Submarines of the World War 2

Germany used submarines to devastating effect in the Battle of the Atlantic where it attempted to cut Britains supply routes by sinking more merchant ships than Britain could replace. While U-boats destroyed a significant number of ships the strategy ultimately failed. Although U-boats had been updated in the interwar years the major innovation was improved communications and encryption; allowing for mass-attack naval tactics. By the end of the war almost 3000 Allied ships (175 warships 2825 merchantmen) had been sunk by U-boats. The Imperial Japanese Navy operated the most varied fleet of submarines of any navy including Kaiten crewed torpedoes midget submarines (Type A Ko-hyoteki and Kairyu classes) medium-range submarines purpose-built supply submarines and long-range fleet submarines. They also had submarines with the highest submerged speeds (I-201-class submarines) and submarines that could carry multiple aircraft (I-400-class submarines). They were also equipped with one of the most advanced torpedoes of the conflict the oxygen-propelled Type 95.