Group Wotan and the Battle for Convoy SC 104, 11-17 October 1942by Rob Fisher (1994)
The battle for convoy SC 104 in October 1942 resulted in the loss of eight merchant ships and the destruction of two U-boats. The Admiralty anti-submarine analysts considered it a hard fought victory for the surface escort, an assessment which has not been challenged by historians, but little attention has been paid to the German perspective of the action.(1) The efforts to intercept and concentrate against SC 104 reveal well the problems that beset U-Boat Command even at this stage of the battle when they had superior intelligence and increased numbers of operational U-boats. The battle for SC 104, however, also illustrates the limitations of the improving tactics, training, and equipment of the surface escort. Indeed, it is the balance between the opposing forces that makes it such a revealing study of the mid-ocean war before it reached its climax.
During early October the wolf packs hunted Allied convoys against a backdrop of hurricane force winds, mountainous seas, and heavy rain and hail. Group Luchs established contact with HX 209 on 3 October but failed to sink any ships in a three day long operation fought in a westerly gale. The storm claimed the only merchant ship the convoy lost while Allied aircraft from Iceland destroyed two U-boats. Another U-boat made contact with ONS 134 on 4 October but atmospheric interference prevented radio communication with U-Boat Command.(2) The patrol line was renamed Group Panther but with no change in luck. It made contact on 9 October with ON 135 in a rain storm but lost sight of it in the poor visibility without pressing home any attacks.(3)
The failure to mount operations against successive convoys in rough weather frustrated Admiral Karl Dönitz, Commander-in-Chief, U-boats, and took its toll on the crews. For example, U-620 was frequently "forced under water by the very high swell with the result that the bridge watch has practically drowned and received minor injuries". Oberleutnant Heinz Stein, the captain of U-620, observed that "The seamen portion of the crew is starting to suffer injuries. All except 5 men have slight injuries. The other bridge watch keepers have been heavily taxed as I remained on the surface even in the heaviest weather and sought to establish contact. There are now sufficient men for only 2 watches".(4) The twenty-one U-boats of Group Panther reformed astride the great-circle route in the eastern Atlantic southwest of Iceland at the outer limits of shore-based air cover. This huge patrol line covered over 400 miles of ocean. It extended over a much greater distance than previous lines because recent experience suggested that convoys were employing more flexible routing.(5)
Special intelligence was not available to the Allies at this juncture but High Frequency/Direction Finding (HF/DF) revealed the broad disposition of German submarines. However, little evasive action could be taken because of the sheer size of the enemy fleet. Commander Rodger Winn, RNVR, head of the Admiralty Submarine Tracking Room, confessed that "Of the 100 or more German U/boats now at sea in the Atlantic between one third and one half are in the North Atlantic between the latitudes of the Azores and Iceland, and between 25 and 45 degs. West, and it is remarkable that any convoy should pass through this area without being intercepted".(6) The inevitable happened on 11 October when Panther made contact with ONS 136 in heavy rain with force 10 winds from the west and sea state 9. Instead of committing the entire force to the chase, Dönitz detached eight boats from the patrol line to operate against ONS 136 as Group Leopard. The pack torpedoed one straggler, however, in return a Liberator from Iceland destroyed U-597. Leopard lost contact on 13 October when the heavy seas from the west prevented the shadowers from matching the convoy's speed. The gaps in Panther created by the departure of the Leopard boats were filled by seven fresh submarines.(7)
The Admiralty U-boat Situation report of 12 October made no mention of a smaller group of U-boats in the western Atlantic, of which it, apparently, was unaware. U-Boat Command had directed Group Wotan to take up stations 300 miles northeast of Newfoundland after being refuelled. Nine of its ten U-boats were on their first war patrol, the lone exception being U-607 under the veteran captain Ernst Mengersen. Most of the boats, however, had taken part in convoy operations in September. The pack was ordered to maintain radio silence "except for messages of tactical importance", depriving Allied HF/DF of the ability to reveal its presence. Dönitz expected an eastbound convoy on 8 October but the pack arrived on station too late to intercept HX 210 because of the rough weather. The B-dienst, German Naval Intelligence, then informed U-Boat Command that SC 104 would pass through Wotan's patrol line on 11 October as the group was still forming up.(8)
SC 104 had sailed from New York on 3 October and included forty-eight merchant ships sailing in ten columns.(9) The mid-ocean escort group, B6, rendezvoused with the slow convoy off St John's on 10 October and relieved the western local escort. Commander Ralph Heathcote, RN, captain of HMS Fame, assumed command as the Senior Officer. B6 included two British destroyers, Fame and Viscount, and four Norwegian corvettes, Acanthus, Eglantine, Montbretia, and Potentilla. The destroyers carried the latest anti-submarine equipment: type 271 radar, HF/DF, and Hedgehog. In addition, the rescue ship, SS Gothland, also carried HF/DF. The corvettes were also well equipped, all had type 271 radar and Eglantine had Hedgehog as well. The Norwegians were well trained and experienced. B6 had come under enemy attack with ONS 122 in August and was thus the only B-group which had tasted action since late 1941.(10)
