* C CODEBREAKING. The German Enigma encoding machine, employed by all military and paramilitary organizations in the Third Reich, was conceived by a Dutchman, Hugo Alexander Koch, in the years immediately following World War I. The patents for it were acquired by a German engineer, Arthur Scherbius, who attempted, unsuccessfully, to market it in the 1920s. Subsequently, two German firms (Heimsoth & Rinke and Konski & Kroger) obtained the rights and marketed the machine for commercial use (cost: $144 plus postage). By 1930 military codebreakers of all major nations had acquired the "commercial" version of Enigma for study. All professional codebreakers understood Enigma's basic principles. The German Enigma encoding machine, employed by all military and paramilitary organizations in the Third Reich, was conceived by a Dutchman, Hugo Alexander Koch, in the years immediately following World War I. The patents for it were acquired by a German engineer, Arthur Scherbius, who attempted, unsuccessfully, to market it in the 1920s. Subsequently, two German firms (Heimsoth & Rinke and Konski & Kroger) obtained the rights and marketed the machine for commercial use (cost: $144 plus postage). By 1930 military codebreakers of all major nations had acquired the "commercial" version of Enigma for study. All professional codebreakers understood Enigma's basic principles.

The Enigma was a small, portable, battery-operated machine about the size of a typewriter. It was compactly housed in a varnished oak box with a hinged lid. It looked something like a typewriter. It had a three-tiered typewriter keyboard of twenty-six letters-but no numerals or punctuation marks. In place of the platen and typewriter keys, there was a flat panel with the twenty-six letters of the alphabet repeated in the same order. Each of the letters on the panel had a tiny light bulb behind it. To encode a message, the sender pecked out the message, one letter at a time, on the keyboard. The machine automatically scrambled-or enciphered-that letter into another that appeared, lighted up, on the panel. In a reverse process, the receiver, operating an identical Enigma, pecked out the encoded message on his keyboard, one letter at a time, and the deciphered letters lit up on the panel.

The scrambling-or encoding-mechanisms inside the machine were fiendishly clever. The basic idea was to route the electrical impulses from the keyboard to the light panel by as devious and complicated a route as possible. The heart of the mixing system was a row of three turning drums or rotors, about three inches in diameter. Each rotor was fitted on both sides with twenty-six electrical contact points, which interconnected with the other rotors by means of spring-loaded and flush contact points. When the operator struck a letter on the keyboard, the first, or right-hand, rotor revolved one notch (or l/26th of a revolution), like an automobile odometer. With this movement the setup of the contact points with the other rotors completely changed, routing the electrical impulse on entirely new entry and exit paths. The second letter struck moved the first rotor another notch (or l/26th of a revolution), creating yet another entry and exit path for the impulses. After twenty-six letters had been struck, the second, or middle, rotor clicked in, extending the process with its twenty-six contact points. Then, finally, the third, or left-hand, rotor with its twenty-six contact points clicked in. Altogether the three rotors had 17,576 positions (26 26 26). Another complicated feature, known as a "reflector," bounced all the electrical impulses back through the maze of rotor contact points, further scrambling them (in effect, creating the equivalent of six rotors) before they lit up the letter bulbs.

Nor was that all. The rotors were removable. They could be rearranged on the shaft or axle in six different combinations (1-2-3, 1-3-2, 2-3-1, etc.). These variables increased the possible rotor positions to 105,456 (17,576 6). Moreover, the rotors were fitted with ratchets on the outer rims, so that they could be set individually to start revolving from any one of the twenty-six different positions. The twenty-six optional rim-settings for each rotor, multiplied by the total 105,456 possible rotor positions, increased the possible electrical contact points available to astronomical levels.

Encoding and decoding messages on identical Enigmas was a fairly simple process for the operators, but it had to be done exactly according to a prearranged and distributed menu, which established what came to be called the "keys." First, both sender and receiver had to insert the three rotors on the axles in the identical left-to-right order (1-2-3 or 1-3-2, etc.). Second, both had to set the rotors to identical rim numbers. Third, both had to turn the three rotors until identical letters embossed on the outer faces of the rotor appeared in tiny peepholes above the rotors. Assuming all three steps had been done correctly on identically wired Enigmas according to the prearranged "keys," the encoder and decoder were then ready to communicate.

Sitting before his typewriter keyboard, the sender commenced the automatic encoding process. As he pecked out the letters of the message, one at a time, the electrical impulses traveled through the maze of circuits, switches, and contact points, automatically scrambling or encoding the letters and lighting the bulbs behind the encoded letters on the panel. ("A" might light up as "R," for example.) An assistant copied down the encoded letters as they lit up on the panel. When the message was completely encoded, the sender gave it to a radio operator, who telegraphed it to the receiver in five-letter groups. In a reverse process, the receiver typed out the encoded message, one letter at a time on his keyboard. The machine automatically unscrambled the encoded letters, one at a time, lighting up letters on his panel in plain text. (The encoded "R" in the example would light up on the receiving machine as an "A.") Cryptologists quite rightly believed at first that messages properly encrypted by Enigma were unbreakable. The total of the permutations offered as a result of the many variables was mind-boggling: six thousand trillion by one calculation. Such huge possibilities ruled out known codebreaking techniques, such as statistical analysis (e.g., letter frequency), and appeared to defy solutions by higher mathematics. Possession of an Enigma wired exactly like that of the enemy was only half the battle. One also had to know the three easily changeable "keys": left-to-right rotor order, rotor-rim settings, and rotor-peephole settings.

The German military was enchanted with Enigma. It was compact, easy to operate, rugged, cheap, and seemingly foolproof. Even if the enemy captured an Enigma, it would not do great harm; the keys could be changed at will. Accordingly, it was adopted by the Reichsmarine Reichsmarine in 1926 and the in 1926 and the Reichswehr Reichswehr in 1929. To increase its security beyond the "commercial" Enigma available to all, the Germans altered the wiring of the "military" version and added yet another layer of encryption: a "plugboard" on the front below the keyboard. This consisted of twenty-six holes, lettered A to Z (or, alternately, 1 to 26). When one (or more) combination of these letters was paired by cables, plugged in like an old-fashioned telephone switchboard, it rerouted the electrical impulses through yet another maze, raising encryption possibilities to figures almost beyond mathematical reckoning. To break this military version thus required knowledge not only of the three rotor keys but also of the plugboard cable arrangement. in 1929. To increase its security beyond the "commercial" Enigma available to all, the Germans altered the wiring of the "military" version and added yet another layer of encryption: a "plugboard" on the front below the keyboard. This consisted of twenty-six holes, lettered A to Z (or, alternately, 1 to 26). When one (or more) combination of these letters was paired by cables, plugged in like an old-fashioned telephone switchboard, it rerouted the electrical impulses through yet another maze, raising encryption possibilities to figures almost beyond mathematical reckoning. To break this military version thus required knowledge not only of the three rotor keys but also of the plugboard cable arrangement.

Enigma was wondrously flexible. It enabled various Third Reich organizations to establish individual and completely different encoding setups. This was achieved in a simple way by distributing different rotor and plugboard keys (to be in force for a specific and limited time) or, in a more complicated way, by altering the internal wiring schemes, or by adding one or more rotors. Thus it was to transpire that the Enigma of the Reichsmarine Reichsmarine and and Reichswehr Reichswehr and the and the Luftwaffe Luftwaffe evolved along different paths and none could read the other's transmissions without obtaining identically wired machines and the keys. evolved along different paths and none could read the other's transmissions without obtaining identically wired machines and the keys.

A team of Polish codebreakers, led by Marian Rejewski and including Jerzy Rozycki and Henryk Zygalski, commenced an attack on German military Enigma in December 1932. Their tools were not inconsiderable: a "commercial" Enigma, acquired earlier; espionage materials (old keys, plugboard settings, etc.), obtained from a money-hungry German traitor, Hans-Thilo Schmidt (codenamed "Asche"), cultivated and exploited by the chief of the French codebreakers, Gustave Bertrand; and a wealth of Enigma messages intercepted by Polish stations.

The Poles were soon thoroughly familiar with German procedure for transmitting Enigma. They noted with special interest one procedural feature. After having set the four keys of their Enigmas according to the predistributed menu, the sender and receiver then engaged in yet another procedural step designed to enhance Enigma security. The sender embedded at the head of the message a three-letter encrypted key, selected at random, for that message only and repeated it twice to be certain the receiver got it, even in poor radio-transmission conditions.

The Germans believed that by instructing the sender to choose the three-letter message key at random, another level of security had been added to Enigma. But they were wrong. German Enigma operators were human and therefore predictable. At first all too many operators lazily-and predictably-chose AAA AAA or or ABC ABC or a three-letter diagonal on the Enigma keyboard, such as or a three-letter diagonal on the Enigma keyboard, such as QSC QSC or or ESY ESY. Moreover, the standing instructions to repeat the message key (to insure reception in poor conditions) revealed to codebreakers vital information: the first and fourth, second and fifth, and third and sixth letters at the head of every message (the message key repeated) would always be identical. This known constant, together with the fact that no encrypted Enigma letter ever replicated itself ("R" never lit up as "R"), made Enigma vulnerable to penetration by certain very complicated higher mathematical processes.

