Battle of Atlantic , September -November 1941 , U-Boat Patrols in West Africa , Off Gibraltar and South Atlantic

Although the patrols to West African waters during the late summer of 1941 had produced scant returns and there were no German resupply ships immediately available, and British diplomatic pressure had closed the Spanish Canaries to U-boats, Dönitz believed patrols to this area should be continued. The presence of U-boats in the South Atlantic forced the British to convoy and to draw ASW forces from elsewhere, and kept pressure on the flow of British supplies to Egypt and the Middle East going via the Cape of Good Hope. Accordingly, two waves of four Type IXs sailed for the Freetown area in the early fall.

The first U-Boat wave to these waters in September wave achieved very little. Believing that British ships might be taking cover in the American hemispheric defense zone, which extended to South American waters, Dönitz sent two of the four boats across the “narrow neck” of the South Atlantic to Brazil: Richard Zapp’s U-66 and Wilhelm Kleinschmidt’s U-111, the first two U-boats to go south of the Equator. Kleinschmidt sank two big freighters sailing alone: a 5,700-ton Dutchman bound for Egypt with a cargo of aircraft, and an 8,400-ton Britisher bound for England with a cargo of pig iron and manganese. Zapp in U-66 sank the 7,000-ton Panamanian tanker I. C. White 600 miles south of the Equator. Patrolling the once-rich hunting grounds off Freetown, Klaus Scholtz in U-108 and Ritterkreuz holder Günter Kuhnke in U-125 were outwitted by British intelligence and ASW forces. Thanks to ULTRA intelligence , British Admiralty rerouted Sierra Leone convoys away from U-boat patrols. Neither boat sank a single ship.

The second wave of four boats had better luck—at first. Southbound off the coast of Africa on September 21, Dönitz’s son-in-law Günter Hessler in U-107 found a northbound convoy, Sierra Leone SL 87. It was composed of eleven big ships and five ill-trained, ill-equipped escorts, led by the ex-Coast Guard cutter Gorleston. Inexplicably, the escorts had not topped off fuel tanks in Freetown; none was fully combat-ready.

When Hessler reported the convoy, Dönitz ordered him to shadow until he could bring up the other three southbound boats of the second wave. The first to arrive was Karl Friedrich Merten in U-68, making his first patrol in South Atlantic waters. In the early hours of September 22, Hessler and Merten attacked the convoy. All four of Hessler’s torpedoes malfunctioned or missed, after which an engine failed, forcing him to withdraw for repairs. Merten fired three torpedoes but he damaged one British freighter Silverbelle.

The escorts fired star shells and churned around, but they mounted no organized counterattack. Three of the five, including Gorleston, stood by the damaged Silverbelle, whose crew was desperately attempting to make repairs. Falling well behind the convoy, Gorleston took Silverbelle in tow until Derby House ordered her, as well as the corvette Gardenia, to rejoin the convoy forthwith. Another of the escorts, the small Free French minesweeper Commandant Duboc, took Silverbelle in tow. A week later Duboc ran low on fuel and was forced to return to Freetown with Silverbelle’s crew, leaving the hulk still afloat.

Early the following night a third southbound boat caught up with the convoy. She was U-103, commanded by Werner Winter, age twenty-nine, making his first full Atlantic patrol as a skipper. He closed the formation after dark, fired a salvo of five torpedoes, and claimed sinking four ships for 24,000 tons and damage to another of 6,000 tons. In reality, he hit and sank two big freighters for 10,600 tons. The three escorts, including the corvette Gardenia, rescued survivors, but again conducted no counterattacks. Low on fuel, Gardenia departed when the Gorleston caught up, leaving a total of three escorts and eight merchant ships.

Merten in U-68 closed that night for his second attack. He saw a damaged freighter and a damaged tanker, he reported later, but he bravely chose to attack one of the “destroyers.” He set up on and fired at one “destroyer,” but both torpedoes missed. It was then discovered that U-68’s batteries were too low to permit a dive, so Merten was forced to break off the attack, withdraw, and commence a battery charge.

The fourth and last boat to arrive was the U-67, commanded by Günther Müller-Stöckheim, age twenty-seven. Commissioned on January 22, 1941, under the command of Ritterkreuz holder Heinrich Bleichrodt (who later went to U-109), the U-67 had been diverted during the spring and summer to R&D experiments. Until now, she had not made a real war patrol and her long-suffering crew was eager for a kill.

