11h 13min, apr 16, 1943 y - Battle of the Atlantic
1943, German U boats continued to sink the allied boats until the US started using Radar and Sonar. Radar detected U-Boats above the water and Sonar could detect U-boats underwater before they could attack. By 1943, Allies were building more ships than Germany could sink and destroying more U-boats than Germany could build. Was important because it lasted for nearly all of the war; there was never a time when there wasn't fighting somewhere in the Atlantic.
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