Hitler’s U-Boat War- The Hunted 1942-45

by Clay Blair

  The aging IXB U-105, severely damaged in June by British aircraft, sailed in late November, commanded by a new skipper, Jürgen Nissen, age twenty-six. Approaching the West Indies, Nissen sank the 6,600-ton British freighter Orfor. When Bleichrodt in U-109 aborted, Nissen replaced him in an area north of Trinidad. Harassed by heavy air patrols day and night, Nissen sank nothing in this area except the 67-ton British sailing ship C. S. Flight, which he boarded and scuttled near the island of St. Lucia.*

  Three other boats patrolled near Trinidad at this time. These were Mohr in U-124, crippled by malfunctioning diesel engines, and two Type VIID minelayers, U-214 and U-217. Kurt Reichenbach-Klinke in U-217, who boarded and scuttled the 2,600-ton Swedish neutral Etna, was under orders to enter the Caribbean and patrol off Aruba and Curaçao. However, following his claim of sinking a 6,000-ton freighter and several hits on another big freighter near Trinidad, Reichenbach-Klinke reported his Metox was out and requested cancellation of his Caribbean assignment. As a result, the other VIID, U-214, commanded by Günther Reeder, who had sunk a 4,400-ton Polish freighter, was assigned to the area near Aruba and Curaçao and U-217 patrolled a less hazardous area off British Guiana.

  Reeder in U-214 entered the Caribbean, but almost immediately he incurred a gyro-compass failure. He arranged a rendezvous with Nissen in U-105, who had compass spare parts. After that, Reeder returned to Aruba and Curaçao, the first U-boat to patrol those waters in many months. Off Curaçao on January 8, he attempted a daylight submerged attack on a convoy of eight tankers, but one of the ships saw a “torpedo splash” (as Reeder reported), spoiling the attack. Altogether Reeder patrolled for nineteen arduous days inside the Caribbean, but he had abysmal luck. Having sunk only the Polish ship of 4,400 tons, he headed for home.

  Reichenbach-Klinke in U-217 patrolled off the coast of British Guiana for the entire month of January without seeing any shipping. He reported that there were “systematic” Catalina patrols extending up to two hundred miles off the coast.* On his return trip to France, Reichenbach-Klinke found and sank by torpedo and gun a 8,000-ton British freighter and captured one officer. Owing to an unscheduled early return of the “Milk Cow” tanker U-462, the recently sailed Type IXC U-504 was directed to replenish U-217, an operation twice delayed by inclement weather. Reichenbach-Klinke arrived in France after ninety-two days at sea—a near record for a Type VIID—having sunk two ships for 10,600 tons.

  Nissen in U-105 patrolled off Trinidad for a full month, from December 15 to January 15, without sinking anything other than the sailing ship. On the return voyage to France, he found and sank the abandoned hulk of the 8,100-ton tanker British Vigilance, damaged earlier by U-514. Three days later, on January 27, he sank the lone 5,100-ton American freighter Cape Decision, heavily laden with war materiel. Like U-217, Nissen refueled from the IXC U-504. In this eighty-four-day patrol, Nissen sank three confirmed ships for about 11,900 tons, plus the 8,100-ton hulk of the British Vigilance.

  Approaching Trinidad on December 16, Johann Mohr in U-124, beset by intermittent engine failure, found a northbound convoy. He counted six big tankers escorted by five “destroyers.” With scarcely a pause, Mohr attacked, shooting a salvo at one of the escorts and at two tankers. He reported that two torpedoes missed the escort, but two hit an 8,000-ton tanker and one hit a 6,000-ton tanker. One tanker sank in five minutes, the other in fifteen minutes, Mohr reported, but neither of these sinkings could be confirmed in Allied records. After reloading his torpedo tubes, Mohr attempted a second attack, but it was thwarted by ASW aircraft.

  During the next dozen days, Mohr patrolled off Trinidad and Tobago. He spent much of the time nursing his failing diesels. On one occasion, a small amount of salt water from the distiller contaminated some battery cells, causing the formation of chlorine gas. It took twelve hours to fix this problem and ventilate the boat. Engine failure, Mohr reported, thwarted effective attacks on two other small convoys. A Catalina air patrol drove him off another convoy. During these trying days he destroyed only one confirmed ship, a 4,700-ton British freighter, sunk by a single torpedo fired from a submerged position on a bright moonlit night.

