Convoy HG-76- the Escorts Strike Back

by Martin Bourne

  U-434 was so badly shook up by these attacks that one of her stern torpedoes exploded of its own accord. Water poured in from the conning tower and the forward torpedo room; the lights and steering gear both failed. Korvetten-Kapitan Hedyn struggled to bring her to the surface to get his crew off. The instant U-434 appeared she was fiercely engaged. So eager were the escorts that Blankney attempted to ram, even though the U-boat was already clearly sinking. Hedyn swung U-434 away and Blankney did as much damage to herself as she did to the submarine. When it became clear that the Germans were abandoning ship the British attempted to board, but the U-boat sank before they could reach it.

  Nor was this all, for during the afternoon two more FW200’s were successfully intercepted by Martlets from Audacity. The reconnaissance planes made a break for it, and only escaped destruction because the fighter’s guns jammed.

  These were heartening successes for the defenders, but on the negative side at 1100 Blankney and Exmoor, the last fast escorts available, had to be detached back to Gibraltar to refuel. The last remaining destroyer, Stanley, was running extremely short of potable water, and would also have to return to Gibraltar by the 20th at the latest.

  U-boats were not the only potential threat. Late in the afternoon of December 18th Stanley spotted an unknown vessel and moved to investigate, fearing it could be a German surface raider. In the event, the contact turned out to be a neutral merchant ship, the Portuguese Nello, but the incident highlights the uncertainty under which the escorts carried out their tasks.

  The U-boats attack.

  As dusk fell the U-boats began to close in on the convoy. In the last glow of the setting sun Penstemon spotted one of them (U-574) and calling for help, moved to attack. Both Stanley and Convolvulous responded, and gunfire quickly forced the U-boat down. The three escorts spent nearly two hours prosecuting the contact with asdic, dropping odd depth charges at intervals. Nonetheless, U-574 managed to give her assailants the slip. During the search U-67 attempted to torpedo Convolvulous, and the corvette was forced to make a hasty turn to comb the tracks of several torpedoes. Finally the escorts gave up and set course to rejoin the convoy.

  This was the opportunity Korvetten-Kapitan Gentelbach of U-574 had been looking for. He surfaced and followed the escorts, hoping that he would be lead directly to the merchant ships. The British were alive to the possibility of this. The corvettes went ahead, while Stanley used a broad zigzag in the rear to try and throw off such a shadowing attempt. Gentelbach was up to the challenge however, and was able to close in on the convoy.

  Around about 0345 Stanley spotted U-574 again. Ten minutes later torpedoes approached her from the port quarter. She turned sharp to starboard at full speed and signalled the flagship that she was under attack. Walker, unsure of Stanley's exact position, ordered her to fire starshell. Before the order could be obeyed the two ships came into view of each other. They were just exchanging challenges when Stanley spotted more torpedoes approaching on her port beam that were too close to avoid. One struck just forward of amidships. There was a titanic explosion, in which flames leaped several hundred feet into the moon-less sky. The luckless destroyer listed heavily, then broke in two and sank. Every merchant ship in the convoy promptly fired off "snowflake" rockets but, as was to happen all too often, the sudden illumination aided the U-boats as much as it did the defenders. The British were lucky, with torpedoes just missing Stork, Audacity and the merchant ship Largo.

  Walker had ordered "buttercup astern", and a large number of escorts turned to the rear to hunt U-574. Stork herself made the contact at a mere 700 yards range and Walker ordered a snap attack. Stork fired two depth charge patterns that were so shallow that she damaged her own dynamo. A third attack was begun, but the submarine had been heavily damaged and surfaced only 200 yards from the sloop.

  Stork manoeuvred to ram, but U-boats are small and agile and U-574 was able to turn inside the escort. The range was too short to depress guns, and so the two vessels madly turned about each other, the crews exchanging curses and shaking fists. They completed three entire circles in the next eleven minutes. Eventually Stork managed to strike U-574 just before the conning tower and rolled her over. The U-boat scraped down Storks side to her aft, where she was finished off by ten depth charges dropped at minimum setting.

