for traffic and why those operational zones are marked with safety zones on the charts that are often ignored by those with local knowledge and local concerns. You fish those waters daily for a year, say, and in all that time you only happen to see two subs, both doing surface exercises, so you think you have a fix on what really goes on there and you discount the markings because you don't need the chart anyway -- it's turf you know.

Add in the silence of the vessel and the roughness of the visibility and you have the simpler, if more tragic and less culpable, hypthesis as the more probable.

But who the hell knows beyond a sort of weighted speculation?

A