FOUR
ANNUS MIRABILIS
The Atlantic is the vital area[,] as it is in that ocean and that alone in which we can lose the war at sea.
—ADMIRAL DUDLEY POUND, FIRST SEA LORD, AUGUST 28, 1941
Annus mirabilis was the only phrase John Godfrey felt accurately described the flood of captured material that transformed the complexion of the cryptographic war in 1941. And not only Godfrey—many in the Naval Intelligence Division and at Bletchley Park rejoiced in this “year of miracles,” especially as the year had got off to a very rocky start.1 The frustration and impotence of the cryptographers in those early weeks had mirrored the miserable collective experience of the British people. Yet, in the vicissitudes of war, fortunes continuously change, and as we shall see, the so-called miracle of 1941 would in turn give way again to despair in 1942—and the pressing need for ever more “pinch” missions on Bletchley Park’s behalf.
For several weeks following the late summer of 1940, while nightly bombings rocked London and other cities during the Blitz, the English had faced the even greater threat of a German invasion from across the Channel. Mounting attacks by German U-boats reinforced the sense of smothering claustrophobia, as the submarines tightened their grip around the British Isles with each passing day. Admiral Karl Dönitz, the brilliant fifty-year-old commander of the submarine fleet, had convinced Hitler that his nimble underwater vessels, working together via radio communications in the “wolf pack” tactic he had devised, could locate, stalk and destroy the convoys and thereby starve Britain and its war economy into defeat.2 Before long, the successes scored by the U-boats in this “Happy Time” transformed Germany’s top-scoring aces—Otto Kretschmer, Fritz-Julius Lemp, Günther Prien and Joachim Schepke—into media darlings rivalling the famed German fighter aces of the First World War. In just six months between June and December 1940, U-boat attacks sank nearly 350 ships and claimed almost 3,000 lives in just 180 days, while only nine of these seemingly invincible submarines were lost. A distraught Churchill lamented, “Without ships, we cannot live, and without them we cannot conquer.”3
It was staggering: in the first twenty-eight months of the war, U-boats claimed some 5.3 million tons of British and neutral shipping, or 1,124 ships—a loss rate five times greater than the number of ships currently under construction in British shipyards.4 Planners projected there would be a seven-million-ton deficit in raw materials, including two million tons of food. But what really alarmed them was the 300,000-ton deficit in the crucial imports of oil that fuelled the British war machine. As imports fell to half their normal levels, strict rationing policies for food, petrol and other essential items in the United Kingdom had to be imposed, threatening to drain the already limited British morale and restrict the nation’s ability to maintain, never mind expand, its power. And more bad news was about to come.
Although Hitler had neglected the U-boat fleet in the run-up to the war—a curious oversight given that German submarines had almost crippled England during the First World War—these early successes soon translated into a crash building program that would see a fourfold increase in the number of U-boats threatening the vital Atlantic lifeline. By the end of 1941, eighty-eight U-boats (up from twenty-eight earlier in the war) were on patrol, even though twenty had already been sunk or captured. Beginning in July 1940, Hitler promised Admiral Dönitz twenty-five new submarines a month—meaning a grand total of three hundred within the year. Although it was questionable that Hitler would reach this target, Churchill, the chiefs of staff, the Admiralty and the NID were nonetheless all deeply worried.
Admiral Karl Dönitz, head of the German U-boat fleet and one of the very few in the Nazi high command to suspect the British of breaking Germany’s Enigma-enciphered messages. He ordered the change from the three- to the four-rotor Enigma machine, which for nearly a year imperilled the Allied war effort. (photo credits 4.1)
Submarines, however, were not the only problem. The Germans also possessed a small but potent surface raiding fleet that posed a major threat to Great Britain’s Atlantic trading routes, even though it was not yet large enough to rival the Royal Navy ship for ship. Admiral Erich Raeder, the head of the Kriegsmarine, was no fool: he had nothing like the Kaiser’s Grand Fleet of the earlier war, but he knew that simply maintaining a “fleet in being” to make periodic convoy raids would do more to tie down British resources than actually engaging in a traditional Götterdämmerung-style showdown with the Royal Navy. In many ways the war at sea was a war of innuendo and perception—not about what your opponent will do but what he could do. However, Hitler grew tired of this chess-like waiting game being played at sea and, in the spring of 1941, ordered his surface raiders, including the super-battleship Bismarck, to launch attacks on British convoys to supplement the deadly work of the U-boats. It appeared that Germany was about to attempt a knockout blow.
