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 In 1896 the Middle Locks (') were built, followed by the North Locks (") in 1929, which were Europe's largest locks at that time. At the eastern end of the canal, east of Amsterdam, the IJ Bay was open to the Zuiderzee until 1872 when the Orange Locks (") were built. With the completion of these locks the North Sea Canal and IJ Bay were no longer open to the sea and a specific water level could be maintained. The canal was dug using manual labour. The workers lived in horrid conditions, being housed in huts built from twigs, driftwood,