by Clay Blair
By this time, group Specht (Woodpecker) had formed up about two hundred miles southeast of Outbound North (Slow) 4 to attack the opposite-sailing Slow Convoy 127. It was comprised of eighteen boats, ten of the southernmost boats of Meise (including six that had refueled) and eight of the newly sailed boats that had attacked the American-escorted Halifax 233, including the IXC U-125, one of the original Drumbeat boats, still commanded by Ritterkreuz holder Ulrich Folkers. U-boat Control directed group Specht, less three boats that had to refuel, to race north to join in the attack on Outbound North (Slow) 4. Should it fail to locate that convoy, Specht, now composed of seventeen boats, was to remain in the more northerly waters on a patrol line running southeast from Greenland.
Otto von Bülow in U-404 held firmly to Outbound North (Slow) 4. On April 24 he spotted Biter and her screen of four destroyers. His report brought up three other boats (two IXs, one VII). That night when one of these had made contact, von Bülow boldly slipped through the destroyer screen and fired all five torpedo tubes at Biter (two FATs, two electrics, and one electric with a Pi2 magnetic pistol). While retreating on the surface, von Blow heard four hits, he reported, and saw “two tongues of flame” rising from Biter. He thought it was the American fleet carrier Ranger, and he “presumed” it sank. The response from U-boat Control and Dönitz was immediate. The next day Hitler awarded von Bülow Oak Leaves to his Ritterkreuz, which the Führer later presented in person.* After the presentation, von Bülow left U-404 to command Flotilla 23 in the Training Command.
On Easter Sunday, April 25, Hesperus DFed another U-boat nearby. This was the U-203, made famous by Rolf Mützelburg, now commanded by Hermann Kottmann, who was preparing to attack Biter. When Macintyre notified Biter, she diverted a Swordfish to run down the DF bearing. The aircraft spotted the diving U-boat and dropped two shallow-set depth charges on the swirl from an altitude of fifty feet. The plane then remained over the spot until the destroyer Pathfinder of Biter’s screen arrived. In the hurried dive, one of U-203’s diesel-exhaust valves had not properly seated and was leaking. Kottmann was therefore reluctant to go deeper than two hundred feet.
Pathfinder held sonar contact and carried out several depth-charge runs, dropping over forty missiles. The close explosions increased the flooding aft to the point that Kottmann became convinced U-203 was doomed. He blew all main-ballast tanks and surfaced close to Pathfinder. The engineer stayed below to open the vents to scuttle the boat and was never seen again. Nine other Germans died in the sinking from shock, hypothermia, or failure to properly don escape apparatus, the British reported. Pathfinder rescued Kottmann and thirty-seven other crew. Biter—not Bogue—was thus the first “jeep” carrier to participate in a confirmed U-boat kill.
Evasive routing, skilled escort work, Biter’s local air cover, and very-long-range aircraft from Iceland and Newfoundland thwarted any further U-boat attacks on Outbound North (Slow) 4. After threading through a dangerous field of icebergs, the convoy was further reinforced by British Support Group 1, commanded by Godfrey N. Brewer, consisting of five warships: three frigates (Wear, Jed, Spey), a sloop (Pelican), and an ex-Coast Guard cutter (Sennen). Every merchant ship of the convoy reached its destination. Macintyre’s escort group, B-2, and the Biter support group, 5, put into Canada to prepare for a return trip to the British Isles.
The Germans were disappointed in these three convoy operations, to say the least. The forty-odd U-boats of groups Meise and Specht sank only three ships for 13,400 tons from Outbound North 178 and only two ships for 17,400 tons from Halifax 234, and none from Outbound North (Slow) 4. Total sinkings by these big groups: five ships for about 31,000 tons. U-boat losses: three (the new IXs U-189 and U-191 and the VII U-203). This was a catastrophic “exchange rate” of 1.7 merchant ships sunk for each U-boat lost.
By April 25, U-boat Control had dissolved group Meise. Three groups remained on the North Atlantic run: two new ones, Amsel (Blackbird) and Star (Starling), and a reorganized Specht (Woodpecker). The Amsel patrol line of thirteen boats began at a point northeast of Newfoundland and ran to the southeast. The nineteen boats of Specht extended Amsel’s line farther southeastward, so that the combined Amsel-Specht line of thirty-two U-boats was nearly five hundred miles long. These boats were to trap eastbound Halifax or Slow Convoys. Star, composed of sixteen boats, was deployed on a line east of Amsel-Specht. These boats were to trap the oppositely sailing Outbound North and Outbound North (Slow) convoys. In keeping with the new policy, the three groups included ten of the unsuitable Type IXs.
