Why did prewar German boiler design rely on British coal if war with Britain was possible?
Short answerGerman leaders believed naval strength would deter Britain from fighting, so the fleet accepted a fuel dependency that became dangerous when deterrence failed.
NotesBoiler performance depended on the grade and characteristics of the coal for which the machinery was designed. German reliance on Admiralty Welsh coal therefore embedded a supply assumption into the fleet's engineering. That choice reflected politicians' belief that a sufficiently powerful German fleet would keep Britain out of a war. Once that political forecast failed, a peacetime fuel preference became a wartime logistics weakness.