Over the curve of the water
Each height has its own distance to the horizon, 1.17 × √(feet) nautical miles. Add the two to get the geographic range.
Skill 8 · Light risingProblem 10003
Height of eye 8 ft: when should Heron Point Light show?
On a clear night your height of eye is 8 ft. You are closing Heron Point Light (Fl W 4s 52ft 14M).
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
| Height of eye | 8 ft |
|---|---|
| Height of the light | 52 ft |
| Nominal range | 14 nm |
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