Had it not been for the two productive minefields planted by U-13 U-13 and and U-15 U-15, the returns from the North Sea ducks and the Type VII U-36 U-36 would have been deeply disappointing. The twenty-three ducks (some making two patrols) and would have been deeply disappointing. The twenty-three ducks (some making two patrols) and U-36 U-36 sank by torpedo or demolitions, or captured, only thirteen small ships for 16,751 tons: two British and eleven neutrals. However, the two minefields added five sinkings for 15,575 tons, raising the total kills or captures by all ducks and sank by torpedo or demolitions, or captured, only thirteen small ships for 16,751 tons: two British and eleven neutrals. However, the two minefields added five sinkings for 15,575 tons, raising the total kills or captures by all ducks and U-36 U-36 in the North Sea to a not inconsequential eighteen ships for 32,326 tons. But the greatest value of the North Sea patrolling was not in numbers. It provoked terror and convoying, and it was a perfect training ground for U-boat officers and men. Almost all the duck skippers-Kretschmer, Schepke, others-would soon "graduate" to Atlantic boats. in the North Sea to a not inconsequential eighteen ships for 32,326 tons. But the greatest value of the North Sea patrolling was not in numbers. It provoked terror and convoying, and it was a perfect training ground for U-boat officers and men. Almost all the duck skippers-Kretschmer, Schepke, others-would soon "graduate" to Atlantic boats.

POISED FOR A N NAVAL R RACE.

The bemedaled U-boat sailors had good reasons to swagger in the bars of Wilhelmshaven and Kiel. For political ends, Hitler had forbidden Luftwaffe Luftwaffe attacks on Great Britain and the Royal Navy. Only German submariners had carried the war to England in the first month of hostilities. attacks on Great Britain and the Royal Navy. Only German submariners had carried the war to England in the first month of hostilities.* Although the statistical returns (sinkings per boat) had been disappointing, in aggregate U-boats had landed stinging psychological and physical blows. The first wave had sunk thirty-nine British ships, including the carrier Although the statistical returns (sinkings per boat) had been disappointing, in aggregate U-boats had landed stinging psychological and physical blows. The first wave had sunk thirty-nine British ships, including the carrier Courageous Courageous and five important tankers, and five important tankers, against the loss of two U-boats and eighty-one men-all captured. They had created panic and confusion at sea and prompted the British decision to initiate convoying, which, as Churchill estimated, was to reduce imports by about one-third, and to wear down hundreds of aircraft and ships on ASW missions, and to divert scores of other vessels to minelaying and minesweeping. against the loss of two U-boats and eighty-one men-all captured. They had created panic and confusion at sea and prompted the British decision to initiate convoying, which, as Churchill estimated, was to reduce imports by about one-third, and to wear down hundreds of aircraft and ships on ASW missions, and to divert scores of other vessels to minelaying and minesweeping.

Besides that, and of transcendent importance, during September, while the U-boat sailors were at sea, Hitler had approved a switch from the Z Plan to the construction of a massive U-boat arm. The main emphasis was to be on the improved mediums (VIIBs, VIICs), which Donitz had been urging for three years. Sixteen shipyards were to tool up for U-boat construction, thirteen for the mediums and three for improved Type IXs (IXB, IXC).* In approving the switch, Hitler assured Raeder that U-boat construction was to take priority over most Third Reich military programs, including the In approving the switch, Hitler assured Raeder that U-boat construction was to take priority over most Third Reich military programs, including the Luftwaffe Luftwaffe's improved JU-88 (Stuka) dive bomber, and that skilled shipwrights who had been drafted into the Wehrmacht Wehrmacht were to be released. The program envisioned a buildup to a production rate of twenty to thirty U-boats per month. Long the impoverished stepchild of the were to be released. The program envisioned a buildup to a production rate of twenty to thirty U-boats per month. Long the impoverished stepchild of the Kriegsmarine Kriegsmarine, the U-boat force was to become its dominant arm, as it had in World War I.

It would take time-much time-to tool up and build all these U-boats. No one was exactly certain how much time; that would depend upon a number of factors, including the sincerity of Hitler's promises of priorities for materials and the release of skilled shipyard labor from the Wehrmacht Wehrmacht. At the very least, Donitz estimated, it would be nearly two years-the late summer of 1941-before U-boats began to join the force in significant numbers. In the meantime, owing to the current glacial pace of U-boat construction, which could barely keep pace with actual and predicted battle losses, the "U-boat war" could be little more than psychological warfare, a reign of terror.

The extent of the daunting challenge facing the U-boat force bears repeating. Not counting coasters and other vessels of 1,600 tons or less, the merchant fleet of the British Commonwealth comprised about 3,000 ships of about 17.5 million gross tons. Of these ships, about 450 were tankers of about 3.2 million gross tons. By way of comparison, the United States merchant marine was only about half that size: about 1,400 ships of about 8.5 million gross tons, including about 390 tankers of about 2.8 million gross tons, plus another sixty-four tankers registered in Panama. Excluding those of Italy and Japan, the third-ranking merchant marine fleet was that of Norway, with about 800 ships of about 4.2 million gross tons, including 268 tankers of 2.1 million gross tons.

To offset the loss of shipping-and imports-caused by U-boats and convoying, and to wage effective warfare, Churchill concluded that the Commonwealth was to require about 3 million gross tons of new merchant ships annually. At his urging the War Cabinet approved an emergency program to build ever greater numbers of cargo ships and tankers. However, British shipyards, already jammed with orders for new warships and hobbled by antiquated construction methods and labor problems, could produce less than half the wartime need: about 1.2 million gross tons per year.

PLATE 6 6.

There were several ways to make up the predicted shortfall. The first and cheapest way was to seize German merchant ships at sea. Another way was to purchase "laid up" ships from the United States.* Yet another way, a very expensive one, was to charter merchant ships from Norway, Greece, and the Netherlands. In the first eight months of war the British brought under control about 100 ships of about a half million gross tons from these sources. Yet another way, a very expensive one, was to charter merchant ships from Norway, Greece, and the Netherlands. In the first eight months of war the British brought under control about 100 ships of about a half million gross tons from these sources.

Apart from the sale of a few "laid up" ships, the United States could not provide Britain any meaningful assistance. That was because of the 1935 Neutrality Act. This act strictly forbade American merchant ships from entering declared war zones to trade with "belligerents" and, as one enforcement measure, forbade the arming of American merchant ships. The act was modified November 11, 1939, to allow the British to purchase armaments from United States firms on a "cash and carry" basis, but the restrictions on American shipping remained in force and the British had to transport the armaments in Commonwealth vessels.

