Ship Log

A ship log, also sometimes referred to as a speed log, common log or chip log, is an instrument which is used to measure a ship’s speed and the distance it has traveled. The speed is determined by referencing the water flowing past the hull (water reference speed) or by the seabed (ground reference speed).

There are five different types of ship log which all work on different principles: the electromagnetic ship log, the pitometer ship log, the doppler ship log, the impeller ship log and the satellite ship log. See their individual glossary entries for more information on each.