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 C — 120°T

Calculate distance traveled between 1725 and 1728 (3 minutes at 15.3 knots = 0.765 miles). Plot the initial position and the target abeam position. Using the relative motion triangle, the course change required to pass the buoy at 0.5 miles to port is 120T.