Quotes from Gerhard Koop

Instead of the heavy cruiser types with which it equipped itself, the German Navy might have been better served by a class of well-armoured, fast, diesel-driven light cruisers of optimum armament for commerce-raiding purposes. This was not given consideration.

Oil for steam-turbine and diesel-driven warships was, naturally, vastly more convenient but had to be imported – and Germany was easy to blockade by sea.

The original intention of the Westwall was to guarantee to Hitler's neighbours to his west that he had no territorial ambitions in that direction.