As Müller-Stöckheim closed to attack, a valve in the main ballast-tank air manifold failed. The engineer logged in his personal diary: “I had to report to the commander that other minor defects had occurred and that the boat was not fully fit to dive.” Undeterred, Müller-Stöckheim pressed the attack, firing three torpedoes at what he believed to be a 7,000-ton ship. He hit and sank a 3,800-ton British freighter, which went down so quickly that it capsized and sucked under its three lifeboats. The escorts rescued the survivors but again conducted no counterattack.

Having repaired his engines, Günter Hessler in U-107 caught up with the convoy in the early hours of September 24. In this second attack, he claimed sinking three ships for 26,000 tons, including a 13,000-ton tanker. He actually sank three freighters for 13,600 tons. In his report to Kerneval, Hessler stated that only one ship of the convoy remained and that it was closely guarded by escorts.

Upon receiving Hessler’s report, Dönitz called off the attack, well pleased at the results. Based on reports from the four boats, he estimated they had positively sunk five ships for 41,000 tons, possibly sunk four more for 24,000 tons, and damaged two for 12,000 tons. Hence, he logged, the entire convoy, “except one ship,” was “wiped out.” In reality, the four U-boats had sunk only about half of the convoy: six of the eleven ships for 28,000 tons. At that time a seventh ship, Silverbelle, under tow by Duboc, was still struggling to stay afloat.

In due course the remaining four ships of Sierra Leone 87, escorted by Gorleston and two other escorts, reached the British Isles. The failure of the escorts to prepare properly for the mission and to carry out vigorous counterattacks drew harsh criticism from Derby House. An account of the failures was circulated to ASW forces as an example of what not to do, and Derby House took steps to ensure that the skipper of Gorleston did not again command an escort group.

The four boats that had attacked Sierra Leone 87 went separate ways. Winter in U-103 and Hessler in U-107 proceeded independently to patrol off Freetown. Also outwitted by British intelligence and ASW forces, neither boat sank another ship. With decoded Enigma traffic , British Admiralty again rerouted convoys away from their patrol zones. Müller-Stöckheim in U-67 and Merten in U-68 could not immediately go further south. A man on U-67 was ill with a veneral disease; Merten in U-68 had fired most of his torpedoes.

When apprised of the situations on U-67 and U-68, Kerneval directed the two boats to rendezvous with Kleinschmidt’s U-111, which was en route home from the South Atlantic. The plan was that a doctor on board U-68 was to examine the sick man on U-67. If the doctor could not administer a cure, the man was to return to France on U-111. At the same time, Merten in U-68 was to take on torpedoes from U-111. In that way both U-67 and U-68 could resume their voyages to the South Atlantic.

BdU Command in Kerneval , ordered the three U-boats to rendezvous in a remote area: Tarafal Bay, Santo Antão Island, in the Portuguese Cape Verde Islands. The British codebreakers intercepted several messages relating to the rendezvous, including an indiscreet one from Kleinschmidt in U-111, which mentioned Tarafal Bay by name. The Admiralty ordered the big River-class submarine HMS Clyde, commanded by David Ingram, which was on ASW patrol in the Canary Islands, to go to Tarafal Bay and attempt to sink all three U-boats.

This order to act tactically on Enigma information was risky. Until then the Germans had not used the Cape Verde Islands for U-boat operations. Should HMS Clyde fail to sink all three boats, a report of her appearance in remote Tarafal Bay at the exact moment of the first U-boat rendezvous there was certain to raise deep suspicion in Germany that Enigma had been compromised.

As scheduled, Merten in U-68 and Kleinschmidt in U-111 arrived in the bay on the evening of September 27. The boats anchored side by side about 200 yards offshore. While Merten and Kleinschmidt had dinner, the crews transferred four torpedoes from U-111’s topside canisters to U-68. Neither skipper felt quite at ease in those confined, unknown waters. Shortly before midnight both boats got under way and stood out to sea, intending to return the following night to meet Müller-Stöckheim in U-67.

At that same moment, HMS Clyde nosed into Tarafal Bay on the surface. Her bridge watch saw U-68 and Ingram turned to shoot a bow salvo. Before he could fire, however, he caught sight of U-111. Believing U-111 was coming in to ram, Ingram broke off the attack on U-68 and turned to deal with U-111. But when Kleinschmidt in U-111 saw HMS Clyde, he elected to crash-dive rather than ram, a decision that drew harsh criticism from his men. HMS Clyde passed directly over U-111, with mere inches between the two hulls.