The American merchant-ship construction industry was only just emerging from a deep sleep. The slow awakening had been prompted by the U.S. Maritime Commission, which Roosevelt had established in 1936 to help upgrade America's aged dry-cargo fleet.* Under the chairmanship of a feisty retired rear admiral, Emory S. ("Jerry") Land, in prewar days the commission had embarked on a ten-year program to build fifty new ships a year. In pursuit of that objective, the commission had designed and ordered several prototypes of big, fast, modern tankers and dry-cargo ships. In the year 1939, the commission delivered the first ships of the new program (twenty-eight for 242,000 gross tons), all to the United States merchant marine fleet. Under the chairmanship of a feisty retired rear admiral, Emory S. ("Jerry") Land, in prewar days the commission had embarked on a ten-year program to build fifty new ships a year. In pursuit of that objective, the commission had designed and ordered several prototypes of big, fast, modern tankers and dry-cargo ships. In the year 1939, the commission delivered the first ships of the new program (twenty-eight for 242,000 gross tons), all to the United States merchant marine fleet.

Upon the outbreak of war in Europe, Roosevelt directed Jerry Land to draw up contingency plans for a massive expansion of the American shipbuilding industry. Land produced these plans-and the specifications required to carry them out-promptly. Thus the stage was set for a maritime race of unprecedented scale. On the one hand, the Germans were poised to build hundreds of U-boats. On the other hand, the Allies were poised to build hundreds of merchant ships. The outcome of this maritime race was to profoundly influence the entire course of World War II.

Donitz later suggested-and others have echoed him-that if Hitler and Raeder had listened to him and had built 300 U-boats in the prewar years, the U-boat arm alone could have won the naval battle promptly. This is nonsense. A peacetime U-boat construction program of that size would have been exceptionally provocative. It would have forced Hitler to abrogate his prized 1935 naval treaty with Britain almost as soon as it was signed, introducing a complex new geopolitical climate. In that era of intensely competing naval powers and renewed naval construction, it is unlikely that the British Admiralty would have sat on its hands and not proceeded to build U-boat counterforces, such as large fleets of destroyers and modern ASW aircraft. Moreover, a massive U-boat construction program would almost certainly have triggered the construction of a counterforce by the United States Navy, which, as one contingency, had to plan against a German defeat of the Royal Navy and the possibility of German naval aggression in the western hemisphere.

* The U-boats and skippers are described in The U-boats and skippers are described in appendices 1 appendices 1 and and 2 2.

Northabout the British Isles, it is about 1,400 sea miles from Wilhelmshaven to the western mouth of the English Channel. Northabout the British Isles, it is about 1,400 sea miles from Wilhelmshaven to the western mouth of the English Channel.

* Early submarines had glass portholes in the conning tower, enabling the boat to be steered, or conned, on the surface from this elevated space. But glass portholes could not withstand depth-charge explosions and had been eliminated. While traveling on the surface, the boat was actually conned from the bridge above the conning tower. Early submarines had glass portholes in the conning tower, enabling the boat to be steered, or conned, on the surface from this elevated space. But glass portholes could not withstand depth-charge explosions and had been eliminated. While traveling on the surface, the boat was actually conned from the bridge above the conning tower.

Submarine candidates practiced escape procedures ashore in control-room mockups built into the bottom of water towers. Not surprisingly, many candidates failed this scary test. Submarine candidates practiced escape procedures ashore in control-room mockups built into the bottom of water towers. Not surprisingly, many candidates failed this scary test.

* So rigged, the maximum cruising speed was a leisurely 6 knots. So rigged, the maximum cruising speed was a leisurely 6 knots.

* A large, fast commercial vessel fitted with 5" or 6" guns, hence, a warship. A large, fast commercial vessel fitted with 5" or 6" guns, hence, a warship.

* The American ambassador to Great Britain, Joseph P. Kennedy, sent an official embassy delegation to Ireland to assist the American survivors and investigate the incident. One member of the party was his second-oldest son, John F. Kennedy, a Harvard student, winding up a summer of travel in Europe. The American ambassador to Great Britain, Joseph P. Kennedy, sent an official embassy delegation to Ireland to assist the American survivors and investigate the incident. One member of the party was his second-oldest son, John F. Kennedy, a Harvard student, winding up a summer of travel in Europe.

* Eleven new capital ships were under construction: five Eleven new capital ships were under construction: five King George V King George V-class battleships and six Illustrious Illustrious-class aircraft carriers.

* From 1931, the British Empire or British Dominions became the British Commonwealth of Nations. From 1931, the British Empire or British Dominions became the British Commonwealth of Nations.

For more detailed information on the British destroyer situation, see For more detailed information on the British destroyer situation, see Appendix 9 Appendix 9.

At the outbreak of the war, a total of 185 British ships had sonar: 100 modern destroyers, forty-five sloops and old destroyers, and forty trawlers. At the outbreak of the war, a total of 185 British ships had sonar: 100 modern destroyers, forty-five sloops and old destroyers, and forty trawlers.

* Four Four Hunts Hunts were commissioned in December 1939, the other sixteen between February and September 1940. were commissioned in December 1939, the other sixteen between February and September 1940.

* A substantial number of the superior A substantial number of the superior S S-, T T-, and U U-class submarines were under construction.

* Called the "grid" system: north-to-south latitudes and west-to-east longitudes were defined alphabetically, A to Z. The large area where the alphabetized designators intersected was denoted by a "bigram." For example, the general area where Called the "grid" system: north-to-south latitudes and west-to-east longitudes were defined alphabetically, A to Z. The large area where the alphabetized designators intersected was denoted by a "bigram." For example, the general area where U-30 U-30 sank sank Athenia Athenia was AM. The large bigram areas, such as AM, were further subdivided into a system of numerical squares, which in turn were further subdivided. By the German grid system, was AM. The large bigram areas, such as AM, were further subdivided into a system of numerical squares, which in turn were further subdivided. By the German grid system, Athenia Athenia was sunk in AM 1631, a substitute for latitude 56 degrees, 44 minutes north and longitude 14 degrees, 5 minutes west. was sunk in AM 1631, a substitute for latitude 56 degrees, 44 minutes north and longitude 14 degrees, 5 minutes west.

* Ten torpedoes in the bow compartment, like the VIIs; two torpedoes for the stern tube; and two spare torpedoes carried in watertight canisters in the superstructure, which, in calm sea conditions, could be lowered below. Ten torpedoes in the bow compartment, like the VIIs; two torpedoes for the stern tube; and two spare torpedoes carried in watertight canisters in the superstructure, which, in calm sea conditions, could be lowered below.

