A vessel being towed astern shall show ________.

• A. Sidelights
• B. Stern lights
• C. A stern light only
• D. A flashing green light

Answer: (A)

When a vessel is being towed astern, it remains a separate moving vessel under the rules and must display navigation lights that clearly indicate its presence and position to other traffic. The sidelights (red on the port side and green on the starboard side) provide crucial information about the vessel’s sides and its bearing, which is especially important for other vessels approaching from the sides or from angles where the stern light alone wouldn’t give a clear sense of direction. A stern light only would show rearward visibility but wouldn’t help others determine on which side the towed vessel is located relative to them. A flashing green light is not a standard signal used for a vessel being towed. Therefore, sidelights are the appropriate requirement to help others see and understand the towed vessel’s position and course.