Question 541 Rules of the Road

The correct answer is A) Five or more short rapid blasts on the whistle. This signal is used by a vessel that is in doubt as to whether sufficient action is being taken by another vessel to avoid collision, as per the International Regulations for Preventing Collisions at Sea (COLREGS). The five or more short rapid blasts on the whistle serve as a warning signal to alert the other vessel that more action may be required to avoid a collision. The other options are incorrect because: B) Firing a gun every minute is not a standard collision avoidance signal, C) One prolonged blast on the whistle is used for other purposes like signaling intent to maneuver, and D) A continuous sounding of the fog horn is used for navigational purposes in restricted visibility, not as a collision avoidance signal.