Chart Navigation & Plotting · Distance to Horizon
From a height of eye of 64 feet, the approximate distance to the visible horizon is (using d ≈ 1.17 × √height in feet):
- AAbout 4.7 nm
- BAbout 64 nm
- CAbout 14 nm
- DAbout 9.4 nm✓ Correct
Explanation
d ≈ 1.17 × √64 = 1.17 × 8 = 9.4 nautical miles. Greater height of eye extends the visible horizon.
Authority: Bowditch (Pub. No. 9), distance to the horizon
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