Enigma was also vulnerable in another way. German military traffic was rigid and stylized, composed of military addresses, titles, salutations, and words often repeated. A close student of these messages could sometimes correctly guess a word or a phrase ("division," "regiment," "operation," or "nothing to report"). Correct guesses from these official messages, or from idle "test" chitchat between operators, or from lapses were known in the codebreaking trade as "cribs." In the early days, before the Germans became skilled at communications security, Enigma yielded numerous cribs.

Astonishingly, the Polish team broke German Enigma in a few weeks and were able to duplicate the machines without ever having seen the German version. Although the Germans tightened security procedures and made refinements to Enigma, for the next six years-to 1938-the Poles broke German Enigma at will and read it consistently and currently. To simplify and speed up the breaks, they developed a "cyclometer" (two sets of Enigma rotors, linked in a certain way) and an immense card file, listing possible keys and other data. In a two-week "test" in January 1938, the ten-man Polish team decoded 75 percent of German Enigma messages received and calculated that with more personnel it might have decoded 90 percent.

During the Munich Crisis of September 1938, and again in December 1938, the Germans delivered the Polish team two stunning setbacks. On September 15, the Germans abolished the procedure of distributing preset peephole settings for starting the message transmissions. Instead, Enigma operators were instructed to choose any three letters at random for the initial peephole settings and to transmit these unenciphered, or in the clear, to the receiver before transmitting the enciphered and repeated three-letter settings for the message itself. Beyond that, on December 15, the Germans distributed two additional rotors to all Enigma operators, making a total of five rotors from which to select three for insertion in the machine. The change in peephole-setting procedure-the random selection of the start position-rendered all the decoding work of the Poles to that time useless. The addition of two more rotors raised the encription possibilities, mathematically, to yet more mind-boggling levels.

The Poles were dismayed, but not discouraged. To attack the increased complexities introduced by the procedural change, they conceived two techniques. One, offered by Rejewski, was an ingenious automated machine, a sort of super-cyclometer, which the Poles called a "bomba."* Its heart was comprised of three linked rotor sets from six Enigmas (eighteen rotors). When prompted in a certain way, the machine "tried out" various combinations of encrypted letters until the embedded message code was found. A total of six bombas (108 rotors) was required to conduct a full range of searching. The other technique, offered by Rejewski's associate Zygalski, made use of large, perforated, heavy paper sheets with horizontal and vertical columns of letters, which when laid one atop the other on a light table in a certain way revealed the message keys by admitting light through the holes. Each sheet had about 1,000 holes. A total of 156 separate sheets (six series of twenty-six sheets), comprising about 156,000 holes, each hand-cut with a razor blade, was required for a full range of search on a three-rotor Enigma. Its heart was comprised of three linked rotor sets from six Enigmas (eighteen rotors). When prompted in a certain way, the machine "tried out" various combinations of encrypted letters until the embedded message code was found. A total of six bombas (108 rotors) was required to conduct a full range of searching. The other technique, offered by Rejewski's associate Zygalski, made use of large, perforated, heavy paper sheets with horizontal and vertical columns of letters, which when laid one atop the other on a light table in a certain way revealed the message keys by admitting light through the holes. Each sheet had about 1,000 holes. A total of 156 separate sheets (six series of twenty-six sheets), comprising about 156,000 holes, each hand-cut with a razor blade, was required for a full range of search on a three-rotor Enigma.

The addition of the two extra rotors in December 1938 posed even greater problems for the Poles. First they had to figure out the wiring arrangement of each of the new rotors. They were able to do so because of another careless communication lapse on the part of the Germans. The Nazi S.S. and S.D. nets adopted the five-rotor option but, inexplicably and foolishly, retained the old system of predistributed initial peephole settings, which the Poles had mastered earlier. By exploiting that lapse and by intuition, the Poles, in yet another astounding crypt-analysis achievement, were able to replicate the wiring of the new rotors. By January 1, 1939, the Poles could read five-rotor S.S. and S.D. traffic accurately and consistently.

However, the solving of the five-rotor military Enigma employing random initial peephole settings, as well as random-encrypted peephole settings for individual messages, defeated the Poles. Rejewski calculated that to search by automated means, each of the six bombas in operation would have to be fitted with thirty-six of the two new rotors (for a grand total of 1,080 rotors) and be operated twenty-four hours a day. Alternately, the laborious perforated-sheet method would require 1,560 different sheets (sixty series of twenty-six sheets) with a grand total of 1,560,000 hand-cut holes. It could be done, of course, but the Poles lacked the resources for so massive an undertaking.

That was where matters stood in August 1939, a few days before the outbreak of war, when the Poles turned over to the British and French copies of all their research materials and the Polish-built German military Enigmas.

The British codebreaking unit, GCHQ, located at Bletchley Park, was directed and staffed by many Veterans of the Admiralty's famous Room 40 of World War I. These included the director, Alastair Denniston, his deputy Edward Travis, and the codebreakers A. Dillwyn Knox, William F. Clarke, and others. All were quite familiar with Enigma principles-the British had bought a "commercial" Enigma in the 1920s-but they had made only cursory attempts to break German Enigma and had had no success. The Polish "gift" was therefore immensely valuable and saved the British many months of tedious work.

Before the war, GCHQ had recruited and vetted a "reserve" force, drawing heavily on academics at Cambridge and Oxford universities. When war came, the reserve was called up to Bletchley Park and divided between the codebreaking and the specialized army, air force, and naval sections, which were located in temporary one-story outbuildings misnamed "huts." Among the first call-ups were three brilliant Cambridge mathematicians: Gordon Welchman, Alan Turing, and John R. F. Jeffreys.

These three mathematicians were assigned different tasks. Alan Turing, who was fascinated by machines, set about designing a bomba which was to be more powerful and "general" in nature than the Polish one and theoretically capable of coping with whatever new complexities the Germans might add to Enigma. John Jeffreys was put in charge of manufacturing the huge numbers of perforated sheets required to solve five-rotor Enigma. Gordon Welchman was directed to study German call signs and to identify various Enigma nets.

The intellectual challenge presented by Enigma enthralled Gordon Welchman. Although GCHQ was strictly compartmentalized for security reasons, Welchman refused to be limited to a study of call signs. In a flash of brilliance, entirely on his own, he reinvented the perforated-sheet method and presented it to Dillwyn Knox, only to learn that it was already being vigorously pursued. Again straying from his limited area, Welchman offered a suggestion for Turing's bomba. This idea, as Turing's biographer put it, was so "spectacular" that Turing was "incredulous." Incorporated into Turing's design, the suggestion gave Turing's proposed machine "an almost uncanny elegance and power."

By December 1939, Jeffreys and his aides had completed two sets of perforated sheets, each set containing about one and a half million punched holes. One set was sent to Paris for the French and Polish codebreakers. Employing the British-made sheets, the Poles found the daily keys of a five-rotor Enigma net for October 28 and broke the net (called "Green" by the Allies) messages for that day only. This was the first Allied break into the five-rotor Enigma. The excitement that ensued was tempered by the fear that on January 1, 1940, the Germans would make changes in the keys or procedures, which would negate this achievement.

But the Germans made no changes on January 1. As a result, the codebreakers at Bletchley Park, employing the sheet-stacking method, broke into the Luftwaffe Luftwaffe Enigma net (called "Red" by the Allies) of January 6. This was the first "all-British" codebreaking triumph over the Germans. Owing to the generally lax Enigma procedure and communications security in the Enigma net (called "Red" by the Allies) of January 6. This was the first "all-British" codebreaking triumph over the Germans. Owing to the generally lax Enigma procedure and communications security in the Luftwaffe Luftwaffe, which yielded cribs, and to cribs intuitively arrived at, thereafter British codebreakers read the Luftwaffe Luftwaffe Red with fair reliability. The British also sporadically broke into the Red with fair reliability. The British also sporadically broke into the Wehrmacht Wehrmacht Green and a Green and a Luftwaffe Luftwaffe training code, Blue, and some other German nets that still employed three-rotor Enigma. training code, Blue, and some other German nets that still employed three-rotor Enigma.

From January 1940 onward, the British at Bletchley Park played the dominant role in breaking Enigma. The Poles and French continued to make contributions, but the importance of their work diminished. Pending the building of the Turing bomba, incorporating Welchman's "spectacular" improvement, the British relied on the sheet-stacking method. It was a tedious and work-intensive process, requiring ever greater numbers of clerks. Nor was it a sure thing. Often as not, the British failed to recover the daily keys.

