The loss of U 225 and U 529

Re-assessment of German U-boat losses in World War II

by Dr. Axel Niestlé

(All Times are European Standard Time (GMT + 1))
25 March 2008

Note: This report and the conclusions therein are protected by copyright and/or other intellectual property laws, and any unauthorized use of the material may violate such laws. No part of this report may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the author.

U 225 (Oberleutnant zur See Wolfgang Leimkühler) left Brest in France at 1530 on 2 February 1943 for its second patrol in the North Atlantic with orders to steer for naval grid square BE 43. This was revised to AK 68 by a signal from U-boat Command timed 1808 on 5 February 1943. Four days later, the boat was directed to wait in that square until further orders. At 1144 on 11 February 1943 U-boat Command ordered U 225 and ten other boats to join the new Group Ritter in order to intercept convoy traffic to and from England on the southern route. Extending from naval grid square AK 3784 to AL 4711, with U 225 to occupy AK 3966, the group was to proceed from 1200 on 14 February 1943 in the direction of 235° true, speed 5 knots. At 1538 on 11 February 1943 the days run for the group was reduced to 60 nautical miles due to the prevailing weather conditions with frequent storms in the North Atlantic. When no convoys were met in the ensuing days, U-boat Command ordered Group Ritter at 2254 on 16 February 1943 to occupy a new patrol line, extending from naval grid square AK 1677 to AK 5646 as from 2200 on 17 February 1943, with U 225 to occupy AK 1889. U-Boat Command hoped to make contact with an expected NE-bound convoy during the following night. If no contact was established by the now 12 boats of Group Ritter until 1100 on 18 February 1943, the group was to form a search line in the direction of 235° true with a days run of 80 nautical miles. Again failing to find the expected convoy, Group Ritter was once more redirected at 2330 on 18 February 1943 to a new stationary patrol line from AK 0299 to AK 9423 as from 0800 on 20 February 1943 with U 225 to occupy AK 6422. The intention to start a search line with Group Ritter at 1000 on 20 February 1943 in the direction of 135° true was quickly abandoned when on the forenoon of 20 February 1943 U 604, operating as part of Group Knappen to the south of Group Ritter, reported contact with an outward bound convoy (ON-166) in naval grid square AK 9616. In order to bring a large number of boats against this convoy, U-boat Command at 1253 on the same day also directed all boats of Group Ritter, except the northernmost boat U 529, which was considered too far away, against convoy ON-166. In the following days most of Group Ritter boats made contact with ON-166 or its escorts. Only the most northerly boat U 377 radioed at 1320 on 21 February 1943 from AK 59 its inability to catch up with the convoy owing to distance and adverse weather conditions and consequently was directed to join Group Neptun, then operating north of it.

U 225 had reported last at 1521 on 7 February 1943 by transmitting a weather report from 50°n and 20°w, equalling naval grid square BE 24. Following concerns about the absence of any signals from U 225, U-boat Command requested the boat at 0951 on 22 February 1943 to send a short weather report by 1700 on the same day. In the absence of a report, the request was repeated at 2224 on 22 February 1943 for a weather report between 0300 and 0600 on the following day. When no report was received, U 225 was ordered at 1538 on 23 February 1943 and again at 1036 on the following day to report its position at once. After its failure to transmit any of the reports requested over the previous three days, U-Boat Command on 25 February 1943 posted U 225 as missing with effect from 22 February 1943.

