This is the AIS track from ACX Crystal that is floating around several news sources, the colored numbers are my additions only as points for discussion.
Some reports say the Crystal 'transponder' was off. This appears to be untrue since we have this AIS track information, however AIS is not the only type of transponder that can generate this kind of data. Anyway, course and speed is not available for each point.
I also do not have a scale for this image.
I also do no have the course/speed and way points of the USS Fitzgerald during this same time period.
Point 1 in Red is where news sources are generally reporting that the collision took place.
Point 2 in yellow is the 180 degree turn, initially claimed was executed before the collision. Now reporting says the turn was executed after the collision to investigate what the containership hit. This would be in agreement with the generally accepted point of collision, red point 1.
Point (or area) 3 in yellow; This is where thing get fuzzy. I believe this are the erratic turns and another 180 degree turns which the US Navy sources initially reported that Crystal had made prior to the collision.
Point 4 in Red - I believe this is where the actual collision took place.
ACX Crystal may have had both AIS transponder and Nav lights turned off, but the track data above proves that something was transmitting the ships position. Considering the reports of auto-pilot issues, I believe the erratic turns have everything to do with the Crystal having an autopilot system failure and trying to regain control or reset the system. I believe its also possible they may have hit something else at point one, a vessel that has not been reported missing yet.
USS Fitzgerald could have been in a number of combat systems configurations where SPY-1 radar is shut down and NAV lights are off. It's a very long explanation as to how many possible scenarios there are where any one or all of these are shut down intentionally or possibly were not working (yes, warships do that stuff ALL the time).
I think the most critical analysis will fall on the Rules of the Road scenario... Was this a passing or over-taking situation? It is possible both vessels had a different perception of whom was stand-on and whom was give-way.
If you want to talk the one hour time difference of reporting; When a US Navy ship advances or retards clocks when passing into new time zones it usually done on night watches even if actually 'crossing the line' actually takes place the next day. It is possible the clocks of the two ships were not in synch, but track data from both ships should be shown in Zulu (GMT).