Question 586 Rules of the Road

The correct answer is A) A vessel engaged in underwater operations. According to the International Regulations for Preventing Collisions at Sea (COLREGS) and the Inland Navigation Rules, vessels engaged in underwater operations, such as diving or submarine activities, are not required to display anchor lights when at anchor. This is because these vessels typically do not pose a significant risk of collision, and their activities may be better served by not displaying lights that could interfere with their operations. The other options (B, C, and D) are incorrect because vessels engaged in mine clearance, pilotage duty, or survey operations are still required to display the appropriate anchor lights when at anchor, as they are not considered "vessels engaged in underwater operations" as specified in the regulations.