The renewal of the U-boat campaign on the North, middle, and South Atlantic convoy routes in July and August absorbed the majority of the U-boats. Even so, Dönitz was reluctant to abruptly discontinue the campaign in the Americas. Apart from the sinkings to be had, a continued U-boat presence in American waters would insure expansions of the convoy network with all its inherent delays, tie down ASW forces, and forestall a shift of them to other areas. Hence twenty-eight more boats sailed to the Americas: ten Type VIIs and seven Type IXs in July, and three Type VIIs and eight Type IXs in August.
Of the ten Type VIIs sailing in July, six were veteran boats from France, the other four new boats from Germany. Two of the six from France were captained by Ritterkreuz holders: Reinhard Suhren in U-564 and Gerhard Bigalk in U-751. Eight of the ten were to patrol the Caribbean area. The other two, Bigalk’s U-751 and the U-98, commanded by Wilhelm Schulze, were to lay TMB (magnetic) minefields at Charleston, South Carolina, and Jacksonville, Florida, respectively.
Bigalk in U-751, who had won his Ritterkreuz for sinking the “jeep” carrier Audacity during the December 1941 battle with convoy Homebound Gibraltar 76, sailed from St. Nazaire. Three days later, on July 17, a Whitley of Coastal Command Squadron 502, piloted by A.R.A. Hunt, spotted the boat on the surface. Attacking from an altitude of fifty feet, the Whitley dropped six 250-pound Mark VII depth charges with Torpex warheads set for 25 feet. The close straddle literally lifted U-751 out of the water, the airmen reported. Nonetheless, the Whitley mounted a second attack with ASW bombs and machine guns.
The U-751 survived these attacks and contrary to doctrine, Bigalk dived. A couple of hours later when he returned to the surface, a big British four-engine Lancaster of Bomber Command Squadron 61, on loan to Coastal Command and piloted by Peter R. Casement, was orbiting overhead. As the Lancaster ran in to attack, the U-751 “fired back with all her guns.” The Lancaster dropped ten close Mark VIII depth charges, then a string of ASW bombs. The bow of the U-boat rose vertically and she slid stern first beneath the sea. The crew spilled into the water, some of them shaking fists in defiance, the British aircrew reported. The British made no attempt to rescue the Germans. None survived.*
Wilhelm Schulze in U-98 laid his dozen mines off Jacksonville on August 9. Something must have gone wrong because the field produced no sinkings. Remaining well offshore, Schulze cruised north to the Cape Hatteras area to patrol in deep water. On the night of August 22, in bright moonlight, he found a convoy off Cape Lookout, but the air and surface escorts thwarted his attack. Upon the return of U-98 to France, it was noted that Schulze had made two long and arduous patrols to American waters without a single sinking, and he left the boat for other duties.
On the day British aircraft sank Bigalk in U-751, July 17, a homebound boat, Hans-Heinz Linder in U-202, found a convoy, Outbound South 34, close to the site of that sinking. Linder shadowed—and reported—until he was forced off by the escorts. His signals brought in two Type VIIs outbound to the Americas, Ritterkreuz holder Reinhard Suhren in U-564 and Ludwig Forster in U-654, as well as two Type IXs, one outbound and one homebound.†
Owing to a shortage of fuel, Linder in U-202 had to break off and continue to France, but by then Suhren had gained and held contact. After Forster in U-654 reported that he was also in contact, Suhren attacked, firing four bow torpedoes at four different ships. He claimed four hits on four ships: two ships for 10,000 tons sunk and two for 13,000 tons damaged. A postwar analysis credited the two sinkings for 11,100 tons but not the damage. The outbound Type IXB U-108, commanded by Ritterkreuz holder Klaus Scholtz, shot a full salvo of six torpedoes (four bow, two stern) at three ships, but all six missed or malfunctioned. No other boat could get in to attack, and the rest of the convoy escaped.
