Seizing the Enigma (19 page)

Behind the face of the bombe was the machinery that drove it, turning all the upper wheels together, all the middle wheels together and all the lower wheels together. The back of the bombe, which opened to give access to the mass of circuitry within, served as a frame for the diagonal board. Keen’s two prototypes, built in part out of punched-card machinery, proved extremely flexible, largely because Keen’s long experience with punched-card equipment had taught him that it was often used to perform tasks not envisioned when it was designed.

The first Turing bombe was installed in Bletchley Park’s Hut 11 on the 8th of August, 1940. Named AGNES, it became a prototype for machines superior to the sorters used by Germany for codebreaking.

The Government Code & Cypher School expanded rapidly, a phantom agency exercising apparently spectral powers. Its organization reflected that of the enemy whose cryptosystems were being read, because those cryptosystems varied according to the needs and usages of the services that employed them. Thus G.C.&C.S. Naval Section dealt with foreign naval intercepts, and other sections worked on foreign army, air force, and diplomatic intercepts. The military and naval
sections each evolved into two parts: cryptanalysis, which cracked the cryptograms, and intelligence, which extracted information from the solved intercepts. These teams were soon known better by the number of their hut than by their formal organizational name.

The naval cryptanalysts, headed by Turing, worked in Hut 8. Seated at cheap wooden desks, they spent their time guessing at possible cribs, looking for loops, and testing them on the bombes; they did sums, drew diagrams, printed letters. They seldom spoke, though occasionally one might express some emotion in a reserved British way. Next to them in Hut 4 were the naval intelligence analysts, who translated and appended comments to the solved intercepts. Hut 3 housed the cryptanalysts solving the German army and air force intercepts; Hut 6, the analysts for these solutions.

The advances made by Turing and Welchman had left Knox far behind; he remained in the Cottage working on the Enigmas without plugboards used by the Italian navy and by
Abwehr
, the German high command’s espionage service. The solutions that his little group produced were designated ISK, for Intelligence Service Knox.

Some of the higher positions of this growing organization were filled by Room 40 veterans summoned from their civilian occupations. Nigel de Grey, a solver of the Zimmermann telegram that helped bring the United States into World War I, a man barely five feet tall and given to wearing fawn-colored trousers, returned from the publishing world as a deputy director. Frank Adcock, a round-faced, secretive classics scholar at King’s College with a way of telling a joke and then cocking his head while waiting for the laugh, returned in 1939. The pantomimist Frank Birch, forty-nine, also a fellow of King’s, came back to head Naval Section. He had taught history at Cambridge from 1921 to 1928, where his histrionic gifts made his lectures extraordinarily vivid. He quit academe to act in and produce plays in London. Of medium height, with close-set eyes in a mobile face, he was a very good comic actor and very good company, very amusing—when he wasn’t working.

As a boss he was less successful, some thought. Birch was a Prussian in his directing style, which didn’t work very well at Bletchley. He never encouraged: if the cryptanalysts got stuck, he’d come in at once and demand, “What’s wrong?” A poor judge of people, he played favorites. Knowing that he would probably be unable to get a knighthood because of wartime secrecy, he sought his reward in power: he liked results that he could display to the admirals. Once he admonished his cryptanalysts, “Don’t tell Hut 3 [the army and air force cryptanalysts] about this.” But although he was not the best leader of the 200 people eventually in his section, and although an element of ruthlessness and prejudice limited the number of his friends, he could be kind. After one of Knox’s young women assistants had been married three days, Birch took her into the operations room. Just as her husband’s convoy was being pointed out to her on the plot of the Atlantic, a U-boat symbol was put down next to it. Birch put his arm around her. “We’ll send the whole navy,” he said.

