Question 135Navigation General

70% to pass

Under the IALA cardinal system, a mark with a quick light showing 9 flashes every 15 seconds indicates that the safest water is on which side of the mark?

A west side of the mark
B east side of the mark
C north side of the mark
D south side of the mark
AI Explanation

The correct answer is A) west side of the mark. According to the IALA (International Association of Marine Aids to Navigation and Lighthouse Authorities) Cardinal System, a quick light showing 9 flashes every 15 seconds indicates that the safest water is on the west side of the mark. This is because the cardinal system uses the number of flashes to indicate the cardinal direction, with the west side having the most flashes (9) in a 15-second period. The other options are incorrect because the east side would have 3 flashes, the north side would have 6 flashes, and the south side would have 3 flashes, which do not match the characteristics of the provided mark.

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