by Clay Blair
• Gustav Poel in the Jaguar VII U-413, got a 3,600-ton Greek straggler from Slow Convoy 117.
• Ulrich von Soden-Fraunhofen in the Haudegen VII U-624 sank a 5,100-ton British freighter from the same convoy.
• Rolf Manke in the Haudegen boat U-358 sank an 8,200-ton Norwegian tanker from Halifax 223.
• The Haudegen VIIs U-607, commanded by Ritterkreuz holder Ernst Mengersen, and U-594, commanded by Friedrich Mumm, teamed up to sink the bow of the 8,300-ton Norwegian tanker Kollbjörg, which had broken in half in heavy weather.
The operation against Slow Convoy 117 and Halifax 223 was another frustrating setback for U-boat Control. Upon cancellation of the chase on January 27, the groups on the North Atlantic run were reshuffled or disbanded,, The boats of Jaguar were withdrawn to refuel or to return to France, A new group, Pfeil (Arrow), replaced Jaguar east of Newfoundland. Group Haudegen, increased to twenty-one boats, remained on a 300-mile patrol line running southeast from Greenland. Group Landsknecht, farther east, which had not sunk a single ship, was disbanded. Its boats with a good fuel supply went to Pfeil. Those low on fuel returned to France.
Two veteran VIIs of the returning Landsknecht group that had adequate fuel were assigned to a high-risk special mission: a sudden, surprise attack on shipping in the shallow water close to Land’s End and the Scilly Islands during the dark of the new moon.
Nothing came of this foray. Harassed by Coastal Command Leigh Light-equipped Wellingtons with centimetric-wavelength ASV III radar, von Bülow in U-404 struck a rock, disabled his bow planes, and returned to France, completing a fallow patrol of forty-nine days. Kurt Nölke in U-584 received permission to abort owing to a noisy propeller shaft. A plan to have Hardo Rodler von Roithberg in the homebound U-71 replace U-404 was shelved.
In the last days of January, B-dienst alerted U-boat Control to a special convoy sailing from the British Isles to Gibraltar. Although Admiral Dönitz and U-boat Control were still reluctant to attack the heavily escorted Gibraltar-bound convoys, this one could not be ignored because of the increasingly desperate situation of Axis forces in Tunisia. Accordingly, U-boat Control hastily organized a group, Hartherz (Stouthearted), at the extreme western edge of the Bay of Biscay.
Group Hartherz was composed of twelve boats (nine VIIs, three IXs), nine of which were newly sailed from France and three of which were inbound to France, including two Vs, Nölke in the aborting U-584 and Rodler von Roithberg in U-71. One of the outbound VIIs, U-590, commanded by Heinrich Müller-Edzards, was diverted to assist another boat disabled by an aircraft, then was compelled to abort owing to corroded fuel pumps. Rodler von Roithberg in U-71 found and shot at a lone corvette, but he missed. The IXC40 U-183, commanded by Heinrich Schafer, picked up propeller noises on hydrophones. The reports from U-71 and U-183 were thought to be indications of the expected convoy but, in fact, the British were alerted to Hartherz from decrypts of naval Enigma and they diverted the convoy around the group. In addition, the convoy’s surface escorts sank one of the U-boats, the IXC U-519, commanded by Günter Eppen, on February 10.*
Group Hartherz also failed. When U-boat Control finally realized it had missed the Gibraltar-bound convoy, the group was dissolved, a complete waste of twelve boats for ten days, not to mention the loss of one IXC. Five of the outbound VIIs joined other groups on the North Atlantic run. The IXs U-107 and U-183 went southward, the former to join anti-Torch groups west of Gibraltar, the latter to American waters. The three VIIs that were low on fuel resumed their homebound voyages.
Owing to the decision to “open out” the sailing cycle from eight to ten days, only thirteen convoys, comprised of about 520 merchant ships, sailed across the stormy Atlantic east or west on the North Atlantic run in January 1943. Although Allied codebreakers read naval Enigma imperfectly in that month, its output enabled the Allies to divert most convoys around the U-boat groups. The large force of U-boats patrolling that area in hideous weather made fleeting contact with ships of only three of the transatlantic convoys (Halifax 222 and 223, Slow 117) and sank only four ships for 31,865 gross tons, plus the bow of the wrecked Kollbjörg, the least remunerative month of the entire war.* Due to the lack of contact with the enemy, U-boat losses on the North Atlantic run in January were slight: Ruwiedel’s new U-337 and Thurmann’s veteran U-553, both to unknown causes.