When U-111 disappeared from view, Ingram resumed his attack on U-68, which was still unaware of his presence. Remaining on the surface, Ingram fired all six bow tubes at U-68, but Merten’s alert bridge watch saw the torpedoes approaching and he turned U-68 on a parallel course and crash-dived. The torpedoes missed, but two hit the distant shore and exploded. Confronting two alerted, submerged U-boats, Ingram dived HMS Clyde to reload his torpedo tubes and search for his quarry by hydrophone. While the three submarines were submerged in the bay, groping blindly for one another, a fourth was entering on the surface. She was Müller-Stöckheim’s U-67. When he heard the two torpedo detonations, he was shocked and puzzled—and promptly dived. He picked up the swish of propellers on his hydrophones, but could see nothing through his periscope. Prudently he decided to surface and withdraw to open sea.

Shortly after U-67 surfaced, Müller-Stöckheim caught sight of a “shadow” on his port bow. This was HMS Clyde, which had reloaded tubes and surfaced with her deck gun manned. Ingram saw U-67 at the same moment and turned HMS Clyde to ram. Recognizing the “shadow” as a big River-class British submarine on a collision course, Müller-Stöckheim backed his engines emergency power and put the rudder hard over. The result was that U-67 avoided being rammed but unintentionally hit HMS Clyde a glancing blow in her stern. The two submarines broke clear and dived. HMS Clyde was not seriously damaged; U-67 was a mess. Her bow was bent around at a 90 degree angle and three of her four bow torpedo tubes were inoperable and leaking. Since the crew could not repair the damage, she had to abort and return to France. During the ensuing day—September 28—the four submarines hauled out to sea and scattered.


After leaving the Cape Verde Islands, Kleinschmidt in the homebound U-111 set a course for France. Since his track was to take him west of the Canary Islands, close to the place where the boats of the second wave had attacked Sierra Leone 87, Kerneval directed him to be on the lookout for the abandoned hulk of Silverbelle, wrecked by Merten in U-68.

While looking for the hulk on the morning of October 4, Kleinschmidt saw smoke on the horizon. Believing he had found a big freighter, he turned U-111 to attack. The smoke was coming from a coal-burning armed trawler, HMS Lady Shirley, which had come out from Gibraltar to salvage Silverbelle or, possibly acting on Ultra information (the records are not clear), to intercept U-111. As U-111 closed, the lookout on HMS Lady Shirley spotted her conning tower at a distance of about ten miles. The lookout thought it was the funnel of a merchant ship, but HMS Lady Shirley’s captain, A. H. Callaway, turned toward the object on the “off chance” that it might be a U-boat. Still believing the trawler was a big freighter, Kleinschmidt dived to position U-111 for a submerged torpedo attack. Listening to HMS Lady Shirley’s screws, the hydrophone operator warned Kleinschmidt that the target was a small ship drawing very close, but Kleinschmidt stubbornly clung to his conviction that she was big and pretty far off.

Coming up pinging, HMS Lady Shirley got a good sonar contact at 1,600 yards. She ran in and dropped four depth charges, two set for 150 feet, two set for 250 feet. These exploded while U-111 was still at periscope depth—fifty feet—and did little damage. In response to this rude and shocking development, Kleinschmidt ordered a gun action. He surfaced U-111 close to HMS Lady Shirley, but both diesels malfunctioned and the engine room filled with dense choking smoke, impeding repairs and making another dive inadvisable.

Thus crippled, Kleinschmidt attempted to proceed with the gun action. But HMS Lady Shirley was bearing in, firing her 4″ gun and smaller weapons. Kleinschmidt got his 20mm gun on the bridge manned, but the close, accurate, and continuous fire from HMS Lady Shirley prevented the Germans from running down onto the main deck to man U-111’s 4.1″ gun.

Like two sailing ships of yore, HMS Lady Shirley and U-111 lay side by side, pumping shells at one another from point-blank range. Having seized the initiative, Callaway in HMS Lady Shirley never relinquished it, and the German gunners could not get to the big deck gun. In the exchange of fire, HMS Lady Shirley incurred five casualties (one killed, four wounded) in her fourteen-man crew, but she killed seven Germans, including the 20mm gunner and all three line officers: Kleinschmidt, first watch officer Helmut Fuchs, and second watch officer Friedrich Wilhelm Rösing, younger brother of Ritterkreuz holder Hans-Rudolf Rösing, who was then commanding Combat Flotilla 3 in La Pallice.

