“You also know that we do not have religious services on board, but it would hardly be appropriate to let this very special, sacred occasion pass without formally recognizing the religious faith that I suppose most of you profess. Therefore, if you would give me your reverent attention, I shall read from the Nativity account as it appears in the New Testament Book of Luke.”5
When the brief reading was over, all hands repaired to their home compartments, where the duty stewards began passing out Hannes’s Christmas pancakes and from their bucketlike food containers, called “long boats,” ladling out beef and vegetable stew. Later, delivering a second course, they moved through the central gangway with fresh fruit and lemonade. For those who wished coffee, Hannes had prepared a brew less strong and more tasty than the usual bridge watch blend he provided the lookouts. The ratings with their mess kits sat where they could on boxes, bunks, or on the floor plates. In the officers’ wardroom and petty officers’ compartment, the mess was served on dishes placed on tables with racks, called “fiddles,” secured to their edges to keep the crockery from sliding off. At the appropriate time the stewards returned with large slices of the Patenbataillon cakes together with Hannes’s own Berliners (jelly-filled doughnuts). Finally, the LI passed through the compartments with large bottles of already prepared wine punch, which added luster to the warm glow left by what even the Old Man called ein festliches Essen—a holiday dinner.6 Most of the men, knowing that this was their last drink for at least a month and a half—an unexpected reprise of “last drinks” taken at the Café les Trois Soeurs two nights earlier—slowly savored the taste from their cups and stretched their contents as long as they could. When the presents and particularly the mail came around, there was little doubt that Christmas sentimentality was very close to the surface among these men who, at other moments, cultivated a hard, soldierlike bravado. The presents from children were touching, but it was the mail from home that moved their hearts. Each man kept to his own self and emotions as he read, over and over, the news and Christmas greetings from family and girlfriends. In the control room Richard Amstein and von Schroeter took turns on Amstein’s accordion, and familiar carols of the season filled the strange steel pipe in the belly of the sea: “Vom Himmel hoch, da komm ich her,” “O Tannenbaum,” “In Bethlehem geboren ist uns ein Kindelein.” Since the Christmas tree was not only a uniquely German creation but for every man on board the most direct symbolic link with hearth and family, it was to be expected that crewmen accepted the Old Man’s invitation and came, singly or in groups, to stand before the control room tree and allow themselves to be mesmerized by its scent and its lights. In each mind’s eye no doubt was the fir tree at home decorated with real candles, with apples or blown-glass baubles, and Kringeln, pretzel-shaped Christmas cookies. Later this day, in the evening hours, the family would gather for the Bescherung when the candles would be lit and the presents distributed. Reinhard Hardegen, with his own small tree on his cubicle desk, pulled closed the green curtain and took out the photographs of wife Barbara and sons, two-and-a-half-year-old Klaus-Reinhard and one-year-old Jörg, while in the control room Amstein’s accordion broke everyone’s heart:
Stille Nacht, heilige Nacht
Alles schläft, einsam wacht….
0700 hours, Christmas Day, boat on the surface, course 275, halbe Fahrt—both ahead two-thirds. Although Walter Kaeding was not the officially assigned navigator, he would end up, by his own choice, doing most of the work. The navigator of record was an Obersteuer-mann (chief helmsman) whose interests on the boat lay elsewhere. Kaeding (who later would make navigator rank himself) was listed on the boat’s roster as petty officer second class and chief bos’n. Corresponding to Hoffmann’s position as number one watch officer, Kaeding was the Old Man’s number one among the noncommissioned crew members. With navigation his hobby, he had offered at every opportunity on earlier patrols to take readings and sightings as well as to keep the dead reckoning (DR) line on the Atlantic chart, and by the start of this latest patrol Hardegen was relying on him to assume those duties on a continuing basis.
