Anemometer

An anemometer measures wind speed, by cup rotation, a propeller vane, ultrasonic time-of-flight, or pressure, and is paired with a wind vane for direction. The bridge display shows apparent wind (the vector sum of true wind and the ship’s motion); true wind is computed from apparent wind, heading, and speed. Marine readings are in knots. Wind speed feeds the Beaufort estimate, mooring and crane operating limits, and weather-routing input.