Upon the death of the three officers, a prospective commanding officer, Hans Joachim Heinecke, who had been helping with the malfunctioning diesels, assumed command of U-111 and ordered her abandoned and scuttled. The engineer opened the vents and the forty-five survivors, including five wounded, jumped overboard. Nineteen minutes after the start of the gun battle, U-111 plunged under for the last time. The triumphant little HMS Lady Shirley fished the survivors from the water and set a course for Gibraltar. One of the wounded Germans who had lost a leg died en route and was buried at sea, leaving forty-four of the fifty-two-man crew. German survivors were shocked and humiliated that Kleinschmidt, a merchant marine veteran, had mistaken a trawler for a big freighter and that the big and powerful U-111 had been bested by a lowly British trawler manned by fourteen men.

As in the case of U-570 and U-501, from which German prisoners had been taken recently, British intelligence officers noted well the inexperience of the U-111 crew. Kleinschmidt, who came from torpedo boats and cruisers, had been in the submarine arm only one year. The first watch officer, Fuchs, age twenty-four, had been in the Navy only four years. Normally a second watch officer, Fuchs was temporarily serving in the higher post because the regular first watch officer had injured himself ashore and did not sail. Rösing, crew of 1936, was actually a year senior to Fuchs, but he had only recently transferred from the Luftwaffe and had no prior experience in submarines and was therefore serving as second watch officer. Among the petty officers, only five had served in submarines before joining U-111 but, as a British report put it, only two of the five would have been considered “experienced” by prewar standards. Some of the enlisted men had been in the Navy only ten months.

Despite repeated assurances from the OKM to the contrary, the appearance of the British submarine Clyde in Tarafal Bay fouling the rendezvous of U-67, U-68, and U-111 convinced Dönitz that the British were reading naval Enigma. He logged on September 28: “It appears improbable that an English submarine would be in such an isolated area by accident. It is more likely that our cipher material is compromised or that there has been a break of security.” Accordingly, an emergency modification to naval Enigma was put into effect on October 1, which blinded Bletchley Park. But within seven days British codebreakers broke back into Enigma and read it currently until October 12, when, as related, another blackout of two days occurred. Then Bletchley Park began to decypher German Naval again all over.

Prodded by Dönitz, the chief of Kriegsmarine communications, Vice Admiral Maertens, intensified his new and supposedly comprehensive investigation into Enigma security. On October 24 Maertens turned in an eighteen-page report to the OKM and Dönitz in which he reaffirmed Berlin’s unshakable belief that Enigma was safe. Maertens dismissed the appearance of Clyde at Tarafal Bay as doubtless the result of a routine ASW patrol. Had the British planned a “trap” based on Enigma decryptions, he wrote, they would certainly have sent more than one submarine. He likewise dismissed other worrisome events that Dönitz had described, attributing them to British DFing or sightings by enemy and neutral ships and aircraft. Thus Doenitz and BdU Command was assured Enigma was safe.


Berlin rightly worried about the Mediterranean Basin. The Italian naval and air forces had failed to gain control of this vital strategic area. Capitalizing on breaks in Luftwaffe Enigma, which directed German aircraft to escort specific convoys, British aircraft, surface ships, and submarines had cut heavily into the flow of supplies from Italy to German and Italian forces in North Africa. The lack of supplies had prevented Rommel’s Afrika Korps from capturing bypassed Tobruk and had undermined the ability of Axis forces to repulse a possible British offensive. Moreover, a belief persisted in Berlin that the British were preparing an amphibious landing behind Axis forces—in Algiers and Oran—to trap Rommel between giant pincers.

To cope with this increasingly perilous situation, the OKM directed that in addition to the six U-boats ordered to the Mediterranean in September, Dönitz must do everything possible to interdict the flow of British supplies to the Mediterranean via the Strait of Gibraltar.