U 529 (Kapitänleutnant Georg-Werner Fraatz) left Kristiansand-South in Norway at 0740 on 2 February 1943 for its first patrol with orders to steer for naval grid square AK 19. At 1808 on 5 February 1943, the boat was ordered, together with U 759 and U 638, to pass through naval grid squares AE 65, AE 67, and AE 79 on its outbound route. At 1144 on 11 February 1943 U 529 was directed to join Group Ritter, which was to be established by 1200 on 14 February 1943, extending from naval grid squares AK 3784 to AL 4711. U 529 was to occupy the northernmost position AK 3784. Like U 225, the boat was to take part in the search line, starting from its datum square AK 3784 by 1200 on 14 February 1943 and proceeding in the direction of 235° true at a speed of 5 knots. On request, U 529 transmitted a short weather report at 0332 on 12 February 1943 from 61°n, 20°W, equalling AE 78. No further report was received from U 529 thereafter. In the ensuing days, U 529 received identical orders as U 225 concerning the movements of Group Ritter, with the boat always being attributed to the northernmost position in the various patrol and search lines. Following the interception of convoy ON-166 in the forenoon of 20 February 1943, U 529, as the sole member of Group Ritter, was explicitly directed at 1253 on that day not to operate against the convoy. Staying some 240 nautical miles north of the reported convoy, steering on a southwesterly course, U-boat command considered the chance remote that U 529 could catch up with the convoy in time under the prevailing weather conditions. Instead, at 1917 on the same day U 529 was detached to Group Neptun, operating immediately north of Group Ritter, and extended its patrol line by one position to the South, but still allocated to naval grid square AK 0299. By the same signal, all boats of Group Neptun were directed to start a search line at 2200 from its datum line between AK 2438 and AK 0299 in the direction of 260° true with speed 3 knots over ground. In its search for convoys towards southwest during the following days, Group Neptun was to pass through various position lines with U 529 to stay in the following approximate mid-night position from 20 to 26 February 1943: AK 6120, AK 5370, AK 5190, AK 4680, AK 4810, AJ 9320 and AJ 9270. At 1700 of 27 February 1943 U-boat Command received a delayed report to the effect that the northernmost boat of Group Neptun, U 759, at 0250 had contacted a convoy (actually HX-227) in AJ 2839. At 1749, Group Neptun boats were consequently informed of U-boat Commands assumption that they would all be operating against the convoy. To overcome atmospheric interference with wireless transmissions in the Greenland area, which had been the cause of the delay in receiving U 759’s convoy sighting report, U 529 and U 664 were detailed to repeat messages. When contact with the convoy could be held only sporadically until the next day, at 2008 of 28 February 1943 U-boat Command eventually directed U 529 and four other boats of Group Neptun, which were considered no longer operating against HX-227, to join a stationary patrol line of nearby Group Wildfang as from 0800 on 3 March 1943. However, if boats preferred to continue operations on the convoy, they were to confirm this by a routine position report. In the absence of a report from U 529, U-boat Command informed the boat by signal 0959 on 2 March 1943 about its assumption that the boat will join the patrol line of Group Wildfang as ordered with U 529 to occupy naval grid square AJ 5817. Failing to make contact with a convoy, Group Wildfang was eventually abandoned at 1615 on 6 March 1943 and U 529 was to join a new patrol line named Group Raubgraf as from 8 March 1943 with the boat to occupy naval grid square AJ 9114. On 10 March 1943 the patrol line was shifted about 120 nautical miles north with U 529 now to patrol in naval grid square AJ 5624.

In the absence of any report since 12 February 1943, U 529 was requested at 2104 on 13 March 1943 to transmit a short weather report between 0300 and 0600 on the following day. When no report was received, U 529 was ordered at 1005 on 14 March 1943 and again at 2125 on the same day to report its position at once. After its failure to transmit any of the reports requested over the previous two days, U 529 was finally posted on 14 March 1943 as missing with effect from 13 March 1943, although U-boat Command acknowledged that her loss could well have occurred some time earlier than that.

From ULTRA signal intelligence the U-boat tracking room at the Operational Intelligence Centre (OIC) of the British Admiralty became soon aware of the loss of U 225 and U 529. By then it had been established that repeated requests to individual U-boats for transmitting weather or position reports usually indicated the probable loss of the boats concerned. However, for the duration of the war the tracking room felt unable to attribute their losses to any specific allied A/S-attack during the period until their losses had been established. Post-war, their losses were finally allocated, based on rough information on the loss of the two boats from the German Naval High Command in June 1945. In autumn 1945 the Admiralty U-boat assessment committee allocated the loss of U 529 to the depth charge attack of Liberator “S” of 120 Squadron RAF at 1204 on 15 February 1943 in the reported position 55°45’n, 31°09’w, while carrying out an A/S-sweep around of convoy SC-119. Likewise, the loss of U 225 was attributed to a depth charge attack by the US Coast Guard Cutter Spencer at 0143 on 21 February 1943 in position 51°25n, 27°28w, while escorting convoy ON-166.

