Question 136Navigation General

70% to pass

In the North Sea area, you sight a buoy showing a quick white light showing 6 flashes followed by one long flash at 15 second intervals. Which of the four topmarks in illustration D031NG below would be fitted to this buoy?

Diagram for USCG Navigation General: In the North Sea area, you sight a buoy showing a quick white light showing 6...
A A
B B
C C
D D
AI Explanation

The correct answer is C. The characteristics of the light described (quick white light showing 6 flashes followed by one long flash at 15 second intervals) indicate that this is a composite group flashing white light, which is associated with a special purpose buoy according to the IALA Buoyage System. The topmark shown in option C, consisting of two black spheres, is the standard topmark used to identify a special purpose buoy. The other options do not match the characteristics of the light described, and would not be the appropriate topmark for this type of buoy.

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Official Resources
USCG Navigation Rules (COLREGS) 33 CFR Navigation Rules USCG National Maritime Center
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