BOTH INTERNATIONAL & INLAND Vessel "A" is underway and pushing ahead when vessel "B" is sighted off the starboard bow as shown in illustration D028RR below. Which vessel is the stand-on vessel?

Correct Answer: Option A — Vessel "B" is the stand-on vessel because it is to starboard of vessel "A".

Rule 15 dictates that when two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her own starboard side shall keep out of the way. Vessel B is to starboard of Vessel A, making Vessel B the stand-on vessel.