Chapter III
Crisis of North Atlantic Offensive
March 1943

Convoy Codes explained...

  1. Restoration of group pattern for eastbound convoys.

  2. Westmark - Ostmark: Encirclement of SC 121.

  3. Neuland - HX 228.

  4. Difficulties and comment.

  5. Raubgraf-Stürmer-Dränger, convoys HX 229 and SC 122 surrounded.

  6. Seewolf, Seeteufel, HX 230, and a hurricane.

  7. Comment on March U-boat operations.


  1. Restoration of group pattern for eastbound convoys.

    The operation on ON convoys had actually netted twenty ships. They had further served to mass U-boats off Newfoundland, many of them, however, in need of fuel. In addition to the U-boats from the ON operations there were the two groups which had completed their western sweeps from 30°W: Neptun and Burggraf. In the course of Neptun's cruise, HX 227 was expected on 26 February and promptly sighted in 56°27'N - 45°48'W by Friedrich (U-759). Bad weather prevented a successful follow-up. The situation was further confused by the sighting of ON 168 on 1 March. Group Neptun was finally ordered to attack individually according to the more favorable target. The result was the dispersal of group Neptun in an unsuccessful attempt against two convoys at the same time. While the U-boats from the ON 167 action reformed as group Waldfang on 26 February, the line so arranged as to join Neptun upon completion of the latter's sweep, group Burggraf was cruising from 56° to 53°N - 28° to 26°W on course 235°, having been delayed until replacements for the originally assigned boats could get into position. With the dispersal of Neptun it was Burggraf which completed the long line off Newfoundland by 4 March. In all, 30 U-boats were in position from 55°N - 50°W to 50°N - 39°W. Ex-Neptun submarines were now coming up from the rear to support the Waldfang-Burggraf line. Meanwhile the sweep replacement group, new group Neuland, was forming with 18 U-boats to proceed on course 240°, beginning at a line from 54° 45'N 27°15'W to 50°57'N - 23°45'W. The exact positions of the line off Newfoundland were read in traffic but twenty-four hours after U-boats had made contact on SC 121.

  2. Westmark - Ostmark: Encirclement of SC 121.

    1. Delayed contact.

      Expected by the U-boats on the afternoon of 4 March, convoy SC 121 had somehow passed through the long Waldfang-Burggraf line at approximately the point where the two groups supposedly came together. It was first sighted by


      an ex-Neptun boat, U-405 (Hopmann), on 6 March in 54°57'N 40° 15'W:

      "Enemy reported is a convoy in naval square AJ 6688." (1056/6 March 1943)

      Possibly skeptical, COMSUBs replied an hour later:

      "Report convoy course and speed at once. No reports have come in to us so far." (1150/6 March 1943)

      Hopmann had been causing trouble for nearly a week. As one of the Neptun's U-boats that had gone off on his own in search of HX 227, Hopmann had added to the confusion by reporting a steamer and three destroyers in a grid position that did not exist. Then he suspected a U-boat trap, whereupon he laid claim to sinkings which prompted this message from COMSUBs:

      "To Hopmann: Your reports afford no clear picture. State again the number and size of ships, including position and time." (2240/2 March 1943)

      Hopmann's reply was no improvement, involving successive positions more appropriate for a speed boat, but meanwhile he was assigned to a 6 x 6 mile waiting area behind the Waldfang-Burggraf line. It was this square from which he reported the convoy on 6 March.

    1. Encircling groups formed.

      Apparently this report was considered reliable, for half of Waldfang and Burggraf were dispatched to the area at top speed while Hopmann was ordered to shadow; "keeping contact is of the greatest importance on account of disposition of other submarines." (1335/6) Ten U-boats were detached from Neuland as new group Ostmark, to operate on SC 121 from ahead. The U-boats coming up from behind were formed as Westmark. Remaining Waldfang-Burggraf U-boats came together as group Raubgraf and waited for the next convoy, HX 228.


