History of the North Sea United Kingdom and Germany signed the Treaty of Heligoland. The Cod War of 1893 erupted between Denmark and Britain over fishing territories. Denmark declared a fishing territory of 13 nautical miles (24 km) around their shores which included Iceland and the Faroe Islands. Britain did not acknowledge this claim. Tensions in the North Sea were again heightened in 1904 by the Dogger Bank incident, in which Russian naval vessels mistook British fishing boats for Japanese ships and fired on them, and then upon each other. The incident, combined with Britain's alliance with Japan and the Russo-Japanese War led to an
Cod Wars would generally protect the British trawling fleet. Over the course of this Cod War, a total of 32 British frigates had entered the contested waters. On 19 July 1974, more than nine months after the signing of the agreement, one of the largest wet fish stern trawlers in the British fleet, "C.S. Forester", which had been fishing inside the limit, was shelled and captured by the Icelandic gunboat V/s "Þór" after a pursuit. "C. S. Forester" was shelled with non-explosive ammunition after repeated warnings. The trawler was hit by at least two rounds, which damaged the engine room and a