Many of the positions immediately beneath these senior levels, such as the heads of huts or the heads of shifts, were occupied by new recruits. Some came, as Turing did, through the King’s College connection. Conel Hugh O’Donel Alexander, called Hugh, was a mathematician with a powerful intellect and extraordinary vitality. A former British boys’ chess champion, he had gained first-class honors in mathematics at King’s but not the star for exceptional distinction that he wanted. He attributed this to having played too much chess, which was probably an accurate assessment: he won the university championship his first year and every year after that but one. Nor did he succeed in becoming a fellow of King’s. Instead he taught mathematics at Winchester, one of England’s great public schools. Then, at the urging of his wife, a cosmopolitan, not to say Bohemian, Australian who had lived in Paris, he took a job in an elegant London’s men’s clothing store where the owner, a chess fanatic, maintained the London Chess Center. It was a ridiculous move, friends thought. As a member of the British chess team, Alexander was in Buenos Aires for
a competition when war broke out. With mental visions of London in flames, he returned home. Early in 1940, he joined the team at Bletchley and was assigned to work in Hut 8, the naval cryptanalysts, under Turing.

Here he became a remarkable asset. His intellect was powerful—one of his coworkers later said that “Alexander was one of the most intelligent people I’ve known, and I’ve known a lot of intelligent people”—and his vitality extraordinary. A lively, talkative, enthusiastic person, he incorporated several contradictions. Though he worked in the solitary pursuit of mathematics, he dealt with people extremely well. He proved an excellent organizer and administrator though he was personally untidy: his desk was a mess, he dressed sloppily, his hair was all over. And though not good at most ball games, he played table tennis in an ungainly but effective way, rarely letting a ball get past him. He soon became Turing’s chief assistant.

One of Alexander’s great friends was Stuart Milner-Barry, the
Times
’s chess correspondent, who had preceded him as British boys’ chess champion, had played chess with him at Cambridge, and had been a member of the team that went to Buenos Aires. When Milner-Barry arrived later at Bletchley, he was very glad to see his old friend. But it was through Welchman, not Alexander, that Milner-Barry got to B.P. He and Welchman were exact contemporaries at Trinity College, Cambridge, had later lived in Cambridge at the same time, and had played tennis together often. Soon after the war started, Welchman thought that Milner-Barry, a chess player, would do well as a cryptanalyst. So he recruited him. And shortly after Milner-Barry joined G.C.&C.S., he began recruiting others, driving his little blue Austin 7 to pick them up.

In other cases, chance and mystery played roles in obtaining people. Because Leonard Forster had gotten along better with his German master than his French at his public school, he specialized in the Teutonic tongue, took his degree in it at Cambridge, spent four years working and studying in German-speaking lands, and finally
returned to Britain to instruct at Cambridge. One day in March 1939 he was summoned to a briefing in Broadway Buildings; he never found out how he came to be invited. He took the introductory course in cryptology that G.C.&C.S. gave and went to London a few times in the spring and summer to help solve a simple two-letter German code. When war came, he went straight to Bletchley, vanishing into an organization that was one of the great unseen fighters of the war.

But neither the recruiting of Britain’s best brains, nor the remarkable breakthroughs of Turing and Welchman, nor the occasional solution of the Luftwaffe Enigma led to the cracking of the naval Enigma. Then, as sometimes happens in war, help came from an unexpected source.

I
N THE FALL OF
1939,
SOON AFTER
W
ORLD WAR
II
HAD BEGUN
, Lieutenant Heinz Rottmann, a slender, energetic, twenty-five-year-old naval careerist, was summoned to the U-boat fleet. The summons came from the man who had captained the cruiser
Emden
during Rottmann’s officer training cruise a few years earlier and who now commanded the entire U-boat fleet, Captain Karl Dönitz. He gave Rottmann his choice of the U-33 or the U-34. Rottmann chose the U-33, a three-year-old Type VIIA submarine because he knew her skipper, Hans von Dresky, from the
Emden
and because he liked her number.

Before Rottmann joined, the U-33 had sailed on an operational cruise—she had actually gone to sea in anticipation of hostilities and was in her patrol area when Dönitz instructed his U-boat captains to “commence hostilities against England at once.” She had sunk three ships and, at her berth in Wilhelmshaven, had been given the highest mark of esteem to which the members of a U-boat crew could aspire: a visit from the Führer himself. Rottmann participated in the U-33’s second cruise, in which she laid mines and sank some trawlers. Then the 700-ton, 212-foot-long submarine was returned to her builder, Germania Werft in Kiel, for an overhaul that included the replacement of a bad diesel.

