Your vessel is steering 143°T at 16 knots. At 2147 a light bears 106°T and at 2206 the same light bears 078°T. What will be your distance off when abeam?

Correct Answer: Option C — 5.9 miles

The run distance is 5.06 miles over 19 minutes. Relative bearings are 37 degrees and 65 degrees. Calculating the distance off at the second bearing and then determining the distance when abeam using the sine of the relative angle yields 5.9 miles, consistent with standard piloting geometry.