BOTH INTERNATIONAL & INLAND A vessel underway at night is displaying the lights shown in illustration D062RR below. What do these lights indicate?

Correct Answer: Option D — under sail

Rule 25(a) states that a sailing vessel underway shall exhibit sidelights and a stern light. These lights indicate a vessel under sail, which is restricted in its ability to maneuver compared to power-driven vessels, requiring other vessels to maintain a proper lookout and adhere to the steering and sailing rules.