The Strait of Dover in the First World War

The Strait of Dover, which the Poles call the Strait of Calais, joins the English Channel to the North Sea at the narrowest point between England and France. During the war the shortest route from England to France ran through it, carrying the soldiers and supplies of the British army, and it was at the same time a short cut by which German submarines could reach the shipping lanes of the Channel and the Atlantic. For four years it was guarded by the Dover Patrol. The British barred it with nets and mines, and the Germans answered from the nearby ports of Flanders with night raids by torpedo boats.

The bottleneck

Between the South Foreland in Kent and Cap Gris-Nez near Calais the strait is only 33.2 kilometres wide. According to Admiral Reginald Bacon, commander at Dover in 1915–1917, all the traffic from the Thames estuary passed through it, as well as the supplies for the French, British and Belgian armies in the north, bound for Calais and Dunkirk. At the Downs anchorage off the Kent coast, ships passing in both directions were examined. Bacon calculated that about 120,000 merchant steamers passed through it in 1915–1917, of which fifty were sunk by mines.

The strait grew in importance in the autumn of 1914. The Germans took the ports of the Belgian coast, and on 2 November the Admiralty declared the whole North Sea a military area and told neutral ships bound for the Netherlands and Scandinavia to go through the strait. There the Royal Navy could more easily search them for contraband, which helped the blockade of Germany.

The Dover Patrol

A separate command to guard the strait was set up on 12 October 1914, just after the fall of Antwerp. The first commander of the Dover Patrol was Rear-Admiral Horace Hood; from April 1915 it was led by Bacon, and from 1 January 1918 by Vice-Admiral Roger Keyes. The patrol had bases at Dover and Dunkirk and gathered a very mixed force: cruisers, monitors, destroyers, armed trawlers and drifters, minesweepers, motor launches, submarines and aircraft. It escorted transports and hospital ships, laid and swept mines, hunted submarines and bombarded German positions on the Belgian coast from the sea.

The first losses came quickly. On 31 October 1914 U-27 torpedoed the seaplane carrier Hermes near Calais, and on 11 November U-12 sank the gunboat Niger off Deal. On 17 November 1915 the hospital ship Anglia, carrying wounded from France, struck a mine off Folkestone laid by the minelaying submarine UC-5. Bacon recorded that she was the only hospital ship damaged in his waters.

The barrages

In the winter of 1915 Hood began to bar the strait with indicator nets, which betrayed the presence of a submarine, and with minefields. On 4 March destroyers destroyed U-8 in its waters, and by early April the barrage was in full operation. On 10 April the German Admiralstab forbade the submarines of the High Seas Fleet to pass through the strait, and from then on they had to sail to the Atlantic round Scotland. The smaller boats from Flanders kept trying, however, and in 1916 the Germans found that the strait could be crossed on the surface at night. Bacon also fenced off from the sea the waters off Zeebrugge and Ostend.

Only the deep minefield from Folkestone to Gris-Nez, laid at the turn of 1917 and 1918 and lit at night by flares and searchlights, truly closed the strait. According to the British official history, between 19 December 1917 and 8 February 1918 five German submarines were lost in it, against only two in the previous two years. The dispute over the effectiveness of Bacon’s barrage also contributed to the dismissal of Admiral Jellicoe and to the recall of Bacon himself.

Night raids

The Germans’ answer was night sorties by torpedo boats from the ports of Flanders. On the night of 26–27 October 1916 two flotillas from Zeebrugge sank the old destroyer Flirt, the transport Queen and several drifters guarding the nets, and in March 1917 the destroyer Paragon. On the night of 20–21 April 1917 the British struck back: the flotilla leaders Swift and Broke sank two German torpedo boats, G 42 and G 85, one of them by ramming.

The last and most successful raid came on the night of 14–15 February 1918. German torpedo boats fell upon the drifters lighting the new minefield and sank seven drifters and a trawler. According to Newbolt, 89 men were killed or missing. The following night a German submarine shelled Dover. The British quickly restored the night patrols, however, and in April the ships of the Dover Patrol themselves struck at the ports of Flanders in the Zeebrugge raid. After the war memorials to the patrol’s sailors were raised on both sides of the strait: an obelisk near St Margaret’s Bay in 1921, and another on Cap Blanc-Nez.