There’s some speculation the first U turn was to return and offer assistance. The second series of circles may be for the pilot to board. Both plausible. Still the freighter not notifying of the collision for so long is extremely odd.
The sailing forums offer some very good perspective. Lots of the contributors are ex-Navy and plenty are familiar with rules of the road in the area of the incident.
I’m ex-Navy too but the flight deck offers little insight. I also have many years experience sailing off the coast of CA around the shipping lanes. It’s busy around LA Harbor but I have to believe it pales in comparison to traffic heading into Tokyo.
If the bridge of the Fitz sounded anything like this it explains a lot.
https://pilotonline.com/news/military/audio-confusion-reigned-before-destroyer-s-collision/article_c7472be8-efcb-5763-93bb-aab66d820175.html
Also ex-Navy. That was a chilling audio recording from the Porter. I know that some Captains like to put their OODs into tense situations, but this CO seemed to make the situation worse; my first CO would've taken command on the spot, got the ship out of that situation, and then taken appropriate action with the OOD later.
That said, we don't know right now, if there were other ships around the Fitzgerald and Crystal, that may have caused an unexpected turn. Still, the Crystal would not make a "sudden" turn; she was far too big to do anything "suddenly." The Fitz should have been far enough away to detect any potential CPA-zero situations, and taken steps to avoid them.