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
North Sea Canal sod, and straw, where disease, fights, and alcohol abuse were rampant. On 1 November 1876, the North Sea Canal was officially opened by King William III of the Netherlands. Over the years the canal has been widened and deepened several times. The North Sea Canal and the IJ have 10 side canals (in Dutch: "Zijkanaal"), which connect to rivers and other canals which used to flow into the former IJ Bay before its reclamation. Vessels with a draft of more than 14 metres should use the IJgeul. To protect access to the channel jetties were built in the sea. In