  Stork and Samphire picked up eighteen survivors from U-574, and another twenty-eight from Stanley. Meanwhile, helped by the illumination, U-108 had closed in on the convoy’s port bow. At about 0515 she put a torpedo into the lead ship of the port column, the Ruckinge. The merchant ship immediately lost all power and came to a dead stop. In spite of the danger another merchant, Finland, bravely dropped back and picked up most of the crew of the Ruckinge, but Stork went on to pick up another fourteen survivors. Walker realised that the hulk of the freighter could not be saved and ordered Samphire to scuttle her. As the corvette moved to obey, another FW-200 Condor appeared at long range and observed the operation. It seemed to bode ill for the future.

  The Germans send Reinforcements.

  Meanwhile, at U-boat headquarters in L’Orient it was becoming increasingly clear that the attack on “HG76” was not going well. Few successes had been reported and there was an ominous silence from at least three U-boats. His advisors believed the operation should be broken off, but Donitz decided to reinforce the wolf pack and press home the attack. As yet he was unaware of both the strength of the escort and the unfavourable weather conditions.

  Three U-boats from the 7th Flotilla based at L’Orient were duly despatched. All were long-serving boats with experienced crews. U-567 was commanded by Korvetten-Kapitan Endross, the U-boat fleet’s reigning top scoring “ace”. Donitz thought his reputation so high that he specifically announced Endross’s assignment to the U-boats already on station, believing that it would act as a fillip to their morale.

  The rest of December 19th and the whole of the 20th passed fairly quietly. The Germans were content to keep their remaining submarines just over the horizon and await their reinforcements, while keeping the convoy under observation with aircraft. Two Focke-Wulf Condors appeared at 1100 on the 19th but were successfully intercepted by two fighters from Audacity. A deadly aerial game of hide and seek ensued, with the bigger German planes trying to dodge between patches of cloud. One Condor was destroyed and the other heavily damaged and driven off.

  In the early afternoon another Condor tried a low-level approach, presumably to try and avoid radar detection. It also fell to the guns of the Martlets. Then one of the patrolling fighters spotted a submarine (U-107) on the surface about seven miles off the convoy's port beam. Deptford, Marigold and Convolvulus were instantly detached to intercept. The Germans were fortunate that this hunting group failed to make contact, as U-107 was directing the reinforcements from L'Orient. The returning escorts were mistaken for U-boats and provoked a flurry of snowflake and starshell, but luckily no gunfire.

  Martlets also chased off another Focke-Wulf Condor on the 20th. Following reports of two U-boats directly ahead later that day the convoy made a sharp turn to starboard to try and avoid them.

  The U-boats mass to attack again.

  At 0910 on December 21st an air patrol detected two U-boats alongside each other about twenty-five miles astern of the convoy. Unusually they did not dive when the Martlet attacked but instead elected to fight it out on the surface. This seemed to confirm that they were engaged in some sort of repair work.

  Walker deliberated. They were really too far away and the surviving escorts too slow to engage in normal circumstances, but the opportunity seemed too good to miss. A hunting group consisting of Deptford, Penstemon, Vetch and Samphire was despatched. Walker also asked for long range aircraft from Gibraltar and Portsmouth to assist, as the short-ranged Martlet would be unable to keep the enemy under observation until the hunting group could attack. None, however, were available. Inevitably the Germans dispersed and two hours later the relief aircraft was unable to locate them. The hunting group was stil
l over twelve miles from their estimated position, and reluctantly Walker ordered them recalled.

  During the afternoon at least three more U-boat contacts were made: one by Marigold; one by Stork; and one by aircraft. It was becoming clear that the U-boats surrounding the convoy were once more closing in and that a concerted attack would develop during the night. With the escort now much weakened Walker decided on a ruse to blunt the onslaught. When darkness fell the convoy was to make a sharp turn to port, away from the expected approach path of most of the submarines. The Deptford hunting group, which had not yet rejoined, would continue on the original course and at a prearranged signal stage a mock battle, complete with snowflake, starshell, and gunfire. This, it was hoped, would draw some if not all the U-boats to the hunting group and away from the convoy.