    1. Convoy scattered.

      Hopmann (U-405) maintained contact with SC 121 until 2322/6 when he was driven off by depth charge. The weather combined with escort activity to make sustained contact impossible. However, the unfavorable weather also provided an advantage to the U-boats in that the convoy was widely scattered, making defense difficult.

    2. Ostmark.

      The only successful attack reported up to 7 March was that of Zetsche (U-591) who claimed a munitions steamer left sinking in 57°03'N - 36°12'W. Not realizing how widely the convoy "had scattered. COMSUBs planned to intercept it the following day by shifting Ostmark to a line from 59°39'N 34°24'W to 57°51'N - 31°48'W, with the reservation that if certain contact was made during the night, the group was to operate directly on the convoy, disregarding the ordered line. By noon of the 9th, U-boats were finding the defense stiff. COMSUBs forced his men with such orders as this to Hopmann:

      "Attack and sink. Give no thought to fuel." (1805/9 March 1943)

      Hopmann replied:

      "Order carried out. Two submarines sank one steamer apiece." (2240/9 March 1943)
      Conclusion of operation.

      Loss of contact for several hours caused COMSUBs to order Ostmark and Westmark to "continue sweep in easterly direction. There are still further chances of striking both the convoy and independent ships." (2215/9) There followed only occasional, brief contacts so that by noon of 10 March, U-boats in a favorable position were instructed to remain in the vicinity of the convoy in order to utilize the last chance for attack; those in an unpromising position were to set off to the west, searching for stragglers in the convoy lane. Schetelig (U-229) found SC 121 again in 50°03'N - 20°12'W, where he claimed to have sunk two steamers. At 1900/10 Brünning (U-462) contacted the remnants of the convoy momentarily but the


      operation was discontinued shortly afterward. Command was forced to be content with the 13 ships torpedoed in SC 121.

  1. Neuland - HX 228.

    HX 228 had passed safely to the south of Raubgraf when she sailed into the Neuland area, Hunger (U-336), who had been ordered on the 7th to join the southeast end of Neuland, sighted the convoy at 1335/10 in 50°27'N - 31°15'W. Neuland was of course immediately ordered to operate at maximum speed. On 13 March, when the operation was discontinued, the score stood at four to two, the U-boats having sunk four ships, one of which was HMS Harvester. Harvester sank U-444 (Langfeld) before she was sent down by U-432 (Eckhardt), which in turn was sunk by FFS Aconit.

  2. Difficulties and comment.

    Group Neuland's contact on HX 228 is a good example of radio intelligence difficulties at this time - the Germans having introduced a stiff cipher change on 1 March. On the basis of past U-boat behavior as seen in traffic read, a message of 27 February ordering 8 fresh U-boats to head for 56°N - 27°W had been interpreted to mean that a new group was forming in this area.1 This information was on hand by 2 March and was incorporated in a memorandum of that date to COMINCH with the statement that the new group would probably form by 5 March from approximately 56°N - 29°W to 53°N - 28°W. By 6 March it was known from traffic read that many additional fresh submarines had been given heading points in the same area and it was assumed that the line was being extended. The general arrangement was clear: a long westerly sweep group forming in mid-Atlantic to support Waldfang-Burggraf, whose composition and general location off Newfoundland were known. Actually Neuland U-boats with a total then of 17 members were ordered on 3 March to form by noon of the 7th from 54°45'N - 27°15'W to 51°N - 23°45'W. As further additions arrived the line was extended southward to 49° 45'N


    as well as northward. Contact on SC 121 by Hopmann had drawn off the northern half of the group before the U-boats could get in line. It was certainly reasonable to assume, as was done, that some of the U-boats, the northerly ones, in the mid-Atlantic concentration would close SC 121 and that the southern members would hold their line and carry out a westerly sweep. This split had taken place before, but it was not possible to fix the exact lines. Past experience had shown, however, that at this time no route north of 50°N could be regarded as safe unless every U-boat could be accounted for day by day and unless every patrol line was known to the last second of position and knot of sweeping speed. With the U-boat group pattern that was made clear in February, Command could cover every lane north of 50°N with his staggered sweeps. Even so he got contacts he had not counted on, for there was no way on either side of allowing for the element of chance. As it was, the convoy HX 228 almost cleared the Neuland concentration, and the escorts gave the U-boats some rough treatment.