* Unaware of this rescue, Churchill wrongly assumed that "40 or 50" of the crew had died in the lifeboats. He likened that to "murder" and demanded that London publicize this "outrage" to the fullest. It should be characterized, he urged, as "an odious act of bestial piracy on the high seas." Unaware of this rescue, Churchill wrongly assumed that "40 or 50" of the crew had died in the lifeboats. He likened that to "murder" and demanded that London publicize this "outrage" to the fullest. It should be characterized, he urged, as "an odious act of bestial piracy on the high seas."

Ten in the bow compartment like the VIIs, four in the stern compartment (two in the tubes; two reloads in the bilges), and up to eight air or G7a torpedoes stored in topside canisters. Ten in the bow compartment like the VIIs, four in the stern compartment (two in the tubes; two reloads in the bilges), and up to eight air or G7a torpedoes stored in topside canisters.

* Three sizes of aircraft bombs had been developed for ASW: 100-pound, 250-pound, and 500-pound-half the weight composed of explosives. The fuse was armed by a little propeller protruding from the nose. To kill a U-boat, extreme accuracy was required. For example, the 500-pound bomb (with 250 pounds of explosives) had to explode within eight feet of the U-boat hull to inflict fatal damage. Aircraft could also be fitted to drop the standard ashcan-shaped depth charge, but lacking a conical nose and tailfins, it tended to tumble in the air and thus follow an erratic path. Since they were not strongly constructed, depth charges also tended to break apart when they hit the water. Hence pilots preferred bombs to depth charges. Three sizes of aircraft bombs had been developed for ASW: 100-pound, 250-pound, and 500-pound-half the weight composed of explosives. The fuse was armed by a little propeller protruding from the nose. To kill a U-boat, extreme accuracy was required. For example, the 500-pound bomb (with 250 pounds of explosives) had to explode within eight feet of the U-boat hull to inflict fatal damage. Aircraft could also be fitted to drop the standard ashcan-shaped depth charge, but lacking a conical nose and tailfins, it tended to tumble in the air and thus follow an erratic path. Since they were not strongly constructed, depth charges also tended to break apart when they hit the water. Hence pilots preferred bombs to depth charges.

* Depth charges had not been much improved since World War I. The standard British depth charge, with an adjustable hydrostatic fuse, weighed 450 pounds and contained 300 pounds of Amatol explosives. It could be preset to explode at fifty-foot intervals from depths of fifty to 500 feet. Depth charges had not been much improved since World War I. The standard British depth charge, with an adjustable hydrostatic fuse, weighed 450 pounds and contained 300 pounds of Amatol explosives. It could be preset to explode at fifty-foot intervals from depths of fifty to 500 feet.

* Changed from Portsmouth to Bristol because of intense British asw measures in the English Channel and because she sailed with an Enigma before the okm prohibited Enigmas in minelaying boats. Changed from Portsmouth to Bristol because of intense British asw measures in the English Channel and because she sailed with an Enigma before the okm prohibited Enigmas in minelaying boats.

* Courageous Courageous and her sister ships, and her sister ships, Furious Furious and and Glorious Glorious, 22,500 tons, were originally battle cruisers, laid down in 1916 and converted to aircraft carriers in the 1920s. Each carried about twenty-four Swordfish biplanes and had a crew of about 1,200.

* So he was. When British forces occupied Iceland in 1940, Schmidt became a prisoner of war and was interrogated repeatedly. He did not reveal the So he was. When British forces occupied Iceland in 1940, Schmidt became a prisoner of war and was interrogated repeatedly. He did not reveal the Athenia Athenia sinking. sinking.

* The relaxations also applied to the "pocket" battleships The relaxations also applied to the "pocket" battleships Deutschland Deutschland and and Admiral Graf Spee Admiral Graf Spee, which were authorized to commence raiding on September 25.

To which should be added the work of the homebound Atlantic boats, which, as related, had sunk one Norwegian and captured one Estonian and two Finns for a total of 5,400 tons. To which should be added the work of the homebound Atlantic boats, which, as related, had sunk one Norwegian and captured one Estonian and two Finns for a total of 5,400 tons.

* The "pocket" battleships The "pocket" battleships Deutschland Deutschland and and Admiral Graf Spee Admiral Graf Spee did not get into action until October. did not get into action until October.

See appendices 2 and 17. See appendices 2 and 17.

* The VIIs and IXs were to be built at a three-to-one ratio. In addition, construction of four big Type XB minelayers and four big Type XIV tankers was continued, as well as construction of sixteen improved ducks, Type IID. But the four 3,000-ton U-cruisers were canceled. The VIIs and IXs were to be built at a three-to-one ratio. In addition, construction of four big Type XB minelayers and four big Type XIV tankers was continued, as well as construction of sixteen improved ducks, Type IID. But the four 3,000-ton U-cruisers were canceled.

France and the Netherlands ranked next, each with about 500 ships of 2.7 million gross tons. Greece, with about 400 ships of about 1.7 million gross tons, came next. France and the Netherlands ranked next, each with about 500 ships of 2.7 million gross tons. Greece, with about 400 ships of about 1.7 million gross tons, came next.

* In 1939 the United States had about 1 million gross tons of merchant shipping in "laid up" status, most of it not worth activating. In 1939 the United States had about 1 million gross tons of merchant shipping in "laid up" status, most of it not worth activating.

* In contrast, the oil companies, which were in stiff competition with foreign carriers, were compelled to keep the American tanker fleet in first-rate condition. In contrast, the oil companies, which were in stiff competition with foreign carriers, were compelled to keep the American tanker fleet in first-rate condition.

TWO.

PLANS AND P PROBLEMS.

By early October 1939, the bulk of the Wehrmacht Wehrmacht and and Luftwaffe Luftwaffe had redeployed from Poland to attack France. Hitler made a final appeal to the British and French to call off the war, but to no avail. He then ordered the Germans to launch the offensive against France, but the German generals were not ready and the action had to be postponed. The delays went on week after week until, finally, the coldest winter in memory set in and the offensive had to be put off until spring. The interval of inaction was called the "Phony War" or had redeployed from Poland to attack France. Hitler made a final appeal to the British and French to call off the war, but to no avail. He then ordered the Germans to launch the offensive against France, but the German generals were not ready and the action had to be postponed. The delays went on week after week until, finally, the coldest winter in memory set in and the offensive had to be put off until spring. The interval of inaction was called the "Phony War" or Sitzkrieg Sitzkrieg or or Drole de guerre Drole de guerre.

