Your vessel is steering 074°T at 12 knots. At 0214 a light bears 115°T, and at 0223 the same light bears 135°T. What will be your distance off abeam?

Correct Answer: Option D — 3.0 miles

Apply the 'bow and beam' or 'doubling the angle on the bow' principle. With a change in bearing from 41° to 61° relative to the course, the run between bearings is 9 minutes at 12 knots (1.8 miles). Using the distance-off formula, the distance abeam is calculated as 3.0 miles.