  1. Raubgraf-Stürmer-Dränger, convoys HX 229 and SC 122 surrounded.

    The attack on HX 229 - SC 122 marks the high point of March convoy operations - in terms of number of U-boats, number of ship's sunk, and last but not least, in terms of German exploitation of their intelligence on convoys. The operation is discussed from the point of view of German intelligence in Volume III, Chapter IV, where the probable compromise of an early HX 229 diversion dispatch is examined.

    1. U-boat group arrangement prior to contact.

      Eleven Neuland U-boats turned back westward from their pursuit of HX 228 with orders to take up a reconnaissance line from 53°45'N - 37°55'W to 50°33'N - 36°15'W as group Dränger. At the same time U-boats to the north (approximately 25) including many from port, were forming group Strumer just west of 30°W and running from about 60°N down to the latitude of Dränger. With Raubgraf off Newfoundland the pattern was complete. Disappointed of HX 228, Raubgraf had turned its attention to ON 170 during the pause while the U-boats waited for the next eastbound convoy. Expected on 10


      March, ON 170 had been delayed by bad weather and was not sighted until the 13th, when Bertelsmann (U-603) reported the convoy in 50°03'N - 44°25'W. The operation failed, contact not being maintained for anyone period long enough to permit successful attack. As the U-boats moved southwest looking for ON 170 they were informed of their next assignment: to form on the 15th across the route of a northeast bound convoy, HX 229. The timing and the location of the line were excellent.

    1. Radio intelligence comment.

      By March 13, Raubgrafs intentions against ON 170 were known from traffic. That the U-boats were moving southwest could be seen from D/F's as they attempted to operate. Hence the convoy diversion of 13 March was sound. The exact location of Stürmer and Dränger U-boats were not known but it was appreciated, again from headings of outbound U-boats and past behavior, that a powerful concentration was building up in the mid-Atlantic north of 50°N. What no one was prepared for at the moment was the sudden intrusion of German convoy intelligence which put Raubgraf at high speed on an interception course.

    2. Contact established after extensive maneuvers.

      At 1847A/14, before Raubgraf could take up the line ordered for the 15th, they were sent east southeast at high speed. The U-boats actually stopped short of intercepting HX 229 and were a little too far behind SC 122. They knew the convoy was there, but it was not until Feiler (U-653) ran into the convoy as he headed for a refueler off to the southeast that U-boats began to move with a final degree of assurance. Before Feiler found HX 229, a new Raubgraf line of nine U-boats was set up, to be in position by 1200/15 from 51° 15'N - 42°05'W to 49°27'N - 40°55'W "for an eastbound convoy to which further groups can later also be detailed." (1920/14) The line was shifted eastward slightly and, in order to make the search as comprehensive as possible, even damaged submarines were by every means possible to arrive in positions. "The convoy must be found." (0443/15) At noon the line was moved southward, patrolling on a southeast course, reversing to northeast at 1000/16 if no contact was made. As a result of Walkerling's (U-91) report of a destroyer and "suspected convoy" in 49°33'N


      - 40°35'W, three other U-boats were detailed to search with him, the remainder of the group moving eastward to form a new patrol line the following day from 51°15'N - 38°55'W to 49°21'N - 37°45'W. The first actual contact was that made in 49°27'N - 37°25'W by Feiler (U-653), who was directed to shadow until other Raubgraf U-boats could close in for the attack.