Dönitz was reluctant to comply. He continued to view the war in the Mediterranean as a distant second in importance to the war in the North Atlantic. Based on the small size and small number of ships in the Gibraltar convoys, he did not believe the flow of supplies from the British Isles via Gibraltar to be all that significant. The bulk of British supplies, he argued correctly, went to Egypt via Freetown, Sierra Leone, and Cape Town, South Africa. Moreover, the U-boat attacks on Gibraltar Convoys 70 and 71 in August had shown that those convoys were very heavily protected by air and surface escorts, so much so that they could almost be viewed as U-boat traps. Only the most experienced U-boat skippers had any chance of success against them and, as the attacks in August had shown, the chances were slight. Those experienced skippers were urgently needed in the North Atlantic, where the opportunities for delivering a meaningful blow at Great Britain’s lifelines were greater and the risks smaller.

The upshot was a compromise. Dönitz was to continue the U-boat war against the Gibraltar convoys; however, the boats, organized into smaller groups of about eight, were to be deployed much farther offshore where British air patrols were less intense and where the U-boats might also intercept Outbound South convoys en route to Sierra Leone, inbound Sierra Leone convoys, and military convoys outbound via Cape Town to Egypt, known as Winston Specials. The packs could be temporarily reinforced, as required, by boats outbound to the North Atlantic or by those with sufficient fuel and torpedoes homebound to France. The Bordeaux-based FW-200 Condor aircraft were to assist the packs in hunting and tracking convoys.

For the first three weeks of September, the hunt for Gibraltar and Sierra Leone convoys was fruitless.
U-boats and Condor aircraft found several, but owing to the ability of the British to read naval Enigma and thus to evade U-boat patrol lines and to miserable weather, neither of the first two packs, group Bosemüller (seven boats) and group Kurfürst (eight boats) sank a ship. As the boats departed for other tasks or to France, the remainder were regrouped into a single pack, group Seewolf, but it had no success either. On September 14, RAF Coastal Command aircraft (as yet unidentified) bombed and seriously damaged two VIICs of this pack, Gerd Schreiber’s veteran U-95 and Robert Bartels’s U-561, forcing both to abort.

Soon after group Seewolf dissolved, an Italian submarine operating west of Gibraltar reported a northbound convoy. This was Homebound Gibraltar 73, consisting of twenty-five ships, escorted by a destroyer, two sloops, eight corvettes, and the fighter-catapult ship Springbank. Only three U-boats were close enough to intercept and attack this convoy, but one of these, U-371, commanded by Heinrich Driver, was en route to the Mediterranean under orders not to attack any ships in the Atlantic.

Driver passed close to the convoy and reported its position. His report enabled Dönitz to put the other two boats on the convoy track. Fresh from France, these boats were U-124 under command of twenty-five-year-old Johann Mohr, the boat’s former first watch officer, and U-201, commanded by Adalbert Schnee, who had won a Ritterkreuz for his dogged attack on Gibraltar 71 in August. The U-124 was a IXB, a type that Dönitz considered to be too large, slow-diving, and too clumsy for attacks on the very heavily escorted Gibraltar convoys, but he had utmost confidence in young Mohr.

Taking up a waiting position about 600 miles west of the English Channel on the afternoon of September 20, Mohr detected smoke on the horizon. It was a convoy, but not the one he was expecting. This one was Outbound Gibraltar OG74, southbound from the British Isles. Composed of twenty-seven ships, it was escorted by a sloop, five corvettes, and the “jeep” carrier HMS Audacity (ironically an ex German merchant ship captured by Royal Navy in 1939 and concveted to an escort carrier) carrying eight Martlet fighter aircraft, on her maiden voyage in convoy duty. Upon receiving Mohr’s report, Dönitz directed him to shadow and send beacons to bring up the only other boat in the area, Schnee’s U-201.

Mohr shadowed until Schnee made contact, then attacked after dark on September 20. In his first salvo, he fired three torpedoes and got three hits. He claimed sinking two freighters for 15,000 tons and damage to an 8,000-ton tanker. In reality he sank two small freighters for 4,200 tons total and did no harm to the “tanker.” The merchant ships lit the sky with brilliant new star shells, called snowflakes,* and chased U-124 off and down.

