From experiment to naval weapon
By the end of the nineteenth century, the earlier experiments described in the article on early submarines had shown the main problems. The twentieth century solved enough of them for the submarine to become a standard naval weapon. The key ingredients were a reliable engine for use on the surface, electric batteries for use below, a periscope, and the self-propelled torpedo.
Holland and the first navy boats
The Irish-born engineer John P. Holland, working in the United States, built several experimental submarines in the late nineteenth century. His design of 1900, accepted by the US Navy as USS Holland, combined a petrol engine for surface running with an electric motor and batteries for diving. It carried a torpedo tube. The Royal Navy ordered a group of Holland-type boats that were launched in the early years of the century, and other navies soon bought or built submarines of their own, some from other designers such as Simon Lake.
These early boats were small and short-ranged, and their crews lived in difficult conditions. Many navies thought of them as coastal defence craft.
The First World War and the U-boat
The German Navy built its own submarines, called U-boats from the German Unterseeboot. When war broke out in 1914, the boats’ effect on naval strategy was quickly demonstrated, though their larger significance emerged over the course of the war. Early successes against warships showed the threat they posed. After the inconclusive Jutland fleet action in 1916, Germany’s leaders turned increasingly to submarines as a way of weakening Britain by attacking merchant shipping.
The sinking of the passenger liner Lusitania in May 1915 was a notable moment, as it killed many civilians, including many Americans, and caused international outrage. It is discussed in a separate article on the Lusitania sinking. In 1917 Germany resumed unrestricted submarine warfare, attacking merchant ships without warning, a decision that contributed to the entry of the United States into the war. The Allied response included more escorts, new anti-submarine weapons such as depth charges, and the organisation of merchant ships into convoys, which became a central defence. Losses to shipping in the war were very heavy, and historians continue to study how close the campaign came to success.
The U-boats of this period were still, in effect, surface ships that could submerge for limited periods, running on diesel engines on the surface and on batteries underwater.
Between the wars
After 1918, treaties restricted the use of submarines against merchant ships, and navies developed larger boats for long patrols. Designs varied among countries. The Japanese, American and British navies built submarines intended for work across large oceans, and the French and Italian navies built many boats for the Mediterranean. Technical improvements included better periscopes, sonar and more dependable diesel engines.
The Second World War
In the Second World War, submarines played a major role in several theatres. German U-boats attacked Allied shipping across the Atlantic, in what is often described as the Atlantic convoy battle. This campaign lasted most of the war, and was shaped by convoys, long-range aircraft, escort vessels, codebreaking and marine radar, which gradually gave the Allies the upper hand. Destroyers, the descendants of the early torpedo boat destroyers, were among the most important anti-submarine ships.
In the Pacific, American submarines carried out a sustained campaign against Japanese merchant shipping and warships, and Japanese and British submarines also served in various roles. Late in the war, Germany introduced new types, notably the Type XXI, which had a streamlined hull and a large battery capacity, giving it better underwater performance than earlier boats. The war ended before it could be used in large numbers. The snorkel, a tube allowing diesel engines to run while the boat stayed near the surface, was another significant development.
Submarine crews suffered high casualties in several navies, and it is a theme in the histories of the war that the service was both dangerous and essential.
The nuclear submarine
A key change came in the 1950s. A nuclear reactor does not need air, so a submarine powered by one can remain submerged for very long periods, limited mainly by supplies and the endurance of the crew. The United States Navy’s USS Nautilus, commissioned in 1954, was the first nuclear-powered submarine. In 1958 she made a voyage under the Arctic ice and passed beneath the North Pole, a milestone related to the history of Arctic ice navigation.
The Soviet Union, Britain, France and later other states built nuclear boats of their own. The first British nuclear submarine, HMS Dreadnought, entered service in the 1960s. Designs also changed in shape: hulls became rounder and teardrop-shaped, which suited underwater speed rather than surface travel.
Missiles and deterrence
During the Cold War, submarines took on a strategic role. In the late 1950s and early 1960s, navies began to arm submarines with ballistic missiles that could be fired from underwater. These missile submarines were intended to be hard to find, and so provide a deterrent that would survive an attack. Alongside them, attack submarines were designed to hunt other submarines and surface ships. The Cold War produced a long game of shadowing and detection, much of it still not fully public.
Later operations
Submarines have been used in more recent conflicts, and the British nuclear submarine HMS Conqueror’s sinking of the Argentine cruiser General Belgrano in the Falklands War of 1982 is widely cited as the best-known instance of a nuclear-powered submarine sinking a ship in war. Accidents have also left their mark, including the loss of the Russian submarine Kursk in 2000. Modern non-nuclear boats now use quiet diesel-electric systems, sometimes with air-independent propulsion, and several navies continue to operate them.
A transformed weapon
The submarine’s twentieth-century story is one of rapid change: from experimental craft to a weapon that forced navies to rethink how they protected shipping, and then to a platform for nuclear deterrence. Its development was bound up with changes in engines, batteries, electronics and weapons, and with the political choices that governed how it was used.