German Torpedoes Sink the Summary

  • Last updated on November 10, 2022

When a German submarine off the coast of Ireland sank the Cunard liner the Lusitania, more than twelve hundred passengers died. The event sparked a serious diplomatic controversy among the United States, Great Britain, and Germany.

Summary of Event

The sinking of the Lusitania was the result of a naval strategy whose foundation lay in the writings of the renowned geopolitical theorist and naval historian Alfred Thayer Mahan. Firmly rooted in the Western imperialism that dominated much of the period, Mahan’s writings emphasized the connection between a nation’s ability to project its power around the world and the likelihood of its success in the international arena. A nation’s destiny, Mahan believed, was directly affected by the size and power of its navy. World War I (1914-1918)[World War 01];submarine warfare Lusitania (ship) Ships;Lusitania [kw]German Torpedoes Sink the Lusitania (May 7, 1915) [kw]Torpedoes Sink the Lusitania, German (May 7, 1915) [kw]Lusitania, German Torpedoes Sink the (May 7, 1915) World War I (1914-1918)[World War 01];submarine warfare Lusitania (ship) Ships;Lusitania [g]Atlantic Ocean;May 7, 1915: German Torpedoes Sink the Lusitania[03790] [c]World War I;May 7, 1915: German Torpedoes Sink the Lusitania[03790] [c]Wars, uprisings, and civil unrest;May 7, 1915: German Torpedoes Sink the Lusitania[03790] [c]Military history;May 7, 1915: German Torpedoes Sink the Lusitania[03790] [c]Diplomacy and international relations;May 7, 1915: German Torpedoes Sink the Lusitania[03790] Mahan, Alfred Thayer Tirpitz, Alfred von Turner, William Thomas Wilson, Woodrow [p]Wilson, Woodrow;World War I[World War 01]

A 1915 artist’s rendition of the torpedoing of the Lusitania.

(Library of Congress)

Mahan eventually developed a naval strategy in which the goal was to destroy a potential adversary’s fleet completely. This destruction, Mahan said, would occur as the result of a single violent naval encounter that would cripple an opponent’s ability to make war. Victory at sea would allow a nation to blockade its opponent’s harbors and would eventually prevent an enemy from conducting international trade. This, in turn, would create economic chaos in the enemy nation, which would gradually lead to the opposing government’s political downfall and eventual collapse.

Mahan also theorized that a weaker naval power could focus its energy on targeting its opponent’s merchant fleet. In fact, this had been the objective in many of history’s naval battles, but Mahan believed that naval warfare in the twentieth century would be characterized by large, powerful navies that fought desperate battles on the high seas. This scenario gave birth to his “decisive battle theory,” Decisive battle theory which dominated the strategies of the world’s major naval powers for many decades.

The modern German nation was founded in January of 1871. A quarter of a century later, Alfred von Tirpitz was placed in charge of the new German navy, and over time he became the nation’s first important naval strategist. His philosophy was deeply influenced by Mahan’s writings, especially the aspect that placed great emphasis on the creation of a strong, modern battle fleet. Building on Mahan’s decisive battle theory, Tirpitz constructed a German naval strategy known as “risk theory,” a battle plan aimed at reducing Great Britain’s naval superiority. Tirpitz believed that the only way Germany could challenge British supremacy was to create a navy that was so powerful that Great Britain would never risk a naval confrontation.

Tirpitz began a massive buildup of naval arms that called for the creation of a sixty-ship German navy, two-thirds of which would be battleships. By the first decade of the twentieth century, however, it was obvious that Germany would be unable to sustain such a costly military presence on the world’s oceans. In reaction to this reality, German naval strategists created a new theory that synthesized Mahan’s concept of targeting an opponent’s merchant fleet with his emphasis on the decisive battle. The submarine, which had the advantages of being small, inexpensive, and able to surprise much larger ships, was to play a pivotal role in this new naval paradigm.

In the weeks following the outbreak of World War I, Great Britain and Germany targeted each other with naval blockades in an attempt to deprive the opposing military of needed materials. England used its navy, the largest in the world, to intercept merchant ships from neutral nations in an attempt to stop the flow of important resources to Germany. Initially, Americans were concerned about the fact that many American ships were taken to British ports and held for a number of weeks while the English military searched for contraband. Despite the fact that such action curtailed the freedom of the United States to take part in international trade, the situation never reached a crisis level, for the most part because Americans believed that Great Britain would make financial restitution for all the materials seized once hostilities were over.

