The Bismarck affair had disrupted the U-boat patrol cycles in the Atlantic and gutted the western patrol line south of Greenland. By June 1, the line consisted of merely four boats. However, seven of the twenty boats that sailed in June were en route to reinforce it, plus U-557, which had withdrawn, temporarily, to refuel from the scuttled Bismarck supply ship Belchen. At the request of the OKM, two other new VIIs sailing from Germany to join the patrol line, U-79 and U-559, were temporarily diverted to the Denmark Strait to assist in a proposed sortie of the “pocket” battleship Lützow (ex-Deutschland).*
Positioned beyond range of ASW aircraft based in Iceland or Newfoundland and close enough to Belchen for refueling, Dönitz expected great results from the western patrol line. But problems arose. Belchen was lost almost immediately and Korth’s U-93 took Belchen’s survivors to Lorient. In addition, another boat, Richard Zapp’s new IXB, U-66, lost all four of its torpedo-tube bow caps and aborted—unnecessarily soon, Dönitz logged. The remaining ten boats, thinly spread across possible convoy routes, were bedeviled by heavy fog, caused when cold Arctic air masses met the warm waters of the Gulf Stream.
From Ultra the Admiralty knew the approximate position and strength of the U-boat patrol line. Working in close harmony, Rodger Winn in the U-boat Tracking Room and officials of the Admiralty Trade Division and those at Derby House in Liverpool routed the eastbound Halifax convoys well around the line. Thus the only ships the boats encountered were the (mostly empty) unescorted westbound singles or doubles, which had dispersed from the outbound convoys west of Iceland before the “end-to-end” escort came into being.
The absence of any Halifax convoys was deeply puzzling to the Germans. Suspecting that the Admiralty might be routing them well to the north of the patrol line, along the edge of the ice pack between Newfoundland and Greenland, Dönitz obtained permission from the OKM to send Kleinschmidt’s U-111—which had refueled from the now-scuttled Belchen—to explore the coast of Newfoundland from Cape Race north to Belle Isle Strait. Since this was to be the first penetration of “American” waters by a U-boat, and Hitler wanted no unnecessary provocations during Barbarossa, Kleinschmidt was barred from shooting at anything except “especially valuable ships” (cruisers or larger warships or huge liners, such as the Queen Mary, converted to troop transports) and was to maintain absolute radio silence during the reconnaissance.
This was a challenging assignment for a boat on its maiden patrol, doubly so because Kleinschmidt had no navigational charts of the Newfoundland area. Upon closing the coast, he encountered heavy pack ice, icebergs, and dense fog. He explored the area for a week, during which he incurred ice damage to two torpedotube caps, then withdrew well to the east to radio a report to Dönitz. He had seen no traffic. Because of the extensive ice pack, Kleinschmidt believed it improbable that the convoys were being routed that way. After reflecting on this report, Dönitz moved the patrol line further south—to no avail.
Although the patrol line found no Halifax convoys, the boats encountered and continued to sink a number of westbound singles and doubles. The top shooter was the Ritterkreuz holder Herbert Schultze, who was taking the famous but weary U-48 home to the Training Command. In merely nine days, Schultze sank five ships for 38,462 tons, including three tankers: the 9,500-ton British Inversuir, the 6,000-ton British Wellfield, and the 10,700-ton Dutch Pendrecht. This tonnage put Schultze over the 200,000-ton mark and Dönitz awarded him Oak Leaves to his Ritterkreuz, the fourth skipper after Prien, Kretschmer, and Schepke to earn that high honor in the North Atlantic.* Schultze left U-48 in Germany and returned to France to command the 3d Combat Flotilla at La Pallice.