  Mohr’s luck changed dramatically on January 9. That night he found a south-bound convoy, Trinidad-Bahia 1 (TB 1). Tracking close with faltering engines, he counted nine ships and four escorts, and dived to conduct a daylight submerged attack. In two separate, bold, well-executed approaches, he sank four American ships for 23,567 tons, the 7,700-ton tanker Broad Arrow and three cargo ships. These and past sinkings and overclaims qualified Mohr for Oak Leaves to his Ritterkreuz, later awarded by Hitler at his headquarters in the Ukraine.*

  The rest of the patrol brought more frustration. On January 10, Mohr chased a lone freighter on one engine. When he finally got close enough to shoot, he missed. A Catalina appeared to spoil a second attack. A Week later, on January 16, he shot a single torpedo at a tanker. Fortunately it missed: The ship turned out to be a neutral. After that chase, Mohr’s engineer warned him that if he did not head for home immediately, the diesels might fail beyond repair. While homebound, Mohr refueled from the IXC U-504, in the wake of U-105 and U-217. In this arduous, eighty-one-day patrol, Mohr claimed sinking eight ships (three tankers, five freighters) for 46,000 tons. His confirmed score—by far the best of the eight boats to reach American waters—was five ships for 28,259 tons. Although Mohr could have chosen a safe job ashore, he elected to remain in command of U-124.

  Apart from Mohr’s patrol, the eleven boats assigned to American waters in November turned in disappointing results. Three boats never got beyond the Bay of Biscay, and Bleichrodt in U-109 aborted with no sinkings. The seven other boats that reached American waters, including Mohr’s crippled U-124, sank nineteen ships for about 92,400 tons, including the 8,100-ton abandoned hulk British Vigilance. In all, the eleven boats sank an average of only 1.7 ships for 8,400 tons per boat per patrol. Three of the Type IXs did not return: U-164, U-507, and U-517.

  From the reports of these and other boats it was clear that the hunting grounds east and southeast of Trinidad and in the waters off British, Dutch, and French Guiana no longer offered easy prey. The Allies had extended the convoy network to those areas with Catalinas and other aircraft escorting most of the way. Yet it was vital for the Germans to interdict that traffic. Most of the loaded tankers and freighters forming into convoys at Trinidad were headed for the Mediterranean, either directly east across the Atlantic or south-southeast via Cape Town. Every one of those Allied ships that was sunk directly helped the retreating Afrika Korps in North Africa.

  ACTION IN THE MIDDLE ATLANTIC

  During the year 1942, British oil stocks (reserves or stockpiles) fell from seven million tons to 5.2 million tons. The reasons were several:

  • Petroleum products for all British forces involved in Torch were drawn directly from reserves in the British Isles. The failure of the Allies to promptly seize Tunisia, prolonging the campaign, produced a further, unanticipated drain on the reserves.

  • The establishment of the extensive convoy network in American waters at midyear, in which most Allied tankers were required to sail, significantly slowed the flow of oil to the British Isles via Halifax convoys sailing from New York.

  • The loss to Axis submarines of 185 Allied tankers from January 1 to September 1, 1942,* while not a crippling blow, nonetheless contributed to the decline in British stocks.†

  • The hideous weather in the fall and winter in the North Atlantic caused heavy damage to many merchant ships, especially to tankers. At the end of 1942, the official British oil historian wrote, nearly one quarter of the British-controlled tanker fleet (1.7 million of 7.6 million deadweight tons) was in repair, awaiting repair, or otherwise immobilized (a few ships, of course, by torpedo damage).

  The drawdown of British oil reserves in 1942 caused great alarm in London. Battle plans for 1943 were contingent upon healthy oil reserves. On December 17, Churchill proposed to Roosevelt a number of drastic measures to arrest th
e decline and rebuild the stocks: .

  • Special oil convoys to sail directly from the Caribbean to the British Isles (or United Kingdom) every three weeks (CU and the reverse, UC). The eighteen inbound convoys per year were to deliver about 1.2 million tons of petroleum products in 1943, enough to arrest the decline. To provide escorts for these special convoys, the British Royal Navy would assume all escort duties on the North Atlantic run with eight close escort groups, releasing three Canadian groups and the American group, A-3, for other convoy duty.

  • Special oil convoys to sail directly from the Caribbean to various Allied-controlled ports in the Mediterranean in support of Torch. These convoys (Oil-Torch, or OT, and the reverse, TO) would enable the British to substantially reduce the flow of oil from British stocks and, in effect, contribute to their rebuilding. Composed only of fast tankers (“Greyhounds” of 14 V2 knots plus), these convoys were to be escorted by a special detachment of modern American destroyers from the Atlantic Fleet.

  • Further rebuilding of stocks by the sailing of Greyhounds from the Caribbean to the British Isles, unescorted.

