Coast Guard Exams
Question 165Navigation General70% to pass

In the North Sea area, you sight a buoy showing a quick white light with 9 flashes every 15 seconds. Which of the four topmarks shown in illustration D031NG below would be fitted to the buoy?

Diagram for question 165
AI Explanation
The correct answer is A. A quick white light with 9 flashes every 15 seconds indicates a safe water mark, which is a buoy or other aid used to mark the middle of a channel or other safe navigable waters. As per the International Association of Lighthouse Authorities (IALA) regulations, a safe water mark should display the topmark shown in option A - a single red sphere. The other options (B, C, and D) represent different topmarks used for different types of buoys and navigational aids, which would not be correct for a safe water mark displaying the described light characteristics.

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