Potentially far more significant were innovations in torpedoes. The new Type G7e was a masterpiece of German engineering. It was powered by a quiet electric motor running off batteries and gave off none of the telltale stream of air bubbles of the standard models, which were propelled by steam engines driven by an expanding vapor mixture of seawater injected into burning air and gas. The German U-boat designers had also invented a closed system that fired the torpedo without sending a blast of compressed air into the water with it; the new design used an air-driven piston to push the seawater and torpedo out of its tube.
The real change, though, was the tactics Dönitz had been honing to counter both convoys and asdic. Asdic could only detect submerged objects. Dönitz was contemplating night surfaced attacks, relying on the concealment of darkness and the U-boat’s low silhouette to get within torpedo range of his targets. That would render asdic simply irrelevant. As for convoys, they were effective for a simple reason of arithmetic: it is not thirty times easier to find thirty ships together than it is to find one ship. If a U-boat did chance upon a convoy it usually could fire only one or two torpedoes at most before fleeing. But if the attack could somehow be continued to sink a significant percentage of ships in a convoy once it was located, the advantage of traveling in a convoy in the first place would be negated. Dönitz had worked on this problem and was convinced he had the solution: a concentration of targets would be met by a concentration of attackers. He devised a plan for deploying U-boats in loose groups along the Atlantic sea-lanes; when a U-boat spotted an enemy merchantman it would transmit a report by radio to the other boats in his group and to U-boat headquarters, which would in turn order additional groups to the area. Meanwhile, the first U-boat would continue to shadow and keep touch with the convoy just at the limit of visibility until nightfall, when the assembled group would move in for the kill. Dönitz tried out the concept in a naval staff war game in early 1939 and in exercises at sea that spring in the Bay of Biscay, and however contrived the conditions of the experiments he was sure they had proved his ideas. “The simple principle of fighting a convoy of several steamers with several U-boats as well, is correct,” he wrote after the exercise.11
The key to making it work was a secure communication system linking the boats at sea with BdU—Befehlshaber der U-Boote, the commander of U-boats. The German military had such a system: since the 1920s it had been using a modified version of a commercial device called the Enigma to encode its radio traffic. The Enigma was a small box containing a typewriter keyboard and a set of lamps labeled with the letters of the alphabet. Pressing a key completed a circuit that sent an electric signal on a meandering path through three wired rotors to light up a corresponding letter; the rotors advanced their position with each successive keystroke, cycling roughly like a mechanical odometer, so that a new scrambler pattern was employed for every successive letter of the message. The radio operator wrote down the coded version of his message produced by the Enigma, then transmitted it by hand over his radio in Morse code. The operator at the other end reversed the procedure, typing the received message into his Enigma machine to rescramble it back to the original text.
Even if a machine fell into enemy hands the system retained its frightful impenetrability. By choosing a different starting position of the rotors, rearranging the left-to-right order of the three rotors as they were inserted into the machine, and, in later models, by plugging a set of jumper cables into various jacks, literally trillions of different encipherment sequences could be generated. The German navy, since May 1, 1937, employed a particularly secure procedure for letting the intended recipient know which of those trillions of settings had been used for a particular message; it involved sending at the start of the message a separately encoded eight-letter code group that could only be deciphered using a printed table distributed once a month to users of the system. These external code tables added an extra layer of security to the navy’s Enigma codes that made it all but impervious to mathematical methods of attack by any would-be code breakers.
Overall, Dönitz was supremely confident that he had in his U-boats a weapon that could not only win battles, but win the war. “It is clear that the attack on English sea-communications alone,” he wrote in a memorandum to the naval staff on May 23, 1939, “can have war-decisive effect in a naval war against England.”12 Dönitz calculated that if he could sink 700,000 tons of shipping a month, he could destroy the merchant ships that Britain depended upon for her survival faster than her shipyards could replace them.
