The Light List shows that a navigational light has a nominal range of 6 miles and a height above water of 18 feet (5.5 meters). Your height of eye is 47 feet (14.3 meters) and the visibility is 1.5 miles. At what approximate range will you first sight the light?

Correct Answer: Option B — 2.0 miles

Geographic range is 1.17 * sqrt(18) + 1.17 * sqrt(47), equaling 5.0 + 8.0 = 13.0 nm. Because the visibility is only 1.5 miles, the luminous range is the limiting factor. The light will be sighted at the distance of the visibility, approximately 2.0 miles.