Question 562 Rules of the Road

The correct answer is A) One white light. According to the International and Inland Navigation Rules, a tug that is underway and not towing must show the same navigation lights as any other power-driven vessel of its size. This includes a white masthead light, sidelights, and a white stern light. The white stern light, visible from behind the vessel, is the correct light to be shown aft to other vessels coming up from astern. The other options are incorrect because they do not accurately reflect the lighting requirements for a tug that is underway and not towing. Two white lights or a combination of white and yellow lights would not be the proper configuration for this situation.