U-BOAT SUCCESSES ON THE NORTH ATLANTIC RUN
U-boat Control sailed a record sixty-seven attack boats against Allied convoy routes in the North and Middle Atlantic in the month of February 1943. These consisted of fifty-four VIIs,† twelve more Type IXs unsuitable for hard convoy battles, and one XB minelayer, U-119. As in January, cine-half of these boats were new or were commanded by new skippers.;
The boats sailing in the first half of February had to contend with Coastal Command’s new and intensified Bay of Biscay offensive, Gondola. However, Al lied aircraft hit only one of the sixty-seven outbound attack U-boats. She was the U-211, commanded by Karl Hause. The attacking aircraft was a B-24 of Army Air Forces Antisubmarine Squadron 1, piloted by Wayne S. Johnson. He dropped six depth charges in a close straddle. The explosion severely damaged U-211 and forced Hause to abort and return to Brest.
There were not nearly enough U-tankers to support the large number of VIIs at sea. Of the five “Milk Cow” XIV tankers, U-459 was in the South Atlantic supporting the Cape Town foray, Seehund, and the U-463 had just returned to France. The U-460 sailed to the North Atlantic the last day of January; the other two, U-461 and U-462 (delayed by repairs), sailed on February 13 and 19, respectively. Therefore U-boat Control directed that after she laid her minefield, the XB U-119 was to serve as a provisional tanker for VIIs in the North Atlantic.
The Allied breaks into naval Enigma continued into February. To process the flow of information on U-boats obtained from Enigma intercepts by British and American codebreakers, Admiral King established a “Secret Room” adjacent to the U.S. Navy’s Submarine Tracking Room. A reserve lieutenant, John E. Parsons, was in charge of the room, which was kept locked at all times. Only Parsons, his assistant, John V. Boland, another reservist, two yeomen, and the Navy’s principal U-boat tracker, Kenneth Knowles, had keys to the room.
There were large charts of the North and South Atlantic and Indian Oceans and the Caribbean Sea on three walls. A symbol representing the date and last known position of every U-boat was pinned on the charts. Different colored tabs were used to indicate the type of U-boat (VII, IX, XB minelayer, and so on). Each wall also had a “Port Board” showing the location of all U-boat forward bases and symbols representing the U-boats in that port, plus the date of their arrival. The information from these charts and boards enabled Knowles to plot the daily estimated positions of U-boats at sea (as opposed to the last known position) on similar ocean charts in the Submarine Tracking Room without revealing the source of his information.
The first challenging task for Parsons and Boland was to positively identify newly sailing U-boats by number and by their skippers. This process began when the U-boat sent a short-signal “passage report” indicating it had safely crossed the Bay of Biscay or the Iceland-Faeroes gap and entered the broad reaches of the Atlantic. These signals were signed not by skipper name or the actual number of the U-boat but by a bigram. Later, however, it might happen that U-boat Control would slip up and respond to a U-boat signal signed by a number with a signal addressed to the skipper by name or vice versa; the U-boat might respond to a skipper message with a number. By consulting a card catalog in. the Secret Room library, it was usually possible from accumulated information to know that a certain skipper commanded a certain U-boat and what type it was. Hence most boats and skippers could be identified fairly quickly—and always within three weeks.
To avoid direct references to individual U-boats in the London-Washington secret traffic (which might be broken by the Germans), each U-boat was permanently designated in Allied records by a bigram, or two-letter code. The first letter in the bigram designated the type
and the second letter the specific boat within that type series. Every second letter of the alphabet was used in the bigrams to designate Type VIIs (A, C, E, G, I, and so on) and the intervening letters to designate Type IXs (B, D, F, H, J, L). The M was reserved for minelayers, the S for U- cruisers, the W for cargo boats, and the Z for U-tankers and torpedo-resupply boats.* As more information accumulated from all sources, the Allies, where possible, assigned a skipper name to the bigram. Hence, hypothetically, bigram “GD” might represent the Type VII U- 598 commanded by Gottfried Holtorf.
The next important challenge was to determine where each U-boat was bound: North Atlantic “wolf pack”? South Atlantic? Americas? This was not easy because the Germans then disguised their system of oceanic bigram grid squares (AK, AL, etc.) by colors and by additives. Hence U-boat Control might order a certain VII, “EB,” to a group forming in oceanic grid square AL 22 in the North Atlantic (south of Iceland) by using “Blue 72,” the additive in this example being fifty. By comparing the files of short signals from other identified U-boats, such as convoy contacts, reports of sinkings, damage, weather, and soon with Huff Duff bearings and other information it was possible to puzzle out that ‘‘Blue 72” was grid square AL 22. But it was tedious work requiring codebreakers with uncanny intuition and infinite patience.