The next day, while Mohr in U-124 and Schnee in U-201 maneuvered to close after dark, Dönitz sent out Condors to attack the convoy. In response, carrier HMS Audacity launched her six Martlets fighters (the British version of the American-built Grumman Wildcat). One of the Martlets shot down a German FW-200 Condor—the first aerial victory for a “jeep” carrier in the war—and another machine-gunned U-124 or U-201, forcing one or the other to dive. However, one of the Condors bombed and sank a freighter that had fallen behind while rescuing the crews of the two ships Mohr had sunk. Mohr and Schnee closed on the convoy after dark from opposite sides. Mohr set up on three ships, intending to fire two torpedoes at each. As he was on the point of shooting, all three ships blew up and sank. Schnee, as Mohr reported to Dönitz, had beat him to the punch. Schnee claimed sinking 14,000 tons, but the three ships totaled only 4,500 tons. Harassed by escorts and the Martlets from Audacity, neither boat was able to make another attack. Total damage to Outbound Gibraltar OG74 by Mohr and Schnee: five ships for 8,700 tons.

However the main assignment for U-124 and U-201 was the heavily escorted, Homebound Gibraltar HG73 convoy previously dicovered, which the Italian boats were still stalking and reporting. Astonishingly, the convoy appeared to be headed directly into the area where Mohr and Schnee had attacked Outbound Gibraltar OG74. On September 24 Dönitz sent Condor aircraft out to check on the Italian reports. The aircraft confirmed the convoy’s position and course, adding that the Italians had attacked it, sinking and/or damaging three ships.* Two other VIIs sailing from France, Rolf Mützelburg’s U-203 and Franz-Georg Reschke’s U-205, were directed to reinforce Mohr and Schnee. Homing on the Condor beacon signals, Mohr in U-124 was first to make contact with Homebound Homebound Gibraltar 73, closing the ships in heavy seas and rain on the morning of September 25. First he shot two torpedoes at what he claimed to be a cruiser, but which was probably a destroyer. Both missed. Then he fired one torpedo at what he claimed to be a destroyer. It also missed. Finally, he fired two torpedoes at what he claimed to be a 12,000-ton tanker. Both torpedoes hit the target, but it was a 3,000-ton British freighter and it sank.

Late that night, Mützelburg in U-203 came up to join Mohr, and both skippers attacked at about the same time. Mohr claimed sinking two more ships for 11,000 tons, but postwar records credited only two small British freighters for 2,700 tons. Mützelburg claimed sinking a freighter and a tanker for 20,000 tons. Postwar records credited three small freighters for 7,700 tons. The escorts drove Mohr and Mützelburg off and under.

During September 26, Mohr and Mützelburg doggedly clung to the convoy, bringing up Schnee in U-201 and Reschke in U-205. After dark, Mohr and Schnee attacked again. Firing off his remaining torpedoes, Mohr claimed sinking a ship of 3,000 tons and possible damage to another of 5,000 tons. Postwar records credited only a 1,800-ton freighter. Schnee claimed sinking a corvette and two freighters for 8,000 tons. No corvette was hit but the 5,200-ton fighter-catapult ship Springbank and another freighter of 2,500 tons went down. Still hanging on, the following night Schnee expended the last of his torpedoes, claiming two more freighters for 8,000 tons, but only one for 3,100 tons was confirmed. Mützelburg in U-203 had no chance to attack again. An aircraft “with United States markings” caught and bombed Reschke in U-205, forcing him to abort to France for repairs.

When Mohr, Schnee, and Mützelburg radioed their sinking reports, Dönitz was elated. Mohr claimed a total of six ships for 41,000 tons; Schnee seven ships for 30,000 tons plus a corvette; Mützelburg two ships for 20,000 tons and possibly another. Total claims: fifteen ships for 91,000 tons plus a corvette definitely sunk; two other ships possibly sunk. By postwar accounting, Mohr had sunk six small ships for 11,700 tons, Schnee six small ships for 15,200 tons (and no corvette), and Mützelburg three small ships for 7,700 tons. Confirmed totals: fifteen ships for 34,500 tons definitely sunk—five for 8,700 tons from Outbound Gibraltar OG74 and ten for 25,800 tons from Homebound Gibraltar HG73.

On October 2 a Condor found a southbound convoy, Outbound Gibraltar OG75, and Dönitz launched a half-dozen boats in pursuit. Hans-Werner Kraus in U-83 and Walter Flachsenberg in U-71 soon made contact and shadowed doggedly, sending beacon signals, but they were hampered by heavy weather and clever British evasions thanks to intelligence provided by ULTRA. Klaus Bargsten in U-563 reestablished contact with the convoy close to the coast of Portugal, but it again evaded pursuit and reached Gibraltar on October 14 without the loss of a single merchant ship. Bravely trailing the ships right into the western approaches to the Strait of Gibraltar, Herbert Opitz in U-206 fired at and hit what he thought was a destroyer, but proved to be the British corvette Fleur de Lys, which sank instantly with heavy loss of life.

