Operation Drumbeat had one other effect. It was so successful that Dönitz's policy of economic war was seen, even by Hitler, as the only effective use of the U-boat; he was given complete freedom to use them as he saw fit. Meanwhile, Hitler sacked Raeder after the embarrassing Battle of the Barents Sea, in which two German heavy cruisers were beaten off by half a dozen British destroyers. Dönitz was eventually made Grand Admiral, and all building priorities turned to U-boats.