Knots are a unique unit of speed used primarily in maritime and aviation settings. While most people are familiar with kilometers per hour or miles per hour, knots remain essential for ships, planes, and even weather reports. Understanding knots requires looking at their history, modern applications, and typical speeds.

The origin of knots goes back centuries. Sailors measured their ship’s speed using a log line—a rope with knots tied at regular intervals. By tossing the line overboard and counting the knots that passed in a set period of time, they could estimate the vessel’s speed. This simple method gave rise to the term “knot” and made it a standard measurement for navigation.

A knot equals one nautical mile per hour. Nautical miles differ from standard miles or kilometers because they are based on the Earth’s geometry, specifically latitude and longitude. This makes knots extremely practical for navigation over long distances, ensuring that speed and distance calculations align directly with charts and routes.

Modern ships and aircraft continue to use knots because they provide a consistent, internationally recognized standard. Shipping routes, flight plans, and wind speeds are all communicated in knots, allowing crews to operate safely and efficiently across oceans and international airspace. Even modern navigation technology still relies on knots as a core unit for speed.

Typical cruising speeds vary depending on the type of vessel or aircraft. Cargo ships usually travel at 20–25 knots, passenger ferries at 30–40 knots, and commercial airliners cruise at roughly 450–500 knots. Military aircraft can go much faster, but even supersonic jets often reference knots for navigation purposes.

Knots are more than just a historical curiosity—they are a practical tool that links centuries-old navigation methods with today’s high-tech travel. By understanding their history, modern use, and typical speeds, we can appreciate why knots remain a critical part of maritime and aviation navigation.