Almost as soon as the support and escort groups came together ‘things began to happen thick and fast’. The boat sighted by Primrose had been the spotter and others were answering her call. More HF/DF detections indicated a build-up and it became clear that a wolfpack was gathering, principally to the north. Acting on HF/DF information, Chavasse asked Biter to carry out searches with the Swordfish backed up by destroyers. A number of U-boats stayed on the surface when spotted and opened fire, wounding a Swordfish pilot in one engagement, but, when a destroyer appeared, the boats submerged hastily.
I don’t think that any of the destroyers got in asdic contact with a submerged U-boat, but they probably kept them well down by plastering the area with depth charges. At least one can say that these tactics prevented the U-boats from concentrating, or even getting near the convoy, which at this stage was never closely threatened.
Information from the Admiralty indicated that at least six U-boats were gathering to attack and Chavasse was told that, as soon as the convoy was within range, shore-based aircraft would be despatched to operate under his orders. Although night attacks were expected, none occurred; night-flying was not possible from Biter.
On the 12th the convoy was within range of shore-based aircraft and a Liberator, which had attacked and damaged a U-boat, reported the engagement to Chavasse, adding that the boat lay on the surface, some distance off the port beam. However, the Liberator had not previously contacted the convoy and, probably due to a navigational error, and reports of other U-boats in the area, provided an inaccurate position for the stricken boat. Although two destroyers of 5th Support Group were sent to finish off the U-boat, their quest was unsuccessful. With the third of Abel Smith’s destroyers carrying out a search astern, only C2’s ships were available to protect the merchantmen. At this juncture one of Biter’s aircraft, returning low on fuel, spotted a surfaced U-boat about six miles ahead of the convoy.
This was dangerous. I told the Commodore to turn … ninety degrees to starboard, and as Broadway was the nearest and fastest of the Close Escort, I abandoned my position, and increased to 29 knots to attack, calling Lagan to follow me at her full speed of 20 knots. I handed over command of the escort to young Lieutenant [Philip] Kitto in the Primrose, the senior corvette captain.
Meanwhile the [Swordfish] had attacked with depth charges and possibly damaged the U-boat, which dived. There followed a piece of copy-book co-operation between us in Broadway and the aircraft. The latter dropped a smoke marker on the spot where the U-boat had dived, and flew back to the convoy. I told the pilot by radio/telephone which [was] my ship, and he circled and flew over me, waving cheerfully, and led me in a beeline to the smoke marker, which I duly sighted right ahead. Reducing speed I almost immediately got firm asdic contact, and the hunt was on. The convoy steamed steadily away from us, with little Primrose in charge. For once the weather was good.
The fix allowed Chavasse to make a Hedgehog attack. However, no rounds struck the boat, which would have been unaware of the attack, allowing Lagan to drop a pattern of depth charges. The boat survived and a prolonged hunt began. U-89 had dived to 400 feet, Korvettenkapitän Dietrich Lohmann, an experienced submariner, using all his skills to avoid being caught in the bombardment. The boat ‘twisted and turned like a snake in ecstasy’ as both ships strove to keep contact.
Finally the lot happened to fall on Broadway. A salvo of bombs from our hedgehog soared beautifully into the air, … splashed in a neat circle 250 yards ahead of us, and then, after the usual anxious pause, we were at last rewarded with a lovely bang. We had hit her fair and square.
Chavasse sent Lagan back to the convoy but remained at the scene because he ‘desperately wanted to make sure’ the U-boat had sunk. There had been many Hedgehog attacks on boats, some apparently successful ‘with a nice bang as one or more of the bombs had struck’ the boat, but never any proof that a U-boat had been sunk. As a result confidence in Hedgehog was diminishing. Broadway waited over the scene of the attack for more than an hour until, with the convoy disappearing over the horizon, patience paid off and wreckage began surfacing.
We didn’t get much, but quite enough to satisfy ourselves: part of an electrical control panel with switches tallied in German, a rather dirty cotton singlet embroidered with an eagle and swastika, and a much-darned sock with the owner’s name-tape in German … but without his foot inside. The crew of U-89 were now lying in 1,700 fathoms. May they rest in peace.
This was the first Hedgehog attack to produce proof positive that a U-boat had been destroyed and the news caused morale to rise in Hedgehog-equipped ships. But the ‘safe and timely arrival’ of HX237 had not yet been achieved. There were still troubled waters to traverse, although the end of the battle was close.
Next morning a Sunderland from No.423 Squadron RCAF at RAF Castle Archdale spotted and attacked a U-boat ‘uncomfortably close’ to the convoy on its starboard side. The U-boat fought back and the Sunderland shadowed it for about twenty minutes, firing some 2,000 rounds and taking one hit. Drumheller forced the boat to dive with gunfire, after which the Sunderland dropped two depth charges. A Swordfish from Biter then dropped smoke markers and Drumheller, having made asdic contact, attacked with depth charges. With the boat immobilized, Lagan delivered the coup de grace. It was believed that the victim was U-456 but she had been sunk the day before by Opportune, having been damaged by a Liberator of No.86 Squadron. The boat despatched by Drumheller and Lagan was actually U-753. Uboat.net suggests that U-753 perished due to the captain’s decision to dive to avoid capture.
