Enigma (35 page)

“Nobody can split a hair f-finer than F-Frank,” said Pinker,
admiringly.

“‘The presumption that the onus is on us to make a moral
choice,’ ” repeated Puck. He smiled across the table at Jericho.
“How very Cambridge. Excuse me. I think I must visit the
lavatory.”

He made his way towards the back of the hut. Kingcome and
Proudfoot returned to their chess game. Atwood picked up Herodas.
Baxter fiddled with his cigarette-rolling machine. Pinker closed
his eyes. Jericho leafed through the Short Signal Code Book and
thought of Claire.

♦

Midnight came and went without a sound from the North Atlantic
and the tension which had been building all evening began to
slacken.

The 2 a.m. offering from the cooks of the Bletchley Park canteen
was enough to make even Mrs Armstrong blanch—boiled potatoes in
cheese sauce with barracuda, followed by a pudding made from two
slices of bread stuck together with jam and then deep-fried in
batter—and by four, the digestive effects of this, combined with
the dim light in Hut 8 and the fumes from the paraffin heater, were
casting a soporific pall over the naval cryptanalysts.

Atwood was the first to succumb. His mouth dropped open and the
top plate of his dentures came loose so that he made a curious
clicking sound as he breathed. Pinker wrinkled his nose in disgust
and went off to make a nest for himself in the corner, and soon
afterwards Puck, too, fell asleep, his body bent forwards, his left
cheek resting on his forearms on the table. Even Jericho, despite
his determination to stand guard over the cryptograms, found
himself slipping over the edge of unconsciousness. He pulled
himself back a couple of times, aware of Baxter watching him, but
finally he couldn’t fight it any longer and he slid into a
turbulent dream of drowning men whose cries sounded in his ears
like the wind in the aerial farm.

∨
Enigma
∧

STRIP

STRIP: to remove one layer of encipherment from a
cryptogram which has been subjected to the process of
super-encipherment (US, gv) ⁄ i.e., a message which has been
enciphered once, and then re-enciphered to provide double
security.

A Lexicon of Cryptography (“Most Secret”, Bletchley
Park, 1943)

LATER, IT WOULD transpire that Bletchley Park knew almost
everything there was to know about U-653.

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 Kapitanleutnant 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 13
th
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 OP WATCH OFFICER
SHOULD NOT HAVE BEEN SENT UNTIL W⁄T SILENCE WAS BROKEN BY GENERAL
CONTACT WITH ENEMY.

It was only on the 23
rd
, after nearly four weeks
at sea, that Feiler redeemed himself by at last making contact with
a convoy. At 6 a.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 25
th
, Feiler radioed his position. On the
26
th
, 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 6
th
, Feiler was ordered into station in a
new patrol line, code-named Kaubgraf (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 Raubgraflme, 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.

§

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 started.” 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?”

“BD1491.”

“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?”