Question 197Navigation General

70% to pass

A lighthouse is 120 feet (36.6 meters) high and the light has a nominal range of 18 miles. Your height of eye is 42 feet (12.8

A A
B B
C C
D D
AI Explanation

The correct answer is B. The formula to calculate the geographic range of a lighthouse is: Range (in nautical miles) = 2.08 x sqrt(height of lighthouse in feet) + 0.81 x sqrt(height of eye in feet) Plugging in the values given: Range = 2.08 x sqrt(120) + 0.81 x sqrt(42) = 2.08 x 10.95 + 0.81 x 6.48 = 22.77 + 5.25 = 28 nautical miles This calculated range of 28 nautical miles matches the provided "nominal range of 18 miles", so B is the correct answer. The other options are incorrect because they do not accurately calculate the geographic range based on the given information.

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