🔍 Key Concepts

• Relationship between true, magnetic, compass, and per ship’s compass (psc) courses • How to correctly apply variation (east or west) and deviation (east or west) using the standard TVMDC table • Effect of leeway (wind pushing the vessel off course) and whether you should add or subtract it from the intended course

💭 Think About

• Start from the true course and work step‑by‑step to the course to steer psc. In which direction do you move when applying east variation? What about west deviation? • Think about leeway: if a northerly wind is blowing, which way does it tend to push your vessel, and do you need to steer more into or away from the wind to compensate? • At each step (true → magnetic → compass → psc), are you moving your angle numerically higher or lower? Track the arithmetic carefully.

✅ Before You Answer

• Write out the TVMDC (True–Variation–Magnetic–Deviation–Compass) line and clearly mark E and W corrections so you don’t reverse the signs. • Confirm whether the leeway should be applied as an addition or subtraction and at which stage (usually as a correction to the heading you steer). • After you get your final psc course, compare it logically: given your true course and the direction of wind and errors, should your steering course be slightly higher or lower than 071°? Eliminate any options that are clearly inconsistent.