  It was a good plan, but poorly executed. The merchant ships had not been completely notified of what was intended, or had not understood it, and the sudden eruption of flares and gunfire came as a surprise to some of them. Therefore, in accordance with their standing orders, several of them fired off their own snowflake rockets, clearly illuminating themselves. In the sudden light Finland, leading the port column, spotted a prowling U-boat off her port beam and attempted to ram. The submarine dived and easily evaded the clumsy merchant ship, but at least had been unable to make an attack. Other U-boats were better able to benefit. A few seconds later U-567 torpedoed the rear ship of the centre column, the Norwegian Annevore. She was heavily laden with iron ore and sank inside a single minute. There were only four survivors.

  There was an even higher price to be paid for the failed ruse. The previous night Audacity had detached herself from the vulnerable convoy. Escorted by Rhododendron she had zigzagged about thirty miles to starboard. Walker suggested that this night she did the same thing but to port, away from the anticipated approach path of the U-boat reinforcements. However, Captain Mackendrick decided to sail to starboard as before. Perhaps he believed that the planned port turn of the convoy that night could cause him problems. Besides, all previous attacks had come from port. Unfortunately the need to fight the mock battle meant that no escorts could be spared to accompany the carrier. She was thus ten miles from any other British ship when U-751, cautiously approaching the illuminated convoy, stumbled across her.

  Korvetten-Kapitan Bigalk of U-751 at first thought he had found a tanker. It was only as he closed to attack that he realised he had the opportunity to destroy an even more valuable target, the Royal Navy's only operational escort carrier. One torpedo of a spread of four struck home. Audacity's engine room flooded and she came to a stop. Conscious of the value of his victim, Bigalk risked closing in to point-blank range, even though he was spotted and engaged by some of Audacity's light guns. Two more torpedoes slammed home at 1000 and ten minutes later the precious carrier sank bow first.

  Well satisfied, and keen to avoid the escorts that he knew must now be hurrying towards Audacity's last position, Bigalk withdrew U-751. Other U-boats pressed home their attacks on the convoy itself. A confused melee ensued. U-67 attempted to torpedo the CAM ship Darwin but missed, and was then forced down and depth-charged for two hours by Samphire. Marigold got a radar contact on a U-boat and chased it for some distance before forcing it down. Deptford detected another U-boat trying to break through the port screen, and when the submarine crash-dived dropped no less than five depth-charge patterns over the next hour. Vetch spent half-an-hour chasing another strong contact on the port beam. None of the escorts claimed any successes, but sometime, somewhere, one of them (probably Deptford) must have destroyed U-567, which was lost without trace. In addition, U-67 was so badly damaged that she was forced to withdraw from the battle completely.

  It was a particularly dark night and as it wore on fog and mist reduced visibility even further. At 0515 Deptford, after her apparently fruitless attacks, inadvertently rammed Stork. She slammed one third of the way into the flagship’s quarter-deck, tragically puncturing a temporary prison for captured U-boat crews, two of whom were horribly crushed to death. The asdic of both ships was wrecked, but fortunately the engines and steering gear of Stork were just missed. The speed of both ships was reduced to ten knots due to the damage suffered. Stork began to settle so much at the stern that depth charges had to be moved forward to lighten her. All in all, it had been a rough night.

  Dawn on December 22nd found the convoy largely intact but the escorts in very poor shape. Audacity and Stanley were both gone, Stork and Deptford both badly damaged and incapable of anti-submarine operations. All crews were exhausted by six days of continuous engagement and most of the radar sets had broken down. Nothing displayed their impotence more than the arrival of another Condor at 1115. Without Audacity's aircraft, the reconnaissance plane was able to circle out of range of the escort's guns and signal their every move. Unbeknown to the escorts U-71 and U-125, diverted from the US east coast, had also made contact.

