During World War II, the
Battle of the Atlantic saw
Nazi Germany conducting commerce raiding against Britain and its allies, again using U-boats,
auxiliary cruisers, and small groups of cruisers and battleships (surface raiders). The goal was to wage a
tonnage war against the British Empire, destroying merchant shipping (and its cargoes) faster than they could be replaced, ultimately strangling the island nation by cutting off supplies it was inevitably dependent upon. Limitations set by the
Treaty of Versailles meant Germany had been unable to build a large battle fleet between the World Wars as she had in the time leading up to World War I; instead, she chose to
covertly develop her U-boat fleet.
Submarines were cheaper and quicker to build than capital ships. This meant Germany was not able to fight battles between fleets, and relied on commerce raiding instead. The extreme early success of
Kriegsmarine U-boat
wolfpacks led to the Allied development of an extensive and naval resource-straining
convoy system. In addition to U-boats Germany also deployed the small numbers of surface warships she possessed, such as the "
pocket battleships", her auxiliary cruisers, and a number of commercial vessels converted into
merchant raiders, perhaps the most famous being . During World War II, elements of the
United States Navy based in Brazil conducted operations in the Atlantic against German commerce raiders and
blockade runners. In the Pacific, the U.S. Navy operated against Japanese merchant shipping, as well as engaging in offensive operations against ships of the Japanese Imperial Navy. The bulk of the Japanese merchant marine was sunk by
American submarines. By the end of the war, only 12% of Japan's pre-war merchant tonnage was still afloat. The
Indian Ocean raid was a naval sortie by the
Carrier Striking Task Force of the
Japanese Navy from 31 March to 10 April 1942 against
Allied shipping and bases in the
Indian Ocean. It was an early engagement of the Pacific campaign of World War II. The staff of the Imperial Japanese Navy decided to send
some raiders to
Indian Ocean waters from December 12, 1941 to July 12, 1942. The Germans had already been operating in the area and conducted mutual aid with Japanese submarines, in the form of re-supply and military intelligence. The Indian Ocean was the largest operating area involving direct contact between the two Axis partners, in which their primary objective was to keep pressure on the shipping lanes. The Japanese Navy participated in some commerce raiding, but concentrated its efforts toward a
"decisive battle" in the Pacific, which never took place. ==See also==