🔍 Key Concepts

• Compass error as the total difference between true bearing and compass bearing • Relationship between variation (earth’s magnetism) and deviation (ship’s magnetism) • The standard formula: Compass ± Deviation = Magnetic ± Variation = True

💭 Think About

• If the compass has no deviation, which part of compass error is removed and which part might still remain? • Think about whether adjusting the compass can remove the Earth’s magnetic field effects or only the ship’s own magnetic effects. • Ask yourself: does compass error stay the same everywhere on Earth, or does one of its components change with location?

✅ Before You Answer

• Be clear on the definition: compass error = True bearing − Compass bearing (or vice versa, depending on convention). • Verify what no deviation means in practice: is the ship’s magnetic influence zero, or is all error zero? • Consider whether variation changes from place to place or remains constant worldwide.