Then, seemingly in an instant, the course of the war at sea began to change.
As the dismal winter gave way to spring, a series of incredible events started to unfold that would continue until the end of the year. In the last few days of March, having broken the Italian naval version of Enigma, a less complex but still daunting version of the German machine, Bletchley Park provided Admiral Sir Andrew Browne Cunningham (nicknamed ABC), the commander-in-chief of the Royal Navy’s Mediterranean Fleet, with an early warning that an Italian naval “task force” had sortied to intercept and destroy highly vulnerable British convoys bringing troops from the Egyptian city of Alexandria to Greece. Swiftly, Cunningham devised a plan to outfox and ambush his Italian adversary, Admiral Angelo Iachino.5 First, he sent reconnaissance aircraft out to “discover” the task force, so as not to betray the source of the intelligence—a requisite for any action based solely on Ultra. Second, he found a way to keep his own movements secret as he made a surprise attack—the key to victory at sea. Cunningham—again through the good graces of Ultra—knew that the Japanese consul general in Alexandria maintained a vigil on his whereabouts, figuring that if Cunningham remained in Alexandria, so too did the Mediterranean Fleet.6 The clever British admiral realized, therefore, that he must delude the consul general.
On this occasion, while the fleet prepared for battle, Cunningham arranged for a false story to circulate in the local golf club about a grand ball aboard his flagship that night. When he arrived in the afternoon for his habitual round of golf, he had his dress uniform in his bag and made his presence felt. That evening, nothing appeared in Bletchley Park intercepts to suggest the Japanese consul general suspected subterfuge, even though by then Cunningham had slipped out the back door of the club, jumped into a waiting car and sped to Alexandria harbour to catch up to his own fleet moments before it sailed for its historic confrontation with the Italian fleet. The only warning Iachino received of an approaching British strike force came from the roar of shot and shell crashing into the decks of his ships.
Two days of heavy fighting ensued, which left three Italian cruisers and two destroyers at the bottom of the sea, while the pride of the Italian navy, the battleship Vittorio Veneto, limped back into the port of Taranto heavily damaged; it would never see battle again. It was, as Churchill later claimed, the “tearing up of the paper fleet of Italy.”7 In forty-eight hours Cunningham had inflicted the greatest defeat in Italian naval history. It not only secured the sea lanes to North Africa for the British but kept the Italian fleet wed to its ports. When the ships emerged two years later, en masse, it was to surrender to the Allies.
Great Britain had scored an outstanding victory at the bleakest of times, one that Churchill suggested rivalled Horatio Nelson’s legendary triumph at the Battle of Trafalgar nearly a century and a half earlier. It also clearly demonstrated to John Godfrey in Room 39 at the Admiralty the full weight and power of what Bletchley Park’s Naval Section could deliver: not only had it defined the Italian fleet’s intentions and location, but it had also ensured that the intelligence source and the subsequent ruse remained undiscovered
. So impressed with the fruits of Ultra was Cunningham that, on his return to England, he made a priority visit to Bletchley Park to thank the cryptographers in person for providing the critical intelligence required for the victory in the Mediterranean—once again Churchill’s “golden eggs” had proved priceless.
In addition to the U-boat worries, the British also had to concern themselves with periodic breakouts into the Atlantic by the deadly German surface raiders, which presented a constant threat to the vital convoys. Between October 1940 and March 1941, the pocket battleship Admiral Scheer sank sixteen merchant ships, accounting for nearly 100,000 tons. In the first three months of 1941, the battle cruisers Scharnhorst and Gneisenau took down another twenty-two ships comprising over 115,000 tons, while the heavy cruiser Admiral Hipper sank slightly more than 40,000 tons during its two raiding cruises.8 However, just two months after the Ultra-inspired victory over the Italian fleet, the cryptographers at Bletchley would contribute in no small fashion to sinking the pride of Hitler’s fleet, the super-battleship Bismarck, after she broke out of the Denmark Strait into the North Sea with the battle cruiser Prinz Eugen, intending to prey on the Allies’ convoy traffic in the Atlantic.
