High Quality Content by WIKIPEDIA articles! All the four cases centered around attempts to navally blockade countries, especially those heavily dependent on merchant shipping to supply their war industries and feed their populations (like Britain and Japan), even though the countries waging the unrestricted submarine warfare were unable to institute a typical naval blockade. It was Fisher who was proved correct, though as will be shown in the following section the Germans themselves did not plan for this kind of warfare and went in practice through the stages which Fisher had predicted.