Enigma
They knew she was a Type VIIc – 220 feet long, 20 feet wide, with a submerged displacement of 871 tons and a surface range of 6,500 miles – and that she had been manufactured by the Howaldts Werke of Hamburg, with engines by Blohm und Voss. They knew she was eighteen months old, because they had broken the signals describing her sea-trials in the autumn of 1941. They knew she was under the command of Kapitänleutnant Gerhard Feiler. And they knew that on the night of 28 January 1943 – the final night, as it happened, that Tom Jericho had spent with Claire Romilly – U-653 had slipped her moorings at the French naval port of Saint-Nazaire and had moved out under a dark and moonless sky into the Bay of Biscay to begin her sixth operational tour.
After she had been at sea for a week, the cryptanalysts in Hut 8 broke a signal from U-boat headquarters – then still in their grand apartment building off the Bois de Boulogne in Paris – ordering U-653 to proceed on the surface to naval grid square KD 63 ‘AT MAXIMUM MAINTAINABLE SPEED WITHOUT REGARD TO THE THREAT FROM THE AIR’.
On 11 February she joined ten other U-boats in a new mid-Atlantic patrol line code-named Ritter.
Weather conditions in the North Atlantic were particularly foul in the winter of 1942–3. There were a hundred days when the U-boats reported winds topping force 7 on the Beaufort scale. Sometimes the gales reached over 100 miles per hour, whipping up waves more than 50 feet high. Snow, sleet, hail and frozen spray lashed submarines and convoys alike. One Allied ship rolled over and sank in minutes simply from the weight of ice on her superstructure.
On 13th February, Feiler broke radio silence to report that his watch officer, one Leutnant Laudon, had been washed overboard – a blatant disregard of operational procedure on Feiler’s part which brought no condolences but a terse rebuke from his controllers, broadcast to the entire submarine fleet:
FEILER’S MESSAGE ABOUT LOSS OF WATCH OFFICER SHOULD NOT HAVE BEEN SENT UNTIL W/T SILENCE WAS BROKEN BY GENERAL CONTACT WITH ENEMY.
It was only on the 23rd, after nearly four weeks at sea, that Feiler redeemed himself by at last making contact with a convoy. At 6 p.m. he dived to avoid an escorting destroyer, and then, when night came, rose to attack. He had at his disposal twelve torpedoes, each 23 feet long with its own electric motor, capable of running through a convoy, turning in a half circle and running back, turning again and so on, and on, until either its power ran out or a ship was sunk. The sensing mechanism was crude; it was not unknown for a U-boat to find itself being pursued by its own armaments. They were called FATs: Flachenabsuchendertorpedos, or ‘shallow searching torpedoes’. Feiler fired four of them.
FROM: FEILER
IN NAVAL GRID SQUARE BC 6956 AT 0116. FOUR-FAN AT A CONVOY PROCEEDING ON A SOUTHERLY COURSE AT 7 KNOTS. ONE STEAMSHIP OF 6,000 GROSS REGISTERED TONS: LARGE EXPLOSION AND A CLOUD OF SMOKE, THEN NOTHING MORE SEEN. ONE STEAMSHIP OF 5,500 GRT LEFT BURNING. 2 FURTHER HITS HEARD, NO OBSERVATIONS.
On the 25th, Feiler radioed his position.
On the 26th, his luck turned bad again.
FROM: U-653
AM IN NAVAL GRID SQUARE BC 8747. HIGH PRESSURE GROUP 2 AND STARBOARD NEGATIVE BUOYANCY TANK UNSERVICEABLE. BALLAST TANK 5 NOT TIGHT. IS MAKING ODD NOISES. DIESEL PRODUCING DENSE WHITE SMOKE.
Headquarters took all night to consult its engineers and replied at ten the following morning.
TO: FEILER
THE CONDITION OF BALLAST TANK NO 5 IS THE ONLY THING WHICH MAY ENFORCE RETURN PASSAGE. DECIDE FOR YOURSELF AND REPORT.
By midnight, Feiler had made his decision.
FROM: U-653
AM NOT RETURNING.
On 3 March, in mountainous seas, U-653 came alongside a U-boat tanker and took on board 65 cubic metres of fuel and provisions sufficient for another fourteen days at sea.
On the 6th, Feiler was ordered into station in a new patrol line, code-named Raubgraf (Robber Baron).