No progress whatsoever was made in breaking Kriegsmarine Kriegsmarine traffic. Naval Enigma employed eight rotors rather than the five rotors of traffic. Naval Enigma employed eight rotors rather than the five rotors of Luftwaffe Luftwaffe and and Wehrmacht Wehrmacht Enigma, ruling out the sheet-stacking method. There was scant traffic to intercept-too little grist for the codebreakers' mill. Enigma, ruling out the sheet-stacking method. There was scant traffic to intercept-too little grist for the codebreakers' mill. Kriegsmarine Kriegsmarine radio operators continued to exercise strict transmission discipline, offering no cribs. Attempts to break naval Enigma before Turing's bomba was completed were bound to fail. And so they did. radio operators continued to exercise strict transmission discipline, offering no cribs. Attempts to break naval Enigma before Turing's bomba was completed were bound to fail. And so they did.

To the technical achievements at Bletchley Park must be added another, no less important. That was the superb management of the information flow. The leaders centralized the gathering, storage, and distribution of all codebreaking intelligence, however trivial. They barred the "interservice rivalry," the jealous withholding of bits and pieces to favor one military service or the other. All hands shared equally in all phases of the operation, from translators to analysts to librarians in the hugely growing data bank to the distributors of the information. And, moreover, they did so without a single leak, so far as was known in 1996.

ATLANTIC O OPERATIONS: JANUARY AND F FEBRUARY 1940 1940.

The winter of 1939-1940 was the coldest in forty years. In early January the Baltic Sea, the Kiel Canal, the Elbe River, and the Jade froze solid. The bitter cold and the thick ice drastically impeded U-boat construction, repairs, training, and movements. The Germans pressed every spare surface vessel into service to break ice, including the old battleship Schleswig-Holstein Schleswig-Holstein, and fitted the U-boats with wooden casings to protect the bow torpedo doors. But numerous U-boats incurred ice damage and some were locked fast to Baltic piers, unable to move.

To escape the ice, Donitz was compelled to forward base the U-boats at the island of Helgoland, in the warmer, ice-free North Sea. German submariners passionately hated this bleak, desolate, windswept, bitterly cold outpost. All facilities for men and ships were primitive. It was difficult to get fuel oil and spare parts through the ice to the island. British submarines prowled the nearby ice-free areas designated for sea trials and training. RAF bombers made occasional raids.

In January 1940, five boats sailed from Helgoland for torpedo patrols in the Atlantic. These included the cranky and clumsy Type I, U-25 U-25, which had twice aborted in December; two new VIIBs, U-51 U-51 and and U-55 U-55; and two Type IXs, the Veteran Veteran U-41 U-41 and a new one, and a new one, U-44 U-44. These boats carried submarine torpedoes in which no one had the slightest confidence. Donitz summarized the torpedo situation in his war diary: The fact that its main weapon, the torpedo, has to a large extent, proved useless in operations has been the greatest difficulty with which the U-boat arm has had to contend since the beginning of the war and it has had a most serious effect on results. At least 25 percent of all shots fired have been torpedo failures. According to statistics covering all shots up to 6 January, 40.9 percent of unsuccessful shots were torpedo failures.... The commanding officers' and crews' confidence in the torpedo is very much shaken. Again and again the boats have tried in the face of strong enemy activity to fire their torpedoes under the best possible conditions and often when they have made a daring attack they have been rewarded with failures and even danger to themselves.... It is very bitter for commanding officers and the executive control to find that the U-boat arm cannot achieve the success expected of it, in spite of thorough peacetime training, because of torpedo failures. I will continue to do all I can to keep up the fighting spirits of the U-boats in the face of all the setbacks.

However, there was then reason for optimism. Raeder had sacked the hidebound chief of the Torpedo Directorate, Oskar Wehr, and appointed a new chief, Oskar Kummetz, and had named the scientist Dr. E. A. Cornelius "Torpedo Dictator." Kummetz was a contemporary of Donitz's and an officer of "great energy." The new men, Donitz believed, were "unprejudiced" and both brought fresh, inquiring minds to bear on the technical problems. After merely a few days on the job, Kummetz had telephoned Donitz to say that he and Cornelius had conducted new tests, which had proved beyond doubt that the torpedoes were defective in several ways. This was an impressive bureaucratic victory for Donitz, but the task of correcting the defects remained.

Because of the cold, the ice, and other factors, crews of the two new VIIBs, U-51 U-51 and and U-55 U-55, embarking on maiden war patrols, were not fully trained. Donitz therefore directed both skippers to patrol in low-intensity ASW areas west of Ireland, to gain further experience before attacking enemy shipping. But neither skipper was keen on conducting a training patrol.

On the day he reached the Atlantic, Dietrich Knorr, age twenty-seven, commanding U-51 U-51, took the boat straight into action. He sank a 1,600-ton Swedish freighter, then went directly to the Western Approaches, where he sank a 1,500-ton Norwegian freighter, from which he rescued two survivors. But U-51 U-51 developed a problem in her bow torpedo tubes and Knorr was forced to abort and return to Germany. developed a problem in her bow torpedo tubes and Knorr was forced to abort and return to Germany.

The brand-new U-55 U-55, commanded by Werner Heidel, age thirty, who had done well in the duck U-7 U-7, also went directly into action. Rounding the British Isles, Heidel sank two small neutrals (a Dane and a Swede), then proceeded to the Western Approaches. On the tenth day of the patrol, January 29, Donitz alerted Heidel to a convoy, which had been detected by B-dienst B-dienst. Heidel responded by sinking the 5,000-ton British tanker Vaclite Vaclite and a 5,000-ton Greek freighter. and a 5,000-ton Greek freighter.

One of the convoy escorts, the sloop Fowey Fowey, left the convoy and pursued U-55 U-55 in foggy seas. Fixing the boat on sonar, in foggy seas. Fixing the boat on sonar, Fowey Fowey attacked with depth charges, driving Heidel to 328 feet. attacked with depth charges, driving Heidel to 328 feet. Fowey Fowey dropped five charges, three set for 500 feet by mistake, two for 350 feet. The two set at 350 feet exploded very close to dropped five charges, three set for 500 feet by mistake, two for 350 feet. The two set at 350 feet exploded very close to U-55 U-55, causing severe flooding and panic. Heidel temporarily contained the damage and panic and slipped away, but Fowey Fowey continued to hunt aggressively through the fog and called for help. Two British destroyers, continued to hunt aggressively through the fog and called for help. Two British destroyers, Whitshed Whitshed and and Ardent Ardent, and a French destroyer, Valmy Valmy, responded, as did a four-engine Sunderland flying boat of Coastal Command Squadron 228, piloted by Edward J. Brooks.

The four ships and the aircraft hunted the damaged U-55 U-55 relentlessly. relentlessly. Whitshed Whitshed got sonar contact and attacked with depth charges. By that time the got sonar contact and attacked with depth charges. By that time the U-55 U-55 crew could no longer contain the flooding. Believing he might escape in the fog, Heidel gave orders to surface and man the deck gun. crew could no longer contain the flooding. Believing he might escape in the fog, Heidel gave orders to surface and man the deck gun. Fowey Fowey sighted sighted U-55 U-55 making off in the fog and opened fire. making off in the fog and opened fire. Valmy Valmy and the Sunderland joined. The Sunderland dropped a bomb and, helpfully, a smoke float and then made a strafing run. Heidel returned the fire-until the breechblock of the gun jammed. and the Sunderland joined. The Sunderland dropped a bomb and, helpfully, a smoke float and then made a strafing run. Heidel returned the fire-until the breechblock of the gun jammed.

Gunless, unable to dive, Heidel was left no choice but to scuttle. The first watch officer and chief engineer volunteered to help Heidel open the vents. When the boat started under for the last time, there was no sign of Heidel. The survivors believed he chose to go down with the boat. The other forty-one men of the crew launched a rubber life raft, jumped into the icy water, and were picked up by Fowey Fowey and and Whitshed Whitshed.

The loss of U-55 U-55 was known immediately to Donitz. Eager to give a lift to the Coastal Command aviators who had patrolled the seas endlessly for months with no confirmed success, the RAF publicly claimed credit for the kill on January 31. The surface forces grudgingly conceded that the Sunderland may have helped-but not all that much. However, a British assessment committee gave Coastal Command partial credit for the kill along with was known immediately to Donitz. Eager to give a lift to the Coastal Command aviators who had patrolled the seas endlessly for months with no confirmed success, the RAF publicly claimed credit for the kill on January 31. The surface forces grudgingly conceded that the Sunderland may have helped-but not all that much. However, a British assessment committee gave Coastal Command partial credit for the kill along with Fowey Fowey and and Whitshed Whitshed. Doubtless some fault for the loss lay in Donitz's decision to send U-55 U-55 against an escorted convoy before she was adequately trained. against an escorted convoy before she was adequately trained.

