Seizing the Enigma (4 page)

But the U-94 had submerged and sneaked between two other columns. Between 7:09 and 7:11, she fired three single shots from her bow tubes and one from her stern tube. The latter missed, but the bow torpedoes struck, almost simultaneously, the big British steamer
Ixion
and the Norwegian
Eastern Star
, a 5,600-tonner, both carrying Scotch whisky. The two ships burst into flames and began sinking. When the U-94’s skipper came to periscope depth to see what he had done, a lookout on the sloop
Rochester
spotted the periscope in the smooth sea at almost the same time that the destroyer
Amazon
gained asdic contact. The
Bulldog
led the depth-bomb attack, which damaged the U-94’s hydroplanes and some gauges. But despite a lengthy hunt, the submarine escaped. The crews of the sunk steamers were rescued, along with a number of cases of Vat 69 Scotch which were perhaps later issued to the seamen for medicinal purposes.

By 11
P.M
. the convoy was back to its normal routine, as were the screening vessels, their watches broken only by the continuous pinging of the asdics and the periodic ringing of the zigzag clocks, which told the helmsman when to zig and when to zag to confuse the U-boats. Baker-Cresswell spent the next day, Thursday, in an unsuccessful search for the U-boat. He felt sure he had driven it off, and the Admiralty sent no more warnings.

In U-boat headquarters, however, Admiral Dönitz was planning another move. He knew that during the spring of 1941 the range of convoy protection had expanded to the west as the number of escort destroyers grew. He had consequently sent his submarines farther west to attack convoys where they were still unprotected. Dönitz estimated the limit of escort protection at between 25° and 30° west longitude. Thus, in the first eighteen months of the war, U-boats sank
only eight Allied ships west of 25°, but in the next two months, March and April 1941, they sank twenty-four. Now, on Thursday, May 8, Dönitz moved some of his northern boats west. They joined the U-110, which had already arrived south of Iceland. Its commander was twenty-eight-year-old Lieutenant Fritz-Julius Lemp.

Lemp was one of the German navy’s most successful U-boat commanders. A jaunty young man with pudgy cheeks, he had joined the navy in 1931 at age eighteen. At the outbreak of the war, he commanded the U-30, a three-year-old Type VIIA, the
Kriegsmarine
’s principal operating submarine, known for its excellent performance.

On the very first day of the war with Britain, Lemp became the first U-boat captain to sink an enemy ship. But this opening of the Battle of the Atlantic harmed Germany more than it helped her. For Lemp had torpedoed the unarmed passenger liner
Athenia
, which he had apparently mistaken for an armed auxiliary cruiser. The loss of 118 lives and the apparent flouting of a Hague convention convinced Britain that Germany had resumed the unrestricted submarine warfare of World War I; consequently she at once initiated all measures against this aggression.

Lemp made eight cruises in the U-30. In August 1940, after an especially successful cruise, he was acclaimed for having put a torpedo into the battleship
Barham
and for having sunk, it was claimed, nine ships. (The actual number was six; U-boat captains, like fighter pilots, continually overestimated successes.) Dönitz, who seems to have had a soft spot for Lemp, awarded him the Knight’s Cross to the Iron Cross.

In November, Lemp commissioned the U-110, one of the new large Atlantic Type IXB boats. The submarine, 252½ feet long and displacing 1,050 tons, could cruise for 12,400 miles. Top speed was 18.2 knots on the surface, 7.3 submerged. It carried twenty-two torpedoes, could submerge in about half a minute, and could dive to 330 feet.

Most of the enlisted men were new, having just come from their various training schools. Lemp brought two of his three officers with him from the U-30. The exception was his second in command, Lemp’s cousin, who was not popular with the crew members. They regarded him as a Jonah because two of his ships had been sunk under him. With 4 officers, 15 noncoms, and 27 seamen, the crew totaled 46. Lemp made a good impression on the men. He was open, avoided spit and polish, and knew how to weld them together He didn’t throw his weight around, but it was clear that he was the boss. The Knight’s Cross gained him automatic respect. The men believed they were serving under one of the best commanders in one of their country’s most important forces.