WITH THE COMING of the war that Winston Churchill had long warned of, Chamberlain could no longer keep out of the government the one man who had so forcefully stood up to Hitler through all the years of appeasement. On September 3, 1939, two days after the German invasion of Poland and the day war was officially declared between Britain and Germany, Churchill joined the cabinet as first lord of the Admiralty. It was the same post he had held a quarter of a century earlier, during the last war with Germany. In his first major speech to Parliament in his new position a few weeks later, Churchill began by saying how strange it was to be back in the same room at the Admiralty, in front of the same maps, facing the same enemy, dealing with the same problems. Then his face broke into an enormous grin. Glancing down at the prime minister, who was seated next to him, he observed in a tone full of innocent wonder, “I have no conception how this curious change in my fortunes occurred.” The entire house roared with laughter—all except Chamberlain, who “just looked sulky,” thought Harold Nicolson, an MP and author who kept a sharply observed diary.
“One could feel the spirit of the House rising with every word” that Winston spoke, Nicolson wrote.13 Churchill’s supreme confidence in the darkest hour, his ready wit, his boyish enthusiasm had already made him the hero of the moment. Congratulatory letters and telegrams poured into the Admiralty. All more or less said the same thing: Thank God you’re back. Churchill swept into his old offices like a whirlwind, ordering up maps and charts, having the old octagonal table he remembered hunted up and restored to its place, issuing a veritable gale of short memoranda that first day and continuing at the same unbroken pace for the next nine months: “Kindly let me know …,” “Please let me have …,” “What are we doing about …,” “Why is work being held up on …,” “Let me have on a single sheet of paper …,” and, with his inimitable love of archaic phrasing, “Pray consider this matter …,” “Pray get this on the move …,” “Pray meet together and put this into shape …” The “First Lord’s Prayers,” they were called. He had little red gummed labels printed up with the words ACTION THIS DAY, which he affixed to memoranda demanding immediate attention. One of his first instructions was that German submarines were henceforth to be referred to in all official papers and communiqués only as “U-boats.”14 He explained that this was to “avoid confusion” with references to friendly submarine forces, but with his instinctive ear for language he knew that calling them U-boats made them sound sinister, and different, from anything that other navies of the world possessed.
Bad news did not wait for the first lord to settle in. At 8:59 p.m. on that very first day of the war, the Malin Head radio station on the northwest coast of Ireland picked up a distress call from SS Athenia, a passenger steamer of the Donaldson Line bound for Montreal from Glasgow. The message began with the staccato alarm… … …, Morse code for SSS, the signal for a submarine attack. Survivors later reported that after sending a torpedo crashing squarely amidships, blowing away the bulkhead between the boiler and engine rooms and destroying the stairs leading to the upper decks from the third-class and tourist-class dining rooms, the submarine had surfaced a bare 800 yards off the liner’s port side. As passengers and crew were taking to the lifeboats, the U-boat fired one or two shells from its deck gun before vanishing into the night. Two British destroyers, a Norwegian cargo ship, and a private Swedish steam yacht picked up the survivors from the lifeboats, but 112 of the 1,418 aboard—including 30 Americans—died,
killed by the initial torpedo blast, trapped belowdecks, or drowned in the chaotic rescue operation. Three quarters of the dead were women and children.