At the same time Parsons and Knowles were solving these riddles, so were Rodger Winn and his associates in the Admiralty’s Submarine Tracking Room. Knowles and Winn exchanged messages almost daily. (“We think GD in Blue 72 is Holtorf in U-598” might elicit a response such as “Agree” or “Do not agree. We show Holtorf in GR in Lorient”) About once a week Knowles and Winn exchanged provisional lists of all U-boats at sea, the skippers, type bigrams, status of fuel and torpedoes, location, group assignments, and so on, and then conducted a transatlantic vetting of the lists until reaching complete agreement. All these data were promptly entered on the U-boat file cards along with all other information.*
The American codebreaking historian George Howe wrote that the Allies read U-boat traffic steadily from February 5 to February 28, 1943, with an average decoding delay of one day. That intelligence was $o up to the minute that it could be used tactically, to evade U-boat groups or for Allied aircraft to “discover” a rendezvous between one or several boats and/or U-tankers and to attack.
The U-boats were likewise the beneficiaries of a flow of information on North Atlantic convoys from B-dienst. On the first day of February, the veteran VII U-456, commanded by Max-Martin Teichert, newly transferred from the Arctic, found a big, fast convoy in mid-Atlantic. This was Halifax 224, consisting of fifty-eight merchant ships guarded by the seven warships of Canadian group C-4: the ex-American British four-stack destroyer Churchill, the Canadian destroyer Restigouche, and five Canadian and British corvettes.
Teichert shadowed and brought up several nearby boats. He then attacked and sank a 7,200-ton American Liberty ship and the 9,500-ton British tanker Inverilen. One other boat, the new U-632, commanded by Hans Karpf, who was low on fuel and inbound to France, found and sank a straggler from the convoy, the 8,200-ton British tanker Cordelia. It was Karpf’s second tinker kill on his first patrol, a total of 16,000 tons.
In all, six boats made contact with convoy Halifax 224. U-boat Control ordered four that had sufficient fuel to continue tracking. One of these was the new VII U-265, commanded by Leonhard Auffhammer, age twenty-five, two weeks out from Kiel On February 3, a B-17 Flying Fortress of British Squadron 220, piloted by K. Ramsden, which had come out to escort Halifax 224, caught and dropped seven depth charges on U-265. She went down with the loss of all hands about five hundred miles west of Scotland.
Karpf in U-632 rescued the chief engineer of the British tanker Cordelia. According to German accounts, he revealed that another big convoy was following exactly in the wake of Halifax 224 and Karpf radioed this information to U-boat Control. It confirmed guesses that the Allies might send a Slow Convoy along the same path, in the belief that all the U-boats were trailing Halifax 224 eastwardly and the waters behind it were apt to be clear. Acting on Karpf s report, U-boat Control shifted into the wake of Halifax 224 the newly forming group Pfeil (Arrow), consisting of thirteen boats: three already in the area, six from the dissolved group Landsknecht, and four recently sailed from France.
While this redeployment was taking place, a boat on the extreme northern end of the reconstituted Haudegen group also reported an eastbound convoy. She was the new U-223, commanded by Karl-Jürgen Wächter, age twenty-six, three weeks out from Kiel. At first U-boat Control believed this contact to be the expected Slow Convoy and ordered the entire northern half of group Haudegen (nine boats) to home on U-223. But Wächter’s second report correctly surmised that the convoy, which he said was comprised of merely five ships, was probably a local one en route to an Allied base in Greenland. Accepting this assessment, U-boat Control reduced the reinforcements for U-223 to four boats (three VIIs, one IX), all of them on maiden patrols from Kiel.
Wächter had indeed found a “local” convoy en route from Newfoundland to Greenland. It consisted of one 5,600-ton U.S. Army troopship, Dorchester, which carried 904 men (130 crew, 751 military personnel, 23 naval armed guardsmen) plus one thousand tons of cargo, and two smaller Norwegian freighters, Lutz and Biscaya. These three merchant ships were escorted by three ice-encrusted Coast Guard cutters: the 240-foot Tampa, and two 165-footers, Comanche and Escanaba. In a night surface attack on this formation, Wächter shot all five torpedoes in his five tubes singly. Three torpedoes missed but two hit Dorchester which, unaccountably, made no distress signals. The other five ships sailed on in the darkness.