During that fall Admiral Raeder urged Hitler to seize neutral Norway by political subversion or military force. His reasons were several. The Kriegsmarine Kriegsmarine believed that the British and French planned to occupy Norway to shut off the winter flow of high-grade iron ore from Narvik to Germany and to gain bases from which to launch air attacks on Germany and believed that the British and French planned to occupy Norway to shut off the winter flow of high-grade iron ore from Narvik to Germany and to gain bases from which to launch air attacks on Germany and Kriegsmarine Kriegsmarine forces and bases in the Baltic Sea. There was also a possibility that Germany's erstwhile ally, the Soviet Union, which had ruthlessly invaded Finland, might overrun all of Scandinavia, dangerously flanking Germany to the north. A German occupation of Norway would not only defeat those possibilities but also gain naval bases for the forces and bases in the Baltic Sea. There was also a possibility that Germany's erstwhile ally, the Soviet Union, which had ruthlessly invaded Finland, might overrun all of Scandinavia, dangerously flanking Germany to the north. A German occupation of Norway would not only defeat those possibilities but also gain naval bases for the Kriegsmarine Kriegsmarine outside the North Sea, from which even the short-legged ducks could reach British shipping lanes. outside the North Sea, from which even the short-legged ducks could reach British shipping lanes.

Hitler grasped the strategic advantages of this proposal. He therefore commenced an attempt to subvert the Norwegian government through a Norwegian traitor, Vidkun Quisling. At the same time he directed his military chiefs to draw plans for taking Norway-and Denmark as well-by force, should subversion fail. The Kriegsmarine Kriegsmarine was to play the dominant role in the conquest, employing all the power it could muster, including every available U-boat. In the revised grand strategy, the conquest of Norway and Denmark was to precede the attack on France by about a month. was to play the dominant role in the conquest, employing all the power it could muster, including every available U-boat. In the revised grand strategy, the conquest of Norway and Denmark was to precede the attack on France by about a month.

Pending the launching of these enterprises, Karl Donitz, promoted to rear admiral, was to continue the U-boat war against Great Britain and France. In planning operations for the fall and winter of 1939-1940, Donitz was beset by three major problems.

The overriding problem was the acute shortage of oceangoing U-boats.

Although Raeder and Hitler had canceled the Z Plan, work continued on numerous surface ships: the two super-battleships Bismarck Bismarck and and Tirpitz Tirpitz; an aircraft carrier, Graf Zeppelin Graf Zeppelin; three heavy cruisers, Prinz Eugen Prinz Eugen, Lutzow Lutzow, and Seydlitz Seydlitz (being converted to an aircraft carrier); and scads of destroyers, motor torpedo boats, minelayers, and minesweepers. As one consequence, it was not possible to initiate action to speed the completion of the U-boats under construction. During the first six months of the war, September 1939 to March 1940, only six new oceangoing boats were to be commissioned: three VIIBs, one IX, and two improved models of the latter, designated IXB. If the September loss rate (two oceangoing boats) continued, by March 1940 there was to be a net loss of six oceangoing boats, down from twenty-seven to twenty-one. (being converted to an aircraft carrier); and scads of destroyers, motor torpedo boats, minelayers, and minesweepers. As one consequence, it was not possible to initiate action to speed the completion of the U-boats under construction. During the first six months of the war, September 1939 to March 1940, only six new oceangoing boats were to be commissioned: three VIIBs, one IX, and two improved models of the latter, designated IXB. If the September loss rate (two oceangoing boats) continued, by March 1940 there was to be a net loss of six oceangoing boats, down from twenty-seven to twenty-one.

Moreover, the hard Atlantic patrolling and combat had uncovered some severe design flaws and weaknesses in the existing oceangoing boats. The engine casings of the Type VIIs were not strong enough. All the VIIs had to go into the shipyards for new engines. The engine-exhaust valves on the VIIs, which closed against (rather than with) sea pressure, leaked dangerously at deep depths, a flaw that had not been discovered earlier owing to the OKM's order to limit peacetime diving to 150 feet. Until these (and other) flaws were corrected, the nine surviving boats of the Salzwedel Flotilla, comprising one-third of the Atlantic force, were unsafe for combat. Owing to the jam-up in the shipyards, the flaws could not be immediately corrected. In the interim, those boats could only be used sparingly.

To bolster the Atlantic force, Donitz was compelled to resort to two fairly desperate measures. First, he made the decision to continue patrolling with the two big experimental boats, U-25 U-25 and and U-26 U-26, regardless of the risks entailed. Second, he confiscated a big U-cruiser, Batiray Batiray, which Krupp was completing for Turkey. However, before this boat (designated U-A U-A) could safely patrol the Atlantic, it had to have extensive modifications in the shipyards.

The second problem confronting Donitz was the spreading belief that the submarine torpedoes were defective.

This was not an easy matter to prove. Torpedoes and torpedo pistols were very complicated. The line officers of the Kriegsmarine Kriegsmarine commanding U-boats, as well as Donitz and his staffers, were not trained engineers or scientists. Few had even attended a college. They had to rely on the experts at the Torpedo Directorate for technical judgments. At first the experts insisted, not without some justification, that most of the reported torpedo failures, malfunctions, and misses were the fault of poor torpedo maintenance and mistakes in shooting by green captains and crews. commanding U-boats, as well as Donitz and his staffers, were not trained engineers or scientists. Few had even attended a college. They had to rely on the experts at the Torpedo Directorate for technical judgments. At first the experts insisted, not without some justification, that most of the reported torpedo failures, malfunctions, and misses were the fault of poor torpedo maintenance and mistakes in shooting by green captains and crews.

From the beginning of this disputation, Donitz took the position that while some failures and misses were doubtless the fault of the crews, not all could be so attributed. No less than thirteen skippers had reported erratic or malfunctioning torpedoes while on patrol in September. These included the analytical-minded Otto Kretschmer in the duck U-23 U-23, who had achieved a nearly perfect shooting score in peacetime, but had unaccountably missed a slow-moving tramp steamer off northeast Scotland with four torpedoes. Two skippers, Glattes in U-27 U-27 and Schuhart in and Schuhart in U-29 U-29, had experienced and reported dangerous "premature" explosions with magnetic pistols after runs of less than 300 yards.*

After compiling a detailed and damning analysis of the torpedo performance by the September boats, Donitz persuaded Raeder and the OKM to order the Torpedo Directorate to conduct an exhaustive technical investigation. Almost immediately the Directorate conceded two flaws that might be adversely affecting the' magnetic pistols: a poorly designed cable layout in the electrics, and some kind of mechanical flaw, not yet isolated, in the air torpedoes. The Directorate recommended a rearrangement of the cables in the electrics, which was certain to cure the problem in those, but pending further investigation, the skippers should use only contact (or impact) pistols in the air torpedoes.

Donitz had deepest misgivings about the results of this "investigation." He and many of his skippers-including Otto Kretschmer-believed the main problem was that the torpedoes were running deeper than set. The Directorate had not even addressed this possibility. Nonetheless, Donitz had no choice but to rely on the technicians. Accordingly, he issued the advisories and new instructions for the boats preparing to sail in October.

