With rudders amidships and negligible wind, a twin-screw vessel moving ahead on the port screw and backing on the starboard screw will __________.

Correct Answer: Option B — pivot to starboard

Going ahead on the port screw and backing on the starboard screw creates opposing longitudinal forces that act in the same rotational direction around the ship's vertical axis, causing the twin-screw vessel to pivot rapidly in place to starboard.