You are underway on course 120°T and your maximum speed is 12 knots. The eye of a hurricane bears 150°T, 120 miles from your position. The hurricane is moving towards 295°T at 20 knots. If you maneuver at 12 knots to avoid the hurricane, what could be the maximum CPA?
• Relative motion between your vessel and the hurricane’s center • Using Speed = Distance / Time and velocity vectors to find closest point of approach (CPA) • How your course choice at 12 knots affects the relative track between you and the storm
• First sketch both positions on a simple x–y grid: put your vessel at the origin, then plot the hurricane 120 miles away on bearing 150°T. Which quadrant is that in? • Draw the hurricane’s motion vector: 20 knots on course 295°T. Then add your own ship’s 12-knot vector. How does changing your heading change the relative velocity between you and the eye? • CPA is the shortest distance between your track and the hurricane’s track. Once you have the relative velocity vector, how can you compute that minimum distance using basic right‑triangle geometry?
• Confirm you are treating both motions as straight-line and constant speed (good approximation for this problem). • Make sure you convert bearings to components correctly (east–west and north–south), keeping track of signs in each quadrant. • Before choosing an answer, check whether your calculated CPA is larger than 120 miles, smaller, or about the same—this can help you quickly reject one or two options.
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