Allied HF/DF intercepted a signal at 1426Z on 11 October and warned Heathcote that a U-boat shadowed SC 104. However, B6's HF/DF had not obtained the bearing and the pack had not yet sighted the convoy, although that was soon to change.(11) Towards the northern tip of the patrol line, U-258 sighted the masthead of a corvette on a northeasterly course at 1545Z but poor radio conditions delayed U-Boat Command's receipt of the contact report. U-258 lost contact that evening when the corvette disappeared in a "rain cloud".(12) In the meantime, U-615 had torpedoed and sunk SS El Lago, an independent vessel which had the misfortune to pass through the patrol line.(13) U-258 re-established contact the following morning with the corvette and this time the report made it through to U-Boat Command. Dönitz ordered Group Wotan to attack even though none of the merchant ships had been observed.(14)
During the morning of 12 October, U-356, another member of Wotan, glimpsed a "large steamer and several smoke clouds" on a westerly course in a rain squall. This westbound convoy could not have been ON 135 or ONS 136 which were still much farther east. In fact, the smoke was probably from the eastbound SC 104, which was very close to U-356's reported position. The shadower submerged at 1520Z when an escort approached within 3,000 metres. U-356 surfaced later but lost all contact searching for the convoy on a westerly course.(15) SC 104 was still within range of Newfoundland-based aircraft on the twelfth but the lone Catalina to reach the area failed to locate the convoy.(16) Fame and Viscount obtained DF bearings on a U-boat signal at 1624Z, 12 miles on the starboard bow. Heathcote directed Montbretia (Lieutenant-Commander Halvos Söiland, RNN) to investigate but the sweep revealed nothing.(17)
Dönitz aborted the operation against SC 104 at nightfall and ordered the boats whose "positions were not too unfavourable" to stalk U-356's westbound convoy. The others were instructed to reform the original patrol line. Group Wotan hunted during the night of 12/13 October in rough seas, rain showers, and bright northern lights. U-221 sighted SC 104 at 2250Z, as it emerged from a rain squall 2,000 metres distant, and crash dived. The U-boat surfaced 15 minutes later only to be forced under again by a destroyer 200 metres astern. Oberleutnant Hans Trojer surfaced at 2326Z and counted twenty merchant ships and four corvettes on the beams and astern. His sighting report was not received by U-Boat Command.(18) Fame obtained a DF bearing astern at 2340Z and followed it up with a radar contact. The destroyer's 271 radar broke down because of the "heavy pounding" of the sea and no further trace of the intruder was found. Heathcote observed that "conditions for RDF and asdics were very bad owing to the steep and rising sea, while spray and occasional snow showers hampered lookouts". The northern lights, however, "kept the visibility of the convoy up to at least 4 miles" at times.(19)
U-221's signal finally made it through to U-Boat Command which ordered Wotan "to operate on the basis of this report". Trojer reconnoitred SC 104 and then slipped into the convoy from ahead, manoeuvring to produce as little spray as possible. He closed the starboard quarter and torpedoed a merchant ship at 0356Z from a range of 800 metres. The victim sank quickly in the rough seas and the escort remained unaware of the attack in the fury of the storm. In the absence of any stirring from the escort, Trojer fired three torpedoes at 0422Z and claimed two hits. He described in his log what followed, "Red flares rose above the ships, initially from the freighters that had been hit and then above the others. The destroyers fired illumination flares--not star shells--and showed cheerful-looking green lights. The area was feebly illuminated....The defensive measures expected do not materialize, presumably we are thought to already be under water. The fireworks gradually die out, only a few diehards keeping firing now and again. The jolly green lights have--sadly--also disappeared". U-221 fired a shot from the stern tube at 0510Z from a range of 2,000 metres and claimed a fourth hit.(20)
In total, three ships had been torpedoed but in which order is not certain. The 2,342-ton SS Fagersten, the second ship in the starboard column, was torpedoed at 0425Z in the second attack. Torpedoes also hit the fourth and fifth ships in the starboard column, the 3,785-ton SS Senta and the 5,227-ton SS Ashworth. B6, except for Montbretia, was not aware of the attacks until 0450Z when Fame stumbled upon Fagersten astern of the tenth column. The escort, which had been deployed in the standard night screen, NE-6, executed Operation Raspberry but found no trace of U-221. At daybreak Heathcote sent Potentilla (Lieutenant-Commander C.A. Monssen, RNN) back to search for survivors but the corvette found only ten men from Fagersten.(21) Catalina aircraft from Newfoundland sighted two lifeboats with thirty men on 14 and 15 October and dropped supplies, but surface vessels did not reach them in time and none of the crews of Senta and Ashworth survived.(22)