The Royal Navy’s legendary hunt for the Bismarck that followed revealed just how potent an intelligence weapon Godfrey’s NID had become by the late spring of 1941, with signals intelligence (cryptography, direction finding, radio finger printing, traffic analysis), naval attachés’ reports and aerial photography all combining to help the Admiralty carry out Churchill’s instruction to “Sink the Bismarck.” Together, they allowed the Admiralty to maintain an almost constant vigil over the movements of the behemoth battleship and gain insights into the intentions and decision making of Admiral Günther Lütjens, the German task force commander, who joined the Bismarck‘s Captain Otto Ernst Lindemann on her bridge for the operation.
This remarkable story began on May 18, when Ultra reports indicated that German aerial reconnaissance had suddenly increased in the area between Jan Mayen, a Norwegian island in the Arctic Ocean, and Greenland. Although the intelligence did not reveal the exact nature of the German interest, it was clear that something was afoot.
That night, unknown to British intelligence, the Bismarck moved quietly from her anchorage in Gdynia, in German-occupied Poland, and the following afternoon entered Kiel, Germany’s traditional home port for its navy, where she joined the Prinz Eugen and a group of destroyers. The next night, they quietly and secretly sailed out through the Great Belt, a strait that divides Denmark in two. It wasn’t until late on May 20 that the Admiralty received a report through its naval attaché in Stockholm that neutral Swedish vessels had spotted “two large warships escorted by three destroyers” making for the northwest.9 The report did not immediately set off alarm bells in the Operational Intelligence Centre in London, though it raised suspicions requiring further investigation. Aerial reconnaissance flights eventually spotted the Bismarck and Prinz Eugen off Bergen, on the southern coast of Norway, but the NID viewed the ships’ movements at this point as nothing more than an administrative reorganization or a training run. Just as the picture was building, bad weather prevented further reconnaissance flights, leaving the OIC in the dark for the next twenty-nine hours—until Bletchley Park came to the rescue. The cryptanalysts had dug up a series of out-of-date decrypts from April, and although the first messages did not reveal anything overt, on May 21 Bletchley Park sent the following message to the OIC: “Bismarck embarked five prize crews with necessary charts at end of April and been carrying out practices in the Baltic with Prinz Eugen.”10
The Operational Intelligence Centre responded immediately: “prize crews” used for manning captured merchant ships plus requests for charts of the North Atlantic could mean only one thing. It informed Admiral John Tovey, the commander-in-chief of the Home Fleet, that “it is evident that these ships intend to carry out a raid on trade routes.”11 With the original message so far in the past, Tovey initially regarded the OIC’s interpretation with some suspicion, thinking that the Bismarck might be sortieing for a “winner take all” showdown with the British ships. However, based on the accumulating evidence, Tovey accepted the OIC’s breakout theory. Now he was faced with another decision that Ultra could not answer: what route would the beast take?
Intelligence is seldom complete or 100 percent certain; it generally requires a highly educated weighing of the odds. Tovey knew that Lütjens had several routes to choose from: he could cruise through the English Channel, or between the Faeroe Islands and either Scotland or Iceland, or through the Denmark Strait. Although the odds heavily favoured a dash through the Denmark Strait, Tovey took no chances and spread his force out to intercept the Bismarck no matter what course she chose. In the process he spread his line too thin, leaving the battle cruiser HMS Hood and the battleship HMS Prince of Wales, along with a collection of cruisers, at the mercy of the Bismarck‘s long-range fifteen-inch guns in the Denmark Strait. In less than ten minutes, the first round was over: the Hood disappeared in a giant explosion following a salvo from the Bismarck, taking the lives of all but three members of her crew of 1,418. The Prince of Wales, severely mauled, pulled back outside the range of the big guns. Immediately the Royal Navy ordered all battleships in the area to join the pursuit—and the race to sink the Bismarck began.
