<P> In World War I and World War II, the Kriegsmarine attempted to close the SLOCs from North America to the British Isles with the use of submarines . In World War I, the British operated a naval blockade of Germany cutting off external trade by sea . In World War II, the Allies engaged in the Battle of the Atlantic, a defensive campaign with escort vessels and convoys to keep the SLOCs open . Also, the US Navy successfully closed the SLOCs to Japan, strangling the resource - poor island nation . </P> <P> Had the Cold War turned hot, Europe would have required resupply and reinforcement from North America . Soviet Navy strategy was to close the SLOCs to maximize their numerical superiority in Europe . </P>

Sea lines of communication control and maritime patrols