You are underway on course 106°T at a speed of 15.3 knots. You sight a buoy bearing 109°T at a radar range of 3.6 miles at 1725. If you change course at 1728, what is the course to steer to leave the buoy abeam to port at 0.5 mile?

Correct Answer: Option D — 120°T

Solving this running fix and parallel-sailing problem requires calculating the vessel's run during the time interval between bearings, constructing the triangle of positions on the relative motion diagram, and determining a course to steer of 120°T to achieve the 0.5-mile port abeam passing distance.