part0008

I peered through the periscope of my submarine U-110, it was late morning and foggy on May 9, 1941. Through my narrow lens just above the choppy sea south of Iceland, I saw a convoy of British ships heading toward Nova Scotia.

My wartime service with the German submarine fleet was brief but glorious. In 10 patrols, we'd sunk over 20 ships and damaged at least another four, and we were only a year into the war. I’d been awarded the Iron Cross, 1st and 2nd class and the Knight’s Cross, one of the most prestigious awards for a German military man. I developed a reputation for being insolent with my senior commanders. It was shocking to me why anyone would volunteer to serve on submarines. They were uncomfortable and dangerous.

The reason I did was because German submarines were so devastatingly effective. Throughout the war, our U-boats sank over 2,500 cargo ships and 175 of their warship escorts. But for all the success we had, we paid a terrible price. Two out of three U-boats were sunk, and we lost over 26,000 men to the bottom of the sea.

Our U-boats kept in touch with headquarters through radio signals. We'd report our progress, positions and receive instructions on where to head next. These reports were always sent in code. It was a code that’d puzzled the British. Their Intelligence Service set up a special code-breaking department to try to crack it. If the British knew where we were in our U-boats, or where we were going, they could avoid us or even hunt us down. Britain depended on food and supplies brought in by ships. Finding a way to crack the German code was a priority for them.

I was ordered to carry out a daytime attack. I felt uneasy. We usually didn’t carry out daytime attacks, especially on convoys protected by warship escorts. It was more difficult for escorts to locate our submarine during a night attack. But the fear of losing contact with my quarry overrode any considerations. Just before noon, we unleashed three torpedoes; two of them hit home, sending a tower of spray into the air by the side of two unlucky ships. I ordered a fourth torpedo to be fired, but it failed to leave its launch tube. This at first seemed like a minor mishap, but it ended up turning into a major disaster for our submarine.

When a torpedo is fired, the water is pumped into the forward ballast tanks to compensate for the missing weight and keep the submarine level under the water. Even though the fired torpedo failed to leave its tube, water poured into the front of the vessel and unbalanced the submarine. Our crew fought to regain control. During the ensuing disorder, several other British warships charged towards our U-boat. Only when we had regained control of our submarine was I able to check the periscope.

I saw a warship bearing down on us and I decided to dive deeper under the sea. This was the procedure for a submarine under attack. But it was too late. Inside the hull, the crew listened to the dull throbbing of approaching propeller blades. Then came the splashes of depth charges that were pitched overboard. My mouth went dry and an awful tightness hit me in the pit of my stomach. I waited for the charges to float down toward us.

The explosions roared and the submarine rocked back in forth as if caught in a hurricane. Main lights went out and for a second, there was total darkness. Then our blue emergency lighting flickered on. My eyes adjusted to the dim light, I was terrified, and I felt disoriented. I'd been under attack before and always played my part to perfection. I leaned casually against my periscope mount and pushed my hat to the back of my head. I warned the crew that if anyone on the submarine panicked and started yelling, the British ships would detect our location with their equipment, and hone in on us rapidly.

A deathly quiet settled over the submarine. Only the occasional ominous creaking and damage reports disturbed the noise. Neither depth charge had hit our submarine directly, but the damage they caused was still considerable. The trim controls which kept the submarine underwater had broken and the rudder no longer worked. The batteries were now contaminated and covered with seawater, and we gave off a poisonous chlorine gas. The depth gauges gave no reading and we couldn’t tell if our submarine was rising or falling to the ocean floor. The worst part was the hissing sound indicating leaks from our compressed air containers. Without this air, the U-110 wouldn’t be able to discharge water from the ballast tanks and rise to the surface.

These words could not have been much comfort in the awful silence that followed. Maybe my crew thought of how their girlfriends or families would greet the news of their deaths. More likely than not, each man imagined the submarine sinking slowly to the dark depths of the ocean. If a section of the sea was deep, steel plates on the hull would creak and groan. A flutter in the gears told the crew the submarine's air pressure had been disturbed by water pouring inside of the ship. Then the submarine would wrench apart beneath their feet, and they’d be engulfed by a torrent of black ice water.

At that depth, there was no chance of anyone reaching the surface. If that section of the sea was shallow, the submarine might simply sink to the bottom. Then men would have to sit in a strange blue light or pitch darkness shivering in the damp cold as their submarine gradually filled with water. Then, the corrosive smell of chlorine gas would catch in their throats, and they would suffocate in the foul-smelling air.

Just as these men were convinced they were about to die, U-110 rocked gently back and forth. A huge wave of relief swept through the men. This was a motion the entire crew recognized; their submarine was bobbing on the surface. I shouted, “Last stop! Everyone out.”

