During the First World War, Britain relied heavily on resources imported across the Atlantic by its merchant marine. From the very beginning of the war, German U-boats targeted the merchant convoys, sinking millions of tons of essential produce and threatening Britain's war effort. Were it not for the heroic efforts of the Q-ships, the naval war could have proven disastrous for the allies. Between 1914 and 1918, nearly 200 commercial vessels were transformed into armed decoy ships that lured U-boats into attacking them at close range before responding with their own deadly fire at the very last moment. (Amazon)