The Royal Navy had begun multiple refit and modernisation programmes but expected to complete much of the work by about 1942. That timetable followed the end of the Ten Year Rule in roughly 1932 and the resulting planning horizon. Germany faced an even longer mismatch because Hitler had promised the Kriegsmarine no major war until about 1948, when Plan Z was meant to mature. The outbreak of war in 1939 therefore tested fleets built around very different future readiness dates rather than fully executed peacetime plans.
Notable Point · 3:10:54-3:11:43
Naval readiness timetables before the Second World War
British modernisation aimed toward 1942 while Germany's Plan Z assumed no major war until 1948, leaving both programmes incomplete in 1939.