The North Sea in the First World War

The North Sea separated the two largest navies in Europe: the British Grand Fleet and the German High Seas Fleet. The Royal Navy did not need to sail up to the German ports. It was enough to close both exits from the sea, the narrow Strait of Dover in the south and the wide stretch of water between Scotland and Norway in the north, to cut Germany off from the ocean and enforce a blockade. The Germans answered with mines, submarines and fleet raids on the coasts of England, but in four years they could not change this situation.

The first months (1914)

Both fleets took up their positions before the war had even begun. The Kaiser recalled the German fleet from its cruise to Norway, and the British First Fleet moved to Scapa Flow in Orkney. On the night of 4–5 August 1914 the German minelayer Königin Luise mined the open sea off the coast of Suffolk, and the next day the cruiser Amphion sank on those mines, the first Royal Navy ship lost in this war.

On 28 August British cruisers and destroyers attacked the Germans right off their own coast and in the Battle of Heligoland Bight sank three light cruisers and a torpedo boat without losing a ship. The Germans struck back with a submarine. On 22 September, off the Dutch coast, U-9 sank three old armoured cruisers, Aboukir, Hogue and Cressy, in about an hour. 1,459 sailors were killed.

On 2 November the Admiralty declared the whole North Sea a military area. Ships bound for Norway, Denmark, the Netherlands and the Baltic were henceforth to go through the Strait of Dover and on along a prescribed route, where it was easier to stop and search them. The Scandinavian states protested, and the Germans cited this step when in February 1915 they declared the waters around the British Isles a war zone for their U-boats.

Raids and battles (1914–1916)

The German command hoped to lure out and destroy part of the British fleet. On 3 November the battlecruisers of Franz von Hipper shelled the area around Yarmouth, and on 16 December Scarborough, Hartlepool and Whitby, where more than a hundred people, mostly civilians, were killed. German Zeppelins also crossed the sea, and on 19 January 1915 bombed England for the first time. Five days later the British, who were reading German signals, caught Hipper at the Dogger Bank. The Germans lost the cruiser Blücher, but their main force escaped.

In 1916 the new commander of the German fleet, Admiral Reinhard Scheer, resumed the raids. On 24–25 April his battlecruisers shelled Lowestoft and Yarmouth, and at the end of May the two fleets met off Jutland. In the Battle of Jutland the Germans sank 14 British ships for the loss of 11 of their own, but did not break British superiority in the North Sea. On 19 August both fleets put to sea again and did not exchange a shot, while German submarines torpedoed two British cruisers. From then on the southern part of the sea became ever more dangerous for battleships.

A sea of mines and convoys (1917–1918)

The war in the North Sea was now fought mainly by light craft. In the autumn of 1917 German cruisers and destroyers twice destroyed British convoys to Norway, in October and in December. In January 1918 the Admiralty accepted the view of Admiral David Beatty that the Grand Fleet should not risk battle in enemy waters.

Instead, the Allies decided to bar the northern exit from the sea to the U-boats. Between Scotland and Norway there were at least 230 miles, so hundreds of thousands of ordinary mines would have been needed. The Americans, however, had a new mine with an antenna, which exploded when a submarine touched the wire hanging above it. From June 1918 the US Navy, with British help, laid the Northern Barrage between Orkney and Norway: 70,177 mines, 56,571 of them American. Four U-boats are believed to have been sunk on it, but by the end of the war the barrage still had gaps, and its effectiveness is still disputed.

The High Seas Fleet never made its last sortie, because the sailors refused to put to sea, and the Kiel mutiny started the revolution in Germany. On 20 November 1918 the first German submarines surrendered off Harwich, and on 21 November the Grand Fleet put to sea and escorted the German ships into the Firth of Forth. The mines remained. Clearing the Northern Barrage took from May to September 1919, and the mines left behind threatened shipping for years.