🔍 Key Concepts

• Standard magnetic compass (psc) vs. true bearings and how to apply variation/deviation from the exam’s plotting sheet or table • How to plot simultaneous compass bearings from three lights to obtain a three‑line fix • How small shifts in the crossing point of the three LOPs (lines of position) affect the latitude vs. longitude on the chart grid

💭 Think About

• First, think about how you convert the given psc bearings of the lights into the form you would actually plot from each light on the chart—are you plotting FROM the light TO your vessel or vice versa? • Once you have three LOPs, consider whether they cross cleanly at one point or form a small triangle of error; how would you pick a most probable position from that triangle? • Look at the answer options: which coordinate changes more between choices, latitude or longitude, and how does that relate to the direction from which the three lights are observed?

✅ Before You Answer

• Verify you have applied any compass error (variation + deviation) in the correct direction (True–Variation–Deviation–Compass, or the reverse depending on what is given). • Confirm that you are plotting the bearing as a reciprocal (back bearing) from the light toward your vessel, not the bearing from your vessel toward the light. • After plotting, carefully read off the nearest latitude and longitude to the fix, paying attention to minutes and tenths of minutes and how they correspond to the small differences among the choices.