Trojer submerged to reload and re-established contact after dawn on 13 October, shadowing SC 104 throughout the day. The pursuit of the non-existent westbound convoy had delayed the arrival of the rest of the pack. During the morning and afternoon U-216, U-599, U-258, and U-607 finally came up to SC 104.(23) Montbretia sighted a submarine on the starboard bow which crash dived before she could get close. Shipborne HF/DF kept Heathcote informed about the number of shadowers--estimated at three or four U-boats--and their positions relative to the convoy. During the afternoon he dispatched Viscount and Eglantine to investigate bearings astern. Eglantine sighted U-356 closing from astern at 1714Z and opened fire. The U-boat had not seen the corvette in the high swell but crash dived to avoid the gunfire. As a result of this sighting, Eglantine and Viscount were still hunting astern when darkness fell while Potentilla had yet to return from her search for survivors. The screen was left with only three escorts at a time when U-boats were known to be in contact and asdic and radar conditions were "most unfavourable".(24)
The weather remained bad with force 6 winds, sea state 5, and rain and hail. U-221 penetrated the reduced screen easily and at 2204Z fired a stern shot from 2,000 metres at a small freighter. Ten minutes later Trojer fired two torpedoes at two freighters "directly next to" one another. The second attack claimed the 5,929-ton SS Susana, the third ship in the ninth column, and one of the other torpedoes probably hit the 3,898-ton Nikolina Matkovic in the tenth column. The fireworks from the convoy did not disturb Trojer unduly and he selected a large whaling factory ship farther astern as his next target. This was the 12,398-ton SS Southern Empress, the last ship in the ninth column, which he torpedoed at 2232Z before diving to reload.(25) The Southern Empress remained afloat while the other ships sank. Heathcote had observed two white rockets from the starboard wing of the convoy at 2205Z, the time of the initial attack, but sufficient escorts were not present for Operation Raspberry to be worthwhile. Indeed, the Senior Officer had no idea which ships actually had been torpedoed until 2235Z when he received a report from the Southern Empress. Fame searched the starboard side in vain for any trace of the attacker.(26)
The fireworks following the torpedoing of the whaling factory ship illuminated SC 104 for U-607 which closed the port column at 2240Z and torpedoed the 4,826-ton SS Nellie to add to the general confusion. Viscount, returning from astern, sighted U-607 only 800 yards distant, and altered course to ram. Kapitänleutnant Ernst Mengersen described what happened next, "I ordered the bridge watchkeepers to clear the bridge and remained up top alone. The destroyer shot by my stern at very high speed at a distance of no more than 70 m[etres]. This was a 2-funnelled destroyer. I already believed that everything was going to work out and ordered hard to port to again move into a firing position on the freighter when the destroyer suddenly turned to port towards me. The yells and shouts on the destroyer's bridge could be heard clearly. Emergency dive. I expected to be rammed but the destroyer's turning circle was obviously too large". Viscount's captain, Lieutenant-Commander John V. Waterhouse, RN, instead fired a pattern of fourteen depth charges set to 50 and 140 feet by eye which exploded when U-607 had reached 60 metres. The depth charges knocked out the boat's rudder, depth rudder, depth gauge, compasses, engines, and communications systems. Viscount failed to make asdic contact after the counter-attack and rejoined the screen.(27)
Meanwhile, Heathcote instructed Potentilla, coming up from astern, to screen the Southern Empress, which was still under way five miles astern. U-221, however, surfaced and from a range of 400 metres applied the coup de grâce to the whaling factory ship at 0121Z with her last electric torpedo. Trojer conversed briefly with some of the men in the lifeboats before submerging for a well-deserved rest. Potentilla later rescued the survivors without finding any trace of the attacker. U-618 sighted the silhouettes of the merchant ships about the same time and closed the decimated starboard column to attack. The U-boat sank the 5,791-ton SS Empire Mersey at 0230Z with a spread of four torpedoes. The escort performed Operation Raspberry and at 0318Z Fame made an asdic contact four miles astern of the convoy. Heathcote dropped a pattern of five depth charges which caused moderate damage and flooding in U-618. Ten minutes later Fame obtained a radar contact 2,000 yards ahead and gave chase until the range had closed to 500 yards. The destroyer opened fire but the U-boat, probably U-615, was observed to have dived and no further contact was made. The remainder of the night of 13/14 October was quiet.(28)
The lull in the action allowed B6 to regroup. During the night fifteen merchant ships had romped ahead of the convoy believing they had been ordered to disperse but at dawn they slowly began to return to the fold. Potentilla had also rejoined to bring the screen back up to full strength. U-216 re-established contact at 0955Z and U-661, U-356, U-410, and U-599 soon followed suit. Trojer, Wotan's most successful captain, had used up his torpedoes and dropped out of the hunt while Mengersen fell back to make repairs. During 14 October Heathcote obtained "a very large number of H/F bearings" and "every effort was made to drive off" the shadowers whose numbers he estimated at four. As a result of this vigorous action, Dönitz complained that the U-boats "were constantly forced to submerge by destroyers" and speculated incorrectly that SC 104 had acquired "additional escort forces" from ONS 136. He ordered the five boats of Group Leopard to operate against SC 104 now that they had lost contact with ONS 136.(29)
