THE LAST GOOD WAR: A Novel (28 page)

One day, Yvonne was obviously shaken. She had just received a codebook from an enemy plane that had been shot down. She couldn't read the last fifteen pages; they were stuck together with fresh blood that was beginning to coagulate. Somehow, the war was much closer. Real people were getting killed.

The three friends picked at their food; none had much appetite.

In the following weeks, the lunches were much less depressing. Anna eagerly awaited Yvonne's reports of newly captured material. In early 1941, a German ship was seized off Norway, providing the Dolphin key tables. Although they were for previous weeks, they allowed BP to read earlier U-boat traffic; they might provide the secret to unlocking future communications. Success could not come too soon; U-boat attacks were intensifying.

Then the destroyer
Bulldog
rocked the U-110 with a series of depth charges. The sub's main power went out. As it surfaced, its terrified captain, Lemp, saw the
Bulldog
bearing down, about to ram his vessel. “Abandon ship!” he shouted. There was no time to set the charges.

As the sub's crew leaped overboard, the Bulldog's captain recognized his golden opportunity. He swung hard aport, missing the sub. A boat was soon lowered, carrying a boarding party.

Too late, Lemp realized his mistake. He had to get back to scuttle his U-boat. He left his men, and vigorously began to swim back. A burst of machine-gun fire erupted from the Bulldog's deck. Lemp—the captain who had breached instructions to sink the liner
Athenia
on the very first day of the war—now faced his own fate; he slipped below the waves.

The boarding party groped their way down the narrow, gloomy corridors lit only faintly by the sub's emergency system. In the radio room, they found a typewriter-like machine; they passed it along to the bridge. Going through Lemp's desk, a British officer found a sealed envelope. It looked important.

It was. The Bulldog had captured not only an Enigma machine, but also the settings to read Dolphin traffic for the first half of May.

Anna thought that they were close to a continuous real-time breaking of Dolphin—the key to routing convoys around U-boat packs. Yvonne reported that there would be a meeting that afternoon: was there any way to steal Enigma material to order, rather than waiting for lucky windfalls? Yvonne would check to see if Anna might attend.

The meeting started with a suggestion: mount a commando attack on a U-boat base, to seize material. The idea was quickly discarded—too dangerous and too costly. Even if it succeeded, which was very doubtful, it would tip the Germans off: the British were after Enigma secrets.

They then turned to a proposal of a naval intelligence officer, Lt.-Commander Ian Fleming. He had submitted an elaborate, written scheme to refurbish a downed Luftwaffe bomber. With a German-speaking British crew, it would join a flight of enemy planes returning from a raid. As it crossed the channel, it would begin to lose altitude and leave a trail of smoke. It would ditch conveniently near a small German navy boat; the crew would wait to be picked up.

Thereupon, the plan was simple: "Once aboard rescue boat, shoot German crew, dump overboard, bring boat back to English port.”

To Anna, the idea seemed far-fetched. She said nothing, but inconspicuously slipped a note to Yvonne:

Fleming has missed his calling. With his supercharged imagination, he should be writing spy novels.

Others were less skeptical; they would try the idea out on the Navy.

Yvonne thereupon passed a note back to Anna:

Cheer up. It's not the craziest idea the Navy has ever considered.

When Anna looked puzzled, Yvonne scribbled an explanation:

During the first war, they considered a plan to blind submarines by training seagulls to poop on periscopes.

Throughout the discussion, Harry Hinsley sat silently and impassively, obviously sunk in thought.

"Let's work backward," he said slowly. "What do we want? More naval Enigma machines and material. Where do they exist? On ships. What ships are most vulnerable? Slow surface ships. What are the slowest, most vulnerable ones? Weather ships. They're continuously sending messages. With radio direction finders, they should be easy to find. They also offer another advantage. A big one. They've got no guns. They don't shoot back."

"Brilliant," was Alastair's response. "But how do we attack the ships, so that the Germans don't twig to the fact that we're after their Enigma machines?"

