Early Dead Reckoning Navigation

Abstract

The reckoning of a ship is the up-to-date record of the courses and distances made through the water since the ship's position was last fixed by observation. The importance of keeping a careful reckoning was paramount in circumstances when observational methods of fixing were not available. In the early days of sea voyaging, even before astronomical methods for checking position had become available, the mariner who would know his ship's position (essentially to estimate his arrival time at his destination) was forced to rely on his reckoning—no other way was at hand when out of sight of land.