The three large boats, U-25 U-25, U-41 U-41, and U-44 U-44, were directed to patrol off the Iberian Peninsula. Arrangements had been made for any or all of these boats to secretly refuel and replenish from a German ship, Thalia Thalia, which had been left in the Spanish port of Cadiz for that purpose.

The clumsy and cranky U-25 U-25 and the brand-new Type IX and the brand-new Type IX U-44 U-44 led the way. En route, both boats found good hunting in the Shetlands area. Viktor Schutze in led the way. En route, both boats found good hunting in the Shetlands area. Viktor Schutze in U-25 U-25 sank three freighters (one Swede, one Norwegian, and one British) for 13,000 tons. While passing southbound through the Western Approaches, Ludwig Mathes, age thirty-one, commanding sank three freighters (one Swede, one Norwegian, and one British) for 13,000 tons. While passing southbound through the Western Approaches, Ludwig Mathes, age thirty-one, commanding U-44 U-44, also sank three freighters (one Norwegian, one Greek, and one Dutch) for 14,000 tons.

After reaching the Iberian Peninsula, Mathes came across several convoys. Operating alone and shooting torpedoes that worked to perfection, in a period of ten days Mathes sank five more ships (two French, two Greek, and one Danish) for 15,500 tons. Distrustful of the proposed secret refueling in Cadiz, Mathes exercised a skipper's option and returned to Germany, where he was showered with ecstatic praise. Overcrediting him by 8,000 tons and perhaps forgetting that Hartmann in U-37 U-37 had also sunk eight ships in one patrol (for greater tonnage), Donitz declared the had also sunk eight ships in one patrol (for greater tonnage), Donitz declared the U-44 U-44 patrol to have been "perfectly executed" and the "most successful" to date against merchant shipping. patrol to have been "perfectly executed" and the "most successful" to date against merchant shipping.

Passing southbound through the Western Approaches, Viktor Schutze in U-25 U-25 sank his fourth ship. Since the OKM was anxious to test the secret Cadiz base and sank his fourth ship. Since the OKM was anxious to test the secret Cadiz base and U-44 U-44 had declined the opportunity, Donitz directed Schutze to refuel from had declined the opportunity, Donitz directed Schutze to refuel from Thalia Thalia. Schutze sneaked U-25 U-25 into Cadiz on the night of January 30, took on food, oil, and other supplies, and returned immediately to sea. There Schutze promptly sank his fifth ship, a 6,800-ton British freighter. into Cadiz on the night of January 30, took on food, oil, and other supplies, and returned immediately to sea. There Schutze promptly sank his fifth ship, a 6,800-ton British freighter.

At that time, ten German merchant ships in Vigo, Spain, were preparing to run through the British blockade to Germany. In order to provide them some protection, the OKM directed Donitz to assign U-25 U-25 as an escort. Donitz protested. Submarines were useless in an escort role. They could not keep up submerged; while traveling on the surface they were highly vulnerable to air attack. Nonetheless the OKM insisted. However, owing to yet another mechanical breakdown, Schutze had to abort the patrol and was thus unable to comply with the order. Limping home, in the Shetlands he sank his sixth ship, the 5,200-ton Danish tanker as an escort. Donitz protested. Submarines were useless in an escort role. They could not keep up submerged; while traveling on the surface they were highly vulnerable to air attack. Nonetheless the OKM insisted. However, owing to yet another mechanical breakdown, Schutze had to abort the patrol and was thus unable to comply with the order. Limping home, in the Shetlands he sank his sixth ship, the 5,200-ton Danish tanker Chastine Maersk Chastine Maersk, giving him a grand total of 27,335 tons, a remarkable achievement for this unsafe and unreliable boat.

The OKM insisted that Donitz provide the German ships in Vigo an escort. Accordingly, Donitz assigned the chore to the other Type IX, U-41 U-41, commanded by Gustav-Adolf Mugler, making his second Atlantic patrol. While en route to Vigo, Mugler ran into a convoy in the Western Approaches. Pausing to attack, Mugler severely damaged the 8,000-ton Dutch tanker Ceronia Ceronia and sank the 9,875-ton British freighter and sank the 9,875-ton British freighter Beaverburn Beaverburn. The lone convoy escort, the destroyer Antelope Antelope, pounced on U-41 U-41, fixed her on sonar, and dropped depth charges. Nothing more was ever heard from U-41 U-41. She was the fourth of the eight Type IXs of the Hundius Flotilla to be lost, the third to be sunk by depth-charge attack.

Donitz planned four minelaying missions for January, but only two Type VIIs, U-31 U-31 (Habekost) and (Habekost) and U-34 U-34 (Rollmann), were seaworthy. As a result, one mission was scrubbed and another was assigned to the leading torpedo shooter, Herbert Schultze in the VIIB (Rollmann), were seaworthy. As a result, one mission was scrubbed and another was assigned to the leading torpedo shooter, Herbert Schultze in the VIIB U-48 U-48. The three boats were to lay eight new, powerful TMC mines and carry six torpedoes. Neither Rollmann nor Schultze had laid a minefield; Habekost had laid the field in Loch Ewe that had damaged the battleship Nelson Nelson, a success still unknown to the Germans.

The two Type VIIs sailed first. On the way, Rollmann in U-34 U-34 attacked a 15,000-ton armed merchant ship with torpedoes, but they missed or malfunctioned. He then laid his mines in Falmouth. Habekost in attacked a 15,000-ton armed merchant ship with torpedoes, but they missed or malfunctioned. He then laid his mines in Falmouth. Habekost in U-31 U-31 returned to the dangerous waters of Loch Ewe. Either these two fields comprising sixteen mines were mislaid or the mines malfunctioned. They produced one sinking: the 7,800-ton British tanker returned to the dangerous waters of Loch Ewe. Either these two fields comprising sixteen mines were mislaid or the mines malfunctioned. They produced one sinking: the 7,800-ton British tanker Caroni River Caroni River in Rollmann's field at Falmouth. in Rollmann's field at Falmouth.

After laying these fields, both boats patrolled the Western Approaches with torpedoes. Rollmann sank a 5,600-ton Greek freighter, but Habekost experienced repeated torpedo failures and sank nothing. Homebound, Habekost came upon two British battleships and a heavy cruiser, but he was out of torpedoes.

Sailing on the last day of January, Herbert Schultze in U-48 U-48 was assigned to lay his mines in the dangerous waters off the British naval base at Portland, in the English Channel. Schultze believed he laid all eight TMC mines in the correct place, but they produced no sinkings. He withdrew to the Western Approaches to hunt ships with his six torpedoes and promptly sank a 6,900-ton Dutch freighter. was assigned to lay his mines in the dangerous waters off the British naval base at Portland, in the English Channel. Schultze believed he laid all eight TMC mines in the correct place, but they produced no sinkings. He withdrew to the Western Approaches to hunt ships with his six torpedoes and promptly sank a 6,900-ton Dutch freighter.

Five boats sailed from Helgoland in February to conduct torpedo patrols in the Atlantic. These were the clumsy and cranky Type I, U-26 U-26, three Type VIIBs, and the now-famous Type IX, U-37 U-37, still commanded by the Hundius Flotilla chief Werner Hartmann, who preferred the sea, however cold and miserable, to a desk and who hungered to sink ships and win a Ritterkreuz Ritterkreuz.

Before going on to regular patrolling, Hartmann had to carry out a dangerous special mission. The task was to land in Ireland two Abwehr Abwehr agents agents* who were to intensify anti-British sentiments. While passing outbound in the Orkneys and Shetlands, Hartmann got the patrol off to a promising start by sinking two ships (one British, one Norwegian) for 5,700 tons. Continuing south, on the night of February 8, he eased who were to intensify anti-British sentiments. While passing outbound in the Orkneys and Shetlands, Hartmann got the patrol off to a promising start by sinking two ships (one British, one Norwegian) for 5,700 tons. Continuing south, on the night of February 8, he eased U-37 U-37 into Dingle Bay on the southwest coast of Ireland and put the two agents ashore. But all for naught. Within a few days, intelligence or police officers detected and arrested both agents. into Dingle Bay on the southwest coast of Ireland and put the two agents ashore. But all for naught. Within a few days, intelligence or police officers detected and arrested both agents.

That done, Hartmann received orders from Donitz to carry out another special mission. B-dienst B-dienst had developed information that the carrier had developed information that the carrier Ark Royal Ark Royal and battle cruiser and battle cruiser Renown Renown were en route from the south Atlantic to Portsmouth, England, escorting the cruiser Exeter, which had been damaged in an engagement with the "pocket" battleship were en route from the south Atlantic to Portsmouth, England, escorting the cruiser Exeter, which had been damaged in an engagement with the "pocket" battleship Admiral Graf Spee Admiral Graf Spee. The OKM directed Donitz to lay a submarine trap at the west end of the English Channel, using The OKM directed Donitz to lay a submarine trap at the west end of the English Channel, using U-37 U-37 and Herbert Schultze's and Herbert Schultze's U-48 U-48 and any and all other available boats. and any and all other available boats.

