Question 992 Rules of the Road

The correct answer is D) Two prolonged blasts on the whistle. According to the International Regulations for Preventing Collisions at Sea (COLREGS) and the Inland Navigation Rules, a vessel that is underway but stopped and making no way through the water in fog must sound two prolonged blasts on the whistle at intervals of not more than 2 minutes. This signal indicates that the vessel is not under command and unable to maneuver as required by the rules. The other answer choices are incorrect because they do not match the specific signal required for a vessel that is underway but stopped in fog. For example, option A would be the correct signal for a vessel that is anchored, while options B and C describe different sound signals that do not apply to this situation.