🔍 Key Concepts

• Compass deviation vs. variation – know the difference between these two errors • How a ship’s magnetic fields and metal structure affect the compass • What error is caused by the Earth’s magnetic field itself

💭 Think About

• Ask yourself: Which option describes something that is unique to this particular vessel, and not the same for every ship in the same area? • Think about which factor would change when you change heading on the same ship, even if you stay in the same geographic position. • Consider which term (deviation or variation) is tied to local magnetic charts showing the Earth’s magnetic field, and eliminate that from this question.

✅ Before You Answer

• Identify which choice refers to the ship’s own magnetism or magnetic influence. • Separate in your mind: variation = Earth’s field, deviation = ship’s influence. • Check which factor would be different for two ships side by side in the same location on the same heading.