And that was all.
On 9 March the U-boats abruptly changed their Weather Code Book, Shark was blacked out, and U-653, along with one hundred and thirteen other German submarines then known to be operating in the Atlantic, vanished from Bletchley’s view.
At 5 a.m. GMT on Tuesday 16 March, some nine hours after Jericho had parked the Austin and walked into Hut 8, U-653 was heading due east on the surface, returning to France. In the North Atlantic it was 3 a.m.
After ten days on station in the Raubgraf line, with no sign of any convoy, Feiler had finally decided to head for home. He had lost, along with Leutnant Laudon, four other ratings washed overboard. One of his petty officers was ill. The starboard diesel was still giving trouble. His one remaining torpedo was defective. The boat, which had no heating, was cold and damp, and everything – lockers, food, uniforms – was covered in a greenish-white mould. Feiler lay on his wet bunk, curled up against the cold, wincing at the irregular beat of the engine, and tried to sleep.
Up on the bridge, four men made up the night watch: one for each point of the compass. Cowled like monks in dripping black oilskins, lashed to the rail by metal belts, each had a pair of goggles and a pair of Zeiss binoculars clamped firmly to his eyes and was staring blindly into his own sector of darkness.
The cloud cover was ten-tenths. The wind was a steel attack. The hull of the U-boat thrashed beneath their feet with a violence that sent them skidding over the wet deck plates and knocking into one another.
Facing directly ahead, towards the invisible prow, was a young Obersteurmann, Heinz Theen. He was peering into such an infinity of blackness that it was possible to imagine they might have fallen off the edge of the world, when suddenly he saw a light. It flared out of nowhere, several hundred yards in front of him, winked for two seconds, then disappeared. If he hadn’t had his binoculars trained precisely upon it, he would never have seen it.
Astonishing though it seemed, he realised he had just witnessed someone lighting a cigarette.
An Allied seaman lighting a cigarette in the middle of the North Atlantic.
He called down the conning tower for the captain.
By the time Feiler had scrambled up the slippery metal ladder to the bridge thirty seconds later the cloud had shifted slightly in the high wind and shapes were moving all around them. Feiler swivelled through 360 degrees and counted the outlines of nearly twenty ships, the nearest no more than 500 yards away on the port side.
A whispered cry, as much of panic as command: ‘Alarrrmm!’
The U-653 came out of her emergency dive and hung motionless in the calmer water beneath the waves.
Thirty-nine men crouched silently in the semidarkness listening to the sounds of the convoy passing overhead: the fast revs of the modern diesels, the ponderous churning of the steamers, the curious singing noises of the turbines in the warship escorts.
Feiler let them all go by. He waited two hours, then surfaced.
The convoy was already so far ahead as to be barely visible in the faint dawn light – just the masts of the ships and a few smudges of smoke on the horizon, and then, occasionally, when a high wave lifted the U-boat, the ironwork of bridges and funnels.
Feiler’s task under standing orders was not to attack – impossible in any case, given his lack of torpedoes – but to keep his quarry in sight while drawing in every other U-boat within a radius of 100 miles.
‘Convoy steering 070 degrees,’ said Feiler. ‘Naval grid square BD 1491.’
The first officer made a scrawled note in pencil then dropped down the conning tower to collect the Short Signal Code Book. In his cubbyhole next to the captain’s berth the radioman pressed his switches. The Enigma came on with a hum.
2
At 7 a.m., Logie had sent Pinker, Proudfoot and Kingcome back to their digs to get some decent rest. ‘Sod’s law will now proceed to operate,’ he predicted, as he watched them go, and sod’s law duly did. Twenty-five minutes later, he was back in the Big Room with the queasy expression of guilty excitement which would characterise the whole of that day.
‘It looks like it may have st
arted.’
St Erith, Scarborough and Flowerdown had all reported an E-bar signal followed by eight Morse letters, and within a minute one of the Wrens from the Registration Room was bringing in the first copies. Jericho placed his carefully in the centre of his trestle table.
RGHC DMIG. His heart began to accelerate.
‘Hubertus net,’ said Logie. ‘4601 kilocycles.’
