Your statement above appears contradictory on its face.
Not trying to be needlessly argumentative but (1) if the vessels were the same size and maneuverability, the vessel coming from the right or starboard would have the "right-of-way". That would put the containership in the clear and the naval ship in the wrong.
(2)In this case, the navel vessel had all the maneuverability and the container ship had little. Compared to the later, the destroyer could turn, stop and otherwise maneuver on a dime. It is like pulling on a railroad crossing in front of a 60 car train.
In a over taking situation the vessel beening over taken has the right of way. IIRC, it has been a long time since I raced sailboats. And of course there is always constrained by draft.
In heavy fog the container vessel should have reduced power to steerage only. 15 kts in heavy fog is crazy. I image then DG was at steerage speed and unable to react when the fast moving container vessel appeared out of the fog.