When traversing land, speed is quantified in either miles per hour (mph) or kilometers per hour (km/h). These units are clear-cut since stationary landmarks allow for easy estimation of distance and speed. However, out on the water, landmarks are frequently absent, making it unfeasible for ships to depend on the same travel systems used on land. This is the reason vessels adopt knots in place of miles per hour for speed measurement.
A knot is characterized as one nautical mile per hour, and a nautical mile is marginally longer than a conventional mile. More specifically, a nautical mile equals 1.1508 miles (1,852 meters), and it is grounded in the Earth’s geometry; one nautical mile equates to one minute of latitude on the globe. This framework renders nautical miles and knots more advantageous for navigation as they correspond with global coordinates utilized on nautical charts.
The origin of the term “knot” can be traced back hundreds of years. Sailors historically gauged speed with a rope that had evenly spaced knots tied into it. The rope was cast overboard, and as the ship advanced, sailors would tally how many knots passed through their fingers within a specific timeframe, hence the term “knots” to describe speed at sea.
By utilizing knots, mariners acquire a practical, universally recognized measure of speed that is directly tied to navigation and chart plotting, an advantage that miles per hour cannot provide in vast oceanic environments.
