One hundred years ago, the shadow of World War I reached across the Atlantic, not in the form of armies landing on American shores, but in the silent, deadly approach of German U-boats. These underwater vessels, or Unterseeboots, as they were known in German, brought the global conflict directly to the United States, challenging the previously held belief that the vast ocean would protect the nation. By the end of the war, German submarines had sunk a significant number of vessels off the coast of North Carolina alone, and many more across the wider Atlantic, marking a profound moment in American maritime history. As we reflect on the centennial of these events, it’s crucial to understand what kind of ship these U-boats were and the impact they had.
Alt text: 1916 illustration depicting a German U-boat attacking a merchant ship, highlighting the nature of submarine warfare during World War I.
While modern naval technology has advanced dramatically, in the early 20th century, U-boats represented a cutting-edge innovation in naval warfare. Developed by Germany, these submarines possessed capabilities that were considered highly advanced for their time. These vessels were engineered to dive to depths of 50 meters (165 feet), achieve surface speeds of 16 knots, and underwater speeds of 8 knots. Impressively, they boasted a range of up to 25,000 miles, allowing them to operate far from their home ports. U-boats were armed with deck guns and carried up to 16 torpedoes. Due to the torpedoes of the era sometimes being unreliable, surface attacks using deck guns were a common tactic. This approach also allowed U-boat crews to board and seize valuable cargo from merchant ships before sinking them. Furthermore, some U-boats were equipped to lay naval mines, adding another layer to their offensive capabilities.
The deployment of submarine warfare became a critical factor in the escalating international tensions of World War I. Following the outbreak of war in 1914, Great Britain, leveraging its dominant navy, initiated a blockade of German ports. This strategy aimed to cripple Germany by restricting the import of essential food supplies, raw materials, and military equipment. Great Britain declared German waters a war zone and began seizing ships bound for the Central Powers, which included Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria. Germany responded to this pressure by establishing its own blockade around the British Isles and the English Channel. This counter-blockade was accompanied by a policy of unrestricted submarine warfare, which meant the German navy would target and destroy all ships, whether belonging to Allied nations or neutral parties, found in these waters.
Alt text: 1915 recruitment poster urging men to join the Navy, referencing the sinking of the Lusitania to evoke patriotism and outrage against German U-boat aggression.
A particularly devastating event that significantly shifted public opinion occurred on May 7, 1915, when the German U-20 submarine sank the British passenger liner RMS Lusitania off the Irish coast. This tragic attack resulted in the deaths of 1,198 passengers, including 128 American citizens. The sinking of the Lusitania dramatically increased tensions between the United States and Germany, leading to a temporary pause in Germany’s unrestricted submarine warfare policy. However, as the war dragged on, and in a desperate attempt to force a swift conclusion by cutting off Britain’s vital supply lines, Germany resumed aggressive U-boat attacks at the beginning of 1917. These renewed attacks targeted both military and civilian ships without distinction. In response to this escalating threat, the United States, having reached its limit of tolerance, joined the Allied Powers – France, Great Britain, Italy, and Japan – and officially declared war on Germany on April 6, 1917.
With the United States now a participant in the war, American resources were channeled towards supporting the Allied effort in Europe. This commitment of manpower, supplies, and naval forces unfortunately left merchant shipping and naval operations along the East Coast of the US vulnerable to German U-boat activity. From April 1917 to November 1918, a total of four German U-boats were deployed to patrol the East Coast of the United States. These submarines were responsible for sinking 10 vessels off the coast of North Carolina and approximately 200 American vessels in total throughout the Atlantic. Among these U-boats, U-140 stands out for sinking the Diamond Shoals Lightship, LV-71, in August 1918. The LV-71 was one of only two ships belonging to the U.S. government to be sunk by a German submarine during World War I. The wreckage of the LV-71 is now under the protection of Monitor National Marine Sanctuary and the U.S. Coast Guard. During the same period, U-140 also sank the USS Merak. Another U-boat, U-117, became infamous for sinking the British tanker SS Mirlo in a dramatic attack off the North Carolina coast, although the Mirlo shipwreck has yet to be located.
Alt text: German submarine U-140, a type of vessel that extensively patrolled the US East Coast during World War I, highlighting German naval power projection.
The impact of U-boat warfare during World War I was substantial. Their ability to operate submerged, launching surprise attacks, resulted in significant losses. German and Austro-Hungarian submarines together sank nearly 5,000 merchant ships during the conflict, causing the deaths of an estimated 15,000 Allied sailors. The Treaty of Versailles, which formally concluded World War I, included stipulations that Germany surrender its existing U-boat fleet and dismantle its submarine construction program. Despite these restrictions, the strategic and tactical value of submarine warfare had become clear to German naval commanders, who continued to develop and refine submarine technology in the interwar period. This clandestine development would prove crucial when German U-boats returned to the waters off North Carolina and the broader Atlantic during World War II, inflicting even greater losses.
Although the major battlefields of World War I were located in Europe, the actions of German U-boats effectively brought the war directly to the United States. The numerous shipwrecks resulting from U-boat attacks off the coast of North Carolina contribute to the area’s grim moniker: the Graveyard of the Atlantic, a region known for its treacherous waters and historical maritime losses.
Alt text: Exploration of a sunken German U-boat by archaeologists from Monitor National Marine Sanctuary, emphasizing the ongoing research and preservation of WWI maritime history.
The Monitor National Marine Sanctuary, initially established in 1975 to protect the wreck of the USS Monitor from the Civil War era, has expanded its mission to include the preservation of World War I maritime heritage. In addition to the Monitor, the sanctuary has been actively involved in researching and documenting numerous shipwreck sites, including those from the U-boat campaigns off North Carolina. Proposed expansions of the sanctuary’s boundaries aim to encompass a wider range of World War I and World War II shipwrecks. This expansion would ensure the long-term preservation of these significant underwater historical sites, safeguarding a crucial part of the nation’s maritime past for future generations.
