When the "Kriegsmarine" began planning for a war with the UK in May 1938, the "Kriegsmarine's" senior operations officer, Commander Hellmuth Heye, concluded the best strategy for the "Kriegsmarine" was a "Kreuzerkrieg" fleet of U-boats, light cruisers and "Panzerschiff" operating in tandem. He was critical of the existing building priorities dictated by the agreement since there was no realistic possibility of a German "balanced fleet" defeating the Royal Navy. In response, senior German naval officers started to advocate a switch to a "Kreuzerkrieg" type fleet that would pursue a "guerre-de-course" strategy of attacking the British Merchant Marine, but they were overruled by Hitler, who insisted on the prestige of Germany building a "balanced fleet". Such a fleet would attempt a Mahanian strategy of winning maritime supremacy by a decisive battle with the Royal Navy in the North Sea. Historians such as Joseph Maiolo, Geoffrey Till and the authors of the "Kriegsmarine" Official History have agreed with Chatfield's contention that a "Kreuzerkrieg" fleet offered Germany the best chance for damaging the UK's power and that the UK benefited strategically by ensuring that such a fleet was not built in the 1930s.