If you observe only the sternlight of another vessel, what does this indicate regarding your maneuvering relation?

• A. You are crossing its course
• B. You are head-on
• C. You are overtaking that vessel
• D. You are behind it

Answer: (C)

Seeing only the stern light tells you that you’re in the other vessel’s rear view—you're lined up from behind and are in an overtaking situation. In Rules of the Road, when one vessel is overtaking another, the overtaking vessel must keep clear of the vessel being overtaken until it has safely passed. That’s why this light pattern points to you being the overtaking vessel. If you were simply crossing, you’d expect to see the other vessel’s sidelight colors (red or green) rather than just the stern light, and if head-on you’d see each vessel’s forward lights.