The Germans had an efficient spy network in place in Algeciras, Spain, and directly across the Gibraltar Strait at Tangier, Morocco. The spies provided Berlin with precise information on Allied ship and convoy movements at Gibraltar and in the strait. Reading the Abwehr Enigma net currently and fluently, the British were aware of the spy network, but they could do nothing to thwart its operations or to disguise the ship movements. The spies reported to Berlin that convoy Homebound Gibraltar HG75 was preparing to sail at any hour. Upon learning this, Dönitz directed the boats that had unsuccessfully chased the Outbound Gibraltar OG75 south to the strait, plus others organized as group Breslau, to prepare to attack Homebound Gibraltar 75. While waiting, two of the six boats, Walter Kell in U-204, which had escorted the blockade runner Rio Grande to the Azores, and Ritterkreuz holder Reinhard Suhren in U-564, clandestinely refueled from the German supply ship Thalia in Cadiz.

Aware from Enigma decrypts that six boats were lying in wait west of Gibraltar to intercept Homebound Gibraltar HG75, the British delayed its sailing for nearly a week. During the wait, Kell in U-204 sank the 9,200-ton British tanker Inverlee; Opitz in U-206 sank a 3,000-ton freighter.

Royal Navy Support Groups based on Gibraltar mounted daily ASW sweeps to clear out the U-boats lying in wait west of the Gibraltar Strait. On October 19, after Kell in U-204 sank the tanker, the sloop HMS Rochester and the corvette HMS Mallow found and counterattacked Kell’s U-204 with depth charges. Coming up to assist, the corvettes HMS Bluebell and HMS Carnation found an oil slick and the air and fuel flasks of a torpedo, but this was not deemed conclusive evidence of a kill. The Admiralty rated the attack as merely “promising,” but, as was discovered later, HMS Rochester and HMS Mallow had sunk Kell’s U-204 with the loss of all hands.

Finally on the evening of October 22, Homebound Gibraltar 75 sailed. It consisted of seventeen ships and a massive escort of thirteen warships—four destroyers, one sloop, seven corvettes—and the 6,700-ton fighter-catapult ship Ariguani. Ten of the thirteen escorts were equipped with radar—three of them with the powerful new Type 271 centimetric-wavelength sets. In what Dönitz logged as “excellent” work, German spies immediately reported the sailing and the exact number and types of ships in the convoy.

Dönitz relayed to group Breslau (five boats) information on the sailing. Several of the boats made contact on the first night, but British escorts beat off the attacks. The destroyer HMS Vidette got a radar contact on a U-boat at three and a half miles and ran in at flank speed to ram, firing her main battery, but the boat crash-dived. HMS Vidette mounted an attack, but her crew botched the depth-charge launching and the boat got away.

On the second night, October 23–24, three U-boats closed the convoy to attack. The corvette HMS Carnation forced one boat under and held her down with depth charges, but the other two boats had better luck. Klaus Bargsten in U-563 missed a freighter but hit the big Tribal-class destroyer HMS Cossack, blowing off her bow. In two attacks, Reinhard Suhren in U-564 fired all eleven internal torpedoes. He claimed hits on six ships for damage, but in reality he hit and sank three British freighters for 7,200 tons. The British tried mightily to save HMS Cossack but she sank under tow.

During October 24 and 25, the boats shadowed and reported while Dönitz sent out several flights of Condors and brought up three Italian submarines. A Catalina of British Squadron 202 spotted one of the Italian boats, Ferraris, on the surface seventeen miles ahead of the convoy. Piloted by Norman F. Eagleton, the Catalina attacked with two depth charges and machine guns, but the charges failed to explode. Seeing the Catalina circling, the destroyer Lamerton raced up, firing her 4″ guns. Mistaking the destroyer for a corvette, Ferraris responded with her 3.9″ gun and tried to run. But Lamerton easily overtook her, whereupon the Italians scuttled their submarine and surrendered.