The third major problem besetting Donitz during the winter of 1939-1940 was a continuous demand from Raeder and the OKM to provide U-boats for special missions.

From the earliest days of hostilities, Raeder and the OKM intended to foul British seaports with magnetic mines. The main planting was to be carried out by destroyers, which were to dash across the North Sea and back in winter under cover of darkness. But the destroyers could only reach the lower east coast ports of the British Isles. Those ports beyond reach of the destroyers-in the western English Channel, the west coast of the British Isles, and the northeast coast of Scotland-were to be mined by aircraft and submarine. In addition, Raeder intended to employ submarines to mine the British naval base at Gibraltar and, provided Hitler approved, the port of Halifax, Nova Scotia, where the convoys from North America formed up.

When presented with this elaborate submarine mining plan, Donitz objected. If carried to its fullest, the plan would require the diversion of virtually every available combat-ready U-boat. Donitz believed it was imperative to continue the torpedo war against shipping for its psychological impact, to hone the skills of the skippers and crews under combat conditions, and to continue the elusive hunt for the torpedo defects. Besides that, many skippers and crews were not qualified in minelaying.

The upshot was a compromise. During the new-moon periods of the winter months, when nights were black and long and thus ideal for minelaying, Donitz was to employ about one-third of the oceangoing U-boat force to lay about fourteen minefields in the west coast ports of the British Isles and Gibraltar. The North Sea ducks were to lay about a dozen fields in east coast and English Channel ports, backstopping the destroyers and aircraft.

In addition to these mining missions, Raeder and the OKM proposed other special tasks for the oceangoing submarines. Donitz deflected most of these proposals, but Berlin insisted on three. The first was to send several boats into the Mediterranean Sea to attack Allied shipping. The second was to send several boats to the Arctic, where they were to secretly base in Murmansk and prey on Allied shipping engaged in transporting timber (for mine props) from Scandinavia to Great Britain. The third was to land Abwehr Abwehr (German intelligence) spies in neutral Ireland, who were to inflame anti-British sentiments. (German intelligence) spies in neutral Ireland, who were to inflame anti-British sentiments.

The shortage of combat-capable oceangoing boats, the infuriating and inexcusable torpedo defects, and the demand for boats to carry out special missions significantly reduced the ability of the U-boat arm to inflict any serious damage on Allied maritime assets during the winter of 1939-1940. Nonetheless, Donitz and his loyal, dedicated submariners were determined to give their utmost.

PRIEN IN S SCAPA F FLOW.

During the first month of the war, Donitz had conceived a plan to deal the Royal Navy another stinging blow. Close reconnaissance of the British naval base at Scapa Flow by ducks and Luftwaffe Luftwaffe aircraft had revealed a possible flaw in its defenses: Kirk Sound, one of a half-dozen channels leading into the base, was not solidly closed by blockships. aircraft had revealed a possible flaw in its defenses: Kirk Sound, one of a half-dozen channels leading into the base, was not solidly closed by blockships.* Donitz became convinced that a U-boat could slip through the gap in the channel under cover of darkness and attack the Home Fleet in its anchorage. If so, the boat might sink one or more capital ships and drive the fleet from Scapa Flow, thus weakening the British blockade and making it less hazardous for Donitz became convinced that a U-boat could slip through the gap in the channel under cover of darkness and attack the Home Fleet in its anchorage. If so, the boat might sink one or more capital ships and drive the fleet from Scapa Flow, thus weakening the British blockade and making it less hazardous for Kriegsmarine Kriegsmarine surface raiders to slip in and out of the North Sea. surface raiders to slip in and out of the North Sea.

Donitz chose Gunther Prien, a daring skipper and skilled seaman, to attempt this hazardous mission. Prien turned in his Enigma and all secret papers and sailed U-47 U-47 in secrecy from Kiel on October 8, going via the Kiel Canal and Wilhelmshaven. Not until he was well out to sea did Prien brief his crew. Although the mission was fraught with danger and the risk of death or capture was great, all hands were enthusiastic. in secrecy from Kiel on October 8, going via the Kiel Canal and Wilhelmshaven. Not until he was well out to sea did Prien brief his crew. Although the mission was fraught with danger and the risk of death or capture was great, all hands were enthusiastic.

That same day, the Kriegsmarine Kriegsmarine's new battle cruiser Gneisenau Gneisenau, escorted by the light cruiser Koln Koln, set sail from Kiel on a brief sortie into the North Sea. There were several reasons for this short voyage: to exercise the ships and crews in a limited combat environment; to pose a threat to North Sea merchant ships, forcing the Allies to form convoys, which were legitimate duck targets; to lure Home Fleet units from their bases into range of Luftwaffe Luftwaffe aircraft; and to assuage Hitler, who had demanded to know why these expensive vessels were not being employed. aircraft; and to assuage Hitler, who had demanded to know why these expensive vessels were not being employed.

The Gneisenau Gneisenau and and Koln Koln went out through the Kattegat and Skagerrak. As intended, the Admiralty got wind of the sortie and Coastal Command dispatched reconnaissance aircraft to the North Sea. Early in the afternoon of October 8, one of them spotted the German ships close to the south coast of Norway. Believing went out through the Kattegat and Skagerrak. As intended, the Admiralty got wind of the sortie and Coastal Command dispatched reconnaissance aircraft to the North Sea. Early in the afternoon of October 8, one of them spotted the German ships close to the south coast of Norway. Believing Gneisenau Gneisenau was headed for a long voyage into the North Atlantic to raid Allied convoys, Admiral Forbes ordered most of the major ships in his Home Fleet to intercept her. was headed for a long voyage into the North Atlantic to raid Allied convoys, Admiral Forbes ordered most of the major ships in his Home Fleet to intercept her.* But But Gneisenau Gneisenau easily eluded the trap. She reversed course that night and reached her berth in Kiel in the early hours of October 10. As planned, the easily eluded the trap. She reversed course that night and reached her berth in Kiel in the early hours of October 10. As planned, the Luftwaffe Luftwaffe found and attacked the Home Fleet units in the North Sea on October 9, but not one of the hundred-odd bombs the pilots dropped hit a British ship. found and attacked the Home Fleet units in the North Sea on October 9, but not one of the hundred-odd bombs the pilots dropped hit a British ship.