  These proposals raised serious questions in Washington. Uppermost was this one: Why should British oil reserves be maintained at seven million tons? Even at the December 1942 figure, 5.2 million tons, the British had more than a six-month supply of one hundred octane aviation gasoline and a comparable supply of fuel oil. No American or Pacific war zone had more than ten weeks of aviation gasoline, and the northeastern United States had a fuel oil reserve of only four weeks. In order to meet Churchill’s proposal for aviation fuel, the training of military pilots in the United States would have to be curtailed appreciably, resulting in a senseless production of aircraft for which no aircrews were to be available.

  Roosevelt responded tactfully that he would continue to help the British in every way he possibly could, but … He opposed opening out the North Atlantic convoys from eight to ten days, the shifting around of the escort groups already in service in that area, the sailing of fast tankers unescorted, and the sailing of tankers into Mediterranean ports, often bombed by the Luftwaffe. New measures already in train, such as special oil convoys directly from the Caribbean to the “New York oil pool,” which were to increase the number of escorted tanker round-trips in fast Halifax convoys, would provide the British with 1.25 million tons of petroleum products a month from the Americas or fifteen million tons per year. This, said Roosevelt’s oil king, Harold Ickes, was enough not only to stop the erosion of British stocks but also, possibly, to rebuild them.

  The discussions about the decline of British imports, including oil, continued with mounting intensity into 1943. In the meantime, the British War Cabinet, more deeply concerned than ever about the so-called oil shortage, directed the Admiralty to sail at least three tanker convoys, protected by British escorts, directly from Trinidad or the Caribbean to the Mediterranean. These were TM 1, a slow convoy with corvettes in the escort, which sailed from Trinidad on December 28, 1942, and TM (Fast) 1 and TM (Fast) 2, both of which had sailed by mid-January 1943, escorted by British destroyers.

  Owing to the prolongation of Torch operations, Washington did, in fact, finally organize and sail OT (Oil-Torch) convoys directly from the Caribbean to Northwest Africa. The first, OT 1, composed of Greyhounds and escorted by American destroyers, sailed from Aruba on February 2 for Dakar. The second, OT 2, sailed from Aruba on February 20 for Gibraltar and Casablanca, but not to Allied ports deep inside the Mediterranean. Delayed by the need to refit or overhaul the American destroyers engaged in the escort, the OT convoys sailed about every two months, delivering an average of about 200,000 tons of petroleum products in each convoy.

  The Americans also finally yielded and commenced sailing oil convoys direct from the Caribbean to the United Kingdom. The first, CU 1, comprised of nine Greyhound tankers escorted by American destroyers, sailed from Curaçao on March 20 and arrived in the British Isles thirteen days later. The second, CU 2, similarly composed, sailed sixty-three days after the first, on May 22. These two convoys delivered 130,000 tons of oil to further replenish British stockpiles.*

  The Type IXs and VIID (minelayers) that patrolled American waters possessed the endurance for the task, but they were not really suitable for attacking convoys or capable of quick dives to elude aircraft. Therefore, Dönitz decided to send, in addition to two IXs, a special task force of a half dozen VIIs to the waters near Natal, Brazil, to attack along the newly organized convoy routes. Adopting the much used codename group Delphin (Dolphin), the boats sailed during the week from December 17 to 22. The task force was to be supported by the “Milk Cow” tanker U-463, commnded by Leo Wolfbauer, which had sailed earlier.

  The two IXs assigned to American waters in December were U-125 and U-514, which, as related, had first to escort the outbound blockade-runner Germania through the Bay of Biscay to safer waters. After the British sank Germania on December 15, and the search for survivors was called off, the two boats were diverted to attack a southbound convoy discovered west of Biscay on December 18 by the outbound VII U-441. When all efforts to assemble a U-boat group strong enough to attack this convoy failed, on December 21 U-125 and U-514 were directed to resume their voyages to the Trinidad area. However, when Ulrich Folkers in U-125 reported serious diesel-engine problems and a lack of the necessary spare parts, he was diverted to a rendezvous first with the “Milk Cow” tanker U-461, then with Helmut Witte in the IXC U-159, returning from his notable patrol to Cape Town. As a result of these delays to pick up spare parts, U-125 lagged about 250 miles behind U-514:

  In the meantime, B-dienst alerted Dönitz to a UGS convoy en route from the Americas to Gibraltar, which was to sail an unusual route to the south of the Azores. Acting on this information, Dönitz halted the Brazil-bound group Delphin and redeployed its six VIIs on a patrol line southwest of the Azores. After one full week of futile searching, on January 2 Dönitz canceled this diversion and directed the Delphin boats to refuel from the group’s tanker, U-463, then resume the voyage to Brazil.