Hartmann moved into a likely interception position, but Schultze ran across an outbound convoy and chased it 350 miles to the west. The chase netted Schultze three ships for 24,700 tons, including a 9,000-ton Dutch tanker, Den Haag Den Haag, and the 12,300-ton British refrigerator ship Sultan Star Sultan Star, but he had no torpedoes left and he had no desire to return to the submarine trap merely to serve as a lookout for Hartmann. When Schultze returned to Germany, Donitz first berated him for going too far west and leaving the trap, then praised him to high heavens. Schultze had not only planted a TMC minefield, but also had sunk four ships for 31,526 tons, raising his total confirmed score to sixteen ships for 109,200 tons. Schultze thus became the first skipper to sink 100,000 tons of enemy shipping. That feat earned him the coveted Ritterkreuz Ritterkreuz-the second such award after Prien's.

The U-26 U-26, commanded by a new skipper, Heinz Scheringer, age thirty-two, from the duck U-13 U-13, attempted to join Hartmann in the submarine trap, but he was slowed by heavy seas and arrived too late. Neither U-37 U-37 nor nor U-26 U-26 found the task force. After being released from the trap, both boats sank two ships in the Western Approaches, then proceeded to their original destination off the Iberian Peninsula. Hartmann arrived there, but the found the task force. After being released from the trap, both boats sank two ships in the Western Approaches, then proceeded to their original destination off the Iberian Peninsula. Hartmann arrived there, but the U-26 U-26 incurred a mechanical breakdown and Scheringer was forced to abort. On the way home he sank a third ship, bringing his total to three ships for 10,500 tons. incurred a mechanical breakdown and Scheringer was forced to abort. On the way home he sank a third ship, bringing his total to three ships for 10,500 tons.

The three VIIBs sailed from Helgoland last. Two of these, U-50 U-50 and and U-54 U-54, were brand-new boats, rushed into service undertrained. The U-50 U-50, commanded by Max-Hermann Bauer, age twenty-seven, son of the famous World War I submariner and historian Hermann Bauer, from the duck U-18 U-18, was compelled by an oil leak to abort in the North Sea, but resailed a few days later. The U-54 U-54, commanded by Gunter Kutschmann, age twenty-nine, disappeared without trace. It is thought that shortly after leaving Helgoland Kutschmann strayed off course and hit a German or a British mine in Helgoland Bight.* The The U-53 U-53, commanded by a new skipper, Harald Grosse, age thirty-three (replacing Heinicke), was delayed by a leaky conning-tower hatch.

Bauer's U-50 U-50 and Grosse's and Grosse's U-53 U-53 finally proceeded to the Atlantic. Rounding the British Isles, Bauer sank a 1,900-ton Swede in the Orkneys, then a 5,000-ton Dutch vessel west of Ireland. At about the same time, northwest of Scotland, Grosse sank four ships (two Swedes, a Norwegian and a Dane) for 11,500 tons and believed he had sunk a fifth, the 8,000-ton British tanker finally proceeded to the Atlantic. Rounding the British Isles, Bauer sank a 1,900-ton Swede in the Orkneys, then a 5,000-ton Dutch vessel west of Ireland. At about the same time, northwest of Scotland, Grosse sank four ships (two Swedes, a Norwegian and a Dane) for 11,500 tons and believed he had sunk a fifth, the 8,000-ton British tanker Imperial Transport Imperial Transport, but she limped into port. Eager to restore U-53 U-53's lost honor, Grosse broke radio silence to boast that he had sunk five ships for 30,000 tons. Then both he and Bauer continued south to the Iberian Peninsula by independent routes.

By mid-February Donitz believed that six boats were near or in "southern" waters. This number of boats offered another opportunity to attempt a pack attack on a convoy that B-dienst B-dienst had reported. He therefore directed the senior captain, Hartmann in had reported. He therefore directed the senior captain, Hartmann in U-37 U-37, to assume tactical command. But unknown to either Donitz or Hartmann, two boats had been lost (U-41 and and U-54 U-54) and one (U-26) had aborted, leaving only three in those waters: Hartmann's U-37 U-37, Bauer's U-50 U-50, and Grosse's U-53 U-53.

In an almost exact replication of the first wolf pack, which had been reduced from six boats to three, two of the three boats found the convoy and mounted a loosely coordinated attack. Hartmann in U-37 U-37 sank three freighters (one Greek, one French, one British) for 16,000 tons; Grosse shot at a French tanker, but his torpedoes prematured. By mistake, Grosse sank a prohibited neutral not in the convoy, the 2,140-ton Spanish freighter sank three freighters (one Greek, one French, one British) for 16,000 tons; Grosse shot at a French tanker, but his torpedoes prematured. By mistake, Grosse sank a prohibited neutral not in the convoy, the 2,140-ton Spanish freighter Banderas Banderas, unwisely sailing blacked out. Having expended all torpedoes, Hartmann in U-37 U-37 and Grosse in and Grosse in U-53 U-53 headed home. headed home.

Bauer in U-50 U-50 did not find the convoy. However, while patrolling alone off Lisbon, he found another. He sank two ships-a Dutch freighter and the 4,600-ton tanker did not find the convoy. However, while patrolling alone off Lisbon, he found another. He sank two ships-a Dutch freighter and the 4,600-ton tanker British Endeavor British Endeavor-and pursued, but during the chase one of his diesels broke down. Unable to make repairs at sea, Bauer was forced to abort and head home in the wakes of U-37 U-37 and and U-53 U-53.

While these three boats were inbound, news of the sinking of the prohibited Spanish vessel reached Berlin and Donitz. The Spanish professed to be Furious Furious. The sinking strained relations between Berlin and Madrid and jeopardized future clandestine refueling operations in Spanish ports. In his eagerness to restore U-53 U-53's lost honor, ironically Grosse had again besmirched the boat.

The U-53 U-53 did not have to answer for this latest sin. In the early hours of February 24, while rounding the British Isles, she was lost. A lone British destroyer, did not have to answer for this latest sin. In the early hours of February 24, while rounding the British Isles, she was lost. A lone British destroyer, Gurkha Gurkha, picked her up in the moonlight shortly after midnight. Gurkha Gurkha immediately turned to ram, but immediately turned to ram, but U-53 U-53, which was on an opposite course inside Gurkha Gurkha's turning circle, dived. Gurkha Gurkha threw over a depth charge "to keep her down," then obtained a "good" sonar contact and prepared for a proper attack. threw over a depth charge "to keep her down," then obtained a "good" sonar contact and prepared for a proper attack. Gurkha Gurkha made three passes over made three passes over U-53 U-53, dropping thirteen depth charges set at 150 and 250 feet. While reloading for a fourth pass, Gurkha Gurkha noted that the sonar echo "gradually faded away and was never heard again." The noted that the sonar echo "gradually faded away and was never heard again." The U-53 U-53 disappeared without trace in water 1,800 feet deep. She was the fourth of the VIIBs of the Wegener Flotilla to fall and the third to leave no survivors. The loss of sister ships disappeared without trace in water 1,800 feet deep. She was the fourth of the VIIBs of the Wegener Flotilla to fall and the third to leave no survivors. The loss of sister ships U-53 U-53, U-54 U-54, and U-55 U-55 within a period of four weeks-two on maiden patrols and all commanded by skippers making first patrols in VIIBs-did not go unremarked. within a period of four weeks-two on maiden patrols and all commanded by skippers making first patrols in VIIBs-did not go unremarked.

Werner Hartmann in U-37 U-37 again came home to rave reviews. He had successfully landed two agents in Ireland, dutifully set up the futile submarine trap for again came home to rave reviews. He had successfully landed two agents in Ireland, dutifully set up the futile submarine trap for Ark Royal Ark Royal, and duplicated his score on his prior patrol by sinking eight ships (including a trawler) for a total of sixteen. This tied Herbert Schultze's record for numbers of ships sunk, but not tonnage. Hartmann claimed 43,000 tons for this patrol, giving him 78,300 tons, but the true figure for the patrol was 24,539 tons, reducing his (confirmed) total to about 60,000 tons. Accepting Hartmann's claims ("80,000 tons in two patrols"), Admiral Raeder sent him and his crew a telegram of congratulations.

Bauer in U-50 U-50 also received rave reviews for his maiden-but aborted-first patrol. He claimed sinking six ships for 36,000 tons. He either greatly exaggerated the tonnage or had torpedo failures. His confirmed sinkings were four ships for 16,000 tons. also received rave reviews for his maiden-but aborted-first patrol. He claimed sinking six ships for 36,000 tons. He either greatly exaggerated the tonnage or had torpedo failures. His confirmed sinkings were four ships for 16,000 tons.

