THE LAST GOOD WAR: A Novel

by Paul Wonnacott

  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

  With 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.

  Each 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.

  The 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.”

  “The weather ships and subs—they communicate with each other?” Lewis Powell wanted to know.

  Anna was slow in responding. She had never heard that soft, mellifluous Southern accent before.

  Yvonne picked up the slack. “Yes, I think so.”

  “Two-way traffic? The submarines also send messages back to the weather ships?”

  Yvonne paused. “Again, I think so.” She obviously wasn't sure.

  “I wonder....” Powell stopped.

  Denniston had been nibbling at his lunch, apparently lost in another world. Now, he came to life.

  “Good question. And the right question's half the game. When U-boats talk to weather ships, they must use only three wheels. It can't be all four. The weather ships—with only three wheels—wouldn't be able to understand. Maybe we can use the subs' messages to figure out how those first three are set. Once we do, we'll have a leg up on the fourth."

  Denniston passed the idea on to Hut 6. They indeed found sub-to-weather ship traffic. The 17 days needed to read submarine messages was reduced. But not enough. A real-time decoding of Shark would have to await another lucky break.

  30 October, 1942. Port of Alexandria, Egypt.

  Aboard the Destroyer, HMS Petard.

  Commander Mark Thornton looked down over the bow of HMS Petard. Workmen had been scurrying all night to complete the installation of a new “hedgehog” antisubmarine system—a set of grenades that could be fired forward. The destroyer would not have to pass over the sub before attacking, the way it would with depth charges.

  An urgent message came from the radio room. Three other British destroyers were stalking a U-boat; they had made several depth-charge attacks in the past four hours. They had the sub trapped against the Mediterranean coast, near Haifa, but had not been able to sink it. Could Thornton help?

  He certainly could.

  He had lived for this chance, keeping his men on constant alert for U-boats. At times, his judgment was overwhelmed by his passion for the hunt. He would climb to the crow's nest, and Ulysses-like, strap himself to the mast, awaiting the siren call of a submarine.

  The remaining workmen were hustled off, and the Petard was soon under way. Even at full speed, it would take eight hours to join the action.

  Aboard U-559, men were grimly silent. They had known the perils when they joined the elite submarine service. But, for many, this was their first taste of the terrors of depth charges—the haunting fear that, at any instant, their vessel might be crushed into a steel coffin. Every time the sub tried to break out toward open water, it was rocked with depth charges. The last were very close indeed; two of the younger men cried out in panic. Several small leaks appeared in the overhead piping; the slow drip, drip mingled with the sweat and stress on the captain's face. The captain ordered oil and debris ejected from the aft tubes. He hoped the attackers were bored, would chalk up a victory when they saw the oil slick, and go away. He directed his sub, dead slow, back toward the coast and let it settle gently toward the bottom. The leaks were under control.

  The pings from the destroyers' sonar shattered the silence, but the attackers could not distinguish the sub from the surrounding rocks. The waiting game had begun.

  It was a grim contest, favoring the destroyers. They could breath. The sub would have to come up for air within 14 hours. The word was quietly sent around. They would wait until 02:00—the time when the enemy above would be least alert—and make a dash. Every man knew: this time would be the final throw of the dice. They would press on, either to the safety of the open sea or to their destruction.

  At 21:10, the hydrophone operator had an urgent report. He detected a fourth ship; another destroyer sent to block their escape? The fourth ship was still far away. But its propellers were thrashing; it was approaching fast.

  The captain's reaction was immediate. No time to waste; they couldn't wait until 02:00. He ordered full speed southward, along the coast, and then westward toward deeper waters.

  A destroyer's signal lamp flashed, informing Petard: the sub is headed south. Block our southern flank.

  As they closed, Thornton was grateful for his new gadget; the sub was turning and diving, obviously expecting an attack. Thornton ordered the hedgehog fired, and a pattern of grenades flew forward. He counted the seconds; the sea erupted in front of his ship. That should mean a hit. Unlike a depth charge, the grenades were designed to explode only on contact. But once one went off, the concussion would set off the rest.

  He wanted to give the sub as little chance as possible. As they passed over the roiling sea, depth charges rolled off the stern. He ordered a hard turn to starboard, returning for a second attack.

  Before the Petard's turn was completed, moonlight glinted off the snout of the U-559 as it broke the surface. Its hatches opened and the crew began to take to dinghies. The destroyer drew up, preparing to take on survivors as its searchlight illuminated the sub.

  A shout came from the bridge: Boarding crew! Boarding crew! A young officer and two ratings stripped. The mission had been drilled into them: they must get code equipment off the sub! Drilled, and practiced. On one training exercise, Thornton had ordered the boarding party to jump into a treacherous, stormy sea and swim around the ship; they were saved from downing only by the presence of a senior officer, who persuaded Thornton to withdraw his order.

  The officer leading the boarding party was about to leap into the sea, when he felt a hand restraining his arm.

  “Not you, mate. You're married.” Lieut. Anthony Fasson was speaking. He too, was stripped to his skivvies. Fasson and the two other men dove into the Mediterranean.

  B
y now, the U-boat crew were climbing rope ladders to the deck of the destroyer. Swimming vigorously in the opposite direction, the three British figures soon reached the sub. Fasson and Able Seaman Grazier were quickly down the hatch, while the third man, as ordered, stood on the conning tower.

  The two men found the wireless room—or more precisely, the wireless cubbyhole. Fasson handed rotors and codebooks to Grazier, ordering him to take them to the conning tower and return as quickly as possible. He began to disconnect what apparently was a coding machine. The water was rising around his ankles, adding urgency to his task.

  Meanwhile, four other men set out for the sub, using one of the German dinghies. As they approached, the nose of the sub settled lower the water.

  Suddenly, it was gone. As the dinghy arrived, it found only one survivor, treading water and holding a codebook and round discs above his head.

  For their heroism, Fasson and Grazier were posthumously awarded the George Cross.

  The new material was quickly sent to Bletchley Park. With it, and with the new machines coming on line, Hut 8 finally succeeded in breaking Shark.

  When they did, they were in for a shock. B-Dienst had been reading the Admiralty's messages to convoys. Not only had the Allies been unaware of the position of U-boats; the U-boats had known where to look.

  With the roles reversed, the hunters now became the hunted.

  15 May, 1943. 10:00 hrs. Kriegsmarine Headquarters.

  Admiral Dönitz sat sullenly staring at the large scorekeeping charts on his wall. The first showed U-boat sinkings of Allied ships, revealing a sharp decline in April. This was not surprising. The British had changed their naval code; the Admiral could no longer guide his submarines to their prey.

  It was the second chart that alarmed him. During the previous week, no fewer than thirteen submarines had been sent to the bottom. How could that be? Was it possible that the enemy had scored a double success, not only denying him access to their messages but also reading the Kriegsmarine's traffic?