Because of trouble in the U-110’s diesels, she did not sail on her maiden war patrol until March 9, 1941. As she searched the vast wastes of the North Atlantic for prey, the seamen stood four-hour watches, the machinists six-hour. Though it was a scramble to eat and sleep in the four hours off, the watches were often boring. Excitement came only during the rare spurts of action. During her first cruise, the U-110 sank two ships. Lemp used the classic tactic of slipping between the first and second columns of a convoy at night, firing torpedoes from the bow at one column and from the stern at another, and then diving deep to avoid the expected attack.

One of Lemp’s log entries reveals his thoughtless enthusiasm:

16.3 [1941] 0022. Tanker passes within 100 meters.… Stern shot.… Hit. Tanker flies in the air with a great flash and is atomized.… Night lit up like day by the light of the fires of exploding tankers. U-boat stays between tanker and destroyer 3,000 meters [2 miles] away in the middle of the convoy as if in a spotlight. Since destroyer turns toward U-boat with big bow wave, emergency dive.

During the depth-bomb attack that followed, Lemp showed his leadership. Often he would give an order just to let the crew hear the
lack of anxiety in his voice. His calmness soothed the younger men. And the boat survived.

Another log entry a week later indicates his honesty and self-confidence. After missing three shots, the last at only 500 yards, “(1) Out of mistrust of torpedoes, (2) out of fury, I order an artillery attack.” But one of the seamen had forgotten to remove the muzzle tampion from the 4.1-incher, and when the gun was fired, it exploded and damaged the U-boat. No longer able to dive fast, the U-110 was ordered back to Lorient, on the Atlantic coast of France, for repairs; after its return Dönitz visited the boat and awarded the Iron Cross to several crew members.

Following two weeks of repairs and furlough, the U-110 sailed again on April 15. The next day, Dönitz radioed the location of her operating area. He was hoping to concentrate the nine U-boats then in the North Atlantic against the convoys. Experience had shown that having one of the subs command the others on the spot did not work; the lead submarine sometimes had to submerge and so lost contact with the rest. Control had to be exercised from Dönitz’s headquarters in France. This required constant radio communications, all enciphered in the Enigma machine. The responsibility for both ciphering and communicating fell on each U-boat’s radiomen.

Of the four radiomen aboard the U-110, the most junior was Radioman Third Class Heinz Wilde. Open-faced and friendly, he had been a radio amateur as a teenager in Breslau before the war. A naval officer had come to one of his club’s meetings in 1937 and persuaded many of the members to join the navy. Wilde entered on November 1, 1939. After basic training, he went to the naval communications school at Flensburg, close to the Danish border. Here he deepened his knowledge of radio, and here he was introduced to the Enigma cipher machine. The instructors boasted that the machine was the best and couldn’t be solved. This emphasis on the machine’s unparalleled cryptographic security, Wilde thought, led many students to think its physical security not so terribly important. Wilde, the best
in his class, was assigned to U-boats; after specialized submarine training, including instruction in acoustic detection, he was assigned to the U-110.

There, in the closetlike radio room, he stood four-hour watches, chatting or reading a book and playing phonograph records over the loudspeaker system for the crew while listening for a signal through the whistlings, peepings, and static that filled his earphones. As soon as he heard the tone of the transmitter, he would turn down the phonograph, stop talking or reading, and begin taking down the Morse message. All messages were taken down, even those addressed to other U-boats; all were deciphered and given to the captain. The locations of other submarines and of convoys were entered on charts. Wilde never received more than four messages on a watch; sometimes none came in. To minimize the number of transmissions and to eliminate clues to its location, a U-boat did not signal receipt of a message. Garbled transmissions, which are difficult or impossible to decipher, were relatively rare; to ensure that important messages were not missed, U-boat headquarters repeated each one half an hour to an hour after the first transmission. During an action, the radioman worked the listening apparatus. This array of hydrophones gave the range and bearing of sound sources, such as torpedo explosions and attacking enemy warships; Wilde thought the data it yielded were imprecise.

On April 21, the day after the U-110 reached the waters west of Ireland where she would begin her patrol, Dönitz radioed her an attack location, AL58 on the
Kriegsmarine
grid, 400 miles west of Ireland’s west coast. The next day, Dönitz ordered “Attack!” Three days later, Lemp sank a 2,500-ton ship steaming alone. He missed on April 28 with a single shot on a fishing trawler. Dönitz moved the U-110 south, then north, then west over the eastern Atlantic, perhaps on the basis of German codebreaking that told him where convoys might be.

