History of the North Sea the North Sea though they saw little action. The Austro-Prussian War (1866) resulted in Prussia's gaining full control of the Kiel Canal, allowing their Baltic ports access to the North Sea. France declared war on Prussia 19 July 1870 which initiated the Franco-Prussian War (1870–1871). The French Navy was, at the time far larger and superior to the North German Federal Navy, the Navy of the North German Confederation. Though the French did take a number of merchant ships bound to and from North Germany, shortages of manpower and coal, as well as conflicting orders, made the attempted blockade of
White Sea–Baltic Canal the USSR in 1941, supported by Finland in the Continuation War, the route of the canal became the front line. On June 23, 1941, the day after the German invasion of the USSR, 16 Finnish commandos were brought to the canal by two German Heinkel He 115 seaplanes, which had taken off in Oulujärvi. The commandos were Finnish volunteers recruited by the German Major Schaller. They wore German uniforms and had German weapons, as the Finnish General Staff did not want to have anything to do with the operation. The commandos' task was to blow up the canal's locks, but,