How many lines of position are recommended for reliable position fixing?

• A. One
• B. Three
• C. Two
• D. Four

Answer: (B)

Using multiple lines of position is about turning a loose cue into a reliable fix. A single line of position only tells you you’re somewhere along that line, not exactly where along it. With two lines, you can locate a crossing point, but real-world measurements have errors—bearings, ranges, and readings may be off—so the intersection can drift and a clean two-line fix might not be as trustworthy. A third, independent line adds redundancy and lets you verify consistency: all three lines should cross near the same point, and any line that doesn’t align with the others can be flagged as suspect. This cross-checking reduces the influence of measurement errors and yields a more confident, stable position fix. Four lines add more redundancy, but three is the practical minimum that provides reliable results without unnecessary effort.