🔍 Key Concepts
• Relationship between gyro course (pgc), true course (T), magnetic/standard compass course (psc), and compass course (c)
• How to apply gyro error, variation, and deviation using the standard conversion table (Gyro–True–Magnetic–Compass)
• The effect of east vs. west errors ("east is least, west is best") when converting between references
💭 Think About
• Start from the given 081°pgc. In the normal Gyro–True–Magnetic–Compass line, which direction (left or right) do you move when going from gyro to standard compass?
• When moving from gyro to true, and then true to magnetic/standard compass, do you add or subtract east and west errors? Think about what happens to the numerical value.
• Look at each option and ask: which choices are realistically reachable from 081° using typical values of gyro error, variation, and deviation (only small corrections, not huge jumps)?
✅ Before You Answer
• Make sure you know whether standard compass (psc) on your exam refers to magnetic compass corrected for deviation or just the ship’s standard magnetic compass reading.
• Check that you are consistently using the rule: east errors are subtracted, west errors are added when converting toward compass, and reversed when converting toward gyro/true.
• Before choosing, mentally run a short Gyro–True–Magnetic–Compass chain (e.g., G → T → M → C) and see which option lies in the reasonable corrected range from 081°pgc.