Seizing the Enigma (35 page)

“What?” replied Wilson. “All this rubbish?”

But Bacon wanted it all, so Wilson told his men to get on with it, ordering Kelly to collect every piece of paper with writing on it. The sailors kept asking Wilson, “What do you want all this rubbish for?” As he perched on a stool in the chart house, they reported to him on the food they found in the refrigerator and the sealskins that were curing in barrels. Kelly told them not to turn on any other lights for fear of a booby trap. After about an hour on board, they had collected thirteen mail sacks full of documents, together with photographs of Hitler and Raeder. Kelly liberated the lamp from Captain Gewald’s cabin. The three small deck guns were removed with their ammunition, as well as the small arms and radio equipment. Everything went back to the
Tartar.

Admiral Burrough had decided not to bring the captured trawler back to Britain with him. He did not wish to immobilize a destroyer to escort her, and he feared that if a German aircraft sighted her with a destroyer or on a strange course, much of the value of the intelligence gained might be lost. The
Lauenburg
’s crew, the rest of whom had been picked up by the
Bedouin
, had been taken below at once so that they could not see what was happening to their ship. When Bacon said he was satisfied that the trawler had been thoroughly searched, Burrough ordered her sunk. The
Tartar
sent torpedomen aboard with scuttling charges. But they failed to explode, and the torpedomen’s rivals, the gun crews, shouted their derision. Then it was their turn, and at a range of 500 yards Kelly’s men slammed four semi-armor-piercing shells from B turret into the
Lauenburg
at the waterline. At 9
P.M.
, in thick fog, the ill-fated ship descended to a grave a thousand fathoms deep. Gewald was brought to the
Tartar
and put in a cabin over the propellers. Kelly gave him a light, and he lit up a cigar, greatly enjoying the first drag.

Bacon had the mail sacks brought to Captain Skipwith’s main cabin, a room larger than his sea cabin and one that sometimes served as a surgeon’s operating room. There Bacon sorted the captured
documents and pieces of paper. Among the vast volume of charts and orders and gun manuals, he found what he was looking for: a table for the July home waters Enigma key, plus two sheets for the plugboard, one for July 1 to 15, one for July 16 to 31, and a sheet of internal settings.

The
Tartar
and the other ships arrived back at Scapa two days later. Bacon was taken to the
Dunluce Castle
, a forty-year-old passenger ship converted into a depot ship that was a regular stop for the ferry that made the hour-long trip across Pentland Firth to the railhead at Thurso on the Scottish mainland. From there, carrying his precious documents in a big canvas bag, he rode to Rosyth, the major naval base near Edinburgh, where a scrambler telephone enabled him to call Bletchley and tell the cryptanalysts what he had and when he would be arriving. He took the night train.

Hinsley and the naval cryptanalysts assembled, and early on Wednesday, July 2, Bacon came in with his canvas bag, flung it on the table, and opened it. “Here it is,” he said. They all had a look, and within five minutes the cryptanalysts had taken the documents to Hut 8 next door. These papers would enable them to read July messages and so were immediately useful. At once the solution times fell. From about forty hours on July 1, to which they had risen when the
München
’s June keys had expired, they fell on the afternoon of July 2 to under three hours. Hinsley felt pleased that it had all worked out so well. But he couldn’t allow himself to wallow in self-congratulation. He had work to do.

T
HE CAPTURED DOCUMENTS FROM THE
U-110
AND THE TWO
weather ships and the subsequent acceleration of solutions had no immediate direct effect on the Battle of the Atlantic. In June 1941, when solution times declined to three or four hours, roughly the same number of tons succumbed to U-boats as in May, when solution times ran three or four days. The same situation obtained in July and August, with their respectively fast and slow solution times. In fact, in the fast-solution months of June and July, U-boats sank almost exactly the same tonnage in the North Atlantic as in the slow-solution months of May and August. As these comparisons demonstrate, intelligence did not always rule in the war against the U-boats. Other factors outweighed it. The July–August loss of tonnage fell to under a third of the May–June figure for reasons unrelated to B.P. More escorts were available and were accompanying convoys uninterruptedly across the Atlantic. The escorts’ experience made them more efficient. The minimum speed of ships sailing independently was raised from 13 to 15 knots. Air cover was increased. Also fewer U-boats were in the North Atlantic because some had been withdrawn to fight shipping to the Soviet Union, the new U-boat crews were less experienced, and Hitler was anxious to avoid clashes with American warships.

But in spite of the failure of codebreaking intelligence to contribute much to the Atlantic battle at that time, its potential to do so
still seemed great. It might yet permit diverting convoys away from the U-boat wolfpacks that became ever more likely as the Germans built more and more submarines. So Hinsley, and Hut 8, continued their efforts.

And bit by bit they were rewarded. The insight gained into German naval communications procedures and the capture of the Short Signal Book from the U-110 enabled the Hut 8 cryptanalysts to concoct and test cribs more efficiently. They were aided by the growing number of kisses, especially in the Dockyard Cipher and in weather systems.

Conditions were further improved by an influx of men and machines. The number of bombes rose to eight by the end of June. All of this meant that after the first week in August, when cryptanalysis resumed, Hut 8 had mastered the Home Waters key. Its messages were at first not read currently, but after mid-August they were solved every day, most of them within thirty-six hours.

This success was made the sweeter by appreciatory visits to Bletchley Park. The first sea lord, Admiral Sir Dudley Pound, passed through on August 9, and a month later the great man himself, Prime Minister Churchill, appeared.