At that time, two big and important convoys were en route to the British Isles: Slow Convoy 127 (fifty-seven merchant ships) and Halifax 235 (thirty-six fast merchant ships). The first convoy, Slow 127, was guarded by Canadian Escort Group C-l, composed of six warships: two Canadian destroyers, a British frigate, and three Canadian corvettes. The second convoy, Halifax 235, was guarded by Canadian Escort Group C-4, composed of five warships: two destroyers (one British, one Canadian) and three corvettes. The American Support Group 6—the “jeep” carrier Bogue and five destroyers—augmented the close escort of Halifax 235, bringing the warships with it to eleven: Bogue, seven destroyers, and three corvettes.
Based on complete and current breaks into naval Enigma, Allied authorities were able to thread Slow Convoy 127 and Halifax 235 through the long Amsel-Specht patrol line. Equipped with twenty-one aircraft (including six Wildcats and twelve Avengers), Bogue, still commanded by Giles E. Short, occupied a position inside the convoy. Taking advantage of improving weather, she launched Wildcats and Avengers daily to scout for U-boats ahead and on the flanks of the convoy. One Avenger found and attacked a U-boat with four depth charges, but no sinking was claimed or credited. Halifax 235 and Slow Convoy 127 crossed the Atlantic without the loss of any ships. Bogue and her destroyer screen attended the Royal Navy’s ASW schools in Liverpool and Northern Ireland, and Bogue was fitted with Huff Duff.
Outwitted by Allied decrypts of Enigma, on April 29 U-boat Control shifted the Amsel-Specht line southwest. Amsel was reinforced by the arrival of two experienced VIIs, increasing its strength to seventeen boats. Two of the nineteen boats of Specht fell out (the veteran IX U-108 to retirement in Germany and the experienced VII U-706 to refuel), reducing its strength to seventeen boats. The thirty-four boats of the Amsel-Specht patrol line searched for eastbound convoys but found none.
The new German U-boat group, Star (Starling), was to be deployed on a 250-mile north-south line midway between Iceland and Greenland. The group was to be composed of sixteen boats: four new IXs and twelve VIIs, of which six were new, four were experienced boats from France, and two were veteran transfers from the Arctic.
One of the VIIs of Star, the new U-650, commanded by Ernst von Witzendorff, age twenty-six, reported a westbound convoy about 250 miles southwest of Iceland on April 28. This was Outbound North (Slow) 5, composed of forty-three merchant ships. It was guarded by British Escort Group B-7, commanded by Peter Gretton in the newly upgraded destroyer Duncan. The group was comprised of seven warships: Duncan and another destroyer, Vidette; the frigate Toy; and four corvettes. The escort was supported by two tankers, one (British Lady) well equipped to refuel escorts, the other (Argon) inadequately equipped. Two ASW trawlers, Northern Spray and Northern Gem, were attached to the convoy to, serve as rescue vessels.
The Allies lost four-rotor naval Enigma on April 26. As a result, they were “blind” for about a week and with the passing of each day, the exact deployment of U-boat groups became less and less certain. This intelligence loss profoundly influenced the fate of convoy Outbound North (Slow) 5.
The weather was so atrocious that the escort vessels could not refuel. This handicap led to a decision to follow the shortest route to Canada. The green skipper von Witzendorff in U-650 hung on to the convoy. On instructions from Control, he broadcast beacon signals to bring up the other fourteen boats of Star. The first two VIIs to arrive were the Arctic transfer U-378, commanded by Erich Mäder, and the new U-
386, commanded by Hans-Albrecht Kandler, age twenty-five. On the way from Kiel, Kandler had sunk the 2,000-ton British freighter Rosenborg, a straggler from convoy RU 71, en route from Iceland to the British Isles.
The weather remained terrible, limiting Allied air cover and convoy and U-boat operations alike. After some other boats arrived, von Witzendorff in U-650 attempted to attack the convoy, but Peter Gretton in the destroyer Duncan drove him off. In retaliation, von Witzendorff fired three torpedoes at Duncan, but all missed. Otto-Heinrich Junker in the new IXC40 U-532 fired a full salvo of six torpedoes. He claimed hits on two ships, but they were not confirmed. All six torpedoes apparently missed or malfunctioned. Wilhelm von Mässenhausen in the veteran VII U-258, who had earlier patrolled with groups Amsel and Meise, fired a full bow salvo into the convoy. He claimed three hits on two freighters. In actuality, only one torpedo hit and wrecked a ship, the aged, 6,200-ton American kerosene tanker McKeesport, sunk later by the frigate Toy.
