Overtaking is a situation in which the vessel astern at night sees only the stern lights of the vessel ahead and the astern vessel wants to pass. The cut off point for stern lights and side lights is 22.5 degrees aft of midships.

• A. The vessel ahead shows both stern and bow lights.
• B. The vessel astern sees only the stern lights of the vessel ahead.
• C. Overtaking occurs when two vessels approach head-on.
• D. Overtaking occurs at any time except when both sides show navigation lights.

Answer: (B)

Overtaking is identified by the direction from which the behind vessel approaches the ahead vessel. If the vessel behind is coming from more than 22.5 degrees abaft the ahead vessel’s beam, it is overtaking. At night, this geometry means the astern vessel will see only the ahead vessel’s stern light, since the forward side lights and bow light are oriented forward and out of view behind the other vessel. The cut-off angle of 22.5 degrees aft of midships is what makes the stern light the only navigation light visible to the overtaking vessel. So, seeing only the stern lights of the vessel ahead correctly describes an overtaking situation. The other options depict head-on or non-specific lighting scenarios that don’t define overtaking.