@Frederick:
The change of course is suspicious if that cargo ship made a course change 10 minutes before impact and hit the destroyer.
I think this course change actually turned out to be a U-turn which the cargo ship made 30 minutes after the collision. The initial reports got the time of impact wrong.
@Frederick:
Could it be that the cargo ship intentionally made a course change to ram the destroyer?
From the position of the people on the bridge of the cargo ship, as long as the destroyer was appearing to them to be left of their centerline, they were legally obligated to [desc=If the other crossing vessel is in your port sector, then you are the Stand On vessel, and you ought not slow down or change course.]stand on[/desc] without changing course or speed. This would only change if the destroyer suddenly appeared to the right of their centerline, in which case evasive action would be required to avoid a collision. Evasive is a misnomer because it takes >10 minutes to make a meaningful course correction in cargo ships of that size.
If I'm the ship in the diagram below then I should expect every ship I pass to stay to my left. As long as they stay there, I can continue full speed ahead. If their plan is to cross in front of me, this changes only their obligations in the passing—not mine. I would remain, from their point of view, to the right of their centerline, where they are obliged to [desc=If the other crossing vessel is in your starboard sector, then you are the Give Way vessel, and you must stop or slow down.]give way[/desc]. Those ships would be seeing my red light, which is a stop sign for them. I would be seeing their green light telling me I am free to 'Go'. Since we know the destroyer was hit on its starboard side, this green light was what they were displaying to the cargo ship — all while dashing in front of them.
Interestingly enough this is the same location where the Andrea Doria was hit—on its starboard side. If you have a ship passing you on the starboard side and you don't give way then you are inviting the collision—because your green light is telling the other ship to "Keep on Movin Dont Stop."