Chart Navigation & Plotting · Distance — Distance to the Horizon
Your height of eye is 25 feet. Using the formula distance ≈ 1.17 × √(height in feet), how far is your visible sea horizon?
- A29.25 NM
- B5.85 NM✓ Correct
- C1.17 NM
- D12.5 NM
Explanation
Distance to the horizon ≈ 1.17 × √25 = 1.17 × 5 = 5.85 NM. The formula accounts for terrestrial refraction; greater height of eye extends the visible horizon.
Authority: Bowditch (Pub. No. 9), Distance of the Horizon
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