Means of measurement and calculation of ship velocity

Abstract

Velocity – a vector measurement, which defines the rate with which the point particle changes position and direction with respect to a specific frame of reference. The velocity of point particle at given moment is equal to the first derivative of distance with respect to time. In the past, the speed of a ship was calculated using a chip log – a wooden board attached to a line called log line, which was thrown into water. Sailor made a note of line’s length passed in a fixed amount of time. It was made by counting knots, tied on the line in equal intervals. These knots were pre-made on the shore so when counted they would show the ship’s speed in nautical miles per hour. This unit of speed was eventually called a knot. When navigating the knot became very useful due to its relation to the minute of meridian.1 knot = 1 nautical mile/hour.