    1. U-boats close from all directions.

      An additional three U-boats were assigned to the convoy upon completion of refueling and the eleven U-boats which comprised the southern half of Stürmer were ordered to operate immediately, while the northern part of the group proceeded on a southeasterly course to circumvent any possible diversion. The 20 U-boats already operating searched for seven hours and found only an occasional steamer until Zurmtihlen (U-601) located the whole convoy again at 1506/16. However, he was immediately driven off by an escort. With so many U-boats in the vicinity of the convoy it was inevitable that contact should be resumed at once, this time by Kapitzky (U-605) who sent beacon signals until midnight. Raubgraf was reminded that:

      "a good fix in that area is of the greatest importance because of the highly irregular currents at the junction of the Gulf Stream and the Labrador current. For that reason always report a new fix." (1628/16 March 1943)

      The accuracy of Kapitzky's sighting reports and his beacon signals succeeded in homing about a dozen U-boats on HX 229 for the critical first night attack. Although four escort vessels had held the attackers at bay from the first sightings until darkness set in, they were hopelessly outnumbered thereafter; the wide convoy formation described by Feiler demanded an omnipresent escort, which was patently impossible.

    2. U-boats run out of torpedoes. "The beginning was first class."

      Bertelsmann (U-603) claimed to have made the first attack and when Walkerling (U-91) reported the sinking of two


      freighters he also reported that the convoy's defenses were apparently weak. After 0400/17 attack and success reports followed hard upon one another with Manseck (U-758) claiming four, Strelow (U-435) a probable three, and Zurmühlen (U-600) "left a 5,000 tonner burning briskly and sinking" (0630/17) after which he retired temporarily in order to send beacon signals. At 0905/17 Walkerling (U-91) reported from 50°51'N - 34°25'W "3 hits on 2 damaged ships. Still 3 large damaged ships remaining. Request (another) sub. Have no torpedoes left." Bertelsmann (U-603) was in the same plight an hour later, two damaged ships in sight and no torpedoes. To forestall any illusion that the success achieved thus far was all that would be required of the U-boats COMSUBs sent the following message: "The beginning was first class. Contact must not be allowed to be lost. Report immediately. At the same time report who has observations on composition and size of convoy..." (1005/17)

    1. SC 122.

      Previously, Kinzel (U-338) had reported a convoy in 51°57'N - 32°45'W. His insistence on the accuracy of the fix led COMSUBs to order the northern half of Stürmer to operate at maximum speed, on the assumption that this was a faster group detached from HX 229, it was later recognized as a second convoy.

    2. U-boat saturation point.

      With the battle in full swing a number of other U-boats, outbound to form Seeteufel, offered to join the slaughter but were told to continue their cruise, unless they stumbled on something too good to miss. A dispatch from Command at 1810/17 indicated that the U-boats already operating needed no assistance. Things were going very well indeed. "Out of a convoy bound for England which was apprehended on 16 March in naval square BD 10, up to now 12 ships of 77,500 tons have been sunk and 6 other ships torpedoed."

    3. Convoy defenses.

      Bahr's (U-305) sighting of a convoy in 52°21'N - 30o55'W at 1428/17 altered the previous assumption of a detachment


      from HX 229 to that of another convoy, which indeed it was SC 122. In addition to the northern Stürmer U-boats which had been ordered to operate on Kinzel's report, a similar part of Dränger was assigned. By this time however, very long range aircraft was available to provide some measure of protection for both convoys and its contribution was evident in the decreased number of attacks.

    1. U-boat Command complains; U-boats begin to lag.

      The seven escort vessels attached to SC 122 doubtless had some foreknowledge of the approaching situation, though they were unable to divert the convoy in time to prevent an attack. Consequently, the second night was by no means as fruitful as the first for the U-boats, so that COMSUBs admonished both groups:

      "What is happening to the shadower reports? With such a large number of submarines contact must not be broken off. Sweep further at top speed. II (0402/18 March 1943)

      Freyberg (U-610) located HX 229 again and sent beacon signals for proceeding at top speed, but, before the group arrived on the scene, he was forced under by a destroyer. A straggler from the group, Schug (U-86), was criticized sharply:

      "Your position 120 miles behind the convoy without enemy action can be explained only as absolute faulty operation. Pursue at top speed. II ' (1757/18 March 1943)

      The order was reiterated in the next message to Raubgraf and Stürmer:

      "Every sub is expected to pursue at maximum speed in order to reach convoy. Search in long sweeps depending on condition of sea. With such a large number of submarines, more submarines should get there. We still have to give this convoy a drubbing." (1851/18 March 1943)


    1. Wind up of the operation.

      Until dusk on 18 March contact were few and then chiefly with escort vessels. By 1951 when Brosin (U-134) reported a slow convoy in wide formation in 53°27'N - 27°55'W the U-boats were running low on fuel and, in order to squeeze the last measure of success for this golden opportunity, COMSUBs directed them to:

      "continue operation long enough so that tanker (Wolfbauer (0-463) in 48°57'N 33°15'W) will be reached with 5 cbm of fuel remaining. Subs which are very low in fuel and in especially good attack position use opportunities to the full. In case of necessity rendezvous will be moved north or another sub will be appointed to transfer its fuel to others." (2115/18 March 1943)

      With renewed vigor the U-boats resumed the attack, but after Trojer (U-221) had sunk two ships, types Clan Mac Dougall and Salacia, he reported that the wide and close escort somehow become stronger in the interim. Again at 2240/18 Brosin sighted about 20 ships in 53°39'N - 27°35'W, speed 8, course 065°; however, the bright moonlight made it difficult for him to do more than shadow. The excellent visibility proved an advantage to the convoys for the U-boats were unable to maintain sustained contact during the rest of the night and by noon of the following day, the surface escort once more was supplemented by aircraft, the presence of which caused COMSUBs to say:

      "In spite of aircraft try absolutely to get ahead, in order to be near the convoy when darkness falls. Take advantage of last chance tonight, since operation will be discontinued tomorrow at dawn." (1738/19 March 1943)

      The attempts of the U-boats to comply were futile: Tippelskirch (U-439) reported Asdic pursuit and depth charge for eight hours, Loeser (U-373) complained that he was constantly being forced under by aircraft, Uhlig (U-527) echoed this complaint and Witermeyer (U-190) suffered ASDIC and depth charge pursuit for nine hours. Although all U-boats were instructed to:


      "utilize chance for submerged day attack on morning of 20. Thereafter break up and sweep for single ships in large area to SW on path of convoy." (2232/19 March 1943)

      they had already fallen too far behind both convoys to permit further operations. As one U-boat after another reported the convoy out of reach, by tacit consent activity gradually ceased.

    1. Conclusion: "despite strong air and surface defense," the "greatest success."

      During the course of the three day attack on HX 229 and SC 122, the majority of the U-boats in the North Atlantic participated. Their disposition before the first sighting and the extent of the battle as regards time and area made it possible for approximately 40 U-boats to engage in the operation. They were available in sufficient numbers at the right time and place. After one group had attacked and fallen behind, the next group was in a position to take up the battle. Furthermore, as the convoy advanced, the inadequacy of its escort forced it to abandon damaged ships, leaving them like so many sitting ducks for the U-boats which had fallen behind. The escorts were outnumbered two to one, as they had been in the case of SC 121 and HX 228. Due to the factors already mentioned plus weather, advantageous to U-boat operations, the toll of ships sunk was 21, 13 from HX 229 and eight from SC 122. In consequence, U-boats received the following commendation:

      "Appreciation and recognition for the, greatest success yet achieved against a convoy. After the extraordinary, successful surprise blow on the first night, tough and energetic pursuit, despite strong air and surface defense, brought splendid successes to the submarines in their attacks both night and day." (1036/21 March 1943)

  1. Seewolf, Seeteufel, HX 230, and a hurricane.

    Despite the 40 odd U-boats that attempted an attack on HX 230 in the closing days of March the operation was a complete failure. Only one convoy straggler was sunk. The attempt was certainly affected by a severe hurricane, but


    whether the weather alone can account for the change in U-boat fortunes seems questionable, for this disadvantage was equally distributed. The operation, or the attempt, is of particular interest in view of its contrast with successful - attacks which preceded it in March and in view of the ineffectiveness which marked U-boat attempts against North Atlantic convoys from that time on.