For more than a week, the Royal Navy’s Home Fleet chased the pride of Hitler’s fleet from the North Sea to the Bay of Biscay and hounded her back again towards the coast of France, using direction-finding (DF) apparatus to pick up a constant stream of radio messages from the hunted ship. The British had a real-time picture of where she was, but not of what she intended to do. The DF apparatus was at the mercy of the ionosphere, and for a whole day the pursuing fleet floundered along amid complete radio silence. Fortunately, the Bismarck resumed regular transmissions, which eventually betrayed her position again to the Operational Intelligence Centre. To identify the transmissions, the OIC called on its radio finger printing and traffic analysis experts. The finger-printing group used a “photograph” of the intercepted radio transmission to distinguish a unique pattern in radio waves produced not only by each transmitter but also specifically by each radio operator—a pattern as recognizable and unique as a human fingerprint. The traffic analysis group examined the characteristics of the method in which the wireless messages appeared. When both concluded that the messages indeed came from the Bismarck, plans went ahead to attack the great German warship with torpedo bombers.
The strike damaged the Bismarck badly enough to force her to forgo her raiding mission and head to port for repairs. But the Operational Intelligence Centre was not privy to the extent of her damage, so had no idea what she would do next. Three courses of action seemed possible: Admiral Lütjens could steam to the west, hoping to fix the probn lem at sea; turn tail and head back through the Denmark Strait, making for a German port; or move southeast towards the French port of Brest or, better yet, St-Nazaire—the only dry dock big enough to properly repair the ship. Soon, new direction-finding bearings indicated that the Bismarck was making for Brest. However, the signals quickly died as Lütjens shut down the wireless sets, leaving Admiral Tovey working from well-reasoned guesses until Bletchley intercepted a series of messages on the Bismarck‘s predicament from land and air sources. They revealed preparations for her arrival and repair at St-Nazaire.12 Within minutes the OIC informed Tovey: “Information received graded A1 that intention of Bismarck is to make for west coat of France.”13
With his hunch confirmed, Tovey confidently proceeded, using a combination of direction finding, traffic analysis, radio finger printing and Ultra intelligence to move in for the kill. After a small but inconclusive encounter that allowed the Prinz Eugen to slip away ahead of the Bismarck and make for Brest, it took almost two full days to catch up with the giant battleship. Finally, on May 27, with the Prinz Eugen already in Brest for repairs, the Royal Navy put more than four hundred shells and several torpedoes into th
e Bismarck.14 Only when the ship had become a burning hulk did the order to abandon ship sound, followed by orders to scuttle the vessel. Quickly the battleship slipped beneath the surface with Lütjens, Lindemann and more than 2,000 of her 2,200 crew.15
The victory over the supposedly invincible Bismarck was a great relief to the Admiralty—one that also provided a massive and desperately needed propaganda coup to inject life back into the sagging morale of the British people. In the space of the following two months, the war at sea took a drastic turn in the Allies’ favour as the Royal Navy’s Home Fleet turned its attention to the battleship’s many support vessels. During the month of May, Bletchley Park provided the OIC with accurate locations for the twenty-one tankers, trawlers and ships that had been tasked with providing fuel, supplies and weather reports to the Bismarck and Prinz Eugen. That information allowed the British to attack the vessels in piecemeal fashion into the second week of July—and by the eleventh they had sunk or captured fifteen of them. Unfortunately, popular history has focused exclusively on the dramatic hunt for the Bismarck and ignored this important epilogue to the battle.16
In the North Atlantic, the “Happy Time” for the U-boats also came to an abrupt end that spring, with the four top U-boat aces captured or killed in action. Until June 1941, with the exception of a slight lull in early winter, the German submarines had continued the deadly pace they had set the previous year. In May alone, U-boats had claimed sixty-six ships or 324,000 tons of British shipping in just one month, followed by another sixty-five and over 300,000 tons in June. But then their success dropped dramatically, to twenty-one ships and 61,000 tons in July and thirty-two ships totalling 81,000 tons in August. By the end of June, despite the rising numbers of U-boats operating in the Atlantic sea lanes, the submarines’ proficiency in locating convoys suddenly vanished, with ships slipping past their patrol lines to arrive unmolested in British ports. More alarming for Admiral Karl Dönitz was the fact that only forty-nine British ships during July and August fell victim to his crews. Meanwhile, by the autumn, sinkings of his own craft had risen at an alarming rate, with thirty-five U-boats gone by the end of the year, ten in December alone.
One Day in August Page 9