During the evening of 14 October the weather "moderated considerably" while the visibility decreased. Heathcote took advantage of these conditions to make course alterations before and after dusk. In addition, he ordered the escorts "to remain closer to the convoy than laid down in NE-6", pulling his screen in to form a tight radar barrier around the convoy. He arranged with the commodore that snowflake would not be fired by the merchant ships. These tactics combined with the improved radar and asdic conditions helped B6 to hold Group Wotan at bay during the night of 14/15 October.(30)
The very dark night and calm sea (sea state 2 or 3) played into the hands of the type 271 radar. After nightfall Acanthus (Lieutenant-Commander E. Bruun, RNN) obtained a radar contact on U-661 at 2150Z and went in pursuit. The corvette sighted the U-boat and forced her under with gunfire. U-607 slammed into "the escorts on the starboard side of the convoy" from astern at 2255Z in visibility "so poor that silhouettes can only be indistinctly seen at 800 metres". The tightness of the screen frustrated Mengersen's attempts to get at the convoy. The wily veteran observed the effect of Heathcote's new tactics, "The situation is very ticklish. The vessels are constantly altering course. If one turns toward me, I will be caught in a pair of pincers as I cannot escape on either side". Fame's radar revealed a U-boat, probably U-607, at 2317Z on the starboard quarter. Simultaneously, Montbretia obtained a radar contact, perhaps U-254, four miles ahead of the convoy on the starboard bow. The warships forced both submarines under where they were temporarily neutralized.(31)
Heathcote made another course alteration at 0100Z in order to throw the submerged U-boats off the convoy's scent and any remaining shadowers off balance.(32) In spite of the darkness and evasive action both U-661 and U-254 surfaced and re-established contact. Viscount made radar contact with U-661 at 0131Z at 6,200 yards on the convoy's port bow. Waterhouse altered course to intercept the U-boat and when the range had closed to 2,000 yards increased speed to 26 knots. Viscount sighted U-661 two minutes later and rammed her "just abaft the conning tower". The destroyer opened fire with her close range weapons and dropped a single heavy depth charge along side the U-boat which sank with all hands. Waterhouse may have also driven off U-254 at this time which had observed a rapidly closing destroyer and crash dived.(33)
Fame and Potentilla obtained the next radar contacts and gave chase. U-599 crash dived at 0255Z and reported that she was "attacked with well-aimed depth charges from destroyer on diving". Potentilla obtained a radar contact five miles astern on the port quarter at 0334Z and shortly afterwards sighted U-254 which crash dived at a range of 600 metres. The corvette dropped a pattern of eight depth charges for good measure. Potentilla and Fame obtained further radar contacts astern and on the port quarter at 0500Z and gave chase. The destroyer followed up with an asdic contact and fired three patterns of depth charges which caused "limited equipment breakdowns" in U-254. The breakdowns compelled U-254 to retire from the hunt and head for port. In addition, defects to U-607's periscopes and hydrophones, caused by Viscount's earlier attack, necessitated her return to base. The loss or departure of three of the five U-boats that had been in contact during the night left Group Wotan in disarray. The escort had seized the initiative from the pack by aggressively pursuing radar contacts in poor visibility. Heathcote considered that the improved weather was chiefly responsible for "The remarkable contrast in the results of this night's encounters compared with those of the two previous nights".(34)
The course alterations in poor visibility had shaken off most of the other U-boats during the night. At dawn on 15 October U-410 (Korvettenkapitän Kurt Sturm) sighted a single freighter of 3,000 or 4,000 tons on a southwesterly course. U-410 torpedoed the merchant ship at 0830Z and the hit was observed from a distance by U-618 and U-356. Sturm could not learn the name of his victim from the 25-30 survivors in lifeboats and Jürgen Rohwer has speculated that she was a straggler from SC 104, torpedoed and damaged the night before. However, the ship was sailing in the opposite direction of SC 104 at a speed of 7-8 which knots which suggests that she had straggled from a westbound convoy. The position of the attack was 50 miles northeast of SC 104 making it unlikely that the vessel belonged to it. The victim was probably the 4,212-ton SS Newton Pine (an 8-knot vessel) which had straggled from ONS 136 on 11 October during a gale and was never seen again. She was about 100 miles astern of ONS 136 when U-410 stumbled upon her.(35)
