The Light List shows that a navigational light has a nominal range of 10 miles and a height above water of 38 feet (11.6 meters). Your height of eye is 52 feet (15.8 meters) and the visibility is 11.0 miles. At which approximate range will you first sight the light?

Correct Answer: Option A — 10.5 miles

Geographic range is 1.17 * sqrt(38) + 1.17 * sqrt(52), equaling 7.2 + 8.4 = 15.6 nm. Because the visibility is 11.0 miles, the luminous range is the limiting factor. The light is sighted at the visibility distance, which is approximately 10.5 miles.