In a well-rehearsed drill, the crew headed for their exit hatches and poured out onto the deck. But our troubles were far from over. As we filled our lungs with fresh air, three British warships bore down on us, intending to ram our submarine before it could do more damage. Shells and bullets whizzed past our ears. None of our men had any intention of manning the guns on the deck or firing any more torpedoes. They just stared death in the face, desperate to abandon the U-110 . Men jumped overboard and drowned. Others were killed by the shells and bullets that rained down on them. Through the wild confusion, one of our ship's radio operators found me and asked if we should destroy the ship's code books and coding machinery. I shook my head and told him the ship was sinking. Below deck, the last few left aboard opened valves to flood the submarine and make sure it sunk. Then they too jumped into the freezing sea.

A board the HMS Bulldog, we steamed into ram the U-110 submarine. When I saw that the members of the enemy crew were throwing themselves off the vessel. I ordered our ship to reverse its engines and slowly come to a halt. The other British ships were now certain that the U-110 was no longer a threat and they stopped firing also.

One of our destroyers pulled up to rescue the German crew. It was our depth charges that had done so much damage. Their submarine captain and fellow officers struggled to stay afloat. I noticed to their horror that the submarine was not going to sink. Clearly, something had stopped water from pouring in. I watched as the submarine commander shouted and tried to climb back on board to sink their boat. But just as he did, a huge rolling wave swept over them, and their U-boat was carried out of reach. The German crew had lost their chance. Most of the men survived long enough in the water to be picked up. The German submarine captain was not one of them.

From our bridge, we surveyed this submarine with great interest. It was floating low in the water but didn’t look like it would sink immediately. Its crew was either killed or being rescued, so it seemed likely to have been abandoned. I was tasked to lead a boarding party of eight volunteers to investigate. We clambered aboard a small boat and were lowered from the HMS Bulldog, and set off across the choppy sea. As we approached the black hull of the submarine, my stomach tightened, and I felt tense. I was the most senior officer in the boarding party, and it was my responsibility to lead my men onto the submarine.

The only way in was through a hatch in the conning tower. There could be submariners inside waiting to shoot anyone who entered. It was standard practice on an abandoned submarine to set off explosives on a timer or flood the boat to prevent it from falling into enemy hands. Besides, the crew had utterly abandoned it. It was probably taking in water fast and could sink at any moment. Expecting to die from either a bullet, explosion, or in a torrent of water. I leaped off my boat and onto the slippery deck of the U-110. My men followed immediately behind me, but no sooner had the last men climbed aboard than a wave picked up our boat and smashed it to pieces on the deck of the submarine. This was not a good omen.

With my heart in my mouth, I climbed onto the conning tower to find an open hatch at the top. I stood before it, looking at it, thinking, fighting back my fears, and thinking this was my gateway to doom. I pulled my pistol from its holster and peered down into the darkened interior. There was a gust of warm air that wafted up to meet me. It contrasted against the icy Icelandic wind blowing off the sea and would’ve been inviting had it not smelled so foul. Submarines have a distinct stench and can be unbearable if you’re not used to it. It's the stale, rotten cabbage smell of 40 men confined for weeks on end in an enclosed airless environment, unable to clean their clothes or even bathe properly.

I could sense the impatience of the men behind me. They wouldn't be the first to be shot, but they were just as vulnerable as I was to explosives or a sinking submarine. I swung down into the interior, expecting a bullet right through my rear end. My boots climbed down the long steel ladder, but there was no one there to greet me. I reached the strange blue interior of the control room, and the others followed quickly behind. As their eyes grew used to the dim light, they blundered through the vessel, searching for any remaining crew. But the U-110 was deserted. My boarding party searched the boat for documents knowing it could still sink or explode at any moment.

Their courage was richly rewarded. Inside the radio operators' cabin was a sealed envelope. It contained codes and other useful information, such as signal logs, instruction procedures, and further codebooks. But there was also a curious machine that looked like a strange sort of typewriter. It had a keyboard, and one of the men pressed a letter on it. A light on a panel above the keyboard flickered on. It was still plugged in. It dawned on me that this was a coding machine, four screws held it to the side of the cabin. These were quickly removed, and the device was carefully put to one side. It was clear there must’ve been a complete panic among the crew to have left everything behind like this.