Donitz mounted four minelaying missions in February, all by Type VIIs of the Salzwedel Flotilla, finally out of the shipyards. Gunter Kuhnke in U-28 U-28 laid eight TMC mines off the British naval base at Portsmouth and afterward sank two ships by torpedo (one Dutch and one Greek) for 11,200 tons. Otto Schuhart in laid eight TMC mines off the British naval base at Portsmouth and afterward sank two ships by torpedo (one Dutch and one Greek) for 11,200 tons. Otto Schuhart in U-29 U-29, granted a "second chance," laid twelve TMBs in Bristol Channel and claimed sinking three British ships for 25,000 tons by torpedo on the way home. (Only two ships for 9,800 tons were confirmed in the postwar records.) This was success enough not only to warrant retaining his command but also to draw praise from the OKM. The U-32 U-32, with a new skipper, Hans Jenisch, age twenty-six (replacing Hans Buchel), who had sunk seven ships for 8,400 tons, including the destroyer Exmouth Exmouth while commanding while commanding U-22 U-22, planted twelve TMBs in Liverpool. On the way to and from Liverpool, Jenisch attacked three ships, firing seven torpedoes. Five torpedoes malfunctioned and two missed, but he sank a 2,800-ton Swede with his deck gun.

These three minefields, planted at great risk, produced scant returns. Kuhnke's TMCs off Portsmouth resulted in no sinkings.* Schuhart's TMBs in Bristol Channel bagged only a small (710-ton) coaster, which should not have triggered a mine. Jenisch's TMBs at Liverpool sank the only important ship: the 5,000-ton British freighter Schuhart's TMBs in Bristol Channel bagged only a small (710-ton) coaster, which should not have triggered a mine. Jenisch's TMBs at Liverpool sank the only important ship: the 5,000-ton British freighter Counsellor Counsellor.

The fourth-and riskiest-mine mission was assigned to von Dresky's U-33 U-33. He was to plant eight TMC mines at the British naval base in the Firth of Clyde, where Buchel in U-32 U-32 had failed earlier. Von Dresky nosed submerged into the Firth of Clyde in the early hours of February 12. Moments later, an ASW patrol boat, the minesweeper had failed earlier. Von Dresky nosed submerged into the Firth of Clyde in the early hours of February 12. Moments later, an ASW patrol boat, the minesweeper Gleaner Gleaner, detected U-33 U-33 by hydrophone. Seeing by hydrophone. Seeing Gleaner Gleaner's searchlight sweeping the water, von Dresky mistook her for a heavy cruiser. Believing the "cruiser" might pass out to sea, he laid U-33 U-33 on the bottom at 183 feet to wait. on the bottom at 183 feet to wait. Gleaner Gleaner fixed fixed U-33 U-33 on sonar and dropped six depth charges set for 150 feet, four of which exploded directly over on sonar and dropped six depth charges set for 150 feet, four of which exploded directly over U-33 U-33, pounding the boat and causing severe leaking.

The attack caught von Dresky by complete surprise. Believing the attacker to be a destroyer, his men urged him to get U-33 U-33 off the bottom and evade to sea, but von Dresky appeared to be paralyzed. Another five charges from off the bottom and evade to sea, but von Dresky appeared to be paralyzed. Another five charges from Gleaner Gleaner, which exploded close and increased the flooding, brought him to life. Believing the boat to be doomed, he ordered his men to surface, scuttle, and abandon ship. Since U-33 U-33 carried an Enigma carried an Enigma and could be salvaged, he distributed the Enigma rotors among the officers, instructing them to swim well away from the boat and discard them. and could be salvaged, he distributed the Enigma rotors among the officers, instructing them to swim well away from the boat and discard them.

When U-33 U-33 surfaced, surfaced, Gleaner Gleaner spotted her at once, opened fire with her 4" gun, and turned to ram. However, when spotted her at once, opened fire with her 4" gun, and turned to ram. However, when Gleaner Gleaner's captain saw the U-33 U-33 crew come on deck, arms raised in surrender, he checked fire after five rounds and lay to alongside crew come on deck, arms raised in surrender, he checked fire after five rounds and lay to alongside U-33 U-33. Meanwhile, von Dresky ordered the engineer to set in motion the scuttling procedures. The first attempt failed but the second succeeded-trapping the engineer below. The U-33 U-33 plunged down by the bow, and the crew jumped into the frigid water. Von Dresky exhorted the men to keep together. Many, including von Dresky, died quickly of shock, exposure, or hypothermia. From a total crew of forty-two, only seventeen men, including three officers, lived to become POWs. The British recovered three Enigma rotors from the officers of plunged down by the bow, and the crew jumped into the frigid water. Von Dresky exhorted the men to keep together. Many, including von Dresky, died quickly of shock, exposure, or hypothermia. From a total crew of forty-two, only seventeen men, including three officers, lived to become POWs. The British recovered three Enigma rotors from the officers of U-33 U-33. These were helpful to the codebreakers at Bletchley Park but not sufficiently so to penetrate naval Enigma.

Donitz knew at once that U-33 U-33 was lost and the minelaying at the Firth of Clyde had failed for the second time. His source was was lost and the minelaying at the Firth of Clyde had failed for the second time. His source was B-dienst B-dienst, which, remarkably, intercepted three signals from Gleaner Gleaner. The first was an alarm at 0525, reporting U-33 U-33 to be on the surface; the second, at 0530, was a notice stating that the to be on the surface; the second, at 0530, was a notice stating that the U-33 U-33 crew was surrendering; and the third, at 0545, was a request for assistance in rescuing the crew. crew was surrendering; and the third, at 0545, was a request for assistance in rescuing the crew.

Counting the seven mining missions, Donitz had mounted eighteen patrols to the Atlantic in the months of January and February, 1940. Five of the eighteen boats had been lost (U-33, U-41 U-41, U-53 U-53, U-54 U-54, U-55 U-55). Three (U-25, U-50 U-50, U-51 U-51) had aborted with mechanical defects. Yet in spite of torpedo and mine problems and unfavorable weather conditions, the eighteen boats had sunk by torpedo or mine fifty-eight ships for 233,496 tons, almost all of them sailing alone. This was an average of 3.2 ships sunk per boat per patrol, a significant improvement over the averages for the earlier months. On March 1, the six leading skippers in tonnage sunk were Schultze, Prien, Hartmann, Schuhart, Rollmann, and Lemp.

When the surviving February boats returned from the Atlantic, Donitz had galvanizing news. Hitler had ordered the military conquest of Norway (and Denmark), to take place anytime after March 10. All available U-boats, including ducks, were to participate. Commencing March 1, the U-boat war against shipping in the Atlantic was suspended indefinitely.

The withdrawal of the Atlantic U-boats for operations in Norway provides a convenient milepost for assessing the results of the U-boat campaign in the first seven months of the war, to April 1, 1940. That assessment can best be made by a careful study of a host of statistics that challenge some and exasperate others, then as now. In brief: * All U-boats (oceangoing and ducks) in all areas sank by torpedo, gun, mine, and demolition a total of 277 ships for about 974,000 tons, including twenty-six trawlers, almost all of them sailing alone or out of convoy.* In addition, the oceangoing boats captured four prizes. The North Sea ducks sank 41 percent of all the ships (113) and about 25 percent of the tonnage (238,000). In addition, the oceangoing boats captured four prizes. The North Sea ducks sank 41 percent of all the ships (113) and about 25 percent of the tonnage (238,000).

* Of the 277 ships sunk, 118 (43 percent) were British, including the twenty-six trawlers. The loss of ninety-two British ships other than trawlers in seven months amounted to about 3 percent of the 3,000 vessels of the oceangoing British merchant fleet. In the same seven months, the British captured, bought, or chartered ninety-two ships from foreign sources, offsetting the British losses to U- boats. Moreover, in the same period, British shipyards produced about 700,000 tons of new shipping, much of it for the merchant marine. Thus, in the first seven months of war, the British merchant marine grew grew, rather than shrank.

* Of the 277 ships sunk by U-boats, surprisingly few were tankers: only twenty-three of about 170,000 tons. Of these, fourteen for about 100,000 tons were British-owned. The other nine were French, Norwegian, Danish, Swedish, or Dutch. The British tanker losses were more than offset by captures or seizures, by new construction, and by purchase and charter of foreign vessels. Thus there was a net gain gain in the British-controlled tanker fleet. in the British-controlled tanker fleet.*

* Notwithstanding the growth of the merchant fleet in these seven months, British imports fell 25 percent, from a rate of about 60 million tons a year to about 45 million tons a year. The drop was caused by convoying. It was not a drop of one-third, as Churchill predicted it would be, but about one-quarter. The drop was inconvenient and led to belt-tightening and scattered deprivation, but it was nowhere near a threat to Britain's survival.