Suhren in U-564 and Forster in U-654 continued southwest to the Caribbean. On July 22, Suhren came upon a heart-stopping sight one thousand miles due west of Gibraltar: two westbound “British battleships,” escorted by three “destroyers.” Suhren shadowed and reported but he could not gain a shooting position. His reports brought up Forster in U-654 and Rolf Mützelburg in U-203, homebound from his notable patrol in the Caribbean, but neither boat could overtake the vessels. Suhren and Mützelburg met at sea the following day so that outbound Suhren could transfer a sick crewman to homebound U-203. Doubtless Suhren, who wore Oak Leaves on his Ritterkreuz, extended congratulations to Mützelburg, who had attained the same honor a week before.
Still traveling in company on August 3, Suhren in U-564 and Forster in U-654 met the new U-tanker U-463, commanded by Leo Wolfbauer. The VIIs topped off fuel tanks, but Suhren needed torpedoes. Upon learning that the luckless Type IX U-154, which was homebound from the Caribbean, had a full load, Suhren arranged via Kerneval to meet U-154 and take on some of her torpedoes.* Afterward the two VIIs proceeded to and entered the Caribbean Sea, Suhren to the area west of Trinidad, Forster farther west to Panama.
By that time almost all Allied shipping in the Caribbean Sea had been organized into convoys, running between Key West, Trinidad, Aruba, Curaçao, and Guantánamo Bay. Most of the air and surface escorts for these convoys were American, but the British and Canadians had each contributed one surface escort group, and the British a squadron of twenty Hudsons from Coastal Command based on Trinidad.
Aware of the expanded convoy networks in the Caribbean, Dönitz encouraged his VII skippers to work together informally, if at all possible. Upon finding a convoy, a skipper was to broadcast a contact report, then attack. If other VIIs were nearby, they were to converge on the contact at high speed, mindful that in the Caribbean there was not much sea room for a prolonged convoy chase, that the number of Allied ASW aircraft was seemingly increasing day-by-day and therefore air attacks were likely, and that radio traffic between U-boats should be kept to a minimum.
When Jürgen Wattenberg in the Type IX U-162 reported a convoy just west of Trinidad on August 19, Suhren in U-564 unhesitatingly raced to the scene, made contact, and attacked. Notwithstanding “two pistol failures,” he claimed he sank a tanker and a freighter for 15,000 tons and damaged two for 13,000 tons, but only the two sinkings for about 13,000 tons could be confirmed, including the 7,000-ton tanker British Consul. Shifting to the area east of Trinidad, in the Atlantic Ocean, for the next ten days, Suhren saw nothing worth a torpedo. However, on August 30, when he closed on Trinidad, he found and sank by torpedo and gun the 8,200-ton Norwegian tanker Vardaas.
Having exhausted all torpedoes, Suhren headed for France. He reported five ships (two tankers) sunk for 35,000 tons—an estimate close to the actuality—and four others for 26,000 damaged. The staff at Kerneval misinterpreted his report, logging that Suhren had sunk a total of nine ships for 60,000 tons. Or perhaps the misinterpretation was deliberate to justify yet another honor: the addition of Swords to Suhren’s Ritterkreuz on September 1.† Upon returning to France, Suhren left the boat. Later he took over a newly created and exalted post in Norway, Commander of U-boats, North.
Ludwig Forster in the VII U-654 patrolled off Panama for ten days, August 12 to 21. During that time he saw only one vessel, a fast-moving motor torpedo boat. Upon receiving his interim report, Kerneval shifted the boat to the area directly south of Guantanamo Bay in the Windward Passage. The next day, August 22, a radar-equipped Army Air Forces B-18 of the 45th Bombardment Squadron caught U-654 running on the surface. Attacking swiftly and skillfully, the pilot, P. A. Koening, dropped four shallow-set Torpex depth charges, which straddled the boat. Moments later oil and debris floated to the surface, the last sign of U-654. There were no survivors.
The other six VIIs that sailed to American waters in July went to the Caribbean via the North Atlantic routes. Kerneval directed several of these temporarily to attack convoys and refuel. As related, one veteran boat, Karl Thurmann’s U-553, sank the 9,400-ton British freighter Loch Katrine from convoy Outbound North 115. During a refueling on August 5, a crewman on the new boat U-598, commanded by Gottfried Holtorf, washed overboard and drowned.