Now Kaeding lifted the aluminum top of the chart case, removed the transparent celluloid cover, and with his pencil added a few millimeters to the DR line he had drawn on the extreme eastern edge of the ocean on paper known as Karte Nr. 1870G Nordatlantischer Ozean. With land features in green and water surfaces in white, the nautical chart was divided up into a mosaic of blue-lined squares, or grids, that bore specific letters and numbers. Naval staff had devised this system, by which each Marinequadrat, or naval square, covered a region of the North Atlantic approximately the size of France. Each bore a two-letter identifier, or digraph; for example, going west to Newfoundland a U-boat would pass through squares BF, BE, BD, BC, and BB. Each artificial square, about 486 nautical miles per side, was subdivided into many smaller squares identified by double-digit numerals, for example, from 11 to 99, and each smaller square was then subdivided nine times, then nine times again. The result was a fine screen that took the immense ocean down to a mesh no larger than six nautical miles per side and provided quick, near-accurate positioning by letter-number coordinates.7 Thus, as Kaeding could readily see, U-123 was positioned now at BF 4411.
With both U-boat and target convoy positions identified in this way, Admiral Dönitz had long feared that one of the grid charts might fall into British or American hands and provide the enemy with a means of locating U-boat stations, particularly if the naval code used in W/T transmissions had been compromised, something that worried him endlessly, though both B-Dienst, the German radio monitoring and cryptographic service, and Naval Staff had assured him repeatedly that British or American penetration of the code was impossible. Still, Dönitz had thought it prudent to camouflage the letter-number identifiers on the grid chart. Accordingly, on 9 September 1941, he sent a signal to all boats detailing a scheme that was to be adopted two days thereafter. It consisted of a contorted inversion of letters and numbers for certain specified naval squares. Knowledge of the new system was to be limited to the smallest possible number of personnel on each operational boat, and base personnel were to have no access to the system at all. The reception of this BdU signal by boats at sea caused widespread perplexity and miscalculation. One sentence toward the end of the transmission read: “If the foregoing is not clear send short-signal YYY.”8 It is said that Ys poured into Hans Meckel’s telecommunications receivers at Villecresnes in great profusion.
To replace that admittedly cumbersome way of disguising grid positions, BdU in November introduced a simpler, published system called the Chart-Cipher Adressbuch (Address Book), and it was for that book, printed on saltwater-soluble paper, that Kaeding now reached in the confidential papers locker off the officers’ wardroom. His DR line showed ¡23 fast approaching ten degrees west longitude, at which point outward-bound boats were required to send a short-signal report (Kurzsignale) to BdU confirming that they were still safely under way at such and such a grid position. (In the following year, when British aircraft—many of them equipped with airborne radar-became more active in the Bay of Biscay, causing boats to make most of their daylight transit into the Atlantic underwater, the reporting point would be changed to fifteen degrees west.) Short signals were brief transmission bursts designed to prevent enemy direction-finding receivers from triangulating the boat’s position; though here again Dönitz had been assured time and again by Naval Staff that it was impossible to obtain directional bearings on a shortwave transmission. Kaeding paged through the Adressbuch manual and found the encryption for 25 December: the BF digraph was to be transmitted that day as Holstenstrasse (Holsten Street), and the street number was to be calculated off a value 2,500 less than the grid number, or in this case 1911. Checking further Kaeding found that the camouflage that day for 1911 was 2250. And U-boat number 123 that day translated to the name Heinrich Krause. Beginning with two assigned Greek letters to alert BdU that this was an outbound passage short-signal position transmission, Kaeding’s
text now read: BETA BETA HEINRICH KRAUSE HOLSTENSTRASSE 2250. He walked it through the hatch and handed it to Rafalski.9
“This is ready to go, Puster,” he said. “A Beta transmission.”
