In the Battle of Jasmund, the Prussian Navy fails in an effort to break the Danish blockade of Prussia
The Second Schleswig War saw the Danish Navy, then superior to that of the German Federation, initiate a blockade of the Prussian Baltic coast. Prussian naval units challenged the blockade in an encounter off Prussia's Jasmund Peninsula. This was the Prussian Navy's first ever engagement and ended with a tactical defeat as the Danes easily held the blockade. Casualties were light on both sides and no vessels were sunk. (By John Osborne)
Michael Embree, Bismarck's First War: The Campaign of Schleswig and Jutland 1864 (Solihull, England: Helion and Company, Ltd, 2007), 274-278.