The use of knots as a unit of speed in seafaring dates back to the 1500s and 1600s. In the past, Dutch sailors used a device called a “chip log,” now more commonly known as a “paraclete,” to measure the speed of ships. The chip log was prepared by tying a knot (knot) every 14.4 meters on a rope attached to a triangular piece of wood. While the ship was underway, the wooden piece was released into the sea, and the time was measured using an hourglass (approximately 30 seconds). During these 30 seconds, each knot that fell into the sea was counted, and after repeating this process several times, the ship’s average speed was determined in knots. The 1 knot measured using this method is equivalent to 1 nautical mile traveled in 1 hour today.