This instrument was designed to aid various speed and distance calculations, in particular tracking the position of a ship relative to others, and was of particular use when moving in large convoys.

The main body of the instrument, which is made of a light alloy, has a degree scale marked on its outer edge. Two celluloid discs are held within it. The bottom one is marked with a distance scale from zero at the centre to 36 in each direction and is free to rotate. The second disc, marked in degrees around the edge, rotates on top of this. The bars on top have scales for distance. The instrument is contained in a wooden box, which carries a spare celluloid disc in the lid.

Station, speed and distance indicators were first developed following the introduction of fast steam ships, when it became more important to be able to calculate the course and speed of other vessels within sight. The Battenberg course indicator was invented in 1892 by Prince Louis of Battenberg (later Louis Mountbatten, Marquis of Milford Haven, 1854-1921), who became First Sea Lord in 1912.