Uncritically accepting all published testimony & AIS data:
(1) the FITZ had been paralleling the ACX due eastwards for quite some time prior to collision
(2) the FITZ was sited at a relative distance & bearing of 3nm @ 40deg from the ACX at 1:15am
(3) the ACX made a slight turn northeastwards onto a 70deg heading between 1:18-1:20am
(4) the FITZ made a sudden turn around 1:20am, onto a collision course with the ACX, and remained thereon for the duration
(5) the WAN HAI made a slight turn around 1:20am, onto its own 70deg heading
Co-plotting all the information, a consistent story arises. Around 1:20am, the FITZ detected that the WAN HAI had turned onto a (near) collision course. The FITZ took avoidance action, cutting quickly in front of the WAN HAI, which then passed safely astern. Perhaps the FITZ’s stern lookout remained fixated on the looming WAN HAI?
However, the FITZ was now cutting across a major, large-vessel, shipping lane. The FITZ’s approximately 130deg heading put the ACX on a “CBDR” collision course. If so, then it was the STARBOARD lookout who could have been more diligent.
According to this picture, the relative approach angle was initially 130-70=60deg. But the final collision impact angle was closer to 30deg. So the wildly evasive action of the ACX Captain, throwing his vessel into full reverse & hard-to-starboard – possibly in conjunction with a corresponding last second action from the FITZ – was apparently partially effective in reducing relative impact speeds & angles.