BOTH INTERNATIONAL & INLAND A vessel displaying the lights shown in illustration D063RR below is which of the following?

Correct Answer: Option D — towing astern

Rule 24(a) mandates that a power-driven vessel towing astern must display two masthead lights in a vertical line. If the length of the tow exceeds 200 meters, three masthead lights are required. The presence of these vertical masthead lights, combined with sidelights and a stern light, identifies a vessel engaged in towing.