🔍 Key Concepts

• Relative motion and plotting the buoy's position over time on a radar or maneuvering board • Using your vessel’s run between 1725 and 1728 to find your new position relative to the buoy • Constructing a tangent track that passes a fixed object at a specified CPA (closest point of approach) distance

💭 Think About

• How far do you travel between 1725 and 1728 at 15.3 knots, and along what direction? Mark that run from your 1725 position to get your 1728 position relative to the buoy. • From your 1728 position, if you draw a 0.5‑mile circle around the buoy, what course line from your position just touches (is tangent to) that circle with the buoy on your port side? • When the buoy is abeam to port, what is the geometric relationship between your course line, the line of sight to the buoy, and the 0.5‑mile CPA distance?

✅ Before You Answer

• Be sure you convert the 3‑minute time interval into hours before computing distance run at 15.3 knots. • Check that the buoy’s position is treated as fixed, and that only your ship’s position moves on the plot between 1725 and 1728. • Verify that the chosen tangent track keeps the buoy on the port side and that the minimum distance from your track to the buoy’s position is 0.5 NM.