* In the same seven months, U-boat losses were heavy, a total of seventeen (30 percent of the force) to all causes: four ducks, eight VIIs and five IXs, manned by about 650 submariners. The loss of oceangoing boats was offset in part by new construction: eight boats, of which four were VIIs and four were IXs. Thus the total number of oceangoing U-boats of the Atlantic force decreased from twenty-seven to twenty-two, of which two, U-25 U-25 and and U-26 U-26, were marginal and several others were out of action for extended repairs. The addition of the marginal Turkish boat, U-A U-A, raised the Atlantic force to twenty-three oceangoing boats by the end of March 1940.

To this point in the U-boat war, both London and Berlin claimed "victory." However, the figures suggest something like a draw. In any case, the U-boats had yet to pose a serious threat to British maritime assets. The real U-boat peril-if it ever fully materialized-lay not in the summer of 1940 as Churchill projected but in the far distant future, 1942 and beyond. Moreover, contrary to Churchill's assertions, U-boat crews had not waged war barbarically or murderously or with callous disregard for the safety of enemy mariners. For the most part, the Germans had conducted submarine warfare in a fair-and at times even chivalrous-manner. As Donitz was to stress again and again, he ran "a clean firm" and he intended it to stay that way.

One important factor in this naval war was the increasingly anti-German, pro-British attitude of President Roosevelt. It was he who had engineered the relaxation of the Neutrality Act, which enabled American firms to sell arms to the British and French. He had also turned a blind eye to the transfer of American tankers to "Panamanian" registry, so that they could transport oil directly into the declared war zones. In addition, Roosevelt had masterminded the "Declaration of Panama" (October 2, 1939), a conference at which twenty-one American republics (not including Argentina) established a Western Hemisphere "Security Zone" that barred belligerents from "conducting warlike operations." Moreover, Roosevelt had directed the U.S. Navy to put in place a "Neutrality Patrol" to enforce the declaration. Not least, Roosevelt, anticipating the forthcoming need for merchant shipping, had again urged Jerry Land at the Maritime Commission to increase significantly America's cargo and tanker shipbuilding capacity.

THE U U-BOAT F FAILURE IN N NORWAY.

Winston Churchill urged the Allied governments to occupy Norway to shut off the wintertime flow of Swedish iron ore from Narvik to Germany, to gain air and naval bases to attack Germany and bottle up the Kriegsmarine Kriegsmarine in the North Sea, and to deny this strategic area to Germany and/or the Soviet Union. After March 12, when the gallant Finns were finally crushed by Soviet forces, Neville Chamberlain and the new French Prime Minister, Paul Reynaud, approved a plan to occupy Norway, and by way of preparation, the Royal Navy's Home Fleet returned to Scapa Flow. in the North Sea, and to deny this strategic area to Germany and/or the Soviet Union. After March 12, when the gallant Finns were finally crushed by Soviet forces, Neville Chamberlain and the new French Prime Minister, Paul Reynaud, approved a plan to occupy Norway, and by way of preparation, the Royal Navy's Home Fleet returned to Scapa Flow.

By that time Hitler had completed his his plan for the occupation of Norway. It was daring and intricate. Small groups of airborne and seaborne shock troops were to simultaneously seize five key Norwegian seaports in a surprise assault. The plan for the occupation of Norway. It was daring and intricate. Small groups of airborne and seaborne shock troops were to simultaneously seize five key Norwegian seaports in a surprise assault. The Kriegsmarine Kriegsmarine was to play the major role in the campaign. Its ships were to dash out under cover of darkness, deliver the seaborne troops, then dash back to Germany before the superior Home Fleet or the RAF had time to react. was to play the major role in the campaign. Its ships were to dash out under cover of darkness, deliver the seaborne troops, then dash back to Germany before the superior Home Fleet or the RAF had time to react.

The Germans were aware of the Allied plans to occupy Norway and therefore realized they were engaged in a race. But owing to the heavy ice in the Baltic Sea, and Raeder's insistence that the operation be carried out when the moon was "new" (or dimmest) and to other factors, D day had to be put off to April 9. Meanwhile, to thwart an Allied occupation of Norway before the Germans could get there, Hitler directed the Luftwaffe Luftwaffe to mount an all-out attack on the Home Fleet at Scapa Flow and the U-boat arm to patrol the North Sea, both offensively and defensively, concentrating its power against Allied warships and troopships. to mount an all-out attack on the Home Fleet at Scapa Flow and the U-boat arm to patrol the North Sea, both offensively and defensively, concentrating its power against Allied warships and troopships.

This was the first time in history that an entire submarine force (however small) had been called upon to participate in a major military campaign involving close cooperation with air, sea, and ground forces. It was to be a radical-and risky-change in roles. Theretofore U-boats for the most part had patrolled alone in distant, deep, open seas with a fair degree of freedom, attacking mostly lone merchant ships with stealth and surprise and evading escorts and U-boat killers. During the Norway operation, they were to operate under very tight control in the confined waters of the North and Norwegian seas, aswarm with enemy aircraft and submarines, attacking Allied warships and troopships, which were certain to be on fullest alert for U-boats.

First and above all else, the U-boat arm had to thwart an Allied amphibious invasion of Norway. Receiving B-dienst B-dienst intercepts indicating that such an invasion was imminent, on March 11 the OKM directed Donitz to immediately deploy ten oceangoing boats off Norway and twelve ducks in the lower North Sea to repel the supposed invasion. intercepts indicating that such an invasion was imminent, on March 11 the OKM directed Donitz to immediately deploy ten oceangoing boats off Norway and twelve ducks in the lower North Sea to repel the supposed invasion.

In the early stages of this deployment, two of the ten oceangoing boats were lost. On March 11, an RAF Blenheim bomber spotted the Type VII U-31 U-31, commanded by Johannes Habekost, on the surface, in home waters, near Wilhelmshaven. Skillfully using cloud cover, pilot Miles Villiers Delap eased in over U-31 U-31 and dropped four improved 250-pound bombs. The and dropped four improved 250-pound bombs. The U-31 U-31 blew up and sank instantly in 102 feet of water, killing her entire crew as well as ten diesel-engine specialists and shipyard workers. She was the first U-boat to be sunk by an aircraft, but she was raised and salvaged. About two days later, probably on March 13, the outbound Type IX blew up and sank instantly in 102 feet of water, killing her entire crew as well as ten diesel-engine specialists and shipyard workers. She was the first U-boat to be sunk by an aircraft, but she was raised and salvaged. About two days later, probably on March 13, the outbound Type IX U-44 U-44, commanded by the promising new skipper, Ludwig Mathes, struck a mine in the Helgoland Bight and also went down instantly with all hands. Donitz substituted another boat for U-31 U-31, but he was unaware of the loss of U-44 U-44 for many days. for many days.

The ten oceangoing boats were directed to patrol defensively off three major Norwegian ports: Narvik, 1,000 miles distant. Four Type VIIBs were sent there: U-46 U-46 (Sohler), from retraining in torpedo shooting; (Sohler), from retraining in torpedo shooting; U-47 U-47 (Prien), from ninety days in refit; (Prien), from ninety days in refit; U-49 U-49 (von Gossler), from ninety days of battle-damage repair; and (von Gossler), from ninety days of battle-damage repair; and U-51 U-51 (Knorr), which had made one prior (aborted) patrol to the Atlantic in January. (Knorr), which had made one prior (aborted) patrol to the Atlantic in January.

Trondheim, 750 miles distant. Two Type VIIs were sent there: U-30 U-30 (Lemp) and (Lemp) and U-34 U-34 (Rollmann), both from refit following Atlantic minelaying missions. (Rollmann), both from refit following Atlantic minelaying missions.

Bergen, 450 miles distant. Four boats were sent there: one Type VIIB, the U-52 U-52, commanded by Otto Salmann, which had been sabotaged in December and, except for a brief, barren patrol in September under another skipper, had not seen any action, and three Type IXs: U-38 U-38 (Liebe), which had made a long, interesting but largely fruitless patrol to Murmansk; (Liebe), which had made a long, interesting but largely fruitless patrol to Murmansk; U-43 U-43 (Ambrosius), from ninety days of battle-damage repairs; and (Ambrosius), from ninety days of battle-damage repairs; and U-44 U-44 (Mathes), which, unknown to Donitz, was already lost. (Mathes), which, unknown to Donitz, was already lost.

While these boats were moving into position, on the night of March 16 the Luftwaffe Luftwaffe struck Scapa Flow. The raid was carried out by twenty-nine JU-88s and HE-111s, many dropping huge (2,200-pound) bombs. The struck Scapa Flow. The raid was carried out by twenty-nine JU-88s and HE-111s, many dropping huge (2,200-pound) bombs. The Luftwaffe Luftwaffe pilots reported great success: two direct hits on a battleship, one hit on another battleship or battle cruiser, one hit on a battle cruiser, one hit on a heavy cruiser, and near hits on other battleships. In fact, only the cruiser pilots reported great success: two direct hits on a battleship, one hit on another battleship or battle cruiser, one hit on a battle cruiser, one hit on a heavy cruiser, and near hits on other battleships. In fact, only the cruiser Norfolk Norfolk was damaged. was damaged.

