You are underway on course 241°T at a speed of 18.2 knots. You sight a daymark bearing 241°T at a radar range of 3.9 miles at 1006. If you change course at 1009, what is the course to steer to leave the daymark abeam to starboard at 1.0 mile?
• Relative motion on a radar plotting sheet when a fixed object is dead ahead • Using distance = speed × time to find how far you travel between observations • Geometry of altering course to pass a fixed object abeam to starboard at a given closest point of approach (CPA)
• From 1006 to 1009, how many minutes elapse, and how many miles do you travel at 18.2 knots in that time? • After you change course at 1009, what straight‑line track from your 1009 position will put the daymark exactly 1.0 NM on your starboard beam when you are abeam of it? • Which answer choices would put the daymark on your port side instead of your starboard side, based on where it lies relative to your new course?
• Convert the time difference to hours correctly before using the speed formula • Draw or imagine a simple triangle: one side is from your 1009 position to the abeam point, one is the 1.0‑mile abeam distance, and one is the line from you to the daymark • Confirm that the final course you pick would make the daymark lie 90° to starboard, not ahead or to port, at the CPA point
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