U-410 and the two other boats which had observed the hit had lost the convoy's scent. The estimates during the previous night of SC 104's position varied greatly, exacerbating the problems of re-establishing contact. In addition, the poor positional fixes undermined U-Boat Command's ability to co-ordinate the operation. U-258 glimpsed two escorts at 1039Z while U-442 sighted the convoy three hours later. Heathcote obtained a DF bearing on the latter boat and swept out, forcing the shadower under. U-258 searched for the main body of the convoy based on U-442's position report without success.(36) During the afternoon the convoy received air cover from Iceland. Liberator H/120 sighted and attacked U-615 and U-437, 25-30 miles on the port quarter. U-356 crash dived at 1755Z because of the sudden appearance of an escort in visibility of 2 miles. Acanthus and Fame had not sighted the U-boat but made asdic contact and counter-attacked with two patterns of depth charges. Below the surface, U-356 sustained minor damage and flooding from the attack but escaped further rough treatment.(37)
In the evening of 15 October Viscount detached for Great Britain because of the damage sustained during the ramming of U-661. The pack continued to search for SC 104 but failed to re-establish contact until after midnight when U-353 sighted the convoy at 0230Z, having now reached almost 300 West. Eglantine detected the lone shadower at 0253Z with radar and went in pursuit, opening fire when the range had closed. It appeared to Oberleutnant Wolfgang Römer that the escort "had not sighted him but had detected him by some device for, though she opened fire, she ran right past him in the dark". He went deep to 150 metres and released a Bold asdic decoy. The corvette made asdic contact and carried out three depth charge attacks which caused minor damage. The convoy was not troubled further during the night.(38)
During 16 October the weather was calm with constant rain which limited visibility to 3 to 8 miles. In the morning twilight, U-258 re-established contact with SC 104 from astern. Liberator B/120 glimpsed the shadower five miles astern a few minutes later and forced her under. U-258 surfaced at 0854Z and went in pursuit but was driven below again by the Liberator two hours later. During the morning and afternoon, B/120 provided close air cover for five hours while other Iceland-based aircraft swept ahead of the convoy at long range.(39) In the meantime U-353 had made contact and worked around ahead to attack, waiting for the convoy at a depth of 20 metres. The boat was below periscope depth, however, and doing about 120 revolutions per minute which blocked hydrophone reception, making the boat both deaf and blind. Fame made asdic contact at 1407Z with the submerged intruder, lurking three miles ahead of the fourth column. Heathcote fired a pattern of ten depth charges set to 50 and 140 feet that exploded around U-353, knocking out the lights, depth gauges, electric motors, and after hydroplanes. Römer ordered the boat deep but without instruments the Engineer Officer could not control her rapid descent, forcing the captain instead to give the order to surface. Heathcote observed U-353 breaking the surface and rammed her, dropping five depth charges astern as the Germans abandoned ship. A boarding party from Fame briefly explored the U-boat but found little of value and barely got away before she sank. The escorts rescued thirty-nine survivors from U-353. The damage sustained by the destroyer during the ramming compelled her to detach and head for port, leaving Lieutenant-Commander C.A. Monssen of Potentilla as the new Senior Officer.(40)
During the morning of 16 October two of the U-boats of Group Panther had made contact with ON 137, one hundred miles ahead of SC 104. Dönitz ordered Group Wotan to break off the operation against SC 104 in the afternoon in order to stalk the westbound convoy as it left the safety of air cover. However, another member of Panther, U-571, re-established contact with SC 104 at 2000Z, observing five merchant ships and two escorts on a easterly course. Potentilla's radar revealed the shadower at 2340Z at a range of 2,800 yards. The corvette closed the distance to 400 yards, sighted the U-boat, and opened fire. An attempt to ram narrowly missed as U-571 crash dived. Monssen carried out two depth charge attacks which brought oil to the surface but only caused slight damage to the enemy boat. Afterwards U-571 failed to re-establish contact in the darkness. Later that night Dönitz finally terminated the operation against SC 104 because of its entry into the "area of continuous air patrol".(41)
Dönitz considered that "the course of the operation was a disappointment for our boats" in spite of an estimated sinking of eleven merchant ships. In his view, two factors had a strong impact on the action: the "Scattered position of [the] boats at the time of first" contact and the "Bad weather from the W[est]". SC 104 was sighted at the northern tip of the patrol line before it had fully formed up, and this combined with the weather and the pursuit of the spurious westbound convoy delayed the arrival of the pack. What was most disturbing, however, was the lack of success during the period of calm weather after all of the boats had come within striking range of SC 104. The Germans attributed the failure to a suspected reinforcement of the surface escort, the appearance of long range aircraft, the variation in the estimates of the convoy's position, and the "Outstanding performance of radar apparatus". Dönitz believed that radar played the most crucial role, remarking that "It is striking that boats were not able to shadow for any length of time without being forced to submerge. At time[s] they were not even able to make first contact report[s]". He realized that the heavy seas prevented the "successful operation of enemy radar" during the first two nights, but was unaware of the way in which shipborne HF/DF and the tighter screen complemented naval radar.(42) The success of Allied radar showed the decisive importance of developing counter-measures such as improved torpedoes and combined radar and radar detection equipment. In this regard, it is surprising that the inability of the new FuMB search receivers to detect B6's type 271 radar passed without comment. The fact that a single U-boat had accounted for over one-half of the sinkings also passed without remark, mute testimony that the effects of dilution were too well known to warrant comment. Dönitz consoled himself that SC 104 must at least have been "a small catastrophe" for the Allies because of the heavy loss of merchant ships.(43)