Finally, in early February 1940, she was ready to sail again. At about 2
A.M
. on the fourth, she was lying at a wharf in Wilhelmshaven’s
solidly frozen harbor, with sailors and longshoremen loading provisions and munitions, when she rapidly and unexpectedly listed 15 degrees to port and dipped by the bow. Water and ice poured through a torpedo hatch into the bow area. One of the seamen ran to the control area and blew all ballast tanks, thus preventing greater problems. At about that time the engineer, Lieutenant Commander Friedrich Schilling, came on board. He concluded that the damage was minor and controllable and, in the morning, when he reported the incident to the submarine’s commander, Dresky ordered the vessel to depart on schedule.

At 8
A.M
., Dönitz came to the dock to see the U-33 off. To the newspaper reader, to the average German watching the newsreels in the cinema, even to some members of the
Kriegsmarine
, a submarine was just the letter U followed by a number; the subs under these impersonal designations seemed indistinguishable. But to Dönitz, each number summoned up the face of the U-boat’s commander, as well as her officers and crew. Each ship was an individual, with her own characteristics, temperament, and qualities. Dönitz saw, rightly, that in addition to making operational decisions such as where to concentrate his boats for the greatest effect, his chief job was to inspire “his” crews, to make them want to do their best for him in their dangerous tasks. So he went down to the harbors to send them off and to greet them on their return. And the crew of the U-33 did not forget that he had come on that wintry morning to wish them a successful cruise.

Of those forty-two men, only four were new. Most were regular seamen; many had been together since the submarine’s 1936 launching, and they had been forged into a team by sharing the thrills and the fears of combat. Time had expunged any lingering claustrophobia: they were used to being enclosed underwater. Morale was good—despite the captain. His first two patrols were successes, but Dresky, tall, with a thin beard and a pointed nose, was not an inspiring leader. He was introspective, too serious, too quiet, and not enough of a driver or daredevil to win the full respect of his youthful,
eager crew. Moreover, he hoped on this voyage to sink one of Britain’s giant ocean liners, the
Queen Mary
or the
Queen Elizabeth
, or some capital ship of the Royal Navy, as Günther Prien had sunk the
Royal Oak
in Scapa Flow four months earlier; he felt that his destiny depended on how well he did. The sense of fate constrained his command. And his men smelled it.

Their baleful feelings grew when the U-33 had difficulty getting out of the harbor. Heavy pack ice forced her back several times. Not until an icebreaker and a freighter preceded her did the U-33 succeed in passing the bar. It was an inauspicious beginning.

Once out in the tumbling, windy North Sea, the crew discovered the cause of the earlier listing: water had come in through two holes, one the size of a thumb hole in the port torpedo tube, the other a quarter-inch accidental drill hole in a copper pipe. The leaks were stopped with a wooden wedge and with rubber until the U-33 reached Heligoland, the cliff-sided German island and naval station in the North Sea. There she lay over for several days owing to thick fog, and the holes were sealed better. But the repairs were not properly completed, and this intensified the crew’s foreboding: they could not forget the three days they had spent on the bottom repairing a diesel during the first cruise.

Finally, at 4:30 in the wintry afternoon of Wednesday, February 7, the U-33 cast off from a tug that had towed her out to sea and began her third war patrol. She moved on the surface in the darkness at 12 to 15 knots; with the coming of daylight, she settled to the bottom, even though she was still within the vast German minefield that protected the north German ports from the Royal Navy. When night fell, she surfaced and headed northwestward, engines running strongly at 85 percent of capacity. Once, to the east of Scotland, her lookouts’ hearts stopped as they spotted several destroyers, almost certainly British. But the warships did not see the low profile of the submarine, and she continued undisturbed. She curved north around Scotland, taking the Fair Isle Passage between the Orkneys and the Shetlands.
Three or four times her lookouts warned of aircraft, but again the submarine was not sighted.