Anna was about to make a suggestion but held back, waiting for someone with naval experience to speak. As she looked around the room, she realized how few people met that criterion. Accordingly, she broke the silence.

"The key to success would be to board the ship quickly, with as little warning as possible. That would mean a small ship, certainly nothing bigger than a destroyer. It could stand off, over the horizon, waiting for fog. Using its radar—do destroyers have radar?—it could appear suddenly out of the fog. Even if the weather ship did get off a quick message, the Germans might simply dismiss it as a chance encounter."

The navy liked Hinsley's suggestion, but not Anna's details. In May 1941, they went after the weather ship München, not with a single destroyer, but with a line of ships—three large cruisers and four of the newest, fastest destroyers, strung out in a line, ten miles apart. The idea was to come on the München as quickly as possible, firing from a distance, trying not to hit the ship but come close enough that the crew would panic and abandon ship without either sending a distress signal or destroying their coding equipment.

The operation was partially successful. The München crew managed to throw their Enigma overboard, but the boarding party seized the Dolphin settings for June. The radio operator was interrupted in the middle of a message and dragged away from his key; presumably he was trying to warn Berlin that they had been boarded.

Toward the end of June, a second weather ship was boarded, with the settings for July. With these keys, BP was able to read Dolphin traffic for those two months.

It would be unwise to press their luck with another ship. The Germans might write off the first two as unlucky accidents. But a third? That would be just too much coincidence—particularly when the weather ships were so isolated.

Furthermore, there was no pressing need. By August, 1941, Turing and his team had their new bombes—the “Jumbos.” They also had two months' worth of decryptions, and enough cribs and sillies to decipher Dolphin almost continuously.

18
Shark

Operational analysis showed that its [a U-boat's] chances of survival after the delivery
of a sixth close [depth charge] attack rapidly diminished, probably because the U-boat captain lost
his capacity to think his way out of danger.

John Keegan, The Price of Admiralty

W
ith the decoded messages, the Admiralty routed convoys away from the wolf packs. The results were striking. Sinkings by U-boats fell by almost two thirds. But just as they were beginning to quietly celebrate their success, Anna got a disturbing call from Yvonne. She had to see her at once.

When Anna got to her old office, Yvonne looked worried.

"You've seen the Enigma machine they've just captured—the one from U-570?"

"Yes. But I didn't inspect it—busy with Army intercepts."

"You should. Carefully. But, before I tell you what to look for, you might like to know how we came by it."

"I'm all ears."

"The sub surfaced south of Iceland to recharge its batteries. Almost directly above was one of our Hudson bombers—more precisely, a Hudson bomber provided by the Yanks. The pilot could scarcely believe his luck. He dropped four depth charges, straddling the sub. It was so badly damaged that it couldn't risk diving. It signaled its surrender to the Hudson, which radioed to a nearby destroyer. It soon appeared and sent a boarding party."

"Interesting. But why, pray tell, should I be concerned with this particular Enigma?"

"Because, my dear Anna, it was designed with room for a fourth wheel. Only three are installed, but there's space for a fourth."

"So when they get around to..."

"When they get around to using the fourth wheel, we may be back to square one. We're winning Round 1 in the U-boat war. But I shudder to think of what will happen when they use that fourth wheel."

Round 2 was indeed coming. It would be tough. But fortunately, the fourth wheel was not operational for almost six months, and before that time, the United States would be drawn, reluctantly, into the war.

1 February, 1942. Bletchley Park.

E
ach day, the codebreakers faced the task of unraveling the basic keys. It was a struggle, even with all the power of the new bombes, reinforced by cribs, sillies, and the sloppiness of German operators. Soon after midnight, when the first messages of the day would begin to come in, the codebreakers would begin their methodical, intense routine, hoping all the while for inspired guesses. Usually the Luftwaffe settings would be broken first; the first cheer of the early morning would go up, sometimes as early as 2:00 a.m. Success with Dolphin came later.

But on this early February morning, there was no second cheer. Noon came, and the day's Dolphin had not yet been unraveled. The afternoon stretched into evening; still no success.