Liberator “S” had sighted a surfaced U-boat 7-8 miles off at 1200 and attacked four minutes later, dropping six depth charges from 70 feet while the conning tower was still visible. The charges straddled the target just aft of the tower. When circling over the place of attack, oil and air bubbles were observed and later also wreckage came to the surface. From the evidence observed it appears very probably that the U-boat attacked was in fact destroyed. However, in 1987 research by the Naval Historical Branch (NHB) had revealed that the attack by the Spencer on 21 February 1943 was actually directed against U 604, which had escaped unscathed, thereby vindicating the original wartime assessment on the attack. Therefore, the NHB challenged the post-war allocations for the two boats. Mainly based on the conclusion that the position reported by the crew of Liberator “S” of 120 Squadron RAF for its attack on 15 February 1943 was somewhat closer to the estimated position of U 225 than that for U 529 and the aircrew statement that the attacked boat was identified as a “517-ton type”, i.e. a Type VII, a description that fits U 225 but not U 529 of the type IXC-class, it was concluded that the U-boat sunk by S/120 must have been U 225. On the contrary, the NHB was unable to produce a satisfactory explanation for the loss of U 529 which was therefore listed as lost through unknown cause, possibly marine or accidental, in February 1943 in the North Atlantic to the south of Greenland.

Detailed interpretation of a photograph (IWM photo collection no. HU 60508J) taken during the attack of Liberator S/120 on 15 February 1943, however, reveals a type IX-U-boat in the process of diving, despite the contrasting aircrew statement about the type of U-boat attacked. The photograph is showing the conning tower with AA-platform, the top of the 3.7 cm deck gun aft of the conning tower and part of the stern still above the water. This strongly supports the conclusion that the U-boat attacked and sunk on 15 February 1943 was indeed U 529, thereby confirming the immediate post-war decision of the U-boat Assessment committee. Moreover, U 529 was by then the only type IX-boat operating in the general area of the attack. At the time of the attack, U 529 should have stayed approximately in square AK 0255, while U 225 was to stay in square AK 6194 in accordance with the orders given to Group Ritter four days before. The reported attack position differs some 70 respectively 40 nautical miles from the approximate U-boat positions. However, experience has shown that position fixing in the open North Atlantic from an aircraft operating some 700 miles from base under adverse weather conditions without help from navigational systems was likely to include large navigational errors. For example, the reported position for the successful attack by Liberator “T” of 120 Squadron RAF at 2018 on 21 February 1943 on U 623 differs some 50 miles from the actual position of the boat, which was confirmed by the positions of U 91, U 628 and U 753, observing the attack from nearby. The position fix of the three U-boats standing nearby is also confirmed by the fact that all were attacked immediately thereafter by escorts from ON-166, whose attack positions match the German positions reported for the attacks.

With U 529 in all probability being sunk on 15 February 1943, the loss of U 225, which must have occurred at some time between the 7 and 24 February 1943 at the latest, remains an open question. During the given time span the following anti-submarine attacks took place along the assumed route of U 225:

1204/15 Liberator S/120 RAF 55°45N / 31°09W D/C A U 529 sunk
0145/21 USCGC Spencer 51°25N / 27°28W D/C B U 604 no damage
1527/21 USCGC Campbell 49°35N / 29°18W D/C G U 623(?) no damage
1948/21 HMCS Dauphin 49°05N / 29°10W D/C H non-sub
2018/21 Liberator T/120 RAF 48°08N / 29°37W D/C E U 623 known sunk
2106/21 HMS Dianthus 48°59N / 29°20W D/C F U 91 slight damage
2117/21 USCGC Campbell 49° N / 29° W D/C F U 628 no damage
0750/22 USCGC Campbell 47°55N / 31°11W D/C F U 753 no damage
0831/22 HMS Dianthus 48°37N / 30°35W D/C F unknown U-boat
1307/22 USCGC Campbell 47°17N / 32°09W D/C G U 621 no damage
2231/22 HMCS Chilliwack 46°45N / 34°55W D/C F U 92 no damage
2235/22 ORP Burza
USCGC Campbell
47°44N / 33°43W D/C A U 606 known sunk
2301/22 HMCS Rosthern 46°59N / 34°30W D/C F U 628 no damage
0336/23 HMCS Trillium 47°00N / 34°30W D/C F U 303 no damage
0733/23 USCGC Spencer 46°36N / 36°41W D/C G U 454 damaged
0820/23 S/S Winkler 48°00N / 32°00W gunfire F U 223 no damage
1009/23 HMS Dianthus 47°05N / 35°23W D/C G U 223 slight damage
2038/23 HMCS Chilliwack 46°08N / 38°10W D/C G U 621 no damage
0750/24 USCGC Spencer 44°57N / 39°11W D/C F U 621 no damage
0822/24 USCGC Spencer 45° N / 39° D/C - U 468 no damage
0827/24 HMCS Rosthern 45°28N / 37°58W D/C F non-sub
0840/24 HMCS Chilliwack 45°30N / 40°26W D/C G U 92 no damage
0851/24 USCGC Spencer 45° N / 39° D/C - U 628 no damage
1415/24 Catalina F/5 RCAF 45°14N / 40°30W D/C D U 604 damaged
2132/24 USCGC Spencer 44°46N / 41°51W D/C F non-sub
2147/24 Catalina B/5 RCAF 45°10N / 41°10W D/C F U 621 slight damage

