Your vessel is steering course 073°psc, variation for the area is 15°E, and deviation is 4°E. The wind is from the southeast, producing a 4° leeway. Which true course are you making good?
• Difference between per ship’s compass (psc), magnetic, and true courses • How to apply variation and deviation (E is least, W is best) when converting compass to true • Effect of leeway from a given wind direction on the course actually made good
• Start from the given per ship’s compass (psc) course and think about whether you must remove or add deviation first, then variation, to reach a true course through the water before applying leeway. • Sketch the wind from the southeast and your approximate heading. Does this wind push your bow more toward the left (port) or right (starboard), and does that make your true course made good numerically larger or smaller? • After adjusting for deviation, variation, and leeway, compare the direction of all corrections (east vs west) to see in which direction the final true value must move from the original compass course.
• Be clear on the conversion sequence: Compass → Magnetic → True before applying leeway. • Remember the memory aid for variation/deviation: “East is least, West is best” when going from true to compass, and reverse when going compass to true. • Confirm whether a southeasterly wind causes port or starboard leeway on a vessel heading generally east-northeast, and how many degrees the final true course should shift because of that.
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