Your vessel is steering course 243°psc. Variation for the area is 5°E, and deviation is 2°W. The wind is from the south-southeast, producing a 2° leeway. What true course are you making good?
• Relationship between compass course, deviation, magnetic course, variation, and true course (the classic "Can Dead Men Vote Twice At Elections" sequence) • How to treat East and West corrections (Add East, Subtract West) when going from compass to true • Effect and direction of leeway (which side of the vessel the wind is on and whether that pushes your actual track to the left or right)
• Start from the steering compass course and move step-by-step to get magnetic, then true. At each step ask: am I applying deviation or variation, and do I add or subtract? • For the wind from south-southeast, picture your vessel’s heading of about 243°. Is the wind on your port or starboard side? Would that push your track to a smaller or larger true course angle? • Once you’ve converted compass to true (before leeway), apply the 2° leeway in the correct direction. Ask yourself: does leeway make your course made good to the left (smaller number) or right (bigger number) of your heading?
• Verify you apply deviation first, then variation when converting from compass to true • Double-check the rule “Add East, Subtract West” is used consistently for both deviation and variation in this direction of conversion • Confirm the side the wind is on at 243° with wind from SSE and therefore which way the leeway pushes your actual track before choosing the closest true course option
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