Dividers

A navigational tool consisting of two hinged legs with pointed ends, used by mariners to measure distances on a nautical chart.

Dividers are an essential instrument in traditional marine navigation, particularly when working with paper nautical charts. They are typically constructed from durable materials such as brass or stainless steel to withstand the harsh marine environment. The two legs of the dividers are connected by a hinge, allowing the user to adjust the distance between the points with precision. Mariners use dividers to measure distances between two points on a chart, which can then be compared to the chart’s scale to determine the actual distance in nautical miles. This is particularly useful for plotting courses, determining the distance to a waypoint, or calculating the separation between navigational hazards.

To use dividers effectively, a navigator places one point of the tool on the starting location and the other point on the destination or feature of interest. The distance between the points is then compared against the chart’s latitude scale or a dedicated distance scale, as latitude degrees are consistent in nautical miles. Dividers can also be used in conjunction with parallel rulers or a plotter to transfer measured distances or bearings across the chart. Despite the advent of electronic navigation systems like GPS, dividers remain a fundamental tool for mariners, especially as a backup in case of electronic failure. Their simplicity, reliability, and precision make them indispensable for safe and accurate marine navigation.