Notoriously ignorant of naval strategy and tactics, and prone to seasickness, Adolf Hitler pays a rare visit to a warship.
Albert Speer, director of German arms production, and Grand wartime Admiral Karl Dönitz, commander in chief of the German Navy.
Helmut Walter, chief German submarine designer in the prewar and years.
Admiral Hans-Georg von Friedeberg, who succeeded Karl Dönitz in February 1943 as chief of U-boats and as commander in chief of the German Navy in April 1945, shown here signing surrender papers in Berlin.
Admiral Eberhard Godt, chief of U-boat Control from February 1943, when Dönitz was promoted to commander in chief.
Dönitz’s son-in-law, Günther Hessler, U-boat ace and principal tactician at U-boat Control.
Big Three at Teheran: General Joseph Stalin, President Franklin D. Roosevelt, and Prime Minister Winston S. Churchill.
Admiral Andrew B. Cunningham, First Sea Lord, succeeding Admiral Dudley Pound upon the death of the latter in 1943.
Admiral Max Horton, commander in chief, Western Approaches, who directed the British end of the Atlantic convoy system from Liverpool.
Air Marshal John Slessor, chief of RAF Coastal Command in 1943, when Allied air power decimated the U-boat force.
Admiral Ernest J. King, commander in chief of the U.S. Navy in World War II.
Admiral Francis S. (“Frog”) Low, King’s chief deputy for antisubmarine warfare.
Admiral Jonas H. Ingram, commander in chief of the U.S. Atlantic fleet, succeeding Royal E. Ingersoll.
Admiral George C. Jones, chief of the Royal Canadian Navy from January 1944, succeeding Percy W. Nelles.
Admiral L. W. Murray, commander of the Royal Canadian Navy’s Northwest Atlantic Command.
Admiral Emory S. Land, chairman of the U.S. Maritime Commission, who directed the construction of more than five thousand ships during World War II, shown here with models of various types, including the famous “Liberty.”
From 1943, the principal nemesis of the U-boat was a radar-equipped aircraft on offensive or defensive patrol. Here, an Allied aircraft attacks the big IXD2 cruiser submarine U-848. Note the unmanned antiaircraft gun array on the U-boat’s bridge.
Johan Hendrick Mohr, skipper of the Type IXB U-124.
Otto von Bülow, skipper of the Type VIIC U-404.
Richard Zapp, skipper of the Type IXC U-66.
Rolf Mützelburg, skipper of the Type VIIC U-203. Destined to become one of the prominent U-boat aces, he died in a swimming accident before realizing that honor.
Carl Emmermann, skipper of the Type IXC U-172
Young Otto Ites, skipper of the Type VIIC U-94. U-172-He discovered hidden flaws in the German torpedoes.
Werner Henke, skipper of the Type IXC U-515. Captured, he committed suicide at the secret American POW interrogation center, Fort Hunt, Virginia.
Alfred Eick, skipper of the Type IXC U-510, who made a successful patrol to the Far East and back.
Heinrich Bleichrodt (right), skipper of the VIIC U-48, the IXC U-67, and the IXB U-109. On his last war patrol he requested—then demanded—relief of command.
Frederic J. (Johnny) Walker, commander of the Royal Navy’s famed hunter-killer Support Group 2, composed of sloops, which sank about twenty U-boats.
Donald Macintyre, commander of the Royal Navy’s Escort Group 5, composed of old destroyers, which also ran up an impressive number of U-boat kills.
Peter Gretton, commander of Escort Group 7, which defended convoy Outbound North 5 in May 1943, in a series of fierce battles on the Newfoundland Grand Banks. Gretton’s group and others sank six U-boats.
Shown here with his flight crew, Terence M. Bulloch (seated, center), commander of RAF Coastal Command’s Squadron 120, pioneered antisubmarine tactics for the B-24 Liberator.
Wilfred E. Oulton, another outstanding RAF U-boat killer.
James D. Prentice developed and taught antisubmarine tactics for the Royal Canadian Navy.
Edward W. Travis, who replaced Alastair Denniston as chief of Britain’s codebreaking unit, the Government Code and Cipher School (GC&CS) at Bletchley Park in 1942.
Captain Joseph N. Wenger, who replaced Laurence F. Safford as head of the U.S. Navy’s codebreaking unit, OP20G, in 1942;
Alan Turing, brilliant British mathematician, who with another brilliant British mathematician, Gordon Welchman, designed a machine (bombe) to break German naval Enigma.