The Admiralty studied the battle for SC 104 in detail. The successful German attacks had occurred in rough seas which negated the surface escort's radar. The Admiralty analysts argued that "Such circumstances are no fault of the escort and set an extremely difficult problem admitting of no complete solution as things are at present". However, "The subsequent recovery of the initiative by the surface escort before the arrival of assistance from the air was a creditable performance". Several sightings and radar contacts "were obtained as a result of HF/DF" and "the discrimination between U-boat transmissions close to and far from the convoy seems to have been accurate and a credit to the operators concerned". No comment was made on the apparent reluctance to use Hedgehog. The effective use of radar and HF/DF to shield the convoy after the second night and the certain destruction of two U-boats in this phase turned the battle for SC 104 from a disaster into a draw or victory.(44)
In effect, the poor radar conditions had absolved B6 from responsibility for the loss of eight merchant ships in two nights in the view of British analysts. However, Heathcote had allowed the screen to be reduced to three escorts while the other escorts hunted contacts or searched for survivors astern. The reduced screen, perhaps as much as the poor radar conditions, contributed to the losses of the second night. Three U-boats penetrated the screen and torpedoed five merchant ships while the escort was under strength. Considering that asdic conditions were also poor, Heathcote should not have permitted so many of his escorts to engage in lengthy searches astern. It is surprising that the Admiralty experts made no unfavourable comment on this costly deployment of forces.(45)
In spite of his shaky performance during the first two nights of attacks, Heathcote displayed outstanding flexibility in adapting from this experience and regrouping B6 to hold the pack at bay the following night. By stationing the screen closer to the convoy than set out in the Western Approaches Convoy Instructions he closed the gaps through which the U-boats slipped to get at the merchant ships. Combined with the greatly improved radar conditions and the very dark night this tactic proved dangerous, even lethal, to the wolf pack. Dönitz later recalled that the pack "had the impression that after October 14 the ring of escorts around the convoy had been materially strengthened and that in consequence it had not been possible...to get through the protective screen".(46) In conclusion Heathcote recommended "that escorts in NE-6 should keep much closer to the convoy in order that attacking U-boats will be unable to get between the escort and the convoy before firing torpedoes". He considered that "The experience gained in this eventful convoy should prove of great value in the future". This remark proved prophetic as in December 1942 Heathcote and B6 provided convoy HX 217 with a superb defence. Unfortunately, his recommendations failed to attract the notice of the anti-submarine analysts at this time and the benefit of this experience was confined to B6.(47)
Although B6 regrouped and provided an effective defence for SC 104, it should also be remembered that Group Wotan intercepted the convoy at the extreme tip of its patrol line and was unable to concentrate against it quickly. As a result, there were never more than five or six U-boats in contact at one time. The escort was indeed fortunate that SC 104 had not blundered into the midst of a wolf pack the size of Group Panther. When the bulk of the U-boats finally got within range, poor visibility and positional fixes prevented most of them from locating the convoy. The few that stumbled on to SC 104 during 16 October were detected through asdic and 271 radar, and quickly driven off or destroyed. However, B6 managed to thwart the pack without the assistance of air cover--a notable achievement. Nonetheless, the arrival of air escort further frustrated Wotan and compensated for the premature departure of the two damaged destroyers.
The Royal Navy thought it had the measure of the U-boats in the summer and autumn of 1942. The sinking of eight merchant ships from SC 104 in two nights showed that even a well-trained and fully-equipped surface escort was not sufficient to fend off a wolf pack in the air cover gap unless conditions were ideal. The weather could be expected to worsen in the coming winter and the ineffectiveness of B6's anti-submarine equipment should have been cause for concern. The heavy losses suffered by British escort groups to much larger wolf packs in February and March 1943 might not have come as quite such a surprise if the lesson of SC 104 had been learned.
