Knots are a unique unit of speed used in both maritime and aviation settings. Unlike kilometers per hour or miles per hour, knots are specially designed for navigation, helping sailors and pilots travel safely over long distances.

The concept of knots dates back centuries. Sailors measured their ship’s speed using a log line—a rope with knots tied at regular intervals. By throwing the line overboard and counting how many knots passed in a set period of time, they could estimate their speed. This simple technique gave the unit its name and became a standard for maritime travel.

One knot equals one nautical mile per hour. Nautical miles are based on the Earth’s latitude and longitude, making them perfect for navigation. Using knots ensures that distance, speed, and charts all match, whether plotting a ship’s course across the ocean or an aircraft’s flight over international airspace.

Modern ships and aircraft continue to rely on knots. Cargo ships typically cruise at 20–25 knots, passenger ferries at 30–40 knots, and commercial airliners at roughly 450–500 knots. Even wind speeds are measured in knots, which helps sailors and pilots adjust their routes and maintain safety. Military jets, while much faster, often still use knots for consistency in navigation.

Knots may have started with simple ropes and logs, but today they remain a vital tool for understanding speed, planning routes, and navigating safely. By learning how knots work, we can better appreciate the connection between historical maritime practices and modern aviation and shipping.