After a few frustrating days, they knew they faced a fundamental problem. No Dolphin traffic had yet been decoded for February. And on these decodings depended the safety of Atlantic convoys.

Reluctantly, they came to the obvious conclusion: the Kriegsmarine had introduced the fourth wheel for communications with U-boats. Dolphin was now relegated to less important communications with surface ships.

The primary responsibility for breaking Shark—BP's name for the new four-wheel cipher—lay with Turing and others at Hut 8; Anna was not intimately involved. But thorny problems were tackled at occasional meetings. The Shark puzzle was not altogether hopeless. Before the official introduction of the fourth wheel on Feb. 1, some U-boat crews mistakenly used it, and, when their error was pointed out, they retransmitted with just the first three wheels. Such lovely, repeated, teenaged kisses, it might have been hoped, would lead to a quick breaking of Shark.

But that was not to be; the new Enigma was very resistant to attacks. Hut 8 finally did figure out the settings for a few days in February and March, but for each of these days, it took six of Turing's bombes an average of 17 days working around the clock.

Seventeen-day old settings couldn't protect convoys. Fortunately, the Germans didn't know that Dolphin had been broken; they didn't know of their huge new advantage with Shark. Fortunately, also—at least for the British—U-boats were occupied with easy pickings off the coast of the United States. It was a time of painful learning for the New World. Rather than use convoys, the Navy sent single tankers along the east coast. They were interspersed with occasional sub-chasers, little more than a nuisance for the U-boats. They simply lay low in the water until the sub-chasers passed.

Furthermore, to put not too fine a point on it, blackout policy was bizarre. Inhabitants of Washington were encouraged to cover their windows—perhaps to give the fuzzy, warm illusion that they were doing their part in the war effort; perhaps as a precaution against a fancied threat from the Luftwaffe. But lights from cars and arcades were left shining merrily in seaside resorts in New Jersey and Florida. Against the glow, the low, slow silhouettes of loaded American ships made easy targets for the raiders of the deep. Exploding tankers provided spectacular fireworks for partygoers, blissfully unaware of their complicity in the fiery deaths of their countrymen. During the first half of 1942, losses to east-coast shipping ranked with the disaster at Pearl Harbor.

Then, belatedly, the navy instituted coastal convoys, and the U-boats turned their attention back to the mid-Atlantic, beyond the range of patrol planes. Sinkings increased spectacularly. By September, with almost a hundred U-boats prowling in wolf packs, they sank almost half a million tons. U-boat losses: 3.

At Bletchley Park, the pressure was on. They might be successful in breaking other German traffic. But they were not providing critical U-boat information, on which all else depended—preparations for an invasion of France, and conceivably even the survival of Britain itself. They concluded that they were not producing bigger and faster bombes quickly enough; they reluctantly accepted America's offer to develop and build new machines. By now, they had little alternative; American codebreakers intended to work on Enigma, with or without British cooperation.

T
he Yanks were coming to BP. Their slim vanguard—only two men—had arrived. They were going to have lunch with Yvonne, to bring them up to speed on BP's progress. If Denniston could get away, he would join them. Would Anna like to come? Yes, she would.

“You'll find them interesting,” Yvonne added. “I certainly do. But then, I've never met an American before.... They're real patricians—courtly and reserved, not at all the brash, exuberant youth I expected. And they're
very
bright.

Anna and Yvonne took turns, providing a brief history of how messages were decoded. They had permission to be frank with the Americans, who had shared details on how they had broken the Japanese “Purple” code. Furthermore, Bletchley Park—in the person of Jim Rose—had been allowed to interview the Americans and pick the ones who would be allowed to come.

Anna and Yvonne talked of cribs, kisses, and gardening. Of the decision to seek out weather ships, and of the stone wall they now faced with the four-wheeled Shark.

Bill Bundy was interested in weather ships. Could they seize a third?

“Not clear how useful it would be,” replied Anna, “even if we could make it look like another 'accident.' Weather ships are still using old, three-wheel machines. It's the subs' four-wheeled Shark that's the problem.”