Rafalski wheeled around to the wall bench and pulled forward his Schlüssel M cipher machine. Resembling a portable typewriter with raised keys, the black metal device occupied a lidded box eighteen by twenty-eight by thirty-three centimeters (seven by eleven by thirteen inches). In addition to the keyboard, the four-volt battery-powered machine had slots on the left rear top for the insertion of three rotable drums, or rotors, and, in the front, a switchboard for the insertion of plugs. Rafalski consulted his HYDRA cipher handbook (prominently marked Geheime Kommandosache!—“top secret”) for the rotor and plug settings for 25 December and made the designated connections and adjustments. This completed, he “typed out” Kaeding’s already encrypted short signal on the keyboard. As he did so a random series of letters appeared in glow holes on the top of the machine, which Rafalski copied onto a pad and divided into letter groups, which might have appeared as: JUZM RFTN XAELL HLQYM OEUCZ CSRBB HTISD GUAWH IXMJA. This imponderable gibberish he then tapped out on his Morse key, which connected through the “Ireland” circuit, 4412 kilocycles, to Hans Meckel’s receivers southeast of Paris.*
0830 hours, Christmas Day, BdU, Kernével, France. After U-123′s position report passed through the receivers south of Paris and made its way by land line to Kernével, it was handed to a naval cipher clerk in Meckel’s three-story white communications building, itself a former chateau, adjoining Admiral Dönitz’s headquarters. The clerk key-boarded the short signal through a Schlüssel M with rotor settings and plug pairs exactly conforming to Rafalski’s, according to the cipher of the day. After decrypting, the signal was taken by messenger across a covered walkway that connected the two buildings and handed to the duty officer, Kptlt. Günter Hessler, the A-1, first operations officer and Dönitz’s son-in-law. Hessler read the report and took it to the operations grid chart in the large situation room, where he affixed the numbers 123 to a small blue flag on a pin he stuck into the chart at the western edge of naval square BF. Learning of 123′s safe passage to date, Hessler knew, would please the admiral at his morning conference. The Lion took a special interest in Gruppe Paukenschlag.
Promptly at 0900 Dönitz entered the chart room and, as was his habit, asked first for overnight attack reports, if any, and then for the disposition of all boats and convoys. Kapitän zur See Godt, assisted by Hessler, briefed him on both. There had been no night actions. Both the Atlantic and Mediterranean theaters were quiet. V-653 west of Ireland had pursued two fast transports at seventeen knots, without result. Oncoming escorts had forced her under and she lost contact. According to intercepts of enemy Morse traffic a British gunboat, K-/96, rammed a U-boat in the Strait of Gibraltar. This may have been U-451, which had not reported in. If lost, that would make six boats presumed lost just within the past several days—together with U-127, 131, 434, 567, and 574—all off Gibraltar.10 U-582 had been ordered to proceed to Trondheim at top speed to replace the stud bolts of her exhaust valves. And U-653 had been assigned to special operations: She was to take up station in naval square AK southeast of Greenland and transmit dummy signals to give the impression of a large number of boats in the North Atlantic. That should distract enemy attention from the Paukenschlag boats and help to disguise their westward routes.
And what was the current status of Gruppe Paukenschlag? Dönitz wanted to know. Two of the Paukenschlag boats have already sortied, Herr Admiral, Hessler reported. Folkers in U-/25 had safely transited the Bay of Biscay and was in the open Atlantic, here—he pointed to a blue flag—at BD 58. Hardegen in V-123 appeared on the chart for the first time—here—at BF44. Zapp in U-66 was scheduled to sortie that day. Bleichrodt in U-/09 and Kais in U-130 would sortie two days hence.
Dönitz listened to the remainder of the briefing on convoy positions, W/T intercepts, and intelligence estimates. After his staff returned to their desks, he remained behind to brood over the chart. Two Paukenschlag boats were now at sea. Their mission and their positions must be guarded with scrupulous care. Maintaining radio silence at both ends of the communications link would ensure optimum security, but silence was not an option. Dönitz had long ago determined that success in the Atlantic war required that he personally coordinate the dispositions and attacks of U-boats by wireless. And that, in turn, required accurate position reports from the boats, also by wireless. The result to date was that BdU commanded the most complex, extensive, and efficient communications system in the history of military signals.11 That the enemy would intercept his traffic was a known risk, but an acceptable one given the assurances Dönitz had received from Konteradmiral Ludwig Stummel, chief of the Second Department (Operations) of the Naval Staff at Tirpitz-Ufer in Berlin. Stummel, whose department superintended naval ciphers, including HYDRA, and who consulted regularly with the Berlin cipher firms Kurski & Kruger and Heimsoht & Rinke, had persuaded Dönitz that for an enemy to puncture the Schlüssel Aí/HYDRA system with its variable range and changes of settings—if the technical feat was possible at all with known methods of mathematical analysis—would require such a protracted time frame that any data developed by the penetration would be long out of date and operationally useless.12 Dönitz usually felt better after his conversations with Stummel.
