INTERNATIONAL ONLY Two power-driven vessels are crossing within one half mile of each other as shown in illustration D042RR below. Vessel "A" sounds one short blast of the whistle. What action should vessel "B" take?

Correct Answer: Option D — Maintain course and speed

Rule 15 and Rule 16 govern crossing situations. Under International Rules, whistle signals are used to indicate maneuvers, not to establish passing agreements. Vessel B, as the stand-on vessel, must maintain her course and speed as required by Rule 17, regardless of the signal sounded by the give-way vessel.