On this day in 1918, a German U-boat submarine fires the last torpedo of World War I, as Germany ceases its policy of unrestricted submarine warfare.
Unrestricted submarine warfare was first introduced in World War I in early 1915, when Germany declared the area around the British Isles a war zone, in which all merchant ships, including those from neutral countries, would be attacked by the German navy. To confront the overwhelmingly superiority of the British navy, the Germans utilized their most dangerous weapon, the stealthy U-boat submarine. A string of attacks on merchant ships began, culminating in the sinking of the British ship Lusitania by a German U-boat on May 7, 1915. The attack on the Lusitania—which killed 1,201 people, including 128 Americans—sparked the ire of U.S. President Woodrow Wilson, who demanded an end to German attacks against unarmed merchant ships. Over the next year, the German navy reluctantly limited the practice at the urging of the country’s government, who feared antagonizing the U.S. and provoking its intervention in the war against Germany.
At the beginning of 1917, however, naval and army commanders managed to convince Kaiser Wilhelm II of the need to resume the unrestricted submarine policy, claiming that unrestricted U-boat warfare against the British at sea could result in a German victory by that fall. On February 1, Germany resumed its submarine attacks on enemy and neutral shipping interests at sea. Two days later, Wilson broke diplomatic relations with Germany; on April 6, 1917, the U.S. formally entered World War I on the side of the Allied powers.
The hope that Germany—despite the deadlock on the battlefields of the Western Front—could win the war by naval warfare persisted until the last months of the war, growing fainter with the Allied resurgence in France and Belgium in the summer of 1918 and the deepening discontent and frustration with the war on the German home front, as well as among its soldiers and sailors. In mid-October 1918, as the German government grappled with how to obtain an armistice without damaging Germany’s chances to obtain favorable peace terms and its army commanders contended with the dire situation at the front, Admiral Reinhardt Scheer dealt the final blow to Germany’s U-boat strategy, ordering all his navy’s submarines to return to their German bases.
The final German torpedo of World War I was fired in the Irish Sea on October 21, sinking a small British merchant ship, the Saint Barcham, and drowning its eight crewmen. In a measure of the characteristic aggression of German submarine warfare, a total of 318 merchant seamen had been killed that month alone. Now, however, the German submarines returned home, leaving the entire strategically important Belgian coast firmly under Allied control.