On Thursday, May 8, Lemp saw smoke and the mast of a warship. Coming up on her starboard, he discovered that she was escorting a slow-moving convoy heading west at 7 or 8 knots. He transmitted a sighting report, which was intercepted by the British Admiralty. It determined the location of the transmitter by a direction-finding fix, then compared the location with its plot of convoys at sea. At 7:07
P.M
., Greenwich mean time, the Admiralty warned OB 318 that it was being shadowed. The convoy altered course 30° to port, away from the U-110.

At about the same time, Dönitz ordered other U-boats to report their positions and directed Lemp to maintain contact with OB 318 and to attack if possible. But the convoy’s turn away broke Lemp’s contact until the listening apparatus again detected the convoy. However, Lemp was unable to take action because the moon was too bright. He decided to attack the next day, when two other U-boats were expected to be nearby. At 2:16
A.M
. local time on Friday, May 9, he again reported the convoy’s position; Dönitz ordered several U-boats to concentrate. A few hours later, the U-201, commanded by Lieutenant Adalbert Schnee, hove into sight. Using light blinkers to communicate, the two captains agreed to attack that day, Lemp first.

Early that morning, Baker-Cresswell came onto the bridge of the
Bulldog
to watch his group take up its day screening positions. It was to be his last day with the convoy. His ship would leave late in the afternoon with sufficient fuel to return to Iceland. By that time the convoy could disperse; it would then be at about 34° west longitude, and no Axis submarine had ever sunk a ship that far west. His good feelings were reinforced by the arrival of his breakfast, wrapped in a napkin and served by his faithful steward. As the morning wore on and nothing happened, those feelings seemed to be justified.

But Lemp had moved into position to attack. From in front of the convoy and to starboard, at periscope depth, he fired three torpedoes at a diagonal distance of 800 yards, or half a mile, at three steamers. Just as Baker-Cresswell was preparing to exchange noon positions
with the commodore of the convoy’s merchantmen, he saw a spout of water on the
Esmond
’s starboard side. A few moments later, the
Bengore
was hit. Her stern rose almost to the vertical and the crated cargo on her deck cascaded into the sea. It looked, one witness said, like “a child pouring toys out of a box.”

Baker-Cresswell, recovering from his astonishment, swung the
Bulldog
to starboard and raced to where he thought the U-boat might be, determined to destroy her. At the same time one of Escort Group 3’s corvettes, the
Aubretia
, which had detected the incoming torpedoes on her asdic, increased speed and turned to starboard. Two minutes later she obtained an asdic contact, then lost it, so the captain stopped her engines to improve the reception. A minute later the
Aubretia
spotted a periscope dead ahead, about 800 yards away, traveling from port to starboard. She sped toward it and dropped a full pattern of depth charges, set to explode at 100 and 225 feet.

The crew of the U-110 heard these explosions and were shaken by the speed of the attack; they had thought they would have fifteen minutes to dive and get away. The explosions, however, were distant. The submarine continued in attack mode. A few minutes later, Lemp, at the periscope, turning his submarine for a stern shot, spotted a destroyer coming at him with great speed. “Down deep!” he ordered. The crew ran forward to speed the dive.

But no sooner had the vessel begun to tilt than at least a score of depth charges, dropped by the
Aubretia
and set to discharge at 150 and 385 feet, exploded very close to the submarine. They blew out the main electric motor switch, stopped the electric motors, shattered all depth meters, and started leaks in the oil bunkers; the submarine started to take water and sank even deeper. The plates that formed the deck of the control center, which normally butted one another, overlapped from the pressure. Wilde and others thought it was the end. Although they were frightened and felt helpless, nobody screamed or wept. Lemp, meanwhile, was trying to blow the tanks
to get the boat to rise. Suddenly, the men felt her moving upward, perhaps pushed up by depth charges.

Her rise caused a patch of water on the surface to become disturbed, drawing the eyes of the men on the
Aubretia
, the
Bulldog
, and another destroyer, the
Broadway.
Then, at 12:35, the U-boat burst up from the seemingly vacant sea. Water streamed from her uppers, and she rolled in the slight swell. Inside, the crew members felt the motion and knew, to their great relief, that they were on the surface. Lemp, instead of releasing pressurized air through a valve, opened the hatch. A cloud of dust blew out The crew was ordered to put on life vests and to get out. Ventilation ports and sea strainers were opened to let in water.