The most formidable naval weapons of the two world wars, German submarines devastated transatlantic shipping, sinking 8,000 merchant ships and warships and killing tens of thousands of people. These submarines (an abbreviation of Unterseebootthe German word for “submarine boat”) prowled the oceans in search of prey and could attack ships 20 times their size both above and below the surface with their deck guns and torpedoes .
Inside the dimly lit and claustrophobic submarines, sailors could not shower or even change their clothes during patrols that could last two months at sea. Fifty men shared two toilets – one of which doubled as a locker food at the start of the patrols – which could not operate 80 feet or more below the surface due to outside water pressure, according to The U-Boats by Douglas Botting.
The submarine crews inhaled a nauseating cocktail of bilge water, sweat and diesel fumes. Mildew has bloomed on their shoes and the cards have even rotted from the oppressive heat and humidity. “I feel like Jonah inside huge shells whose vulnerable parts are covered with armor,” wrote German war correspondent Lothar-Günther Buchheim on patrol in 1941.
Submarines were still primitive naval weapons when Germany became the last major naval power to build one in 1906. By the start of World War I in 1914, however, Germany had caught up with the competition. His 20 combat ready The submarines were more sophisticated than submarines from other countries and could travel 5,000 miles without refueling, allowing them to operate along the entire British coast.
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U-Boats come of age in World War I
German submarines parked in the harbour, circa 1914. Front row (left to right): U-22, U-20 (sunk the Lusitania), U-19 and U-21. Back row (left to right): U-14, U-10 and U-12.
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The U-boat fleet made its first strike on September 5, 1914, with an attack on a British light cruiser off the coast of Scotland that killed over 250 sailors. Seventeen days later, U-9 sank three British battlecruisers in an hour, killing nearly 1,500 people. Despite these strikes, the Germans lost more U-boats than they sank in the first month of the war.
In February 1915, Germany announced the start of unrestricted submarine warfare in which all ships, even merchant ships from neutral countries, would be sunk without warning in a war zone around Britain. The idea that submarines would attack merchant ships had been dismissed by many Britons, including the First Lord of the Admiralty Winston Churchill who wrote: “I don’t believe it would ever be done by a civilized power.
The submarines not only attacked food and oil supplies bound for the British Isles, but also passenger ships. On May 7, 1915, U-20 torpedoed the liner Lusitania off the coast of Ireland and killed nearly 1,200 passengers, including 128 Americans. Alarmed by the prospect of American entry into the war, Germany finally pledged to protect the safety of passengers before sinking unarmed ships.
An illustration of the sinking of the Lusitania by a German U-boat, 1915. The tragedy killed 128 American citizens, helping to bring the United States into World War I. (Credit: Three Lions/Getty Images)
The Allies struggled to counter the U-boat threat. The Royal Navy camouflaged warships with paint jobs to impersonate merchant ships and stacked haystacks to conceal guns. Some British patrols even carried canvas bags and hammers which they could use to cover and smash the lenses of submarine periscopes.
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After announcing the resumption of unrestricted submarine warfare against Allied and neutral shipping on January 31, 1917, the U-boats had sunk over 500 ships by the end of April. The submarines nearly succeeded in defeating Britain, but attacks on American merchant ships played an important role in bringing the United States into the war.
U-Boat arrives in US waters
Germany’s development of the U-cruiser submarine allowed it to strike the Atlantic coast of its new enemy. The first German submarine arrived in American waters in May 1918 and sank 13 ships – six of them in a single day – in addition to laying mines in American ports and cutting two telegraph cables on the seabed during of his 12,000 mile patrol.
Grouping merchant ships into convoys and escorting them with warships, Allied countermeasures began to blunt U-boats, although German U-boats managed to destroy over 10 million tons of cargo at the end of the First World War.
Although the subsequent Treaty of Versailles required the surrender of all submarines and prohibited their future possession by Germany, submarine construction resumed after Nazi leader Adolf Hitler repudiated the peace pact in 1935. The First World War had demonstrated that long-range submarines could be powerful. weapons, and when war returned in 1939, so did U-boats.
U-Boats target shipping lanes during World War II
A German submarine on a mission in the Atlantic Ocean, as seen during World War II, May 1942.
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When World War II began, Germany had 57 submarines under the command of Commodore Karl Dönitz, who had served on submarines in World War I. Dönitz believed that the war would be decided in the Atlantic and that he could win it with 300 U-boats.
In May 1940, Hitler approved unrestricted submarine warfare on all ships around Britain after initially rejecting the idea of avoiding provoking the United States. Once in possession of ports in Norway and western France, Germany extended the range of its submarines to disrupt merchant shipping. The submarines stalked their targets for days and attacked in groups the British called “wolf packs”. From the summer of 1940 to the spring of 1941, each submarine at sea sank an average of eight merchant ships per month in what Germany called “Happy Time”.
Although the British established a convoy system early in the war, it was poorly protected for the first 18 months. The radar remained primitive. Aircraft were few in number, did not have sufficient range, and could not provide escort cover at night. While the Allies lacked adequate intelligence on the movements of the submarines, Germany intercepted cables between American marine insurance companies and European insurers to learn more about the ships’ cargoes, departure dates and the destinations.
After the United States entered World War II, a wave of 16 U.S. submarines attacked merchant shipping along the American and Canadian coasts in Operation Drumbeat. Taking advantage of weak and disorganized defenses, U-boats scoured as far as the Gulf of Mexico and roamed the coastal shipping lanes during the first half of 1942. U-boats that lurked along the shipping lanes of North Carolina sank 78 merchant ships and killed 1,200 merchant marines. .
Once American merchant ships began sailing in transatlantic convoys with continuous sea and air escorts, attacks dropped dramatically. Along with the breakdown of submarine ciphers, improvements in radar technology and the effectiveness of attacks by long-range bombers and escort carriers led to the sinking of 41 submarines in May 1943, including eight in one day. Dönitz responded by ordering his submarines to withdraw to more distant locations such as the Indian Ocean where the targets would be unescorted.
Submarines returned to the British coast in 1944 after the development of diving ventilation tubes allowed them to operate longer and deeper underwater to reduce the chance of detection by radar and enemy aircraft. However, they suffered heavy losses and little success. After Hitler’s suicide on April 30, 1945, Dönitz succeeded him and ordered German forces to cease operations and surrender. All 45 submarines at sea surfaced and proceeded to ports designated by the Allies.
According to some estimates, Germany lost three-quarters of the submarines it built during World War II. Although they ravaged Allied shipping in both World Wars, U-boats also became steel coffins on the ocean floor for around 30,000 of the 40,000 sailors who manned them.
