Question 583 Rules of the Road

The correct answer is D) One prolonged blast followed by two short blasts on the whistle at intervals of not more than two minutes. This is the correct answer because under both the International Rules and the Inland Navigation Rules, a vessel restricted in her ability to maneuver and at anchor in restricted visibility is required to sound this signal. The prolonged blast followed by two short blasts indicates the vessel's restricted maneuverability, and the signal must be sounded at intervals of not more than two minutes. The other options are incorrect because they do not match the specific signal required for a vessel restricted in her ability to maneuver and at anchor in restricted visibility.