Believing that all these supposedly damaged capital ships would limp to home ports for repairs, or that the entire Home Fleet might again abandon Scapa Flow, the OKM ordered Donitz to form an "attack group" of oceangoing boats to intercept them. Accordingly, Donitz diverted five such boats bound for Norway (including the lost U-44 U-44) to positions west of the Orkneys. The other five boats continued to Norway.

To avoid another Luftwaffe Luftwaffe attack, the Home Fleet did in fact leave Scapa Flow on March 19. At dawn that day, Prien in attack, the Home Fleet did in fact leave Scapa Flow on March 19. At dawn that day, Prien in U-47 U-47 spotted three battleships, escorted by destroyers. Prien was submerged; the battleships were about five miles off, running at high speed. Since the ships were beyond torpedo range, there was nothing Prien could do. Owing to the heavy enemy air, patrols in the Orkneys, he could not surface to report until dark. No other U-boats of the attack group saw these ships. spotted three battleships, escorted by destroyers. Prien was submerged; the battleships were about five miles off, running at high speed. Since the ships were beyond torpedo range, there was nothing Prien could do. Owing to the heavy enemy air, patrols in the Orkneys, he could not surface to report until dark. No other U-boats of the attack group saw these ships.

Donitz held the attack group in the Orkneys for about ten days. Two of the four boats found targets. Liebe in U-38 U-38 sank three Danish ships for 10,300 tons; Prien in sank three Danish ships for 10,300 tons; Prien in U-47 U-47 sank a Dane for 1,146 tons. All the boats encountered foul weather and intense ASW measures-air patrols and destroyer hunter-killer groups. For the second time sank a Dane for 1,146 tons. All the boats encountered foul weather and intense ASW measures-air patrols and destroyer hunter-killer groups. For the second time U-47 U-47 was depth charged, but she incurred no serious damage. was depth charged, but she incurred no serious damage.

Believing the attack group was a "waste of time," Donitz urged the OKM to replace it with ducks. The OKM agreed to that but insisted that some oceangoing boats remain in the Orkneys area until the ducks arrived. Accordingly, Donitz reshuffled the oceangoing boats. He recalled (the lost) U-44 U-44 (Mathes), (Mathes), U-47 U-47 (Prien), and (Prien), and U-49 U-49 (von Gossler) to Wilhelmshaven to replenish for Norway, left (von Gossler) to Wilhelmshaven to replenish for Norway, left U-38 U-38 (Liebe) and (Liebe) and U-43 U-43 (Ambrosius) in place, and brought (Ambrosius) in place, and brought U-52 U-52 (Salmann) from Bergen. Liebe sank a Norwegian freighter, but neither (Salmann) from Bergen. Liebe sank a Norwegian freighter, but neither U-43 U-43 or or U-52 U-52 found targets. When the ducks arrived on about April 1, Donitz recalled these three oceangoing boats to Wilhelmshaven. found targets. When the ducks arrived on about April 1, Donitz recalled these three oceangoing boats to Wilhelmshaven.

The four boats assigned to patrol defensively off Norway were restricted to sinking enemy warships, submarines, and troopships. Off Trondheim, Lemp in U-30 U-30 found and attacked a British submarine, but his torpedoes missed or malfunctioned. None of the other boats found any permissible targets. Donitz left found and attacked a British submarine, but his torpedoes missed or malfunctioned. None of the other boats found any permissible targets. Donitz left U-46 U-46 (Sohler) and (Sohler) and U-51 U-51 (Knorr) off Norway but recalled (Knorr) off Norway but recalled U-30 U-30 and and U-34 U-34 for replenishment. The for replenishment. The U-46 U-46 remained at Narvik; the remained at Narvik; the U-51 U-51 went south to replace went south to replace U-30 U-30 and and U-34 U-34 at Trondheim. Inbound, at Trondheim. Inbound, U-30 U-30 (Lemp) rescued a (Lemp) rescued a Luftwaffe Luftwaffe air crew that had ditched. The two recalled boats were hurriedly made ready to help repel the invasion. air crew that had ditched. The two recalled boats were hurriedly made ready to help repel the invasion.

Fourteen ducks deployed into the North Sea in March. Two of these, replacing the oceangoing attack group in the Orkneys, found targets. Joachim Schepke in U-19 U-19 sank four small Danish freighters for 5,500 tons. Claus Korth in sank four small Danish freighters for 5,500 tons. Claus Korth in U-57 U-57 sank two ships for 7,000 tons, including the 5,700-ton British tanker sank two ships for 7,000 tons, including the 5,700-ton British tanker Daghestan Daghestan, which had been damaged by the Luftwaffe Luftwaffe. No other ducks sank ships. Two ducks were lost: U-21 U-21, commanded by Wolf Stiebler, which ran aground off Norway and was later salvaged, and U-22 U-22, commanded by Karl-Heinrich Jenisch, which disappeared off northeast Scotland with the loss of all hands, probably the victim of a British mine. The twelve surviving ducks returned to Germany to prepare for the invasion.

In total, twenty-four U-boats had deployed in March to thwart the supposed Allied invasion. But it was all a waste of time. For various political and military reasons, the Allies had also been forced to postpone Norway operations. Liebe, Prien, Schepke, and Korth had sunk twelve small freighters for 28,000 tons. Against that inconsequential score, four boats had been lost: the oceangoing U-31 U-31 (salvaged) and (salvaged) and U-44 U-44, and two ducks, U-21 U-21 (salvaged) and (salvaged) and U-22 U-22. The crews of the other twenty boats, poised for the greatest challenge the U-boat arm had yet faced, were exhausted from these nerve-racking patrols, but they had no time to rest and recuperate.

On the eve of the German invasion of Norway, April 1, the U-boat arm had shrunk to forty-eight commissioned boats, nine fewer than the day the war began. Donitz deployed thirty-two of the forty-eight for the invasion: fourteen of the twenty-two oceangoing boats and eighteen of the twenty-six ducks. At the insistence of the OKM, two of the fourteen oceangoing boats first had to carry out special missions: temporary escort service for the outbound merchant-ship "raiders," Atlantis Atlantis and and Orion Orion* The other twelve oceangoing boats, including the VIIBs The other twelve oceangoing boats, including the VIIBs U-47 U-47 and and U-52 U-52, still on patrol, were assigned to waiting positions in the most distant waters, north of Bergen. The eighteen ducks were assigned to waiting positions south of Bergen and in the lower North Sea.

The Germans invaded Norway and Denmark on the morning of April 9. By nightfall, German forces held all the key cities in both nations! Outwitted, the Allies were shocked by the swiftness and efficiency of the operation. They hastily geared up for air, sea, and land counterattacks in Norway.

The Kriegsmarine Kriegsmarine incurred grievous losses. British naval forces trapped ten fleet destroyers at Narvik. Norwegian shore batteries sank the heavy cruiser incurred grievous losses. British naval forces trapped ten fleet destroyers at Narvik. Norwegian shore batteries sank the heavy cruiser Blucher Blucher at Oslo. British aircraft, flying from the Orkneys, sank the light cruiser at Oslo. British aircraft, flying from the Orkneys, sank the light cruiser Konigsberg Konigsberg at Bergen. A British submarine, at Bergen. A British submarine, Truant Truant, fatally holed the light cruiser Karlsruhe Karlsruhe at Kristiansand. British submarines and the Polish submarine at Kristiansand. British submarines and the Polish submarine Orzel Orzel sank six or more merchant ships in the supply train. British and/or Norwegian forces slightly damaged the sank six or more merchant ships in the supply train. British and/or Norwegian forces slightly damaged the Gneisenau Gneisenau and and Scharnhorst Scharnhorst, the "pocket" battleship Deutschland Deutschland (renamed (renamed Lutzow Lutzow), the new heavy cruiser Hipper Hipper, the light cruiser Emden Emden, and an old training cruiser, Bremse Bremse.

The gravest setback for the Germans on D day occurred in Narvik, where British naval forces trapped the ten fleet destroyers. A picture-postcard town nestled at the foot of majestic snow-covered mountains, Narvik is about 120 miles north of the Arctic Circle on the latitude of northernmost Alaska, yet owing to the warm sea wash from the Gulf Stream, it is ice-free year around. To mariners it is both spellbinding and challenging. To reach it they must transit nearly sixty miles of twisting narrow fjords, first Vest, then Ofot, mindful of the 11-foot tidal changes that occur four times daily, creating swift, swirling currents.