From the opening day of the war until the cessation of hostilities, the Atlantic was a major theatre of operations. It became the longest campaign of the war. Before the Allies could build an army to take back North Africa or the European continent, they had to secure and protect an armada crossing the shipping lanes to England.
At the end of World War I, the Allies decried and outlawed unrestricted submarine warfare at the London Naval Treaty Conference of 1930. Unrestricted submarine warfare was one of the stated causes of American entry into World War I, and the use of submarines was seen as a terror weapon against a civilian population.
At the start of World War II, the Germans had several pocket battleships capable of commerce raiding, converted merchant ships called Q ships for stealthy attacks, and fifty-seven U-boats; only twenty-six were oceangoing U-boats. The early German torpedoes, like the Americans later in the war, suffered from faulty torpedoes that broke up upon impact instead of detonating. Admiral Karl Dönitz had commanded the first U-boat group in 1936, and had risen to command all the U-boats by the start of the war. Unlike the Americans, he quickly moved to fix the torpedo problem. It was not completely fixed until December 1942, well into the war.
Had the Allies known that the Germans were having torpedo problems, they would have been grateful for that small favor. The Germans scored early successes that forced the British to adopt exactly the wrong tactics to fight the U-boats. In September 1939, U-29 sank HMS Courageous, and torpedoes that hit HMS Ark Royal broke up on impact. The Admiralty under Winston Churchill pulled the carriers from antisubmarine patrol and put the merchantmen into convoys. While this allowed mutual assistance among the convoy ships, it also allowed the Germans to focus multiple U-boats on the convoy and vector in subsequent attacks by radio. By October 1, 1939, the Germans had sunk forty-one merchant vessels for a total of 153,000 tons displacement. It was a “happy time” for the U-boats. Imagine what havoc the U-boats would have wreaked with fully functional torpedoes.
Even though the number of U-boats on patrol was cut in half in October as ships returned to port to rearm and refuel, more were sunk the next month. U-48 sank HMS Royal Oak inside the supposedly submarine-proof home anchorage in Scapa Flow on October 14, 1939. Throughout the end of 1939, more ships were being sunk then were being built.
Things would only get worse the British. Churchill reported to Parliament in 1940 that twenty ships with 120,000 tons of food and fuel oil had to dock every day in order for Britain to hold out and win the war. But as the fortunes of France soured, so did the fortunes of the merchant marine supplying England with arms and materiel.
The fall of France on June 22, 1940 allowed the Germans to base U-boats closer to the Atlantic. The first one arrived on July 7, 1940. Dönitz put his ’Wolf Pack” tactic he developed in the 1930’s into operation. With forward bases hardened against air attack in Lorient, France, several U-boats could track and attack convoys, stretching the Allies’ already hard-pressed escorts with simultaneous attacks.
The only other thing in the Allies’ favor, besides their enemies’ faulty torpedoes, was the lack of serviceable U-boats. In February 1941 Dönitz could only send twenty-two submarines into the Atlantic, with 30% on patrol at any given time.
The convoy system and long-range aircraft cut down on losses near land, but in the ’mid-Atlantic gap” where long-range aircraft could not reach, the U-boats concentrated their attacks.
The United States Navy was actively engaged before the German declaration of war in December 1941. USS Reuben James was sunk on October 31, 1941 by U-562. This angered many “America Firsters” who thought this would bring the United States closer to the European war.
Actually the first aggression came from the Japanese. When the Germans followed suit on December 11, 1941, a second “happy time” would lie off the shores of the United States. The worst naval defeat in United States history, one overlooked by history and overshadowed by the losses at Pearl Harbor, would crash into the unprepared American merchant marine in the form of German torpedoes. Dead American sailors began to wash up on the American coastline, and civilians watched nightly as tankers and cargo ships burned in the night offshore. War had come to America.