83. INLAND ONLY You sight a vessel displaying an alternating red and yellow light. What does this light indicate?

A vessel displaying an alternating red and yellow light inland indicates it is engaged in public safety activities, as defined by 33 CFR 88.11. This signal is distinct from distress signals (Annex IV), law enforcement vessel lights (33 CFR 88.05), and signals for vessels restricted in maneuverability (Rule 27).