The Rise of Germany’s Silent Service

In the tense autumn of 1939, as Europe plunged into another catastrophic war, an unconventional naval strategy was about to change the course of maritime warfare. While Adolf Hitler remained fixated on the might of surface fleets – his beloved Bismarck-class battleships symbolizing traditional naval power – a quiet revolution was brewing beneath the waves under the leadership of Karl Dönitz, commander of Germany’s U-boat forces.

Dönitz, a veteran submariner from World War I, had developed radical theories about economic warfare through submarine operations. Stationed aboard the supply ship at Kiel Harbor on September 3, he received orders to commence operations against Britain. Unlike Hitler’s obsession with grand battleships, Dönitz envisioned strangling Britain’s maritime supply lines through coordinated U-boat attacks. His calculations suggested needing 300 submarines to effectively blockade Britain, yet he began the war with only 56 U-boats, just 22 of which were suitable for Atlantic operations.

Early Operations and Political Constraints

The opening months of war saw Germany’s U-boats operating under severe restrictions imposed by Hitler, who feared provoking neutral nations, particularly the United States. These constraints became painfully clear after the controversial sinking of the passenger liner SS Athenia by U-30 on September 3, 1939. The incident, which killed 128 civilians including 22 Americans, forced Germany into embarrassing denials and led to strict prohibitions against attacking passenger ships.

Dönitz chafed under these limitations, believing they rendered his submarines nearly impotent. Through persistent lobbying with Grand Admiral Erich Raeder, he gradually secured loosened restrictions throughout September and October 1939. Each relaxation expanded the hunting grounds for his wolf packs: first allowing attacks on ships using radios after being stopped (September 23), then removing protections for French vessels (September 24), followed by lifting North Sea restrictions (September 30), and finally permitting unrestricted attacks on darkened ships west of 20° longitude (October 19).

Turning Points in Submarine Warfare

The U-boat campaign’s credibility received dramatic boosts from two pivotal engagements in September 1939. On September 14, U-39 under Kapitänleutnant Gerhard Glattes launched a premature torpedo attack on the British aircraft carrier HMS Ark Royal near the Hebrides. Though the attack failed and U-39 was subsequently sunk by escorting destroyers, it demonstrated submarines’ potential against capital ships.

Three days later, U-29 commanded by Kapitänleutnant Otto Schuhart achieved what U-39 could not. After losing track of a merchant vessel, Schuhart spotted the 22,500-ton aircraft carrier HMS Courageous. When the carrier turned, exposing its broadside, U-29 fired three torpedoes, sending the warship to the bottom with 518 crewmen. This success proved submarines could sink major fleet units, earning Dönitz political capital to expand his operations.

The Audacious Scapa Flow Raid

Dönitz set his sights on an even more ambitious target – the British naval base at Scapa Flow in Scotland’s Orkney Islands. This heavily defended anchorage held symbolic significance; it was where the German High Seas Fleet had scuttled itself after World War I. After careful reconnaissance, Dönitz selected Günther Prien and U-47 for this perilous mission.

On October 13, 1939, under cover of darkness and unusual auroral activity, Prien navigated U-47 through treacherous Kirk Sound, dodging sunk block ships and navigating strong currents. Inside the harbor, he found the battleship HMS Royal Oak and fired three torpedoes at 00:58 on October 14. When initial results proved disappointing, Prien courageously reloaded and launched a second salvo at 01:16. This time, three explosions rocked the 29,150-ton battleship, which capsized within minutes, taking 833 sailors with it.

Prien’s daring escape through the narrow channel amid British countermeasures became legendary. The operation’s success had immediate strategic consequences: Hitler approved massive expansion of U-boat production and lifted remaining restrictions, authorizing unrestricted submarine warfare.

Strategic Impact and Historical Legacy

The early U-boat successes of 1939 fundamentally altered naval warfare. Dönitz’s submarines demonstrated that relatively inexpensive, stealthy weapons could challenge traditional naval supremacy. The sinking of Courageous and Royal Oak proved aircraft carriers and battleships were vulnerable to submarine attack, while the Scapa Flow raid showed even heavily defended bases weren’t immune.

These operations marked the beginning of the Battle of the Atlantic, which would become the longest continuous military campaign of World War II. Dönitz’s wolf pack tactics and focus on merchant shipping nearly strangled Britain in 1940-1941 before Allied countermeasures turned the tide. The technological and tactical innovations from this period – improved torpedoes, snorkel systems, and coordinated attack strategies – influenced submarine development for decades.

Historically, these events marked a paradigm shift in naval warfare, demonstrating how asymmetric strategies could challenge traditional sea power. The U-boat campaign forced massive Allied investments in convoy systems, anti-submarine warfare, and intelligence operations like codebreaking, diverting crucial resources from other theaters. While ultimately unsuccessful in isolating Britain, Germany’s submarine warfare delayed Allied victory and established principles of undersea combat that remain relevant in modern naval strategy.

The story of these early U-boat operations reveals how technological innovation, when combined with visionary leadership and tactical daring, can temporarily overcome material disadvantages. Dönitz’s submarines, initially dismissed by Hitler as insignificant, became Germany’s most effective naval weapon, proving that in modern warfare, stealth and precision often trump brute force.