Question 165Navigation General

70% 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 USCG Navigation General: In the North Sea area, you sight a buoy showing a quick white light with 9...
A A
B B
C C
D D
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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Official Resources
USCG Navigation Rules (COLREGS) 33 CFR Navigation Rules USCG National Maritime Center
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