Unaware that Gneisenau Gneisenau had returned to port, the Home Fleet units from Scapa Flow continued the hunt for her north and northwest of the Orkneys. Finding no trace of the Germans, Forbes finally ordered the fleet to break off the search and return to bases. The battleships had returned to port, the Home Fleet units from Scapa Flow continued the hunt for her north and northwest of the Orkneys. Finding no trace of the Germans, Forbes finally ordered the fleet to break off the search and return to bases. The battleships Nelson Nelson and and Rodney Rodney, the battle cruisers Hood Hood and and Repulse Repulse, and the carrier Furious Furious, which had sailed from Scapa Flow, put in to various naval bases in Scotland. Only the old (1916-1917) 30,000-ton battleship Royal Royal Oak Oak, which to then had been employed on convoy escort, returned to Scapa Flow. Thus the sortie of Gneisenau Gneisenau had the effect of emptying Scapa Flow of the major Home Fleet capital ships. On October 12, the had the effect of emptying Scapa Flow of the major Home Fleet capital ships. On October 12, the Luftwaffe Luftwaffe, which was also apparently unaware of Prien's mission, flew a low-level reconnaissance over Scapa Flow. Some British interpreted this as a prelude to a major bombing attack, so the big ships were retained at Loch Ewe.

Meanwhile, Prien in U-47 U-47 inched cautiously northward in the shallow North Sea, avoiding all ships and lying doggo on the bottom during daytime. On the night of Friday, October 13, at 1915, he surfaced to begin a slow, four-hour approach to Scapa Flow, timed to bring inched cautiously northward in the shallow North Sea, avoiding all ships and lying doggo on the bottom during daytime. On the night of Friday, October 13, at 1915, he surfaced to begin a slow, four-hour approach to Scapa Flow, timed to bring U-47 U-47 to Kirk Channel when the tide was highest. to Kirk Channel when the tide was highest.

Going to the bridge, Prien found the sky clear but "disgustingly" bright, lit by an undulating aurora borealis-the northern lights. Despite this unexpected and inconvenient phenomenon, Prien pressed on, planning, if necessary, to carry out the attack submerged, by periscope. At 2200, on schedule, the Orkney navigational lights came on for thirty minutes, enabling Prien to precisely fix U-47 U-47's position. Approaching a jut of land, Rose Ness, at 2307, the bridge watch saw a merchant ship plodding along. Prien dived to avoid the vessel and, as a test, tried to put it squarely in his periscope crosshairs. Despite the northern lights, he could not see the ship. The lack of periscope visibility ruled out a submerged attack inside Scapa Flow. They would stay on the surface.

Prien surfaced at 2331, got his bearings, and ran due west on the flood tide. The visibility was not as good as it seemed. By mistake, he headed for the wrong channel, Kerry, separating Lamb Holm and Burray islands. He detected the mistake just in time. "By altering course hard to starboard, the imminent danger is averted," he logged.

Realigning the boat for the passage through Kirk Sound, Prien made the decision not to go south of the two blockships in the channel, the course Donitz had suggested. Instead, he aimed for a gap between the center and northernmost block-ships, clearing the northernmost blockship "with 45 feet to spare." Borne along by the swift flood tide, the penetration was made "with unbelievable speed," Prien logged. But it was nerve-rattling. During the passage, the current slewed the boat sharply to starboard, directly into a cable anchoring one of the blockships. "Port engine stopped," Prien wrote, "starboard engine slow ahead and rudder hard to port, the boat slowly touches bottom. The stern still touches the cable, the boat becomes free, it is pulled around to port, and brought onto course again with difficult rapid maneuvering.... But ... we are in Scapa Flow." It was twenty-seven minutes past midnight.

Enhanced by the undulating northern lights, visibility in the wide bowl of the anchorage improved. Prien, his first watch officer, Engelbert Endrass, and the lookouts hungrily scanned the waters with binoculars. They could see no big ships in the usual anchorage between Burray and Cava islands. It seemed impossible. Was Scapa Flow empty?

Circling north, Prien scouted deeper into the basin. Then suddenly he sighted "two battleships," identified as Royal Oak Royal Oak and and Repulse Repulse, lying at anchor, unusually close to the rugged north shore, about one and a half miles apart. Actually, the ships were the Royal Oak Royal Oak and the old 6,900-ton seaplane transport and the old 6,900-ton seaplane transport Pegasus Pegasus, which was scheduled to be fitted with an experimental aircraft catapult for convoy escort.

Closing to a position about 3,500 yards equidistant from both ships, Prien made ready all four bow tubes. At 0055 he fired two of the electrics with magnetic pistols at "Repulse" and two at Royal Oak Royal Oak. The torpedo in tube number 4, intended for "Repulse," misfired-did not go. The other three ran out silently and wakeless at about 30 miles per hour. The one aimed at "Repulse" missed and probably ran ashore. About three and a half minutes after firing, one of the two torpedoes fired at Royal Oak Royal Oak struck her on the starboard bow; the other missed. The hit blew a huge hole in the stem and keel of struck her on the starboard bow; the other missed. The hit blew a huge hole in the stem and keel of Royal Oak Royal Oak near the paint and anchor-chain lockers. But the noise was not sufficient to cause undue alarm elsewhere in the big ship and near the paint and anchor-chain lockers. But the noise was not sufficient to cause undue alarm elsewhere in the big ship and Royal Oak Royal Oak's captain, roused from his bunk, attributed the explosion to some internal cause and took no special precautions.

In the darkness and confusion it was difficult for Prien to know what had happened. Wrongly believing he had damaged "Repulse" with one hit, and had missed Royal Oak Royal Oak, Prien mounted another attack. While the torpedomen reloaded bow tubes number 1 and 2, and readjusted the balky number 4, he swung ship and fired his stern torpedo at Royal Oak Royal Oak. No explosion. This torpedo also missed and probably ran ashore.* Therefore, when number 1, 2, and 4 bow tubes were ready, Prien swung back around and fired all three at Therefore, when number 1, 2, and 4 bow tubes were ready, Prien swung back around and fired all three at Royal Oak Royal Oak, which he mistakenly believed to be unharmed.

All three of the torpedoes struck Royal Oak Royal Oak on her starboard side. The hits blew a huge hole in the engine room and two other holes amidships, and set off a raging fire in a magazine, hurling debris into the sky. The ship shook violently, the lights and P.A. system went out, and flames spread rapidly. Taking on a flood of water through the holes, on her starboard side. The hits blew a huge hole in the engine room and two other holes amidships, and set off a raging fire in a magazine, hurling debris into the sky. The ship shook violently, the lights and P.A. system went out, and flames spread rapidly. Taking on a flood of water through the holes, Royal Oak Royal Oak almost immediately listed 45 degrees to starboard. Thirteen minutes after the last three hits, the old battleship rolled over and sank, with the loss of 833 of her 1,200-man crew. almost immediately listed 45 degrees to starboard. Thirteen minutes after the last three hits, the old battleship rolled over and sank, with the loss of 833 of her 1,200-man crew.

