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THE SECOND WORLD WAR
Germany’s secret code, 1941-1945
Kapitänleutnant Fritz-Julius Lemp peered through the periscope of submarine U-110. It was late in the morning of May 9, 1941, the last day of his life. Through the narrow lens, which surfaced just above the choppy sea south of Iceland, he could see a convoy of British ships bound for Nova Scotia.
Lemp’s wartime service with the German submarine fleet was brief and glorious. In 10 wartime patrols he had sunk 20 ships and damaged another four. Less than a year into the war, and all before he turned 27, he had been presented with the Iron Cross 1st and 2nd class, and the Knight’s Cross - among the most prestigious awards available to German military men. This allowed him to be astonishingly insolent with his senior commanders. One instruction from navy headquarters sent to him on his U-boat received a curt two word dismissal: “S***. Lemp”.
The medals, and the tolerance which greeted his outbursts, were a recognition of his calling. It was a wonder anyone, on any side of the war, volunteered to serve on submarines. It was an uncomfortable and highly dangerous life. But the reason they did volunteer was that submarines were devastatingly effective. In the course of the war, German U-boats sank 2,603 cargo ships and 175 of their warship escorts. But for such success they paid a terrible price. More than two out of three U-boats were sunk, taking about 26,000 submariners to the bottom of the sea.
U-boats kept in touch with their headquarters via radio signals. Here they would report their own positions and progress, and receive instructions on where to head next. Such reports were sent in code of course. It was a code that had incessantly perplexed the British. Their intelligence service had set up a special code-breaking department at Bletchley Park, Buckinghamshire, to try to crack it. If the British knew where the U-boats were, or where they were going, they could avoid them or hunt them down. For an island so dependent on food and material brought in by cargo ships, cracking the German navy code became one of the most vital tasks of the war.
On that May morning, Lemp was uneasy. He did not usually carry out daytime attacks, especially on convoys protected by warship escorts. It was far more difficult for such escorts to locate his submarine during a night attack. But his fear of losing contact with his quarry overrode such considerations. Just before noon, U-110 unleashed three torpedoes. Two hit home, sending towering columns of spray into the air by the side of two unlucky ships. But when Lemp ordered a fourth torpedo to be fired, it failed to leave its launch tube.
This minor mishap soon added up to a major disaster for U-110. When a torpedo is fired, water is immediately pumped into the forward ballast tanks, to compensate for the missing weight and keep the submarine level under the water. So, even though the torpedo failed to leave its tube, water still poured into the front of the vessel, unbalancing the submarine. Inside U-110 the crew fought to regain control. During the ensuing disorder, several British warships charged toward the U-boat. Only when Lemp had regained control of his submarine did he check his periscope. Seeing a warship bearing down on him, he immediately decided to dive deeper under the sea - the standard 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 two splashes as a couple of depths charges* were pitched overboard. With dry mouths and an awful tightness in the pit of their stomachs, the crew of U-110 waited for the charges to float down toward them.
When the explosions came with a huge thunderous peal, the submarine rocked to and fro as if caught in a hurricane. The main lights went out, and for a few seconds there was a deathly total darkness. Then, blue emergency lighting flickered on. As their eyes adjusted to the dim light, terrified and disoriented men looked over to their captain for reassurance. Lemp had been under attack before, and he played his part to perfection. Leaning his short, stocky frame casually against his periscope mount, hat pushed to the back of his head, he looked like a suburban bus driver plodding though his usual dreary journey. Lemp’s act had a serious purpose. If anyone on the submarine panicked and started yelling hysterically, the British ships would pick up the noise on their sound detection equipment, and home in on them rapidly.
Now, a deathly hush settled on the submarine, only disturbed by the occasional ominous creaking, and damage reports from other parts of the boat. Neither depth charge had hit the submarine directly, but the damage they caused was still considerable. The trim controls (which kept the submarine level underwater) had broken and the rudder no longer worked. The batteries had been contaminated with seawater and were now giving off poisonous chlorine gas. The depth gauges gave no reading, so it was impossible to tell whether the submarine was rising or falling in the sea. Worst of all, a steady hissing sound indicated that compressed air containers were leaking. Without this air, the submarine would not be able to blow water out of its ballast tanks and get to the surface. Now, even Lemp could not pretend that everything was going to be OK. “All we can do is wait,” he told his men. “I want you all to think of home, or something beautiful.”
These soothing words cannot have been much comfort. In the awful silence that followed, perhaps his crew thought of how their girlfriends or families would greet news of their deaths. More likely than not, in his mind’s eye, each man imagined the submarine sinking slowly into the dark depths of the ocean.