The speed of a cargo ship is 36kn, which is the speed of the cargo ship at sea. In mathematics, the meaning of 36kn is composed of three 1000, six 100, k 10 and n 1. The symbol of node unit is kn, which is a speed unit dedicated to navigation. Kn is a unit of speed and is often used in navigation. That is 1kn = 1852/3600 m/s.