By the night of October 25–26, when the convoy had been reduced to fourteen ships and ten escorts, three boats ran in to attack. Walter Flachsenberg in U-71 shot four torpedoes at a “destroyer” but missed. Other escorts pounced on U-71 and depth-charged her for seven hours, Flachsenberg reported. Kraus in U-83 fired his last three torpedoes at three different ships, claiming all sank. In reality he hit only one ship, the fighter-catapult ship Ariguani, which was saved and towed back to Gibraltar. While preparing to shoot, Bargsten in U-563 was intercepted, attacked, and driven under by the corvette HMS Heliotrope, but she, too, botched her depth-charge attack. Bargsten fired two torpedoes at a “destroyer” (perhaps Heliotrope) from extreme range and claimed a sinking, but his torpedoes also missed. Group Breslau had shrunk to two boats by the evening of October 26: Bargsten in U-563 and Suhren in U-564. That night Bargsten fired five of his remaining six torpedoes at two freighters, but all missed. Having downloaded one torpedo from a deck canister, Suhren fired it at a freighter from extreme range. He claimed sinking a 3,000-ton ship, but he also missed. Using radar and intership radio to good effect, the destroyer Duncan, the sloop Rochester, and the corvette Mallow counterattacked both boats and held them off.

Although Bargsten and Suhren had only one torpedo between them, during October 27 both boats shadowed the Homebound Gibraltar 75 tenaciously. Their reports and several sightings by Condors enabled Dönitz to vector one other boat to the convoy. She was Heinz-Otto Schultze’s U-432, homebound from the attack on Slow Convoy SC48. Homing on Bargsten’s and Suhren’s beacons, in the early hours of October 28 Schultze closed and fired at two freighters. He claimed both sank, but only the 1,600-ton Ulea, which had bravely attempted to ram U-432, went down.

Based on flash reports from all the boats, Dönitz calculated that group Breslau had won a sensational victory over Homebound Gibraltar HG75: a destroyer and seven freighters for 34,000 tons sunk by Kraus, Bargsten, and Schultze, six ships for 25,000 tons damaged by Suhren. The reality was much less, reflecting the smaller size of ships in these convoys: the destroyer HMS Cossack and four freighters for 8,800 tons sunk, the fighter-catapult ship Ariguani damaged. Two boats were lost: Kell’s U-204 and Italian submarine Ferraris.

On the night of October 31, the U-96, commanded by Ritterkreuz holder Heinrich Lehmann-Willenbrock, who was outbound to a Greenland patrol line, came upon a convoy. This was Outbound South 10, consisting of thirty-four big ships and six escorts bound for Sierra Leone. When Dönitz received Lehmann-Willenbrock’s shadow report, he deployed Condoraircraft and directed ten other inbound and outbound U-boats to home on U-96’s beacons. The boats were organized into a new group, Stoertebecker. While they were converging, Lehmann-Willenbrock attempted a second attack on Outbound South 10 during the night of November 1–2, but the escorts, ex-American fourstack destroyer HMS Stanley and ex-Coast Guard cutter HMS Gorleston, and the British corvette HMS Verbena drove U-96 off with gunfire and depth charges.

Dönitz had great hopes for the eleven boats of group Stoertebecker. But the group ran into a massive storm—vividly captured on film by Buchheim—which killed any chance for a coordinated attack. After two days of frustration, Dönitz canceled the chase and directed the group to intercept a reported Homebound Gibraltar convoy. When this hunt failed, Dönitz redirected the group to intercept the northbound convoy Sierra Leone 91, but that pursuit failed as well. Outwitted by British evasions and diversions and bedeviled by foul weather, fuel shortages, and mechanical problems, group Stoertebecker was finally dissolved. It sank no ships.

These several U-boat groups patrolling the eastern Atlantic waters in September and October of 1941 to shut down the flow of British supplies to the Mediterranean via the Gibraltar Strait also turned in quite disappointing results. They had mounted attacks against four Gibraltar convoys (Outbound 74 and 75; Homebound 73 and 75) and had sunk nineteen small ships for about 43,400 tons, plus the destroyer HMS Cossack and corvette Fleur de Lys. However, most of the damage in this arduous and risky campaign had been inflicted on the less vital Home bound convoys. To the end of November 1941, all these boats sank only five small Gibraltar-bound merchant ships totaling 8,700 tons and one ship for 6,000 tons from Outbound South 10. This was not much help to Rommel’s Afrika Korps.