Knots are used to measure the speed at sea. "1 knot" = 1 nautical mile per hour. The English word "node” as well as “knot” has a value and a knot on a cable, and measures speed - miles per hour. This is due to the fact that in ancient times the speed of a sailing vessel was measured by releasing the rope overboard marked up at regular intervals with line tied at the end of the sector. Speed was measured by the number of knots that went overboard for a certain period of time, which was determined by the hourglass.