Cave was listening to someone on the telephone. He put his hand over the mouthpiece. ‘Direction finders have a fix.’ He clicked his fingers. ‘Pencil. Quick.’ Baxter threw him one. ‘49.4 degrees north,’ he repeated. ‘38.8 degrees west. Got it. Well done.’ He hung up.
Cave had spent all night plotting the convoys’ courses on two large charts of the North Atlantic – one issued by the Admiralty, the other a captured German naval grid, on which the ocean was divided into thousands of tiny squares. The cryptanalysts gathered round him. Cave’s finger came down on a spot almost exactly midway between Newfoundland and the British Isles. ‘There she is. She’s shadowing HX-229.’ He made a cross on the map and wrote 0725 beside it.
Jericho said: ‘What grid square is that?’
‘BD 1491.’
‘And the convoy course?’
‘070.’
Jericho went back to his desk and in less than two minutes, using the Short Signal Code Book and the current Kriegsmarine address book for encoding naval grid squares (‘Alfred Krause, Blucherplatz 15’: Hut 8 had broken that just before the blackout) he had a five-letter crib to slide under the contact report.
R G H C D M I G
D D F G R X ? ?
The first four letters announced that a convoy had been located steering 070 degrees, the next two gave the grid square, the final two represented the code name of the U-boat, which he didn’t have. He circled R-D and D-R. A four-letter loop on the first signal.
‘I get D-R/R-D,’ said Puck a few seconds later.
‘So do I.’
‘Me too,’ said Baxter.
Jericho nodded and doodled his initials on the pad. ‘A good omen.’
After that, the pace of events began to quicken.
At 8.25, two long signals were intercepted emanating from Magdeburg, which Cave at once surmised would be U-boat headquarters ordering every submarine in the North Atlantic into the attack zone. At 9.20, he put down the telephone to announce that the Admiralty had just signalled the convoy commander with a warning that he was probably being shadowed. Seven minutes later, the telephone rang again. Flowerdown intercept station. A second E-bar flash from almost the same location as the first. The Wrens hurried in with it: KLYS QNLP.
‘The same hearse,’ said Cave. ‘Following standard operating procedure. Reporting every two hours, or near as damn it.’
‘Grid square?’
‘The same.’
‘Convoy course?’
‘Also the same. For now.’
Jericho went back to his desk and manipulated the original crib under the new cryptogram.
K L Y S Q N L P
D D F G R X ? ?
Again, there were no letter clashes. The golden rule of Enigma, its single, fatal weakness: nothing is ever itself – A can never be A, B can never be B … It was working. His feet performed a little tap dance of delight beneath the table. He glanced up to find Baxter staring at him and he realised, to his horror, that he was smiling.
‘Pleased?’
‘Of course not.’
But such was his shame that when, an hour later, Logie came through to say that a second U-boat had just sent a contact signal, he felt himself personally responsible.
SOUY YTRQ.
At 11.40, a third U-boat began to shadow the convoy, at 12.20, a fourth, and suddenly Jericho had seven signals on his desk. He was conscious of people coming up and looking over his shoulder – Logie with his burning hayrick of a pipe and the meaty smell and heavy breathing of Skynner. He didn’t look round. He didn’t talk. The outside world had melted for him. Even Claire was just a phantom now. There were only the loops of letters, forming and stretching out towards him from the grey Atlantic, multiplying on his sheets of paper, turning into thin chains of possibility in his mind.
They didn’t stop for breakfast, nor for lunch. Minute by minute, throughout the afternoon, the cryptanalysts followed, at third hand, the progress of the chase two thousand miles away. The commander of the convoy was signalling to the Admiralty, the Admiralty had an open line to Cave, and Cave would shout each time a fresh development looked like affecting the hunt for cribs.
Two signals came at 13.40 – one a short contact report, the other longer, almost certainly originating from the U-boat that had started the hunt. Both were for the first time close enough to be fixed by direction finders on board the convoy’s own escorts. Cave listened gravely for a minute, then announced that HMS Mansfield, a destroyer, was being dispatched from the main body of merchantmen to attack the U-boats.
‘The convoy’s just made an emergency turn to the southeast. She’s going to try to shake off the hearses while Mansfield forces them under.’
Jericho looked up. ‘What course is she steering?’
‘What course is she steering?’ repeated Cave into the telephone. ‘I said,’ he yelled, ‘what fucking course is she steering?’ He winced at Jericho. The receiver was jammed tight to his scarred ear. ‘All right. Yes. Thank you. Convoy steering 118 degrees.’ Jericho reached for the Short Signal Code Book.