It had apparently been more a case of mistaken overeagerness than deliberate ruthlessness. Expecting that Britain and France might yet abandon the war once his swift conquest of Poland was a fait accompli, Hitler had ordered the U-boats initially to stick to the prize rules, and Dönitz’s war orders so instructed. The next day Dönitz reiterated the orders with a signal to all U-boats: “By order of the Führer, on no account are operations to be carried out against passenger steamers, even when under escort.” At a conference with Raeder on September 7, Hitler pointed to “the political and military restraint showed by France and the still hesitant conduct of British warfare.” France had done nothing with its mighty army, which remained hunkered behind the defense of the Maginot Line on Germany’s western border as Hitler’s panzers plunged eastward through Poland. Raeder recorded the Führer’s general policy instructions at the meeting: “Exercise restraint until the political situation in the West has become clearer, which will take about a week.”15
The parallels with the Lusitania were all too apparent, and repercussions in America were also something Hitler wanted to avoid. The German government at first announced that the Athenia must have either been torpedoed in error by a British warship or struck a British floating mine. A far more audacious lie followed once Dönitz, Raeder, and Hitler ascertained the truth a few days later: that the attack had indeed been carried out by a German submarine that had just returned to port—U-30, under the command of Oberleutnant Fritz-Julius Lemp. Hitler’s propaganda chief, Dr. Joseph Goebbels, took to the airwaves himself to reveal that the sinking had been part of a “devilish game” by the “British Ministry of Lies” to generate “a new Lusitania case”: she had in fact been blown up by a bomb secretly placed aboard her by the British Admiralty. “We believe the present chief of the British navy, Churchill, capable even of that crime,” Goebbels solemnly averred. Other German news reports pointed to photographs of British destroyers coming to the aid of the stricken liner as confirmation of this conspiratorial explanation: why else had British warships been so conveniently close by just at the right moment? Dönitz obediently fell in line with the cynical cover story. He personally swore Lemp and the crew of U-30 to secrecy and ordered the boat’s logbook altered. Churchill dryly noted in his memoirs that the Germans’ story of his sinister hand in the sinking of the Athenia “received some credence in unfriendly quarters.”16
Because of an acute shortage of escort vessels, the Admiralty originally planned to limit convoys to the east coast of Britain and to rely on other means, chiefly evasive routing and zigzagging, to protect merchant ships crossing the Atlantic “until and unless the enemy adopted unrestricted U-boat warfare,” Churchill wrote. “But the sinking of the Athenia upset these plans.”
Organizing a comprehensive system of convoys was a monumental task: on average there were 2,000 British merchant ships at sea at any given moment. Before going to bed in the early morning hours of September 5, Churchill personally wrote up the conclusions of the first Admiralty conference he had held that night, which focused on the convoy issue. The Admiralty’s Trade Division, responsible for controlling shipping movements, was to set up a control room within twenty-four hours, equipped with a large chart plotting the location of every merchant vessel within three days’ sailing of British shores. Destroyers were to be “scraped from the Eastern and Mediterranean theatres” to add to the available escort force. The logs of arriving merchant ships were to be examined promptly by a “competent naval authority” to make sure that ships’ masters were following orders and “examples made” of serious defaulters. All independent sailings were canceled. Within a week, outbound convoys were running to the Atlantic from Liverpool and the Thames; a week later the first homeward-bound convoy sailed from Halifax, Nova Scotia.17
Churchill’s other bold intervention in the U-boat war was a disaster. Convinced that aggressive measures were what it took to defeat an enemy, the first lord ordered the creation of “hunting groups” that would roam the oceans independently seeking out their quarry: he drew an analogy to a cavalry division. It was the wrong strategy for almost every possible reason. Although convoys had the superficial air of being passively defensive, they had a powerful offensive character in practice, forcing a U-boat to confront an escort vessel armed with asdic and depth charges if it wanted to get within striking distance of the convoyed ships. The vastness of the oceans made it an extraordinarily inefficient procedure to maraud about in a random hunt hoping to stumble on a U-boat by chance: the place to look for U-boats was where their prey was.
As a stopgap Churchill assigned two aircraft carriers, Courageous and Ark Royal, to the U-boat hunt. They were clearly the wrong tools for the job. Courageous was a converted First World War battle cruiser equipped with obsolescent Fairey Swordfish biplanes. The Royal Navy’s aircrews had no experience hunting submarines and their torpedoes and bombs were useless for attacking a U-boat once it had dived—equipping aircraft with depth charges was an idea still in the future. But Churchill was in an improvising mood as he cast about for anything that might be rushed into the fight.