Believing he had been seen, and that destroyers were after him, Prien turned about at 0128 and headed at high speed for the Kirk Sound escape route. Actually, he had not been seen, and no destroyers were after him. All British hands were either engaged in rescue efforts at Royal Oak Royal Oak or frozen in shock. Prien could have reloaded his five remaining torpedoes for a second attack on " or frozen in shock. Prien could have reloaded his five remaining torpedoes for a second attack on "Repulse" without fear of enemy counterattack. But even if the torpedoes ran true, a second attack would only have bagged inconsequential Pegasus Pegasus. Hence his instinctive decision to get out was correct, but for the wrong reasons.

About two and a half hours after entering Scapa Flow, Prien reached the west end of Kirk Sound and began the exit. This time he went south of the blockships, in the "gap" Donitz had recommended. "Things are again difficult," he logged. Making constant changes in speed and helm, he passed the southern blockship "with nothing to spare." Free of the blockships and their anchor cables, Prien just barely avoided a mole, then, clear of all obstructions, he bent on flank speed in Holm Sound. At 0215, he logged, "we are once more outside," adding that it was "a pity that only one [ship] was destroyed."

The next day, October 14, the Admiralty released the sad and humiliating news that Royal Oak Royal Oak had been sunk in Scapa Flow with a great loss of life. Berlin first heard the news from a radio report, but it withheld a celebration or public comment pending a report from Prien. Home Fleet commander Forbes immediately barred all Royal Navy ships from Scapa Flow. Until the defenses had been improved had been sunk in Scapa Flow with a great loss of life. Berlin first heard the news from a radio report, but it withheld a celebration or public comment pending a report from Prien. Home Fleet commander Forbes immediately barred all Royal Navy ships from Scapa Flow. Until the defenses had been improved the Home Fleet was to base in Loch Ewe, the cruisers of the Northern Patrol at Sullom Voe in the Shetlands, even though the defenses there were skimpy and the facilities primitive. the Home Fleet was to base in Loch Ewe, the cruisers of the Northern Patrol at Sullom Voe in the Shetlands, even though the defenses there were skimpy and the facilities primitive.

Southbound on the surface, in the early hours of October 16, Prien got off an encoded radio report to Donitz: Royal Oak Royal Oak sunk; " sunk; "Repulse" damaged. The Germans were ecstatic. "A glorious success," the OKM gloated. It logged in its war diary that the loss of Royal Oak Royal Oak and damage to " and damage to "Repulse" were "hard blows" that "greatly impairs British prestige," "enhances respect" for the Kriegsmarine Kriegsmarine, and "awakens affection" for the "young submarine arm" that had amply demonstrated its "outstanding operational efficiency."

Believing the damaged "Repulse" had limped to a shipyard in Rosyth in the Firth of Forth, Berlin mounted a Luftwaffe Luftwaffe attack on Rosyth on October 16-the first German air attack on a Royal Navy base. attack on Rosyth on October 16-the first German air attack on a Royal Navy base. Luftwaffe Luftwaffe pilots confirmed (erroneously) that " pilots confirmed (erroneously) that "Repulse" was in the shipyard. The planes hit the cruiser Southampton Southampton with one bomb, but it failed to explode. The only notable result of the attack was slight damage to a destroyer. Still quite unharmed, with one bomb, but it failed to explode. The only notable result of the attack was slight damage to a destroyer. Still quite unharmed, Repulse Repulse sailed from there with the carrier sailed from there with the carrier Furious Furious for convoy duty. for convoy duty.

By this time it was customary for returning U-boats to paint the names of enemy "kills" on the conning towers in white. The first watch officer, Engelbert Endrass, personally carried out this pleasurable task. Believing that merely the name Royal Oak Royal Oak was insufficient to convey the full drama of the kill, Endrass, who had fired the torpedoes for Prien, embellished the conning tower with a crude portrait of a massive bull charging with lowered horns and steaming nostrils. Later, a refined version of the "Bull of Scapa Flow" was to become the official insignia of the Wegener Flotilla. was insufficient to convey the full drama of the kill, Endrass, who had fired the torpedoes for Prien, embellished the conning tower with a crude portrait of a massive bull charging with lowered horns and steaming nostrils. Later, a refined version of the "Bull of Scapa Flow" was to become the official insignia of the Wegener Flotilla.

By the time U-47 U-47 entered Wilhelmshaven on the morning of October 17, its great feat of arms was known throughout Germany. Admirals Raeder and Donitz were standing on the pier to greet Prien and his men. When the lines were secured, the admirals crossed the brow to shake hands with every man in the crew and to confer on Prien the Iron Cross First Class and to all others the Iron Cross Second Class, and to announce that Adolf Hitler was sending his personal plane to fly the crew to Berlin. entered Wilhelmshaven on the morning of October 17, its great feat of arms was known throughout Germany. Admirals Raeder and Donitz were standing on the pier to greet Prien and his men. When the lines were secured, the admirals crossed the brow to shake hands with every man in the crew and to confer on Prien the Iron Cross First Class and to all others the Iron Cross Second Class, and to announce that Adolf Hitler was sending his personal plane to fly the crew to Berlin.

The drama and daring of the Scapa Flow deed personified the image of military courage and ingenuity Hitler was seeking to project. He directed Propaganda Minister Goebbels to give Prien and his crew the full treatment. German radios trumpeted heroic and exaggerated bulletins (including the supposed damage to Repulse Repulse). By the time the U-47 U-47 crew arrived at Berlin's Templehof Airport, the German people had been whipped to a frenzy of enthusiasm. Thousands turned out at the airport and along the motorcade route and at the Kaiserhof Hotel to present flowers, candy, and other gifts, or merely to catch a glimpse of the naval heroes. It was the greatest and most exhilarating celebration in the history of submarine warfare, and it would never be equaled again in Germany or elsewhere. The reigning U-boat hero, Otto Schuhart, who had actually outdone Prien by sinking the far more versatile and valuable capital ship crew arrived at Berlin's Templehof Airport, the German people had been whipped to a frenzy of enthusiasm. Thousands turned out at the airport and along the motorcade route and at the Kaiserhof Hotel to present flowers, candy, and other gifts, or merely to catch a glimpse of the naval heroes. It was the greatest and most exhilarating celebration in the history of submarine warfare, and it would never be equaled again in Germany or elsewhere. The reigning U-boat hero, Otto Schuhart, who had actually outdone Prien by sinking the far more versatile and valuable capital ship Courageous Courageous, was all but forgotten.*

The celebration and ceremonies continued for several days. Hitler invited the crew to the Reichs Chancellery for lunch and presented Prien a new and exalted medal, the Knight's Cross of the Iron Cross, or Ritterkreuz Ritterkreuz, as the submariners called it. Afterward Hitler's publicist, Dr. Otto Dietrich, introduced Prien to the German and foreign press. (The American radio journalist, William L. Shirer, noted in his diary that Prien was "a clean-cut, cocky, fanatical Nazi, and obviously very capable.") That night the crew were guests of Goebbels at the Wintergarten Theater, where a fawning audience forced Prien to make a speech. Still later the crew was entertained at a night club.