On Dorchester there was mass panic and disorder as the 904 men abandoned ship in near-freezing water. Only two of fourteen lifeboats were used to full advantage. When the escort belatedly realized that Dorchester was missing, the senior vessel, Tampa, commanded by Joseph Greenspun, went on to Greenland with the two Norwegian freighters and sent Comanche and Escanaba back to hunt for U-boats and rescue the survivors of Dorchester. After a futile U-boat hunt, the crews of the two cutters heroically plunged into the water to tow rafts and/or individual survivors to waiting hands. But they were able to rescue only 229 of the 904 persons on Dorchester. In this rare American troopship disaster, 675 men died, 404 of them U.S. Army personnel.
On that same day, February 4, U-boat Control redistributed the twenty boats of group Haudegen. The five boats on maiden patrols that had been sent after the Dorchester convoy, redesignated group Nortstrum, remained on a likely shipping lane midway between Newfoundland and Greenland. Five experienced boats that had sailed from France from January 7 to 9 were detached to group Pfeil for the attack on the expected Slow Convoy. The remaining ten boats (four on maiden patrols) were deployed very close off St. John’s, $long the Newfoundland coast.
Alerted by Enigma decrypts, Allied aircraft (as yet unidentified) caught and bombed two of these ten boats, Heinz-Ehlert Clausen’s U-403, newly transferred from the Arctic, and the new U-414, commanded by Walter Huth. The latter incurred such heavy damage that Huth was forced to abort to France. The boat was out of action until April.
The expected Slow Convoy trailing Halifax 224 was SC 118. It sailed from New York on January 24 with forty-four ships. Nineteen ships from Newfoundland joined, making sixty-three. She was guarded by the crack British group B-2, usually commanded by Donald Macintyre in Hesperus, but his ship, which had rammed and sunk U-357 on a prior trip, was in repair in Liverpool. The temporary group commander was F. B. Proudfoot, new skipper of the British destroyer Vanessa. The group was quite strong: Vanessa, and three other British destroyers, Vimy, Witch, and the ex-American four-stack Beverley; the big American Treasury-class Coast Guard cutter Bibb; and four corvettes, one British, three French. All nine escorts had radar. Vanessa, Bibb, and the indefatigable rescue ship Toward also had Huff Duff.
The convoy sailed through the Pfeil patrol line undetected in the early hours of February 4. Then, as luck would have
it, a seaman on the Norwegian freighter Annik accidentally fired a brilliant snowflake flare. One of the Pfeil boats, Ralph Münnich’s new IXC40 U-187, about three weeks out from Kiel, saw the flare. He closed on the convoy from ahead and radioed a contact report for the benefit of the dozen other boats of group Pfeil. Bibb, commanded by Roy L. Raney, and Toward DFed Münnich’s B-bar short-signal contact report.
Proudfoot directed two of the British destroyers to run down the Huff Duff bearing of the U-boat: the four-stack Beverley (ex-U.S.S. Branch), and the Vimy, commanded by Richard Stannard, who had earlier Won Great Britain’s highest award, the Victoria Cross. The two destroyers raced out. Beverley spotted U-187 at about five thousand yards, but owing to the rough seas, she could not fire her main battery. In the event, when he saw the destroyers gaining, Münnich dived and went deep.
Vimy got U-187 on sonar and, with Beverley, commenced a methodical attack with Hedgehog and depth charges. Münnich released a Bolde noisemaker and attempted to creep away on his motors, but the destroyers held fast. Vimy’s Hedgehog did no damage but some of her thirty depth charges cracked the boat’s pressure hull center and aft, flooding the control room with fuel oil and the aft areas with salt water. Much too heavy aft, the boat nosed up at a terrifying 45 degree angle. Two and a half hours into the hunt, when he saw that U-187 was doomed, Münnich ordered the crew to surface and scuttle. Most of the crew concluded that escape was impossible and shook hands in lugubrious farewells. But their luck held. With the last gasp of high-pressure air, Münnich achieved sufficient positive buoyancy to reach the surface.
When U-187 appeared, Beverley and Vimy opened fire with main batteries and antiaircraft cannons. The fire killed nine Germans, including Münnich and probably his chief engineer. The U-187 upended and sank stern first, leaving the rest of the crew in the water. Beverley and Vimy rescued forty-five men, including three officers, after which the two destroyers rejoined the convoy.