All of this talk of collision at sea has reminded me of two other collisions. The October 2, 1942 collision of RMS Queen Mary with HMS Curacoa, my grandfather was aboard Queen Mary at the time, and the July 25th, 1956 collision of MS Stockholm with SS Andrea Doria.
I wonder if one of the contributing factors in the USS Fitzgerald-ACX Crystal collision was a misunderstanding of what the radar was showing the watch officers? It has been years since I read anything about the Andrea Doria but I seem to recall reading that the radar display on Andrea Doria's bridge was set to a short range mode but the officer in charge of navigation thought it was in the long range mode and so believed that he had more maneuvering room than actually existed. All it would take is a similar mistake for the watch on the USS Fitzgerald to think they had sufficient sea room and time to pass in front of the ACX Crystal.