[Oztrich Boy]

But if you look, the ACX Crystal did make a course change to port of a couple of degrees at around 0120 local time (about ten minutes before the collision) so it is plausible that there is some credibility to this.

Actually 13-14 minutes before.
and No there is a very good explanation of that course change.

Crystal waa on the southern edge of the Traffic Separation lane, which means Fitzgerald crossed the lane without noticing that every Merchantman there was making the turn

Everything that has come out indicates the ACX Crystal was sailing properly.

[rlmorel]

I never thought the ACX Crystal was doing anything wrong, she always looked like she was just steaming from point A to point B...

I did speculate the captain’s account may have opportunistically used that routine change to burnish her side of it, but that’s all it was...speculation.

[TXnMA]

Oztrich Boy, I think you may have turned up something very significant here!!

1. IF the ACX Crystal was in the Tokyo-inbound lane -- then the USS Fitzgerald MAY have had to cross the Tokyo-outbound lane to have been in collision position..

2. IF the lanes and course change shown on your chart correspond to the ~16:17Z course change to 70 degrees by ACX Crystal -- then the Crystal was off-charted-lane-course (60 degrees) -- by ten (10) degrees to port.

I'll see if your chart and my AIS plot matches up, and will toss it all into my vector-graphics drawing software to see what effect a 10-degree off-lane-course error by ACX Crystal would have produced.

~~~~~~~~~

This event sounds stranger, all the time...