No less aggressive was the Ritterkreuz holder Engelbert Endrass in the equally weary VIIB U-46. But he was bedeviled by torpedo failures—four, he reported. On June 2 and 6, he attacked and hit a freighter and a tanker, but each time the torpedo failed to detonate. On June 8 he simultaneously attacked a tanker and a freighter. Two more torpedoes failed to detonate, but nonetheless Endrass damaged the 6,200-ton British tanker Ensis and sank a 5,300-ton freighter. In retaliation, Ensis turned on U-46 and rammed her, knocking out the attack periscope. Endrass put Ensis under with a finishing shot, then aborted to France. Inbound to Lorient he sank a 5,600-ton freighter by torpedo and gun. His overclaims of 16,500 tons sunk also put Endrass beyond the 200,000-ton mark and he, too, was awarded Oak Leaves to his Ritterkreuz.†
Another Ritterkreuz holder, Wolfgang Lüth in the old but recently rehabilitated Type IX U-43, replaced Endrass in the patrol line. He sank two ships for 7,500 tons, but U-43 was not really combat-worthy. When Lüth returned to Lorient, the boat went back into the yard for another overhaul, to remain there until November, having completed only two war patrols in twelve months, during which Lüth sank only five ships.
The other skippers of the patrol line—some on maiden voyages—sank another fourteen ships between June 1 and June 18. The most successful of these was Klaus Scholtz in the Type IXB U-108, making his third Atlantic patrol. He claimed sinking four ships for 27,300 tons, including a 14,000-ton auxiliary cruiser. In reality he sank four freighters for 17,000 tons.†
Erich Topp in U-552, who had made three patrols to North Channel in the duck U-57 and two in U-552, requested that dangerous area again. In view of the fact that the duck U-141, on indoctrination patrol, had been severely damaged there in recent days, Dönitz was hesitant, especially since the shortest nights of the year were fast approaching. Finally, Dönitz consented.
The plan was for Topp to coordinate operations, if possible, with three Type IID ducks on indoctrination patrols close to the British Isles: the U-141, repaired in Lorient; the U-143, sailing from Germany; and the U-147, which had earlier sailed from Germany. Unknown to Dönitz, the U-147, commanded by Eberhard Wetjen, had been sunk on June 2 by British warships, the destroyer Wanderer and corvette Periwinkle, following Wetjen’s bold solo attack on convoy Outbound 329.
Topp found the area teeming with ASW aircraft, forcing him to crash-dive up to ten times a day, a nerve-racking routine during which several of his men broke down. Nonetheless, he found and sank three ships for 24,400 tons, including the 11,000-ton British freighter Norfolk. These sinkings brought Topp’s claims to 100,000 tons, earning him a Ritterkreuz.* On June 18, Topp came upon an inbound convoy and attempted to attack and bring in the ducks and other boats, but the escorts drove him off. The duck U-141was unable to cooperate with U-552 but she shot at two ships, sinking one.
Another duck, the U-138, commanded by twenty-five-year-old Franz Gramit-sky, who had served in combat under Schepke and Lüth on other ducks, had arrived in Lorient from Germany for a top-secret special mission. Gramitsky was to penetrate the mined British naval base at Gibraltar for the specific purpose of sinking the battleship Renown or an aircraft carrier or, at the very least, a heavy cruiser. Should he succeed in sinking a capital ship—as Prien had at Scapa Flow—he was assured of a Ritterkreuz. Should’he run into difficulty, the crew was to scuttle and swim to Spain, where it was to be assisted in making its way back to Lorient.
Gramitsky sailed from Lorient on June 12. Other than he, no one on the boat knew the purpose of the mission. Early on the morning of June 18, when U-138 was about 100 miles west of the Strait of Gibraltar, inbound on the surface, the bridge watch spotted what was believed to be a “cruiser” and dived. Actually, the “cruiser” was the destroyer Faulkner, which in company with four sister ships of the 13th Destroyer Flotilla, Fearless, Forester, Foresight, and Foxhound, was conducting a sonar sweep, probably forewarned by Ultra to be on the lookout for U-138. The skilled sonar teams on Faulkner and Forester had helped kill the first U-boats of the war, U-27 and U-39.
Faulkner obtained sonar contact on U-138 and attacked immediately, dropping six depth charges set for 100 to 250 feet. These exploded with uncanny accuracy, wrecking and flooding the boat. Out of control, her internal spaces awash with water, she twice slid down to 650 feet before Gramitsky could blow her ballast tanks and get her to the surface. When she popped up, the entire crew jumped overboard. Forester saw the doomed boat on the surface and attacked with guns. She dropped six more close depth charges before she realized U-138 was already sinking, vertically, stern first. Faulkner fished out the entire crew of twenty-eight men; there were no serious casualties.