1. Great Britain, Admiralty, Anti-Submarine Warfare Division, "Analysis of U-boat Operations in the Vicinity of Convoy SC 104, 11-16 October 1942", 15 December 1942, Public Record Office (hereafter PRO), ADM 199/2011. For example, Stephen Roskill, The War at Sea, II (London: HMSO, 1956), 212-213; Marc Milner, North Atlantic Run: The Royal Canadian Navy and the Battle for the Convoys (Toronto: University of Toronto Press, 1985), 171-74; and Donald Macintyre, The Battle of the Atlantic (London: Pan Books, 1969), 146-50.
2. Befehlshaber der U-boote (BdU) War Diary, 3-6 October 1942, Directorate of History, National Defence Headquarters, Ottawa, Canada (hereafter DHist), 79/446, Vol.6; Jürgen Rohwer and Gerhard Hümmelchen, Chronology of the War the at Sea, 1939-1945 (Annapolis, MD: Naval Institute Press, 1992), 166. SS Robert H. Colley was not torpedoed by as sometimes claimed.
3. BdU War Diary, 9 October 1942; and U-753, War Diary, 9 October 1942, DHist, 83/665. Excerpts from U-boat war diaries translated by Commodore Jan Drent.
4. U-620, War Diary, 6-7 October 1942.
5. BdU War Diary, 7-11 October 1942.
6. Great Britain, Admiralty, Operational Intelligence Centre, U-boat Situation, 12 October 1942, PRO, ADM 223/15.
7. BdU War Diary, 11-14 October 1942; U-620 and U-254, War Diaries, 11-13 October 1942; Jürgen Rohwer and Gerhard Hümmelchen, Chronology of the War at Sea, 167.
8. BdU War Diary, 5-8, 10-12 October 1942. HX 210 was in position 51003' North, 46031' West on 8 October. Group Wotan included ten U-boats on 11 October: U-216, U-221, U-258, U-356, U-410, U-599, U-607, U-615, U-618, and U-661. The patrol line was to stretch between German naval quadrants AJ 82 and BC 43.
9. The stated size of SC 104 varies from 47 to 49 merchant ships in different sources.
10. Marc Milner, North Atlantic Run, 148. U-Boat Command conducted few wolf pack operations on the transatlantic route between December 1941 and July 1942. Most of the convoys attacked since July 1942 had been escorted by Canadian or American groups.
11. Analysis of U-boat Operations, SC 104.
12. BdU War Diary, 12 October 1942; and U-258, War Diary, 11 October 1942. The daily situation report for 11 October 1942 for the northwest Atlantic issued by the Commanding Officer Atlantic Coast, Halifax, shows that the escort sighted by U-258 must have been part of SC 104.
13. Jürgen Rohwer, Axis Submarine Successes, 1939-1945 (Annapolis, MD: Naval Institute Press, 1983), 127; and U-615, War Diary, 11 October 1942. Allied records state incorrectly that SS El Lago was in convoy ONS 136. In fact, the vessel was torpedoed in quadrant AJ 88, 600 miles ahead of the convoy.
14. BdU War Diary, 12 October 1942; and U-258, War Diary, 11-12 October 1942.
15. BdU War Diary, 12 October 1942; and U-356, War Diary, 12 October 1942. Most historians have believed that the westbound convoy was ON 135. In fact, SC 104 was in position 51035' North, 47010' West at 0700Z/12 while ON 135 was in position 52045' North, 39045' West at 1400Z/12, about 220 miles to the east. ONS 136 was in position 56018' North, 29020' West at 1200Z/12.
16. W.A.B. Douglas, The Creation of a National Air Force: The Official History of the Royal Canadian Air Force, Volume II (Toronto: University of Toronto Press, 1986), 526-7.
17. HMS Fame, Report of Proceedings, SC 104, 19 October 1942, PRO, ADM 199/714; and Analysis of U-boat Operations, SC 104.
18. U-221 and U-356, War Diaries, 12-13 October 1942; and BdU War Diary, 12 October 1942.
19. HMS Fame, Report of Proceedings, SC 104; and Analysis of U-boat Operations, SC 104.
20. U-221, War Diary, 13 October 1942; and BdU War Diary, 12 October 1942.
21. HMS Fame, Report of Proceedings, SC 104; Analysis of U-boat Operations, SC 104; and Jürgen Rohwer, Axis Submarine Successes, 128.
22. Canada, Royal Canadian Air Force, No 1 Group, Intelligence Report for Week ending 16 October 1942, DHist, 181.003 (D2178).
23. BdU War Diary, 13 October 1942; and U-221, War Diary, 13 October 1942.
24. HMS Fame, Report of Proceedings, SC 104; Analysis of U-boat Operations, SC 104; and U-356, War Diary, 13 October 1942.