Details about the attacks yet unable to be attributed to an individual U-boat are as follows:

At 1527 on 21 February 1943 Campbell obtained a sonar contact at 900 yards and after the attack at 1531 the target moved slowly to the left and then rapidly to the right. An 11-charge pattern was set at 100-150 feet with no visible results. Two minutes later the cutter delivered three charges from the starboard throwers set at 250-300 feet, since Campbell was believed to be passing astern of the target. Again, there were no results. At 1538, the range was opened to 1,500 yards for another approach. Double and triple echoes were now obtained, indicating a wake or bubble screen, and the target motion was away and to the right, so a lead of 15° to the right was taken and a 10-charge pattern set to 200-300 feet, fired without visible results. If the contact was a genuine U-Boat, it must have been U 623, which was known to be in the area but was sunk a few hours later before reporting again on the radio. U 225 should have been still north of the position at that time. However, there is also a probability that it was a non-sub contact. In any case, it is unlikely that the attack caused any damage.

At 2132 on 24 February 1943, Spencer made radar contact at 2800 yards during a high-speed sweep on port bow of the convoy to drive down possible shadowers. Five minutes later sound contact was established at a range of 400 yards, which was attacked at 2140 with one depth charge. At 2158, contact was regained and attacked with a mousetrap pattern. Two minutes after firing, a heavy underwater detonation was heard, but no further results were observed. None of the boats then in contact with the convoy reported the attack. Therefore, it appears probably that it was directed against a non-sub target.

The most promising attack was carried out at 0805 on 22 February 1943 by the Dianthus, trying to rejoin the convoy after having hunted U 91 the evening before but still some 15 miles astern. The corvette picked up a radar contact at 5.400 yards, classified as surfaced U-boat. While chasing the target at full speed, the U-boat dived at 0825 when distance had been reduced to 2.000 yards. ASDIC contact was gained immediately thereafter and held continuously until 0831, when a pattern of eight depth charges set to 100 feet was dropped, considered a perfect attack. Contact was regained and at 0839 a second pattern of ten depth charges set between 50 and 140 feet was dropped, but attack was considered poor. This was followed by a hedgehog attack at 0847, resulting in two violent explosions four seconds after hitting the water, followed shortly after by several more muffled explosions and bubbling. At 0857 another heavy underwater explosion was heard, appearing to be almost underneath the corvette. U 454 also recorded this explosion, then staying surfaced several miles away. With target echo fading and stopped, a final pattern of five charges set between 100 and 385 feet was dropped at 0902. Contact was not regained thereafter despite a box search and good ASDIC conditions. When nothing further was observed thereafter until 0947, Dianthus set course to rejoin the convoy. The assessment committee later graded the attack as having inflicted probably heavy damage, but expressed doubt concerning the claimed destruction because of the absence of visible evidence of damage or wreckage. None of the boats then operating against convoy ON-166 that returned to base thereafter reported the attack. Of those boats which did not return from patrol, U 623 is known sunk on the day before and U 606 intercepted the convoy on a easterly course starting from naval grid square BD 4355 at 2200 on 21 February 1943. Contacting ON-166 for the first time at 1024 on the next day in naval grid square BD 5551, U 606 is unlikely to have crossed the track of HMS Dianthus well astern of the convoy. In addition, the boat did not mention any attack in its subsequent radio signals. Also, no mention of an attack is made in the report covering interrogation results from its survivors. Thus, U 225 is the only likely candidate for the attack. Pursuing ON-166 from its northerly position within Group Ritter, it should have closed the convoy position early on the 22 February 1943. The absence of any radio signals from the boat indicates that it must have been sunk before having made contact with the convoy itself.

Based on the information presented above it is proposed to amend the records to show that:

U 529 lost with all hands at 1204 on 15 February 1943 by depth charges from Liberator S/120, piloted by F/O Reginald Thomas Frederick Turner, RAF, in position 55°45’n, 31°09’w.

U 225 lost with all hands at 0847 on 22 February 1943 by depth charges from the corvette HMS Dianthus, commanded by Lt. N.E. Israel, RNR, in position 48°37’n, 30°35’w.

This article was published on 12 Dec 2009.

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