  On the following day, January 3, the Trinidad-bound U-514, commanded by Hans-Jürgen Auffermann, encountered by chance a convoy of nine fully laden, big, fast tankers en route from Trinidad to the Mediterranean. This was TM 1, the first special British oil convoy, too thinly escorted by British Escort Group 5, commanded by Richard C. Boyle: the destroyer Havelock and three British corvettes, Pimpernel, Godetia, and Saxifrage. The tankers were fast ones, but the need to stretch the fuel of the corvettes reduced the speed of the convoy to about eight knots, leaving it much more vulnerable to U-boat attack.

  Upon receiving Auffermann’s report, Dönitz told him to shadow “without fail” but also authorized him to attack. Folkers in U-125 (250 miles east) and group Delphin (nine hundred miles east) were to close on the convoy at high speed. Dönitz believed Folkers could help Auffermann, but, as he logged, he felt there was “little hope” that group Delphin could. Nonetheless, owing to the “pressing need” to shut down Torch oil traffic, every possible effort had to be made.

  Auffermann attacked and hit the 8,100-ton tanker British Vigilance. It exploded in a fireball but did not sink.* Auffermann mistakenly reported his victim to be the 17,000-ton whale factory ship Kosmos II, serving as a tanker. Owing to the weakness of the escort group and to failures in the radar and/or Huff Duff sets, the four British warships were unable to take effective action against the lone shadower, U-514. Unfortunately for the Germans, Auffermann’s radio and his diesels partly failed. Thus most of his contact reports were unreadable and he could only make 13 knots. Nonetheless, he hung on. As a result of Auffermann’s radio failures, Folkers in U-125, still beset with diesel-engine problems, could not find Auffermann or the convoy and played no further role in the battle.

  At this time a number of U-boats, both inbound and outbound, were in the vicinity. Among the outbound boats were several of another group, Seehund (Seal), en route to Cape Town and the Indian Ocean.* At the same time that Auffermann rep
orted convoy TM 1, the new U-cruiser U-182, commanded by Ritterkreuz holder Nikolaus Clausen, which was loosely attached to group Seehund, found and reported a westbound convoy. Since Clausen’s convoy was merely 360 miles from the center boat of the group Delphin patrol line, Dönitz canceled the orders for them to attack U-514’s convoy (TM 1) and directed the group to attack U-18Ts convoy.

  The convoy that Clausen came upon was GUF (Gibraltar-United States Fast) 3, which sailed from Casablanca on December 29. It was composed of twenty-four ships, powerfully escorted by American men-of-war: the battleship New York, the light cruiser Philadelphia, and nine destroyers. The new destroyer Earle, commanded by Hamilton W. Howe, who, as skipper of Roper had sunk U-85 off Cape Hatteras, got U-182 on radar, ran down the bearing, and opened fire by searchlight. Joined by another new destroyer, Parker, Earle hunted U-182 for ten hours, Howe logged.

  As a result of this long and persistent chase, Clausen lost contact with the GUF convoy. Nonetheless, based on his reports and good guesses, the next night four of the Delphin boats found it and reported. But before they could attack, the destroyers Earle and Parker and others drove the U-boats off and under. After receiving reports from these boats, including one from Günther Heydemann in U-575, who reported a “very heavy” depth-charge attack, Dönitz decided to cancel Delphin operations against this heavily escorted convoy and shift the group back to U-514’s weakly escorted convoy (TM 1), even though the latter was at least four days distant and might never be found.

  It was a risky decision but it paid off. Stubbornly dismissing a recommendation from London to divert to the north of the Azores, escort commander Boyle held to his original game plan. As a consequence, on the afternoon of January 8, convoy TM 1 sailed right into the center of the Delphin patrol line. Wilhelm-Heinrich von Pückler und Limpurg in U-381 found, reported, and tracked the convoy. Upon receipt of his report, the five other Delphin boats closed. In addition, Dönitz ordered four other boats in the area to join the hunt: two Type IXCs of the outbound Seehund group (U-511 and U-522) and two boats inbound from prolonged patrols in the South Atlantic (U-128 and U-134). Later, Dönitz also directed Wolfgang Lüth in the IXD2 U-cruiser U-181, inbound from the Indian Ocean, to join. These orders put thirteen attack boats (five IXs, seven VIIs, one U-cruiser) on the trail of the eight remaining tankers of TM 1. However, three of the IXs (U-125, U-128, and U-514) had no hope of catching up with the convoy and of getting into the battle.