Germany, on the other hand, was becoming increasingly concerned about the development of an undeclared alliance between the United States and Great Britain: Every time a potential controversy about the British blockade appeared, the United States seemed more than willing to accept a compromise. Furthermore, German intelligence had collected evidence that American arms were flowing directly into English ports. German agents were positive that Great Britain was using passenger liners such as the Lusitania to transport large amounts of weapons and ammunition.

The German high command believed that the Anglo-American relationship posed a direct threat to German security, and it reacted to the challenge by issuing a proclamation. This document asserted that as of January, 1915, the German war zone included the entire area around the British Isles, and it went on to declare that, as of February 4, all ships believed to be delivering contraband to Great Britain would be attacked. The German navy would employ submarines Submarines;World War I[World War 01] to enforce the newly established quarantine around the British Isles.

German submarine tactics were based on a modified version of Mahan’s and Tirpitz’s theories: These attacks focused on destroying Britain’s ability to wage war by disrupting its capacity to conduct international trade. The Germans realized, however, that the fruits of their labors would come not from one major battle but from a prolonged and extensive interdiction of supplies headed for England. This approach, the Germans hoped, would result in the defeat of both Great Britain and its system of alliances. The 1,201 passengers killed—including 128 Americans—aboard the Lusitania were among the first victims of the German’s submarine-based strategy.

In the days leading up to their voyage, passengers booked on the Lusitania read notices published by the German government in various New York City newspapers warning them that they would be sailing into the newly established war zone. In fact, shortly before the Lusitania reached the critical area, the ship’s captain, William Thomas Turner, received a message from the English high command informing him that there had been a number of submarine sightings in his vicinity. Twelve hours later, on the morning of May 7, 1915, the Lusitania was enveloped by a thick fog off the coast of Ireland. In an attempt to navigate through an area of low visibility, Captain Turner reduced the ship’s speed, and he also stopped the zigzag pattern that was part of the standard operating procedure followed to avoid enemy submarines. These two decisions enabled a German U-boat to target and launch an attack against the passenger liner. A torpedo hit the ship, exploded, and was followed a few moments later by a second, more devastating explosion that ripped a large hole in the ship’s side. Eighteen minutes later, the Lusitania had sunk to the bottom of the ocean.


The British government immediately denounced the attack and vehemently denied that the second explosion was the result of contact between the German torpedo and a large cache of contraband weapons. Descriptions of the disaster led to a number of violent uprisings across the British Isles against English citizens of German ancestry, and in the United States a small contingent lobbied for a declaration of war. Although most Americans rejected military intervention, many supported the British cause.

Most important, the event prompted President Woodrow Wilson to draw a “line in the sand,” informing the Germans that the United States would take military action against them if they did not stop the unrestricted use of submarines. The German government agreed to Wilson’s demands and signed the Sussex Pledge, in which Germany promised to curtail the strategy of unrestricted submarine warfare. Early in 1917, however, the German military resumed submarine operations, and this action was one of the primary reasons the United States became a combatant nation in World War I. World War I (1914-1918)[World War 01];submarine warfare Lusitania (ship) Ships;Lusitania

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Butler, Daniel Allen. The Lusitania: The Life, Loss, and Legacy of an Ocean Legend. Mechanicsburg, Pa.: Stackpole Books, 2000. Provides the reader with important firsthand accounts of the sinking of the Lusitania.
  • citation-type="booksimple"

    xlink:type="simple">Kagan, Donald. On the Origins of War and the Preservation of Peace. New York: Anchor Books, 1995. Offers an excellent account of German naval strategy during World War I.
  • citation-type="booksimple"

    xlink:type="simple">O’Sullivan, Patrick. Lusitania. Dobbs Ferry, N.Y.: Sheridan House, 2000. Discusses the importance of the sinking of the Lusitania to the overall outcome of World War I.

Outbreak of World War I

World War I

Germany Begins Extensive Submarine Warfare

United States Enters World War I

U.S. Curtails Civil Liberties During World War I

United States Establishes the War Industries Board

Categories: History