Battle of Heligoland
1864 CE.
Shown on the map at 54.050°, 7.850°.
The Battle of Heligoland (or Helgoland) was fought on 9 May 1864, during the Second Schleswig War, between a Danish squadron led by Commodore Edouard Suenson and a joint Austro-Prussian squadron commanded by the Austrian Commodore Wilhelm von Tegetthoff. The action came about as a result of the Danish blockade of German ports in the North Sea; the Austrians had sent two steam frigates, SMS Schwarzenberg and Radetzky, to reinforce the small Prussian Navy to help break the blockade. After arriving in the North Sea, Tegetthoff joined a Prussian aviso and a pair of gunboats. To oppose him, Suenson had available the steam frigates Niels Juel and Jylland and the corvette Hejmdal. On the morning of 9 May, the two squadrons encountered each other off the island of Heligoland, then controlled by neutral Great Britain. Tegetthoff attacked with his two frigates while the slower Prussian vessels lagged behind, unable to effectively engage the Danish warships. Tegetthoff's flagship, Schwarzenberg, bore the brunt of the Danish gunfire and caught fire three times, the last of which could not be put out quickly and forced Tegetthoff to seek shelter in the neutral waters around Heligoland.
Text from the Wikipedia article Battle of Heligoland (1864), licensed CC BY-SA 4.0.