Technical Description:- It consists of following major parts :
a) The main body of Battenburg is made of Aluminium Alloy and has a degree scale marked ( 00 – 3590 ) on its outer edge.
b) It is screwed to the main aluminium sheet frame with three handles at the back for holding and resting of Battenburg.
c) A circular aluminum base-plate, rotatable through cut-away portions in the back of the frame, is engraved with continuous parallel black lines in one axis and interrupted parallel black lines in the other axis. Figures in black represent distance or speed.
d) A Rotatable Perspex disc is superimposed on the base-plate and can be clamped in any desired position. It is engraved with green concentric rings at radii of 10, 20 and 30 units centre, and with red rings for every intervening 2 units out of 36 units. The perimeter is marked in degrees from 0 to 359 in red and red radial lines mark every 10 degrees.
e) Two metal speed-bars, pivoted about the centre, are engraved with figures from 0 to 35. Each bar has a movable slider which can be clamped in any required position. The milled screw heads are green and red.
f) A circular distance/time scale is engraved on the back of the frame. The outer scale is marked in seconds from 15 to 60 and minutes from 1 to 60. The inner rotatable scale is marked in miles from 0.1 to 40. By setting the ship’s speed against the 60-minute mark, the distance covered in a specified time may be discovered. Conversely the speed or time may be found if the other two factors are known.
It is a mechanical calculating device for taking station other vessels whose range, bearing, course and speed are known. By extension, it has a range of other functions related to relative velocity calculatons. The instrument has been designed to aid various speed and distance calculation, in particular tracking the position of a ship relative to others and is of particular use when moving in large convoys.