Four of the six boats patrolled close to the Windward Passage, on the lookout for Key West-Guantanamo Bay and Key West-Trinidad convoys, which they hoped to attack in loosely coordinated actions. On August 12, the new VII U-658, commanded by Hans Senkel, age thirty-two, found one, Key West-Trinidad 13. His alert brought in the other three VIIs, which found, in addition, the northbound Trinidad-Key West 12. In the attacks that ensued, Senkel claimed sinking a tanker and freighter for 21,000 tons and a hit on a 6,000-ton freighter, but only one minor sinking, a 1,311-ton Dutch freighter, was confirmed. Gottfried Holtorf in the new U-598 sank two British ships, a 2,300-ton freighter and the 7,000-ton tanker Empire Corporal, and damaged the 6,200-ton British tanker Standella. Karl Thurmann in U-553 sank two freighters for 10,000 tons and so badly damaged a third, the 7,000-ton British Empire Bede, that she had to be sunk by the British corvette Pimpernel. The new U-600, commanded by Bernard Zurmühlen, which had earlier sunk a 130-ton British sailing ship but missed a “destroyer” with a salvo of three torpedoes, sank two freighters for 9,600 tons. Total for the four boats: eight confirmed freighters for 37,200 tons sunk, one tanker damaged.
The overlapping battles with these two opposite-sailing convoys were fierce. The boats reported “strong” air and surface escorts. Zurmühlen in U-600 stated that the Allied aircraft were able to locate his boat with great precision at night, indicating they were equipped with ASV radar. Moreover, he said, the surface escorts had “very good sonar” and their depth charges were uncomfortably “accurate.” As a result, the U-600 had incurred “considerable” damage that the crew could not repair, and Zurmühlen was forced to abort. Holtorf in U-598 likewise reported heavy depth-charge damage that forced him to abort. Homebound, Hans Senkel in the fuel-short U-658 found another convoy (Panama-Guantánamo 6) from which he sank two freighters for 10,835 tons and damaged another one for 6,466 tons.
Thus three of the four boats at the Windward Passage left for France. Shortly after clearing the Caribbean, Zurmühlen in U-600 ran across a big, fast freighter but in spite of “faultless data,” he missed with two torpedoes. En route home, he and Senkel in U-658 and Holtorf in U-598 refueled from Leo Wolfbauer’s tanker U-463. While entering the channel leading into La Pallice, U-600 triggered a British mine. The boat survived, but two months were required to repair both this battle damage and that incurred in the Caribbean. Holtorf’s U-598 remained in port for 105 days, undergoing battle-damage repairs.
Karl Thurmann in U-553 patrolled the Caribbean for another ten days but found no more targets. Having refueled on the way to American waters and exercised strict fuel discipline, he did not require a refill to get home. His claims, in cluding the big freighter sunk in the North Atlantic, totaled five ships for 32,000 tons, plus a 6,000-ton tanker damaged. Counting overclaims, Thurmann qualified for a Ritterkreuz, which was awarded on August 24, while he was still in the Caribbean. Berlin propagandists cheered the award, crediting Thurmann with sinking eighteen ships for 106,000 tons plus damage to twenty others.* When Thurmann reached France, U-553 underwent a four-month overhaul and did not resail until January 1943.
After refueling from a U-tanker, the new U-217, a Type VIID (minelayer), patrolled off Aruba and Curaçao. On the night of August 18, her commander, Kurt Reichenbach-Klinke, age twenty-five, poked his bow into the harbor at Willemstad, Curaçao, and shot three torpedoes at the tanker Esso Concord, moored to a pier. He claimed a sinking but it could not be confirmed. The next day he attacked and sank with his gun the 75-ton British sailing vessel Seagull D, which he claimed was transporting “fifty soldiers.” While U-217 was engaged in this action, an Army Air Forces B-18 found and attacked the boat with depth charges and bombs, inflicting so much damage that Reichenbach-Klinke was compelled to withdraw to a distant area to make repairs. Reporting that “several” of his crew had been felled by heat strokes, Reichenbach-Klinke returned to France on October 16, completing a miserable patrol of ninety-five days, during which he sank no ships other than the sailboat.
