The merchant ship was on the starboard side of the Fitzgerald, and, given damage to the merchant ship, on the port side of the bow, it was approaching from abaft the beam. Now, this is the crucial legal question - was it a crossing situation (merchant forward of 2 points abaft the beam [then the merchant had right of way]) or was it an overtaking situation in which the merchant had a duty to stand clear.
Regardless, the OOD on the Fitzgerald had both a right and a duty to maneuver once an "in extremis" situation occurred, and obviously it occurred. Further, in the open ocean you never assume that a merchant is keeping an adequate look-out, and you do not risk an expensive naval vessel to the presumption that the other side will steer clear.
The obvious maneuver in this case was to increase speed to pass clear ahead until there was no longer a danger of collision. The second was to turn to starboard for a port-to-port passing and then return to base coarse after clear of the collision.
So sayeth a long-time sailor and former submarine deck officer.
Many here question how ships equipped with radar can collide. See Andrea Doria vs. Stockholm. Radar-guided collisions are a hazard taught to every bridge officer, military or merchant. As soon as the risk of collision becomes apparent (steady bearing and decreasing range), communications and bold course changes are called for so that the ships’ aspect changes are obvious by her lights and on radar.