how far can you see at sea
The distance you can see at sea depends on several factors, including:
-
Visibility Conditions: This is the most important factor. In clear weather, visibility can be up to 10 nautical miles or more. In poor weather (e.g., fog, rain, or haze), visibility can drop to less than 1 nautical mile.
-
Height of the Observer: The higher the observer’s eye level above sea level, the farther they can see. For example:
- At 5 meters (16.4 feet) above sea level, you can see about 8-10 nautical miles.
- At 15 meters (49.2 feet), you can see about 12-15 nautical miles.
- At 30 meters (98.4 feet), you can see about 20 nautical miles.
-
Curvature of the Earth: The Earth’s curvature limits the distance to the horizon. The formula to calculate the distance to the horizon is approximately:
[
\text{Distance to horizon} = \sqrt{2 \times \text{height} \times 6371}
]Where:
- Distance is in kilometers.
- Height is in meters above sea level.
- 6371 is the Earth’s radius in kilometers.
- Atmospheric Conditions: Clear air allows for better visibility, while haze or pollution can reduce it.
So, if you’re standing at a height of about 1.7 meters (5.6 feet) above sea level (the average human height), you can see about 5 kilometers (2.7 nautical miles) to the horizon. From a taller structure or a ship’s bridge, the range increases significantly.
