As part of our ongoing series of monthly WW2 battle maps, we have already looked at some of the most famous and significant battles of the Second World War. This month, we’re focusing on the Battle for the Atlantic. In particular, we will be looking at the Kriegsmarine’s strategy and its development of quadrant maps.
As early as WW1, the concept of waging submarine warfare against Britain had been in the minds of German naval commanders. With the aim of cutting off the supply of vital materials to Britain, the Imperial German Navy waged unrestricted submarine warfare in the Atlantic. Although the campaign ultimately failed to bring Britain to its knees, Germany’s U-boats proved highly effective.
In the years following the end of WW1, German naval planners began anticipating a second U-boat campaign. Much of the interwar period was devoted to devising new tactics and strategies to combat the British Royal Navy. An important part of this was the development of a new mapping system. In 1934, the Kriegsmarine introduced a new map to facilitate future operations. The new map, called the Marinequadratkatre, divided the Atlantic Ocean into a system of grid squares. This made it easier for Kriegsmarine vessels to report their coordinates and those of enemy ships.
The new map divided the Atlantic into large sections measuring nearly 500 nautical miles in length and width. Each of these sections was designated with two letters. ‘AN’, for example, encompassed the North Sea. These areas were subdivided into nine quadrants, making a 3-by-3 grid in each section. Each quadrant was still a large area covering 162-by-162 nautical miles. These quadrants were each designated by a number from 1 to 9. On top of this, each area was divided still further into another 9 squares. This meant that each main two letter section was divided into 81 smaller quadrants, each designated with two numbers between 1 and 9. For example, AC71 would point to a location just off the Norwegian North coast. Finally, each small quadrant was divided into 6-by-6 nautical mile squares, each given a number in the same way as the larger sections. Thus a designation of CA2745, for example, would point to a small 6-by-6 nautical mile area just off the coast of New York. Although this may seem complicated, the system in fact was exceedingly easy to operate. Coordinates were able to be relayed using a short 6 digit alpha-numeric code.
With the outbreak of WW2, the new system was put to the test in combat for the first time. It soon proved to be as effective as had initially been hoped. It was particularly effective when the Kriegsmarine introduced the new Wolfpack doctrine. Using the new tactics, a single U-boat would relay the coordinates of an enemy convoy to nearby U-boats. All available submarines would then mass and attack the convoy after dark. The new quadrant map system helped the Kriegsmarine’s wolfpacks rapidly pinpoint and intercept Allied convoys.
The Kriegsmarine’s Marinequadrantkarte greatly aided Germany’s war in the Atlantic. Although the Allies ultimately emerged victorious, the German Navy had enjoyed significant successes.