Question 637 Rules of the Road

The correct answer is B) 4 to 6 seconds. This is based on the regulations for both international and inland navigation rules, which state that a prolonged blast of the whistle should last 4 to 6 seconds. This duration is used to signal certain navigational situations, such as when a vessel is turning, backing up, or indicating its position in restricted visibility. The other options are incorrect because they do not align with the established regulations for the duration of a prolonged whistle blast. A blast shorter than 4 seconds would not be considered a "prolonged" blast, while a blast longer than 6 seconds would be outside the defined range.