  The good news was that “HG76” was now within the range of RAF Coastal Command and was escorted by Liberator aircraft throughout the afternoon and evening. One of them forced down a U-boat seventeen miles off the port bow of the convoy at 1245. Another discovered two more just off the horizon from the convoy at 1600, forcing them to crash-dive as well.

  Although the U-boats had been effectively suppressed throughout the day, it was quite clear they were still in contact and that another attack would develop during the night. Although his ruse had not worked the pervious night, Walker considered that it had hardly been given a fair chance and made arrangement for a repeat performance. Deptford and Jonquil were chosen to fight the mock battle, while the convoy was given specific instructions to make a sharp turn to port and not to fire snowflake.

  All went ahead as planned, and that night no U-boat was able to make a successful attack. U-751, U-125 and U-71 all attempted and failed to penetrate the screen. U-751 was spotted on asdic by Vetch and was lucky to escape destruction. The explosions of the depth charges caused quite a panic in the Ogmore Castle, and several of the crew thought she had been torpedoed and despite the fact that she was still moving somehow took to a lifeboat. It took over an hour and a half to recover them.

  December 23rd.

  “HG76” was now nearing the British Isles and more and more support was becoming available. A reinforcement group from Western Approaches command began to close in the afternoon. One of them, Witch, spotted some smoke at 1620 which turned out to be a submarine on the surface ahead of the convoy. Witch called for support and attacked, but the good visibility that had betrayed the U-boat enabled her to spot the destroyer too. She dived while still some eight miles away. The escorts searched with asdic for over an hour, but the submarine got clean away.

  This clash proved to be the last trial for “HG76”. The failure of the last night’s attacks was the final straw for Donitz. His crews were also very tired and dispirited by their lack of success and heavy losses. By the time of this incident U-boat command had already decided to officially abandon the operation against “HG76”. U-67 was ordered home and the others directed to other areas. The rest of the voyage passed uneventfully and “HG76” arrived in the United Kingdom on December 27th.

  Analysis of the battle.

  The passage of convoy “HG76” was a watershed in the battle of the Atlantic. For the first time a large scale wolf pack attack on a convoy was fended off with little loss to the merchants and heavy losses to the attackers. Five U-boats was far too high a price to pay for the destruction of only two merchants, even given the hefty damage also meted out to the escorts. Commander Walker, long overlooked, was lauded when he reached London. He was invited to numerous anti-submarine committees and conferences, and his ideas and theories listened to and thoroughly discussed.

  There were many elements of the British success. Large numbers of escorts and tight formation control of the merchants were certainly important factors. Commander Spero has used the quieter opening few days of the voyage to practice collective turns to good e
ffect. The double ring of escorts proved difficult for the U-boats to penetrate, particularly as it was unexpected.

  Radar and asdic performed extremely well, but the sets in use were still too rare—and worse, unreliable. Rough weather and rough handling soon rendered them useless. It was clear that both more and better sets would have to be made available.

  Even more important than radar and asdic was air cover, which not only forced the U-boats down but also fended off the reconnaissance aircraft they relied upon to guide them to their prey. Audacity had performed sterling service with only four small fighters. It was quite apparent that the provision of larger escort carriers with bigger air groups would offer enormous benefits. Requests to convert merchant ships in the past had been resisted as unwarranted distractions. Following “HG76” four merchant ships under construction were earmarked for conversion to escort carriers, and more purpose built escort carriers were ordered from American yards as part of the lend-lease agreement.

  Undoubtedly the most important factor of all however was Walker’s new aggressive tactics. Instead of waiting for U-boat attacks to develop, Walker vigorously took the fight to them. Even if these counterattacks were unsuccessful, they forced the submarines to dive. This would usually result in them losing contact with a convoy, owing to their low underwater speed. Walker continued to expand his theories with several follow-ups to “Buttercup”, right up until his untimely death of natural causes in 1944.