Battle of The Atlantic - Submarine Warfare

Submarine Warfare

Early in the war, Dönitz submitted a memorandum to Grand Admiral Erich Raeder, the German Navy's Commander-in-Chief, in which he estimated effective submarine warfare could bring Britain to her knees because of her dependence on overseas commerce. He advocated a system known as the Rudeltaktik (the so-called "wolf pack"), in which U-boats would spread out in a long line across the projected course of a convoy. Upon sighting a target, they would come together to attack en masse and overwhelm any escorting warships. While escorts chased individual submarines, the rest of the "pack" would be able to attack the merchant ships with impunity. Dönitz calculated 300 of the latest Atlantic Boats (the Type VII), would create enough havoc among Allied shipping that Britain would be knocked out of the war.

This was in stark contrast to the traditional view of submarine deployment up until then, in which the submarine was seen as a lone ambusher, waiting outside an enemy port to attack ships entering and leaving. This had been a very successful tactic used by British submarines in the Baltic and Bosporus during World War I, but it could not be successful if port approaches were well patrolled. There had also been naval theorists who held submarines should be attached to a fleet and used like destroyers; this had been tried by the Germans at Jutland with poor results, since underwater communications were in their infancy. (Interwar exercises had proven the idea faulty.) The Japanese also adhered to the idea of a fleet submarine, following the doctrine of Mahan, and never used their submarines either for close blockade or convoy interdiction. The submarine was still looked upon by much of the naval world as "dishonourable", compared to the prestige attached to capital ships. This was true in Kriegsmarine as well; Raeder successfully lobbied for the money to be spent on capital ships instead.

The Royal Navy's main anti-submarine weapon before the war was the inshore patrol craft, which was fitted with hydrophones and armed with a small gun and depth charges. The Royal Navy, like most, had not considered anti-submarine warfare as a tactical subject during the 1920s and 1930s. Unrestricted submarine warfare had been outlawed by the London Naval Treaty; anti-submarine warfare was seen as 'defensive' rather than dashing; many naval officers believed anti-submarine work was drudgery similar to mine sweeping; and ASDIC was believed to have rendered submarines impotent. Although destroyers also carried depth charges, it was expected these ships would be used in fleet actions rather than coastal patrol, so they were not extensively trained in their use. The British, however, ignored the fact that arming merchantmen, as Britain did from the start of the war, removed them from the protection of the "cruiser rules", and the fact anti-submarine trials with ASDIC had been conducted in ideal conditions.