On the previous 19 November, concerned that to date convoys had been detected only by individual boats and not, with one exception, by patrol lines, Dönitz had worried in his war diary that the enemy might have decrypted HYDRA traffic and steered convoys around his “rakes.” Armed with Stummel’s reassurances, however, he added the notation: “This matter is being continually examined by the Naval War Staff and is considered as out of the question.”13 Just the day before, for that matter, on Christmas Eve, Naval Staff, commenting on the loss oí Atlantis and Python, declared: “It cannot be assumed that the enemy was able to break our ciphers since the execution of numerous other operations gives no reason for such a supposition. In the opinion of the Naval Staff, U-Boat Division, our ciphers are safe. Conspicuous are recurring losses of ships while cooperating with U-boats. This might be explained by special concentration of enemy intelligence on U-boat warfare.”14 Stummel had argued that such losses were the result of chance-sighting reports from undetected reconnaissance planes, the activity of French agents, radio directional guesses, or brilliant deductions by the British Secret Service.
Perhaps. But Dönitz continued to fret that the cryptographic security of the HYDRA c ipher might have been compromised and that U-/23′s just-received position report, among others, was being read by someone “on the other side of the hill.” Did the alternative explanations put forward by Naval Staff truly explain the losses of Atlantis and Python? (Dönitz did not think surface refueling and replenishing of U-boats would ever again be possible.15) How to explain, except by a breach of security, that in the wake of the sinking of the Bismarck seven months earlier the Royal Navy identified the positions of all eight tankers and supply ships that OKM had deployed to support Bismarck and the heavy cruiser Prinz Eugen and in the space of a month sank or captured seven of them? Had the Prinz Eugen remained at sea would she have been caught up in the same unprecedented sweep? Was it only striking coincidence that those supply vessels stationed at widely separated points in the Atlantic were so quickly located and disposed of? And was it not suspicious that three British submarines happened upon the controlled rendezvous of three U-boats in the Cape Verde Islands the previous September? More worrisome still was the Uboot-waffe’s mounting failure in the past summer and fall to sight convoy targets in the North Atlantic and the U-boats’ declining success rate against them.16 It was manifest that convoys were methodically evading U-boat formations. And now in these last several days, the loss of six boats off Gibraltar! Was all this the result of conventional British intelligence and reconnaissance? Or—though a thorough investigation had failed to disclose a trait
or—could it be treachery? Did it not suggest, despite Naval Staff’s persistent effort to discount the possibility, that somebody in London was reading his mail?
The vexed admiral took one last look at the few blue flags and returned to his office.
2340 hours, 27 December, U-/2J on the surface, position BE 1976. There was a saying throughout the Ubootwaffe: The most interesting things to know on a boat were the things you were not supposed to know. To few crews at this particular moment was the import of that saying more telling than to the crew of V-J23. The tantalizing wait for information began when Bootsmann Kaeding passed word to the other petty officers, who then relayed it to all ranks, that the boat had crossed twenty degrees west. That meant, first of all, that Eins Zwei Drei was once again a Frontboot with all the concomitant combat-duty bonuses in French francs thereunto appertaining. A whoop and a hurrah for that! In the second place it meant that the Old Man could now open his sealed orders, the news of which everyone now awaited with the usual high interest, particularly since wagers had been placed in the forward torpedo room. The boat’s course, known to all, could lead to any number of patrol lines south of Greenland, east of Nova Scotia, or off the Newfoundland Bank. Just please don’t send us back to Belle Isle Strait! one mixer mock-pleaded to Admiral Dönitz. (He need not have worried: Ice closed the Strait of Belle Isle to navigation from December to early July.) Since most of the enemy convoys formed up off Halifax, the general environs of that port city were the most popular choice of those who cared to make a guess or wager about the boat’s destination. Sydney was a close second. Washington, D.C., was laughed out of the compartment—“It’s not even a port!” When it finally did happen, word spread rapidly from fore to aft: The Old Man had opened his curtain, called for the officers, and closed the forward and control room hatches.
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