‘Will they manage to get away?’ asked Baxter.
Cave bent over his chart with a rule and protractor. ‘Maybe. It’s what I’d do in their place.’
A quarter of an hour passed and nothing happened.
‘Perhaps they have done it,’ said Puck. ‘Then what do we do?’
Cave said: ‘How much more material do you need?’
Jericho counted through the signals. ‘We’ve got nine. We need another twenty. Another twenty-five would be better.’
‘Jesus!’ Cave regarded them with disgust. ‘It’s like sitting with a flock of carrion.’
Somewhere behind them a telephone managed half a ring before it was snatched out of its cradle. Logie came in a moment later, still writing.
‘That was St Erith reporting an E-bar signal at 49.4 degrees north, 38.1 degrees west.’
‘New location,’ said Cave, studying his charts. He made a cross, then threw his pencil down and leaned back in his chair, rubbing his face. ‘All she’s managed to do is run straight from one hearse into another. Which is what? The fifth? Christ, the sea must be teeming with them.’
‘She isn’t going to get away,’ said Puck, ‘is she?’
‘Not a chance. Not if they’re coming in from all around her.’
A Wren moved among the cryptanalysts, doling out the latest cryptogram: BKEL UUXS.
Ten signals. Five U-boats in contact.
‘Grid square?’ said Jericho.
Hester Wallace was not a poker player, which was a mistake on her part as she had been blessed with a poker face that could have made her a fortune. Nobody watching her wheel her bicycle into the shed beside the canteen that afternoon, or seeing her flick her pass at the sentry, or squeezing up against the corridor wall in Hut 6 to let her march by, or sitting opposite her in Intercept Control – nobody would have guessed the turmoil in her mind.
Her complexion was, as ever, pale, her forehead slightly creased by a frown that discouraged conversation. She wore her long, dark hair like a headache, savagely twisted up and speared. Her costume was the usual uniform of the West Country schoolmistress: flat shoes, grey woollen stockings, plain grey skirt, white shirt and an elderly but well-cut tweed jacket which she would shortly take off and hang over the back of the chair, for the afternoon was warm. Her fingers moved across the blist in a short, staccato pecking motion. She had hardly slept all night.
Name of intercept station, time of interception, frequency, call sign, letter groups …
Where was the record of settings kept? That was the first
matter to determine. Not in Control, obviously. Not in the Index Room. Not in the Registry. And not next door in the Registration Room, either: she had already made a quick inspection there. The Decoding Room was a possibility, but the Type-X girls were always complaining they were cramped for space, and sixty separate Enigma keys, their settings changed daily – in the case of the Luftwaffe, sometimes twice a day – well, that was a minimum of five hundred pieces of information every week, 25,000 in a year, and this was the war’s fourth year. That would suggest a sizeable catalogue; a small library, in fact.
The only conclusion was that they had to be kept where the cryptanalysts worked, in the Machine Room, or else close by.
She finished blisting Chicksands, noon till three, and moved towards the door.
Her first pass through the Machine Room was spoiled by nerves: straight through it to the other end of the hut without even glancing from side to side. She stood outside the Decoding Room, cursing her fears, pretending to study the noticeboard. With a shaking hand she made a note about a performance of Die Fledermaus by the Bletchley Park Music Society which she had no intention of ever attending.
The second run was better.
There was no machinery in the Machine Room – the origin of its name was lost in the glorious mists of 1940 – just desks, cryptanalysts, wire baskets filled with signals and, on the wall to the right, shelf after shelf of files. She stopped and looked around distractedly, as if searching for a familiar face. The problem was, she knew nobody. But then her gaze fell upon a bald head with a few long, ginger hairs combed pathetically across a freckled crown, and she realised that wasn’t entirely true.
She knew Cordingley.
Dear old, dull old Donald Cordingley, the winner – in a crowded field – of the Dullest Man in Bletchley contest. Ineligible for military service due to a funnel chest. By profession: actuary. Ten years’ service with the Scottish Widows Assurance Society in the City of London, until a lucky third place in the Daily Telegraph crossword competition won him a seat in the Hut 6 Machine Room.
Her seat.
She watched him for a few more seconds, then moved away.