Distance to Horizon Explained
Why the horizon distance depends on height of eye and how to calculate it.
Author: OceanCalc Editorial Team · Publisher: Albor Digital LLC
The distance to the horizon depends on how high your eyes are above the water. The formula is distance (nm) ≈ 1.17 × √(height in feet). From a typical cockpit at 6 feet, the horizon is about 2.9 nautical miles away. From the mast at 30 feet, it's about 6.4 nm. This matters for identifying landmarks and for understanding when you'll first see a light or object.
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Frequently Asked Questions
How is horizon distance used in navigation?
You use it to predict when a light or object will appear or disappear over the horizon, and to interpret radar or visual detection ranges. It's also part of the formula for geographic range of a light.