The last of the July boats to enter the Caribbean was Günther Krech in the VII U-558. Mere hours behind him came Ritterkreuz holder Otto Ites in the VII U-94, who sailed from France on August 2. Both boats refueled from Bruno Vowe’s tanker, U-462, on August 20, each filling their tanks to the brim. The boats then proceeded to the Windward Passage to hunt for convoys. On August 24, Krech in U-558 slipped through the passage and sank a 2,000-ton British freighter on the south side, a romper from convoy Trinidad-Key West 15. He broke radio silence to report that while in the passage he was bombed and depth-charged by an enemy ASW group composed of aircraft and destroyers working in cooperation. Kerneval directed Krech to leave the area and patrol westward along the south coast of Cuba to the Yucatan Channel.
Ites in U-94 combed the southern approaches to the Windward Passage, hunting convoys. On August 27 he found one and flashed an alarm. It was the main body of the heavily escorted northbound convoy Trinidad-Key West 15, consisting
of twenty-one merchant ships and nine escorts of mixed nationality. There were no other Type VIIs near enough to attack, but a Type IXC of the July group, U-511, commanded by Friedrich Steinhoff, responded.
That evening a radar-equipped Catalina of Patrol Squadron 92, based at the American naval installation at Guantanamo Bay, Cuba—facing the Windward Passage—joined the convoy to provide air escort. It was a beautiful tropical night, illuminated by a bright, full moon. At about 3:00 A.M., August 28, the airmen picked up U-94 on radar and then saw her on the surface astern of the convoy. The pilot, Gordon R. Fiss, attacked from an altitude of about seventy-five feet, dropping four new, experimental, 625-pound Mark XXIX depth charges,* set to detonate at fifty feet. Ites saw the plane coming and dived, but it was too late to get deep. The heavy, close explosions blew U-94 back to the surface and damaged her propulsion system, cutting her maximum speed to about 11 knots, not enough to evade even the slowest escorts, so Ites dived again.
Airman Fiss flew to one of the escorts, the Canadian corvette Oakville, commanded by Clarence A. King, and flashed an alert by signal lamp. King rang up full speed and upon reaching the site where Fiss had dropped flares, threw over five depth charges set for 100 feet. After the water calmed, King’s men got U-94 on sonar and then by moonlight saw the boat dead ahead on the surface. King unhesitatingly turned Oakville to ram, machine guns and cannons blazing. Oakville struck U-94 a glancing blow, skewing the U-boat around wildly. Hauling off so that he could bring his 4” gun to bear, King got off four rounds, one of which blew away U-94’s deck gun. Then King rammed U-94 a second time, simultaneously throwing over one depth charge set to explode directly beneath the U-boat.
Incapable of diving or firing back or outrunning Oakville, Ites gave orders to abandon and scuttle. He and his men swarmed topside into the hurricane of machine-gun and cannon fire from Oakville, which killed or fatally wounded about a dozen Germans. Hit twice in the leg, Ites leaped into the water as King swung Oakville around to ram U-94 for the third time. Oakville hit the U-boat hard and square abaft the conning tower, tearing gaping holes in her own bottom. At the moment of collision, a “boarding party” consisting solely of one of Oakville’s officers, H.E.T. Lawrence, and a petty officer, A. J. Powell, courageously jumped onto the bow of U-94 with pistols drawn to thwart the scuttling and to capture Enigma documents and/or perhaps even the entire U-boat. At nearly that same moment, the wounded Ites and another severely wounded German swam up to Oakville and were hauled aboard.
Complying with standard procedure, the boarders, Lawrence and Powell, rushed the conning tower with pistols to hold the Germans below and thereby thwart the scuttling. The Canadians shot two Germans in the conning tower who ignored their orders. The “extremely frightened” Germans who were still below “set up a terrific clamor,” Lawrence reported, so much so that he allowed them to come topside. While Powell held these Germans in loose captivity with his pistol, Lawrence rushed below to the pitch-dark control room, which was rapidly flooding and smelled of “gas.” In a hurried search by his own dimming flashlight, Lawrence could find no “secret papers” of any kind. As U-94 upended and sank, stern first, he grabbed four pairs of binoculars and rushed topside. Boats from Oakville and from another escort, the American four-stack destroyer Lea, fished the two Canadians and twenty-four Germans from the water.
