🔍 Key Concepts

• Difference between true and magnetic north on charts • How a compass rose is drawn: usually two concentric circles with different references • Relationship between variation/deviation and the information shown on the compass rose

💭 Think About

• Ask yourself: When navigating with the chart only (no compass), which north do you normally use for plotting courses? Is that shown on the inner or outer circle? • Think about your magnetic compass on board: which part of the compass rose helps you relate your compass readings to the chart? • Consider which one (true or magnetic) must be tied directly to the meridians (longitude lines) printed on the chart.

✅ Before You Answer

• Verify which ring (inner vs outer) is aligned with the chart meridians (true north) • Check which ring is labeled with variation information such as “Var 7°15’ W (2025) decreasing 8’ annually” • Confirm that deviation is specific to your vessel’s compass and is NOT printed as part of the chart’s standard compass rose.