25. U-221, War Diary, 13-14 October 1942; and Jürgen Rohwer, Axis Submarine Successes, 128. Allied records show that Nikolina Matkovic was torpedoed at 2337Z/13. The position of her sinking was the same as that of the other ships so this time may be wrong. The sinking of Nikolina Matkovic is sometimes credited to U-661 but this submarine made several different reports to U-Boat Command on 14 October and none of them claimed an attack. U-661 was destroyed on the fifteenth so her war diary has not survived. No other U-boats made attacks at this time.
26. HMS Fame, Report of Proceedings, SC 104; Analysis of U-boat Operations, SC 104.
27. U-607, War Diary, 14 October 1942; Analysis of U-boat Operations, SC 104; and Jürgen Rohwer, Axis Submarine Successes, 128. The times provided by Allied reports for the sinking of SS Nellie are also off.
28. HMS Fame, Report of Proceedings, SC 104; U-618, War Diary, 14 October 1942; Jürgen Rohwer, Axis Submarine Successes, 128; and BdU War Diary, 13-14 October 1942.
29. HMS Fame, Report of Proceedings, SC 104; and BdU War Diary, 14 October 1942.
30. HMS Fame, Report of Proceedings, SC 104.
31. HMS Fame, Report of Proceedings, SC 104; U-607, U-661, and U-254, War Diaries, 15 October 1942; Analysis of U-boat Operations, SC 104; and BdU War Diary, 14-15 October 1942.
32. HMS Fame, Report of Proceedings, SC 104.
33. Analysis of U-boat Operations, SC 104; BdU War Diary, 14-15 October 1942; and U-254, War Diary, 15 October 1942.
34. HMS Fame, Report of Proceedings, SC 104; Analysis of U-boat Operations, SC 104; BdU War Diary, 14-15 October 1942; U-254, U-607, and U-599, War Diaries, 15 October 1942.
35. U-410, U-618, and U-356, War Diaries, 15 October 1942; and Jürgen Rohwer, Axis Submarine Successes, 128. U-410 torpedoed the merchant ship in quadrant AK 5733. SC 104 was in position 53045' North, 34036' West (quadrant AK 5789) at 0700Z/15. ONS 136 was in position 54045' North, 36056' West (quadrant AK 46) at 1200Z/15.
36. HMS Fame, Report of Proceedings, SC 104; U-258, War Diary, 15 October 1942; and BdU War Diary, 14-15 October 1942.
37. Analysis of U-boat Operations, SC 104; BdU War Diary, 15 October 1942; and U-356, War Diary, 15 October 1942.
38. Analysis of U-boat Operations, SC 104; and Great Britain, Admiralty, Monthly Anti-Submarine Report (December 1942), "The History of U-353", 32.
39. Analysis of U-boat Operations, SC 104; and U-258, War Diary, 16 October 1942.
40. HMS Fame, Report of Proceedings, SC 104; Great Britain, Admiralty, Monthly Anti-Submarine Report (December 1942), "The History of U-353", 32-33.
41. Analysis of U-boat Operations, SC 104; BdU War Diary, 16 October 1942; and U-258, War Diary, 16 October 1942. Panther made contact with ON 137 in quadrant AL 47.
42. BdU War Diary, 16 October 1942.
43. BdU War Diary, 16 October 1942. At least four of the U-boats had the FuMB search receiver: U-258, U-607, U-662, and U-353. It was not able to detect type 271 radar but could detect the older type 286, Canadian and American naval radars, and the airborne ASV II, all of which operated on longer wavelengths. U-258 did detect radar from a surface escort with ON 137 on 16 October. The Germans had more success with FuMB in late October while operating against HX 212.
44. Analysis of U-boat Operations, SC 104.
45. Marc Milner, North Atlantic Run, 173-4. Milner is correct in arguing that the British would have been less charitable on this point with a Canadian or American Senior Officer. The evidence for this is the strident reaction to similar errors by the escorts of ON 115 and ON 127.
46. Karl Doenitz, Memoirs: Ten Years and Twenty Days (London: Weidenfeld and Nicolson, 1959), 273.
47. HMS Fame, Report of Proceedings, SC 104. This convoy was the source of a dispute
between the two Royal Navy authorities which shared responsibility for ASW. Captain C.P.
Clarke, RN, Director of Anti-Submarine Warfare, argued that his division's analyses of U-boat
operations were "bound to be more accurate" than those of Western Approaches Command
because they were based on all available information; but that "conclusions based on the local
report inevitably carry the greater weight with the staff" at Liverpool. Clarke felt that it was
imperative that criticism and conclusions should only "be drawn from and promulgated with the
final report" of the ASW Division. See Minutes attached to Fame's Report of Proceedings for
SC 104 in PRO, ADM 199/714.