    1. The group formation.

      The successive runs on eastbound convoys in March had their effect in draining the Newfoundland area of U-boats. Further, in Command's effort to destroy the convoys he had thrown all of his mid-Atlantic submarines into the battle. In consequence, there had been no westerly sweep group to arrive off Newfoundland as Raubgrafs relief after the manner of Haudegen and Neptun, Waldfang and Burggraf. It may have been his anxiety to hasten new groups into area west of 30°W that led him to forbid fresh U-boats from joining in the action against HX 229 and SC 122. As the fresh U-boats were reinforced by those putting back west after the HX 229 - SC 122 action, six U-boats (Wölfchen) were ordered on ahead to make contact on the next northeast convoy while Command could get his other boats organized for attack. Command was being pressed in his effort to maintain the -March tempo. Shadowing group Wölfchen was low on fuel and was to head off to a refueler as soon as it had delivered the convoy. The attacking group Seewolf, with 19 U-boats, was moving to take up a line on the 25th from 55°33'N - 39°45'W to 50°27'N 35°15'W, there to expect HX 230. Meanwhile Seeteufel had already been formed to cover the northerly routes from 61°N to 57°N along 28°W. On the basis of detailed convoy intelligence which is believed to have been decryption but never been identified, Seeteufel was distracted by expectations of a westbound convoy. It began to sweep west, however, as new U-boats were added, on a course that would make connection with the northwest end of Seewolf. The results would be one line of more than 40 U-boats from Cape Farewell to 49°N - 34°W. It will be noted that this was a simplified group pattern.


    1. Radio intelligence comment.

      Traffic at this time was being read with a lag of about two days. The positions of both groups were known several days in advance. Seeteufel's disguised squares. caused some trouble but had been correctly deciphered by 21 March. Of interest is the fact that correct decipherment was made possible by Command's clarification of Seeteufel's expectations (i.e. west or east) together with the radio circuit which the group was assigned.

    2. Seeteufel and the aircraft carrier. (USS Bogue).

      In the course of her southwest sweep to join Seewolf, Seeteufel had some obscure skirmishes with a southwest convoy during which there was much to do over an iceberg that looked like a whaling ship. One event, however, deserves particular notice. At 2023/26 Schmid (U-663) reported an aircraft carrier from 57°45'N - 40°00'W. The carrier must have been the Bogue which had left Argentia, Canada 20 March to join convoy SC 123. COMSUBs informed Seeteufel that:

      "The sinking of the aircraft carrier is particularly important for the progress of the convoy operation. Do not on that account, however, let any other chances slip." (2148/26 March 1943)

      He did not seem unduly alarmed.

    3. Operation on HX 230.

      The expected convoy, HX 230, was first sighted at 1450/27 by Bahr (U-305) in 56°39'N - 40°24'W. Upon receipt of his report COMSUBs ordered Seeteufel to discontinue its operation on the SW convoy and operate at maximum speed with Seewolf on HX 230. By noon of the 28th not one of the U-boats had been able to maintain contact on the convoy. The numerous U-boat reports of being forced off by depth charge are evidence of the efficiency of the support group which had been detached from SC 123 on the previous day and detailed to protect HX 230 when the first sighting reports were intercepted. The increasingly bad conditions had, by the afternoon of the 28th, reached the proportions of a hurricane,


      blowing from the southwest. This prompted COMSUBs to instruct all U-boats to:

      "use the west weather situation well in order to run ahead at top speed. Subs may under no circumstance be behind the convoy. Forward again and again at top speed in order to thrust upon the convoy from ahead." (1223/28 March 1943)

      As a consequence of this order, COMSUBs was rewarded with sighting reports from 13 U-boats which reported single steamers and destroyers, or groups of three to. four ships, all in about 56°N and at intervals along a line from 38° to 31°W. The possibility that German blockade runners might be in the area added to the confusion of the U-boats, causing those which sighted independent to ask COMSUBs in each case "Shall I sink her?" until COMSUBs instructed them to establish identity of the ships and ask no more questions. He concluded that the convoy might be in the area of single ships reported and ordered U-boats to:

      "try to gain ground in heavy weather, in order to be near the convoy when the weather improves. In case contact with independents is made, stay doggedly with them so that you can sink them when better weather comes." (1739/28 March 1943)

      Beginning about 1700/28 there was an increase in the number of complaints that U-boats were being forced to submerge because of aircraft (very long range aircraft patrol). The only attack reported from the onset of the operation to this time was Neide's (U-415) miss with two torpedoes on a single freighter in 56°N - 33°W, followed by two unexplained detonations after which the steamer was lost in a hail squall.

    1. COMSUBs yields to the weather.

      With no further satisfactory activity on the part of the U-boats, COMSUBs assumed that:

      "during the hurricane, the convoy was completely broken up. Ships will attempt independently to head for North Channel on due east course. Count on these ships


      proceeding at a speed of 9 knots. When the weather improves, all U-boats must be ahead of ships so that they cannot get through the large group of U-boats to the east" (1133/29 March 1943)

      "Even in heavy seas, take advantage of all chances for attack." (1152/29 March 1943)

      Zetsche (U-591) gained momentary contact with a convoy group shortly afterward:

      "about 7 ships, 5 destroyers in full circle. Large straggler behind. Submerged because of flying boat. Lost contact" (1158/29 March 1943)

      Due to the severity of the weather, COMSUBs exhibited unusual tolerance as regards the continued lack of success, advising three U-boats to catch up since they were too far behind and reassuring the others that:

      "if the weather improves, U-boats will have good chances of success with the large number of independents. Course of the ships is certain to go south of Rockall Bank into the North Channel." (1658/29 March 1943)

      Shortly after midnight Zitzewitz (U-706) reported little improvement in the weather, and in view of the strong air patrol, did not consider it advisable to continue the operation. COMSUBs arrived at the same conclusion and ordered both groups to:

      "discontinue operation on convoy insofar as there is no contact with convoy or single ships. Move off westward in convoy lane and count on single ships. Stay tenaciously with these until they are sunk." (1048/30 March 1943)

      Aside from occasional sighting reports, the combined efforts of some 40 U-boats produced no tangible results save for Freyberg's (U-610) spread of three several times on a 10,000 ton steamer and his claim to have sunk the William Pfryedat at 2340/29 in 56°N - 24°W. The following day Schug (U-86) reported a probable sinking in 55°N - 25°W, after a hit on a 5,000 ton steamer. One of these claims is substantiated


      by the fact that HX 230 arrived at its destination minus one straggler.

  1. Comment on March U-boat operations.

    March recorded the highest monthly total of ships lost in convoy since the war's beginning. It should be remembered, however, that more than twice as many ships were convoyed in March as in February. March also recorded the highest number of U-boats in the Atlantic (including outbound and inbound submarines). The strain of the winter offensive, however, was telling on the U-boat navy. The number of submarines giving battle decreased only slightly from February to March, but in April the number dropped from about 120 to 90. New U-boats had come out in great numbers during February - almost one a day - but U-boat losses and damages had pruned the growth in operating strength. Not until May did U-boat Command again attain the strength at sea which characterized February and March. And then it was too late.

    Certain additional comments should be noted here:

    1. The U-boat navy reached its peak late.

    2. The introduction of new cipher tables on 1 March and the consequent delays in reading traffic undoubtedly cost us ships in the first weeks of March.

    3. German radio intelligence probably cost us the worst convoy defeat, or at least played an important part in obtaining contact. (HX 229 - SC 122)


Groups Wildfang, Burggraf, Westmark, and Ostmark - SC 121, March 1943


Groups Raubgraf, Dränger, and Stürmer - HX 229 and SC 122, March 1943


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1. Records of the National Security Agency, US. Navy, OP-20-GI, "Memoranda to COMINCH F-35 on German U-boat Activities, December 1942 - September 1943," SRMN-051, 116, National Archives, Washington, D.C., Record Group 457.

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