On August 15, 1939, Grand Admiral Erich Raeder, chief of the Kriegsmarine, directed his staff, the OKM, to send a war alert to Karl Dönitz, commander of the German submarine force. The message stated that all senior submarine staff officers and U-boat commanders were to report for a “reunion” on August 19 at Dönitz’s headquarters on the submarine tender Hecht, moored at a naval pier in Kiel. The word “reunion” was a coded order to deploy the German submarine force for war—merely four days hence.
Dönitz rushed back from leave the following day. Others concerned reported on board Hecht that day or the next in high excitement. When all had gathered, Dönitz outlined the complicated geopolitical situation that had developed, the perils entailed, and the submarine war plans.
The Führer, Adolf Hitler, had definitely made up his mind to invade Poland. The date had been moved forward from September 1 to August 26. Great Britain and France had pledged to come to Poland’s aid. Although Hitler did not believe the British or French would fight, Dönitz thought otherwise: War with those nations was not only possible, but probable. There was a further complication. To avoid the prospect of a two-front war, Hitler was attempting to negotiate a nonag-gression pact with the Soviet Union. But, so far, Joseph Stalin was foot-dragging. Conceivably, Moscow might reject Hitler’s overtures and align with London and Paris and pledge support for Warsaw. The Kriegsmarine therefore had to be prepared for numerous, dizzying contingencies: war with Poland alone; war with Poland assisted by Great Britain and France; war with Poland assisted by Great Britain, France, and the Soviet Union; war with Poland assisted only by the Soviet Union.
The Kriegsmarine was by no means prepared for a naval war with Great Britain and France. Notwithstanding the naval arms-limitations treaties of the 1920s and 1930s, those nations combined had an awesome array of surface ships: twenty-two battleships and battle cruisers, seven aircraft carriers, eighty-three cruisers, and countless destroyers, plus seven new battleships and eight carriers under construction. Against that the Kriegsmarine had two battleships (Bismarck, Tirpitz), and one carrier (Graf Zeppelin) under construction, two battle cruisers (Gneisenau, Scharnhorst) in commission but not combat-ready, three “pocket” battleships (Deutschland, Admiral Graf Spee, Admiral Scheer), of which only two were combat-ready, eight conventional cruisers, and about twenty destroyers in various stages of readiness. Altogether the Allies enjoyed a superiority of ten-to-one in surface ships.
Great Britain and France likewise enjoyed a superiority in numbers of oceangoing submarines. Great Britain had about fifty in commission, France about seventy, for a total of about 120. Against that the Kriegsmarine had twenty-seven. Not all the Allied submarines were of good quality or combat-ready, but the same was true of the German submarines. Of the twenty-seven oceangoing German boats in commission, two large ones, U-25 and U-26, were experimental and not really suitable for combat and five were brand new or in shipyards for extended refit or overhaul, leaving only twenty fully (or nearly) ready for war on August 19.
In addition, the Germans had commissioned thirty pint-sized, 250-ton submarines—the so-called ducks. The ducks were used principally for basic or advanced training purposes, but they had three torpedo tubes and could carry six torpedoes or nine mines. Therefore all but one duck (U-11), which had been permanently detached for experimental work, could be assigned to limited combat roles in the North Sea or Baltic Sea. About eighteen of the twenty-nine ducks were fully (or nearly) ready for combat on August 19.
The Kriegsmarine war plan was designed to make the best of the several contingencies. The two combat-ready “pocket” battleships, Admiral Graf Spee and Deutschland, each with one supply ship, were to slip secretly to sea and take up waiting positions in the North and South Atlantic. Sixteen of the twenty combat-ready oceangoing submarines were to occupy waiting positions off the Atlantic coasts of Great Britain and France and off the Strait of Gibraltar. Seven ducks were to take up waiting positions in the North Sea. Should Great Britain and France declare war, the “pocket” battleships and submarines in the Atlantic were to operate offensively against the maritime forces of those nations; the submarines in the North Sea, offensively and defensively. The remaining combat-ready naval forces, including four oceangoing submarines and eleven ducks, were to operate offensively in the Baltic Sea against the tiny Polish Navy (five submarines, four destroyers, several minelayers) or, if necessary, the more formidable Soviet Navy.
That was the plan. Should Great Britain and France declare war, Raeder had no illusions about the outcome. The best that the men of the Kriegsmarine could do, he wrote in his memoir, was to “go down fighting” and “show that they knew how to die gallantly.”
The “pocket” battleships and submarines deployed in secrecy per plan, August 19 to August 23. The Admiral Graf Spee, her supply ship Altmark, and fourteen oceangoing U-boats loaded with torpedoes sailed on the night of the 19th. Two other oceangoing U-boats, delayed in the shipyards, sailed on the nights of August 22 and 23. The Deutschland and her supply ship Westerwald sailed on the night of the 23rd. That same night the North Sea U-boat force (seven ducks) and the Baltic Sea U-boat force (three oceangoing boats and eleven ducks) sailed to waiting positions. In total, thirty-four of the fifty-seven commissioned U-boats (65 percent) deployed: sixteen to the Atlantic, seven to the North Sea, and eleven to the Baltic Sea.