Captain Howard T. Engstrom, chief of the OP20G research and development section, who played a key role in the design and manufacture of the American four-rotor bombe used for breaking German naval Enigma. He is shown here accepting the award of a Distinguished Service Medal from Secretary of the Navy James V. Forrestal.
U.S. Navy WAVES, who operated the bombes, sit for a “working portrait” at desks adjoining the bombes, which were housed at a former girls’ school in Washington, D.C. The machines were manned twenty-four hours a day.
A Navy WAVE poses before the workhorse Model 1530 U.S. Navy four-rotor bombe. In strictest secrecy, the engineers and technicians at National Cash Register Company, Dayton, Ohio, manufactured about 120 such bombes during the war. From October 1943, U.S. Navy codebreakers assumed full responsibility for breaking U-boat codes with these machines
Commander Kenneth A. Knowles, who managed the U.S. Navy’s Submarine Tracking Room in Washington, relied to a great extent on signals intelligence.
Captain Rodger Winn, who managed the Royal Navy’s Submarine Tracking Room in London utilizing signals intelligence.
The well-trained and aggressive escorts and the occasional Allied aircraft that got through bad weather attacked and severely damaged three new U-boats, forcing them to abort to France: Kandler in U-386, Georg von Rabenau in the IXC40 U-528, and Junker in the IXC40 U-532, who was hunted and depth-charged for fifteen hours.
Kandler in U-386 and Junker in U-532 eventually made it home to France, but von Rabenau in U-528 did not. Pilot W. A. Shevlin in a U.S. Navy Catalina of Squadron VP 84, based on Iceland, had hit U-528 with a close straddle of four depth charges and forced her to abort. When the damaged boat reached the western edge of the Bay of Biscay on May 11, pilot James B. Stark, in a Halifax of Squadron 58, who was providing air cover for convoy Outbound South 47, Caught U-528 on the surface. Before von Rabenau could dive deep, Stark attacked, dropping five shallow-set depth charges.
Believing he had sunk the U-boat, Stark dropped a smoke flare at the site and notified the convoy’s Escort Group 39, commanded by H. V. King in the sloop Scarborough. King immediately sent the other sloop of the group, Fleetwood, to the sinking site to look for survivors or debris, to make sure a kill had occurred and that the U-boat posed no danger to the convoy.
When Fleetwood, commanded by W. B. Piggot, reached the smoke flare, she got a sonar contact. Piggot carried out eight attacks on the target, dropping about sixty depth charges. These blasts further damaged U-528, forcing her to a depth of seven hundred feet. After assessing the damage, von Rabenau concluded U-528 could not remai
n submerged, and he ordered the crew to surface and attempt to escape.
Meanwhile, Piggot in Fleetwood, who had no more depth charges, was reinforced by another of the convoy escorts, the corvette Mignonette. When U-528 surfaced, both Fleetwood and Mignonette immediately saw her close by and opened fire with all guns that could bear. This fire forced the Germans topside to jump overboard. Von Rabenau gave orders to abandon ship and scuttle. Forty-five Germans survived. Fleetwood fished out von Rabenau and thirty-eight others; Mignonette picked up six. The Admiralty gave equal credit for the kill to the Halifax aircraft and to Fleetwood.
Reduced to thirteen boats, group Star groped westerly for Outbound North (Slow) 5 in the foulest possible weather and waves thirty feet high. On April 30, Wilhelm-Heinrich Pückler und Limpurg in the experienced U-381 caught sight of the convoy, but lost it one hour later. In fact, the storm had scattered the convoy over a wide area. In spite of the weather and small icebergs (“growlers”) Gretton in the fuel-guzzling Duncan and the other destroyer, Vidette, were able to refuel from British Lady. To assist in reforming and protecting the convoy, Allied authorities ordered British Support Group 3, consisting of five Home Fleet destroyers commanded by J. W. McCoy, to reinforce Gretton. The first of these destroyers, Oribi, arrived from Iceland on April 30.
The weather remained foul. The other four destroyers of McCoy’s support group (Offa, Impulsive, Penn, Panther), which sailed from Newfoundland, found the nucleus of the convoy (about thirty-two ships) and joined. This raised the escort to twelve warships: seven destroyers, one frigate, and four corvettes. It was sufficient strength to enable Gretton in Duncan, who, owing to a leak, was again critically low on fuel, to fall out to refuel in Newfoundland. He left R. E. Sherwood in the frigate Tay in charge of close Escort Group B-7. Three of the support group destroyers also had to fall out to refuel: Impulsive to Iceland, Penn and Panther to St. John’s. These departures reduced the escort to eight warships: three destroyers (Vidette, Offa, Oribi), the frigate Tay, and the four corvettes.