On the morning of September 18 he traveled to Scotland to inspect the Home Fleet, anchored at Loch Ewe in the Western Highlands. He wrote in his memoirs that he felt “oddly oppressed” by his memories that day. “No one had ever been over the same terrible course twice with such an interval between. No one had felt its dangers and responsibilities from the summit as I had or, to descend to a small point, understood how First Lords of the Admiralty are treated when great ships are sunk and things go wrong.” Arriving the next morning at Euston Station in London on the overnight sleeper, he was surprised to see the first sea lord, Admiral Dudley Pound, on the platform waiting for him. Pound’s face was grave. “I have bad news for you, First Lord,” he said. “The Courageous was sunk yesterday evening in the Bristol Channel.”18
Churchill would describe it as a “hundred-to-one chance” that the carrier had “happened to meet a U-boat” just at the moment she was turning into the wind and slowing to recover her aircraft, but meeting U-boats was after all what she was supposed to be doing, and sinking them; instead she was hit in quick succession by two torpedoes fired by U-29. An enormous secondary explosion followed the impact of the second torpedo. In twenty minutes Courageous went down in a calm sea, taking 518 of her crew of 1,260 to their deaths.
In his speech to Parliament a week later on the U-boat war, Churchill said, “Risks have to be run all the time in naval war, and sometime grievous forfeit is exacted.” This was true enough but missed the point when the risks were yielding so little in return. He confidently asserted that “six or seven” U-boats had already been destroyed, calling that a “safe figure” and “probably an understatement.” After the war it would be clear that the real figure was two. He also confidently asserted that history was not repeating itself, for all the obvious parallels:
… the U-boat attack upon British ocean-wide commerce was one of the most heart-shaking hazards of the last war. It seemed during the early months of 1917 that it might compass our total ruin. Only those who lived through it at the summit know what it was like. I was at that time not in office, but … I watched with a fear that I never felt at any other moment in that struggle the deadly upward movement of the curve of sinkings over the arrival of new construction. That was, in my opinion, the gravest peril which we faced in all the ups and downs of that war.
“We have no reason, upon the information and experience which are now available,” he concluded, “to suppose that such a situation will recur.” As he would later admit, “I had accepted too readily when out of office the Admiralty view of the extent to which the submarine had been mastered.” Still, in that September speech to Parliament he also spoke frankly of the “cruel and ruthless” fight that lay ahead. “Such is the U-boat war—hard, widespread and bitter,
a war of groping and drowning, a war of ambuscade and stratagem, a war of science and seamanship.”19
ALTHOUGH THE BRITISH CONCLUSION that Germany had once again embarked on unrestricted warfare with the sinking of the Athenia was premature, it was a perfectly accurate perception of German intentions. “The German leopard does not change its spots,” concluded the Daily Record & Mail, and even The Times, its editorial writers at last permitted to pass unpleasant remarks about the German character, suggested that this violation of the Submarine Protocol had afforded the world “yet one more opportunity of judging exactly what value is to be placed on the most solemn German promises.”20
On September 23, 1939—just three weeks into the war—Hitler discussed with Raeder gradually removing the restrictions placed on U-boat commanders by the laws of naval warfare. He agreed to one immediate change: ships transmitting the SSS signal could now be torpedoed without warning, though “rescue of crews is still to be attempted.”
In a series of incremental steps over the next two months, all remaining pretenses of abiding by the requirements of the Submarine Protocol and the German navy’s own official prize regulations to halt, board, and remove the passengers, crew, and ship’s papers of merchant vessels before sinking them were abandoned. At the September 23 conference with Raeder the Führer had made plain his intention to do so; he was only waiting to see for sure “if the war against France and England has to be fought out to the finish.” Hitler suggested various pretexts. Merchant ships definitely identified as British or French could be fired upon without warning “since it may be assumed they are armed.” He cautioned that “the notorious expression ‘unrestricted submarine warfare’ is to be avoided”; instead, the phrase “the siege of England” would be used, as a way to “free us from having to observe any restrictions whatsoever on account of objections based on International Law.” To avert international criticism, “a neutral ship should occasionally be treated especially well in order to show that the system has not been fundamentally altered.”
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