🔍 Key Concepts

• Difference between a gyro bearing (pgc) and a true bearing (°T) from the chart • How to determine if gyro error is east or west based on which value is larger • Relationship: "Gyro Best, Error West" and "Gyro Least, Error East"

💭 Think About

• From the chart, what is the true bearing of Latimer Reef Light when it is in line with the Fishers Island cupola? • Compare that true bearing with the observed 024°pgc. Which is larger? By how many degrees? • Based on which is larger (true or gyro), does that indicate an east or west gyro error?

✅ Before You Answer

• Use the chart to carefully measure the true bearing from your vessel to the lined‑up marks (cupola and light) • Compute the numerical difference between the true bearing and 024°pgc (ignore E/W at first) • Then apply the memory aid "Gyro Best, Error West / Gyro Least, Error East" to decide whether the error is E or W