As my search party continued, the overpowering dread that we first felt entering the boat had faded. An explosion never came. But there were other things to worry about. The Bulldog and other warships guarding our convoy had gone off to chase enemy submarines. If the U-110 sank in the meantime, we had no boat and no immediate chance of rescue. Finally, the HMS Bulldog returned to wait for our boarding party to finish the work. I sat in the U-boat captain's cramped cabin and reflected that my life was starting to look up. When my men had finished their search. They sent a boat to collect us and attached a tow rope to the U-110 . The next morning the submarine sank in rough seas.

I was upset. A captured submarine was quite a prize and could’ve been manned by a British crew and used again against the Germans. The news quickly spread that the HMS Bulldog had captured a coding machine from the U-110 . It caused a sensation at British Naval Headquarters and they replied by ordering our crew to maintain the strictest secrecy. When we reached the Navy base at Scapa Flow in Scotland, two naval officers immediately came on board. They were eager to examine the items that we'd seized. The documents also excited great interest. They were thrilled that we had the coding machine, one officer said, “we've waited the whole war for one of these .”

The next day as the Bulldog sailed back to its Icelandic patrol. I received a thinly veiled message from the commander in chief of the Royal Navy. He said, “congratulations, the petals of your flower are of rare beauty .”

The typewriter device my party found was a fully working Enigma machine, the ingenious coding instrument devised by the German military. Enigma was used for scrambling a message so that it became diabolically difficult to crack. There were literally billions of possible combinations for each coded message. The Enigma had a keyboard layout like a typewriter, but it only contained the 26 letters of the alphabet. When a letter key was pressed, it sent a signal to a plug bored at the front of the machine. This was arranged in a standard keyboard layout with a variable arrangement of cable leads that could go from any direction. For example, C to V and then from U to K, this was the first stage of scrambling a message.

From the plugboard, the signal was routed to a series of replaceable interconnected rotating wheels. Each with all 26 letters of the alphabet around the rim. These scrambled the original letter and were between three and five of these wheels inside the enigma. Depending on the model, the wheels were chosen from a standard selection of eight. From the wheels, the signal was sent to a lamp board position behind the keyboard that lit up another letter, which the operator would then write down. In this way, messages would be fed through for coding and then transmitted via Morse code as regular radio signals.

The Enigma machine was invented in 1919 by a German engineer named Arthur Scherbius. Each keystroke, even of the same key, produced a different letter. If the operator pressed three keys for example, the rotating wheels could create three separate letters, Q, M, and Y. On machines with three wheels, it would not produce the same letter until the key had been pressed over 16,000 times. This was when the internal mechanism returned to its original position.

This type of complexity created its own problems. Messages from one machine to another could only be correctly decoded. If both machines were set up identically, each wheel had to be inserted in one specific position, and in a particular order. This meant the front plugboard had to be arranged in also the same way. This created difficulties for the German Navy. Their ships and submarines would be away at sea for months on end. They were sent out with codebooks that gave precise details on how the Enigma machine should be set up for each day of the week and months ahead.

It would be a disaster for the Germans if such a codebook or coding machine fell into British hands. The machine I captured and all the accompanying material was sent at once to Bletchley Park. The grand mansion and its grounds were set up as the British intelligence code-breaking headquarters in 1939. Just before the start of the war. The work was done in a makeshift collection of prefabricated huts. With collapsible chairs and trestle tables. It was staffed by some of the greatest mathematical minds in the country.

Chiefly run by Alan Turing, a Cambridge and Princeton University professor. His groundbreaking work led to decoding the Enigma messages using primitive computers, which were the forerunners of what we use today. Turing's team had a colossal task. The Enigma code was difficult enough to begin with. But to make it even more difficult, the code was changed every day. And the coding procedures regularly updated throughout the war.

The Enigma machines themselves also went through several design improvements. At the height of the conflict, over 2,000 messages were sent daily from branches of the Armed Forces to Bletchley for decoding. Even with the brightest brains in the country, the staff of Bletchley Park could not crack the Enigma code without direct assistance.

They relied on lucky breaks, and it was myself and my boarding party, which helped them. The books and documents I rescued were especially useful. They gave information on settings and procedures for encoding the most sensitive top-secret information, which the Germans called officer codes. The Enigma was like a huge jigsaw puzzle. Any codebooks or machines captured help put the puzzle together for a few days or weeks. Until the codes in the machine changed. Instead of decoding sensitive and highly useful messages about U-boat positions or Air Force strikes. Codebreakers would find themselves churning out reams of meaningless gobbledygook.

For the staff at Bletchley Park, these moments were heartbreaking disappointments. They were still well aware of how their work could save the lives of thousands of people. I still wake up at night, all these years later, to find myself going down that ladder. But thanks to the courage of our brave fighting men, the staff of Bletchley Park was provided with further opportunities to break the enemy's code.