While Oakville and Lea—and the Catalina—were so distracted, Friedrich Steinhoff in the Type IXC U-511 moved in and attacked the convoy. He fired a full salvo at three different tankers. Astonishingly, in these first shots as skipper, Steinhoff hit all three. He sank the 13,000-ton British San Fabian and the 9,000-ton Dutch Rotterdam, and damaged the 8,800-ton American Esso Aruba, which limped into Guantanamo Bay under her own steam. One of three American SCs in the escort rescued the fifty-nine survivors of the two sunken tankers.
The Americans took custody of the twenty-six German survivors of U-94 at Guanánamo Bay. They were smugly satisfied to discover that in Ites they had captured a Ritterkreuz holder, or “star.” Over the next several weeks American intelligence officers grilled Ites and his men, who appeared to cooperate and talk freely but who actually revealed very little of value. When the Americans queried Ites about the Enigma machine on U-94, he was disarmingly casual. The machines were not secret, he said. Before the war they had been sold on the open market but they were “useless if the settings were not known.” Had he known the Allies wanted an Enigma, Ites went on cavalierly, he would have “brought mine along for you.”
There was an unpleasant aftermath to the U-94 sinking. The commandant of the Guantanamo naval base, George L. Weyler, attempted to enlarge the American contribution and diminish that of the Canadians by insisting that the destroyer Lea had “opened fire” on U-94 and therefore had earned part credit for her destruction. Furthermore, Weyler’s official report of the action to higher American authorities contained veiled criticisms of the Canadians. Based on the reports of the American crews of the Catalina and Lea, Oakville’s skipper, Clarence King, was able to demolish Weyler’s case and refute his tactless report. Official credit for the kill was divided equally between Catalina pilot Fiss and his aircrew, and skipper King and the Oakville crew. The U-94 was the sixth U-boat to be killed all or in part by Canadian forces within six weeks, a remarkable achievement, but one that was not realized at the time.
Dönitz deduced promptly that Ludwig Forster in U-654 and Otto Ites in U-94 had been sunk, most likely, he believed, by enemy air. The loss of the much-admired twenty-four-year-old Ritterkreuz holder Ites—who had discovered the cause of the deep-running torpedoes in January—was keenly felt throughout the U-boat arm. His loss may have influenced Dönitz’s decision to send no more Type VIIs to the Caribbean to attack convoys. The area was too confined, the convoys too heavily guarded by Allied ASW forces. Thus U-94 became the last of the Type VIIs to draw an assignment inside the Caribbean or the Gulf of Mexico.
Unaware of these actions, Günther Krech in U-558, the only Type VII to make two patrols inside the Caribbean, cruised westward along the south coast of Cuba to the southern approaches to the Yucatan Channel. He remained in that once-rich area for ten days without seeing anything worth a torpedo. Then he cruised south to Panama and eastward to Aruba, Curaçao, and Trinidad. Finally, on September 13, he ran into a convoy sailing from Trinidad via Aruba to Guantánamo. In two successive attacks, Krech claimed numerous hits that sank a tanker and freighter for 15,000 tons and damaged a tanker and freighter for 12,000 tons. Postwar analysis credited three big ships sunk: two freighters for 15,200 tons and the 6,700-ton Norwegian tanker Vilja. Three days later in the waters west of Trinidad, he sank a 2,600-ton American freighter, bringing his confirmed sinkings for this patrol to five ships for 26,400 tons. These sinkings qualified Krech for a Ritterkreuz, which was awarded on September 17* as he pointed U-558’s prow eastward. Upon reaching France, the boat underwent a three-month overhaul and did not resail until January 1943.
Besides Ites in U-94, only two other Type VIIs sailed to American waters in August. Both were veteran boats: Ulrich Grä in U-69 and Hans-Heinrich Giessler in U-455. Both were assigned to lay TMB (magnetic) mines: Gräf in U-69 to reseed the entrance to Chesapeake Bay where Degen in U-701 had planted a field; Giessler to foul Charleston, South Carolina, in place of Bigalk in U-751, who was lost before he got out of the Bay of Biscay. Both boats carried torpedoes as well.