All instrumentsDeviation cardG-CLRD
Variation and deviation
Work from true heading to magnetic heading and on to compass heading. And back again.
You see the compass card from behind. Heading north, 030 is to the left of the N.
| For | 360 | 030 | 060 | 090 | 120 | 150 |
|---|---|---|---|---|---|---|
| Steer | 359 | 028 | 058 | 088 | 119 | 150 |
| For | 180 | 210 | 240 | 270 | 300 | 330 |
| Steer | 181 | 212 | 242 | 272 | 301 | 330 |
- True heading
- 090°
- Variation
- +66° W
- Magnetic heading
- 096°
- Deviation
- −22° E
- Compass heading
- 094°
Variation 6° W, so add it. Deviation on this heading 2° E, so subtract it.
From true to magnetic heading, and from magnetic to compass heading: add west, subtract east. West is best, east is least. Working back, do exactly the opposite.