Hitler’s negotiations with Stalin, meanwhile, proceeded at a maddeningly slow pace. On August 20 Stalin agreed to a preliminary trade agreement, but this hardly satisfied Hitler. That day Hitler intervened directly, cabling Stalin to suggest that he receive the German Foreign Minister von Ribbentrop, who would have full powers to sign a treaty on behalf of Germany. Stalin agreed to see von Ribbentrop on August 23 and that same night, to Hitler’s immense relief, Stalin signed the pact. The published treaty (binding for twenty years) specified that neither Germany nor Russia would attack the other or support a third party, or a coalition, in an attack on one or the other. The unpublished protocols and agreements doomed Poland and the Baltic States. Germany and the Soviet Union would invade Poland and divide that nation roughly in half at the Vistula River. The Soviet Union was to exercise “influence” over Finland, Estonia, and Latvia, while Germany was to exercise “influence” over Lithuania.
D day for the invasion of Poland remained fixed for August 26. But on the day before, Hitler received several pieces of news that gave him pause. The British announced ratification of a formal mutual assistance pact with Poland, which iterated in no uncertain terms Britain’s determination to fight for Poland. The French ambassador called on Hitler to make it crystal clear that France would do likewise. A letter arrived from Italian dictator Benito Mussolini, stating that Italy was not prepared for war and could not immediately go to war against Great Britain and France unless Hitler provided Italy with enormous quantities of military supplies. As a result of these developments, Hitler postponed the invasion from August 26 to its original date, September 1, gaining time for another attempt to negotiate Great Britain and France into neutrality.
The frantic diplomacy and the postponement of D day prompted the OKM to realign the U-boat deployment. The pact with Stalin reduced naval requirements in the Baltic Sea; the belligerent statements from London and Paris made it prudent to deploy more U-boat strength to the west. Accordingly, between August 23 and 28 Dönitz shifted four oceangoing U-boats and ten ducks from the Baltic Sea to the North Sea. One oceangoing boat, U-36, sailed to backstop the ducks in the North Sea; the other three were held in reserve.
By August 28, two other oceangoing U-boats had completed refits. The first was the big, unsteady Type I, U-26. The OKM directed Dönitz to load her with mines and six torpedoes. In event of war, U-26 was to lay mines off Portland, a British naval base facing the English Channel. Although the boat was not really suitable for combat, after laying the mines she was to attack Allied shipping with her six torpedoes. The second boat was a new Type VIIB, U-53, flagship of the Wegener Flotilla. She sailed last (with flotilla commander Ernst Sobe on board), raising the number of boats for the Atlantic, including the minelayer U-26, to eighteen.*
The deployment of the Atlantic boats was dictated by their fuel capacity—or range. Six medium-range Type VIIs of the Salzwedel Flotilla were to patrol individually in a semicircle off the Atlantic side of the British Isles. Six new VIIBs of the Wegener Flotilla, with twice the fuel capacity, were to patrol individually on a similar arc, but farther out—or westward—and southward to the Bay of Biscay. Five big long-range IXs of the Hundius Flotilla, with flotilla commander Werner Hartmann embarked in U-37, were to patrol a southern area off the Iberian Peninsula and the Strait of Gibraltar. The minelayer, U-26, was to wait for final orders off the west end of the English Channel.
To minimize the possibility of detection, the eighteen Atlantic-bound U-boats did not use the convenient English Channel. They went the much longer way, around the north end of the British Isles, remaining submerged in daytime, avoiding all contact with shipping. It was a slow, tedious, fuel-consuming journey during which all boats maintained absolute radio silence.† None was detected. Nor were the two “pocket” battleships. Upon reaching the Atlantic, the U-boats took up preassigned waiting stations.
The North Sea U-boat force was composed, finally, of seventeen ducks and the oceangoing Type VII, U-36. In event of war, five ducks were to lay mines in English and French ports. Two ducks were to patrol offensively off the northeast coast of Scotland, in hopes of mounting surprise torpedo attacks on British men-of-war. The other ten ducks and the U-36 were deployed in defensive patrol lines in the North Sea to warn of and thwart attempts by the Royal Navy to counterattack toward Germany.
While the U-boats were taking up positions, Raeder met with fleet commander Hermann Boehm and Dönitz in Kiel. Believing that a naval war with the west was inevitable, Boehm and Dönitz urged Raeder to scrap the big ships of the grandiose Z Plan and approve an “emergency” plan to build with all possible speed 300 U-boats, to include at least 200 improved Type VII mediums. Dönitz remembered later that Raeder verbally “approved” the proposal and directed Dönitz to submit his ideas in writing to the OKM through channels. A few days later, the OKM scrapped the Z Plan and adopted the Dönitz plan to build hundreds of U-boats. But this drastic—and historic—change in direction required Hitler’s approval and he was too busy with Poland to deal with naval matters.
The Germans invaded Poland on September 1. Per plan, the Kriegsmarine supported the Wehrmacht and Luftwaffe by attacking the Polish Navy and bombarding shore installations. Three Type II ducks, basing from Memel, joined the attacks. Two ducks claimed to have sunk Polish submarines, but in fact, all five Polish submarines (big French-built minelayers) got away. Three ran to internment in neutral Sweden. Two, Wilke and Orzel, eventually escaped from the Baltic Sea and joined the Royal Navy, as did three of the four Polish destroyers.
On September 3, the British and French declared war on Germany. But the Allies were powerless to help Poland. The Soviet Union invaded Poland from the east on September 17. Caught between the Germans and Russians, Polish forces fought heroically, but were overwhelmed and surrendered on September 27. On that day Poland ceased to exist.