He had long been intensely interested in the results of code-breaking. It was into his hands that the Russian naval attaché had placed the
Magdeburg
codebook in October 1914, and he had witnessed the first successes it brought the Royal Navy. In November 1924, when he had just become chancellor of the exchequer following a Conservative landslide, he pleaded with the foreign secretary to be allowed to see the intercepts. “I have studied this information over a long period and more attentively than probably any other Minister has done,” he wrote. “… I attach more importance to them as a means of forming a true judgement of public policy in these spheres than to any other source of knowledge at the disposal of the State.” In September 1940, four months after he became prime minister, Churchill ordered that he be given “daily all Enigma messages.” This proved impracticable,
but by the summer of 1941 he was getting each day a selection of several dozen, together with reports on the progress of cryptanalyses, brought to him in a special dispatch box, buff-colored to distinguish it from the black boxes for other official papers. The box was to be unlocked only by Churchill, who carried the key on his key ring. Extremely watchful about access to these papers, he minuted once: “I am astounded at the vast congregation who are invited to study these matters,” and he urged restrictions. This source of information was disguised at first under the codename
BONIFACE
, but later
ULTRA
came to be used as the collective cover name for the solutions of the Enigma intercepts. With those in the know, he used the solutions vigorously. He discussed them at his daily meetings with his chiefs of staff, fired off messages based on them to his field commanders, and in general used them to the maximum in running the war.

So on Saturday, September 6, 1941, as Churchill was driving to a friend’s country estate for the weekend, he stopped off at Bletchley Park. Some thirty to forty of the higher-level workers gathered around him on the grass as he stood on the trunk of a felled tree near Hut 6 and said, in his incomparable tones, and with a mischievous twinkle in his eye, “You all look very innocent.” The grateful and security-conscious prime minister praised them as the geese that laid the golden eggs and never cackled. He related a few stories of how their work had helped him and emphasized the great value of their accomplishments. Then he visited a few of the huts. In Naval Section, where a nervous Alan Turing was introduced to him, he was shown as a prize exhibit the Dockyard-Enigma kisses.

Gordon Welchman had, upon instructions, prepared a five-minute talk. He began, “I would like to make three points.” He had completed only two when G.C.&C.S.’s second in command, Commander Edward Travis, interrupted: “That’s enough, Welchman.” Churchill winked at the speaker and said, “I think there was a third point, Welchman.” Welchman presented John Herivel to Churchill as one of the solvers of Enigma. Herivel was thrilled.

Word of the visit raced through the Park. Those not present at the prime minister’s speech heard that he had said “something great.” The episode boosted morale. It was just as well that the Bletchleyites did not hear his remark to Sir Stewart Menzies, who as head of the Secret Intelligence Service was formally the director of G.C.&C.S., after viewing the unkempt crew of workers: “I know I told you to leave no stone unturned to find the necessary staff, but I didn’t mean you to take me so literally!”

In addition to lifting spirits, the visit had a more significant effect. Back in April, the
Kriegsmarine
had slightly modified the Home Waters key for U-boats, probably to keep other German units from eavesdropping on submarine messages. This gave Hut 8 no trouble. In October, however, the navy set up a separate U-boat message cipher net called
TRITON
, which delayed the British solutions a little. The extra work entailed in solving the new settings perhaps contributed to the overworking of the punched-card section of Hut 8, compelling it to cut out night shifts. This delayed the recovery of any naval keys by at least twelve hours every day. To this serious problem were added others: failure to supply enough women to work on the bombes and insufficient personnel to decipher a Luftwaffe key for North Africa, which was providing data about General Erwin Rommel’s air unit’s order of battle, supplies, and tactical policy—all of great value as Britain was preparing an offensive. Yet no one seemed to be doing anything about these problems.

So around the middle of October, emboldened by Churchill’s visit, Welchman, acting head of Hut 6, which solved German army and air force messages, gathered three other middle managers to discuss the possibility of appealing over Denniston’s head to the prime minister himself. The others were Alan Turing, head of Hut 8; Hugh Alexander, Turing’s deputy; and Stuart Milner-Barry, Welchman’s deputy and an old and close chess-playing friend of Alexander’s. They may have met first at the Shoulder of Mutton Pub, where Milner-Barry and Alexander lived, but most of the subsequent discussions took place
in Hut 6. All agreed with Welchman’s plan, and Welchman, who spent much of his time writing powerful memoranda that he called “screeds,” drafted the letter.

“Dear Prime Minister,” it began. “Some weeks ago you paid us the honour of a visit, and we believe that you regard our work as important.” The letter made plain that Travis, Denniston’s deputy, was not to blame for the problems, pointing out that Travis had kept them well supplied with bombes and “has all along done his utmost.”

We think, however, that you ought to know that this work is being held up, and in some cases is not being done at all, principally because we cannot get sufficient staff to deal with it. Our reason for writing to you direct is that for months we have done everything that we possibly can through the normal channels, and that we despair of any early improvement without your intervention. No doubt in the long run these particular requirements will be met, but meanwhile still more precious months will have been wasted, and as our needs are continually expanding we see little hope of ever being adequately staffed. … as we are a very small section with numerically trivial requirements it is very difficult to bring home to the authorities finally responsible either the importance of what is done here or the urgent necessity of dealing promptly with our requests.

The letter then set out three areas where staff shortages were delaying work: recovery of naval Enigma keys, solution of Africa Luftwaffe keys, and bombe work. The four manager-cryptanalysts implied that Denniston could not solve these problems when they stated that “we have written this letter entirely on our own initiative” and concluded by saying that “if we are to do our job as well as it could and should be done, it is absolutely vital that our wants, small as they are, should be promptly attended to.”