The Prien hoopla gave Donitz and the U-boat force a tremendous boost. There was no instant return; no immediate increase in U-boat production. But the feat at Scapa Flow had certainly got Hitler's attention and firmly planted the idea in his and all German minds that a single cheap U-boat manned by merely forty-four men could sink a huge battleship manned by 1,200 men. From that it was not difficult to imagine what carnage a vast fleet of U-boats could inflict on Great Britain's thinly armed merchant marine. Thus the idea that Germany might, after all, defeat Great Britain at sea with U-boats gained credibility. The long-term impact of Scapa Flow was therefore immeasurably beneficial for the U-boat arm.

THE F FIRST W WOLF P PACK.

By the time Donitz was ready to launch the second wave of U-boats to the Atlantic in early October, the Allies had organized most merchant shipping into convoys. Composed of thirty to forty ships, the majority of the convoys arrived and departed the British Isles through the Western Approaches. The heaviest convoy traffic ran across the North Atlantic between the British Isles and the strategically situated British colony of Newfoundland and its neighbor, the Canadian maritime province of Nova Scotia.*

By October 1939, the North Atlantic convoy system was fully in place. On the western end, the port of Halifax, Nova Scotia, was the gathering place. All ships bound for the British Isles that cruised between 9 and 15 knots had to join convoys. There were two types of convoys: Halifax Fast (designated HX-F), composed of ships that cruised at 12 to 15 knots; and Halifax Slow (HX), composed of ships that cruised at 9 to 12 knots. Ships that cruised at speeds over 15 knots (considered too fast to be vulnerable to U-boats) were allowed to proceed alone, as were ships that cruised at less than 9 knots (considered too slow and not valuable enough to warrant the holdup of faster ships).

On the eastern end, the British Isles, departing convoys were categorized as Outbound. Those convoys bound for Halifax or elsewhere in the western hemisphere (the reverse of the Halifax convoys), composed mostly of ships in ballast, were designated Outbound B or OB. Some ships in OB convoys peeled away after some days of travel and went due south down the mid-Atlantic to ports in West Africa. Ships outbound from the British Isles that cruised faster than 15 knots or slower than 9 knots were also exempt from convoys.* Most North Atlantic convoys were escorted only during part of the voyage. The inexperienced and small Royal Canadian Navy (six destroyers) and the Royal Canadian Air Force (RCAF) provided escort on the western end, going east several hundred miles with eastbound convoys and returning with westbound convoys. British and French surface ships and aircraft provided escort on the eastern end for Outbound convoys in a similar manner for a like distance. The important Halifax Fast convoys were escorted all the way across to the British Isles by Royal Navy capital ships (battleships, carriers) and their destroyer screens, or by cruisers. But only reluctantly. The long transatlantic voyage was very hard on these warships. The old destroyers assigned to this task (V and W class) could not cross the Atlantic without refueling, and the Royal Navy had not fully mastered ocean refueling. The modern destroyers could just barely make it across in heavy weather, which was the usual condition. Convoy escort was "defensive," tedious, and boring for sailors trained to attack big German ships in complex fleet actions. Most North Atlantic convoys were escorted only during part of the voyage. The inexperienced and small Royal Canadian Navy (six destroyers) and the Royal Canadian Air Force (RCAF) provided escort on the western end, going east several hundred miles with eastbound convoys and returning with westbound convoys. British and French surface ships and aircraft provided escort on the eastern end for Outbound convoys in a similar manner for a like distance. The important Halifax Fast convoys were escorted all the way across to the British Isles by Royal Navy capital ships (battleships, carriers) and their destroyer screens, or by cruisers. But only reluctantly. The long transatlantic voyage was very hard on these warships. The old destroyers assigned to this task (V and W class) could not cross the Atlantic without refueling, and the Royal Navy had not fully mastered ocean refueling. The modern destroyers could just barely make it across in heavy weather, which was the usual condition. Convoy escort was "defensive," tedious, and boring for sailors trained to attack big German ships in complex fleet actions.

The Germans possessed a fairly accurate picture of Allied maritime traffic. During the 1935 crisis in the Mediterranean, when Italy invaded Abyssinia (Ethiopia), the Kriegsmarine Kriegsmarine codebreaking unit codebreaking unit B-dienst B-dienst (later directed by Heinz Bonatz) had broken the Royal Navy's old-fashioned (nonmachine) operational codes and, later, the nonsecure British merchant marine code. From the outset of the war, (later directed by Heinz Bonatz) had broken the Royal Navy's old-fashioned (nonmachine) operational codes and, later, the nonsecure British merchant marine code. From the outset of the war, B-dienst B-dienst codebreakers had supplied the OKM with current information on the movements of most British capital ships and other naval formations as well as convoy routing and rendezvous points for the convoy escorts. codebreakers had supplied the OKM with current information on the movements of most British capital ships and other naval formations as well as convoy routing and rendezvous points for the convoy escorts.

In the initial U-boat offensive the OKM had deployed the Atlantic boats to individual patrol zones before the convoys had formed. Almost all of the merchant ships they sank had been sailing alone. Now that convoying was in full swing, Donitz believed the time was ripe to initiate his group (or "wolf pack") tactics. The packs were to capitalize on convoy information provided by the codebreakers in B-dienst B-dienst.

Donitz planned to deploy two packs in October, composed of the ten boats he had recalled earlier: five Type VIIBs of the Wegener Flotilla and five Type IXs of the Hundius Flotilla. But that plan went awry. Five of the ten boats were unavailable: U-47 U-47 (assigned to the Scapa Flow mission) and (assigned to the Scapa Flow mission) and U-52 U-52 (undergoing major repairs), (undergoing major repairs), U-38 U-38 (assigned to a special mission to Murmansk), (assigned to a special mission to Murmansk), U-39 U-39 (lost), and (lost), and U-41 U-41 (undergoing major repairs). (undergoing major repairs).

The upshot was that Donitz could mount only one pack, composed of six boats of an unwieldy mixture of types, from two different flotillas, which had not before exercised as a group: three VIIBs, U-45 U-45, U-47 U-47, U-48 U-48, and three IXs, U-37 U-37, U-40 U-40, and the U-42 U-42, the latter brand-new and rushed into service before completing a full workup. The senior officer, Hundius Flotilla commander Werner Hartmann, age thirty-seven, who had taken command of U-37 U-37, was to tactically direct the pack at sea.