This was the final act in HX237’s battle:
Just as we felt we were getting into our stride, Biter and her destroyers were withdrawn to assist another convoy in peril. Simultaneously, any survivors of ‘our’ wolfpack evidently decided to give it up as a bad job, and an unearthly silence descended over our stretch of the Atlantic, which for the past five days had been almost deafening with German and British radio.
Lieutenant Commander Chavasse ordered C2 to Splice the Main Brace. Three U-boats had been destroyed and no ship in the convoy had been lost, although three stragglers were. Gretton writes that one of Biter’s Swordfish was shot down, but this was probably an aircraft that failed to return. (Losses such as this led to an order that Swordfish should fly in pairs.) The convoy was delivered safely to Britain and C2 made for Londonderry. Subsequently Chavasse was awarded the DSO for:
good services during an A/S hunt on 12th May, 1943, which, after several setbacks, resulted in the destruction of an enemy submarine. Lieutenant Commander Chavasse has been favourably commented upon on several occasions in the past for his keenness and enthusiasm and it is evident that the result of his zeal has been to keep his ship’s company in a high state of efficiency.
This recommendation, from Commodore George ‘Shrimp’ Simpson, Commodore (D) Western Approaches, was endorsed by Horton who added that Chavasse’s command and control of C2, his co-ordination of HF/DF intelligence and excellent use of aircraft ‘all contributed to the safe and timely arrival of the convoy with relatively light losses and considerable loss and damage to the enemy’.
As C2 continued to Londonderry, 5th Support Group, which Western Approaches Command had withdrawn from HX237 once it was safely under shore-based air cover, was about to add its considerable muscle to the escort for SC129, then crossing the Atlantic under threat from a wolfpack. A small convoy of twenty-four ships, SC129 included a rescue ship and an escort oiler and was protected by B2, commanded by Commander Donald Macintyre. The group included Macintyre’s ship, the destroyer HMS Hesperus, the modified W-class destroyer Whitehall, the frigate Spey, the corvettes Campanula, Clematis, Gentian, Heather and Sweetbriar and the ASW trawlers Lady Madeleine and Sapper. It was a strong and well-balanced escort, particularly as Biter’s No.811 NAS could provide almost continuous daytime air cover.
Macintyre was under no illusions about the journey. He knew that the Battle of the Atlantic was reaching its climax since ‘an unprecedented number of U-boats’ had been operating in the ocean for two months, forcing convoys to fight their way through. ‘We were therefore on tip-toe in anticipation of the encounter we knew must come. There was no longer any possibility of evading the U-boats – they were too thick for that.’
B2’s crews were on full alert with close attention being paid to HF/DF sets, including that in the rescue ship, whose operators were sometimes more skilful than those of the warships. On the afternoon of 11 May, six days after B2 had sailed, the HF/DF operators heard their first U-boat signals, although Macintyre’s operator considered that the boats were not close. Since ‘I had learnt to trust implicitly in ‘B-Bar’s’ estimates and up to date he had never been wrong’, Macintyre accepted this judgement. Whitehall and Clematis were sent to sweep the horizon but found nothing. Then, at 6.00pm, in broad daylight, two ships were torpedoed. Both sank rapidly, all but two of their crewmen being picked up by the rescue ship, or an escort. U-402, which had torpedoed them, eluded the escorts.
For Macintyre it was a particularly galling experience, the first time in his nine months commanding B2 that a ship had been lost in a convoy under his protection – and that by a U-boat penetrating the convoy in daylight. Next day, however, Hesperus pinpointed and sank U-186. On the 14th a Halifax of No.58 Squadron accounted for U-266, a sinking attributed initially to a homing torpedo from a Liberator of No.86 Squadron which had actually attacked U-403 without causing damage. Hesperus also damaged U-223. In his book U-boat Killer, Macintyre recounts the battle between Hesperus and U-223, giving the German side of the story as far as possible, including the fact that, despite serious damage, her captain managed to get back to St Nazaire, a twelve-day voyage.
From HX237 and SC129 three dozen U-boats had sunk only five ships, three of which were not in convoy when attacked, for the loss of five of their number. Escort commanders had noticed that ‘there were clear signs that attacks were being pressed home with less determination’ and the same held true for the next convoys to cross the ocean. ON184, with C1 and the American 6th Support Group, including the Bogue, lost no ships. HX239, with B3 and 4th Support Group, plus the escort carrier Archer, had a similar experience. Two of Bogue’s Avengers sank U-569 with depth charges while one of No.819 NAS’s Swordfish from Archer accounted for U-752 using air-launched rockets, a new weapon recently added to the Fleet Air Arm’s inventory. Surfacing to gain speed, the U-boat began shadowing the convoy. One of Archer’s Swordfish, flown by Sub-Lieutenant H. Horrocks RNVR, had spotted the periscope and used cloud cover to approach undetected to within 300 yards. Although U-752 tried to crash dive, it was too late and a rocket pierced the pressure hull. Unable to dive, the boat fought it out on the surface but a Martlet from Archer swept U-752’s bridge with her guns, killing the captain and several crewmen. In a hopeless situation, the engineer officer flooded the tanks and the submarine sank. Apart from Biter’s success, this was the first time aircraft from a British escort carrier were responsible for sinking a U-boat. It was also the first time a rocket was fired operationally by any of the Western Allies. The projectile, with a solid head weighing 25lb, was fired from about 600 yards and at a suitable angle. It could penetrate both the outer and inner plating of a submarine’s pressure hull.
Three of 819’s Swordfish had been fitted with rockets only two months after their use against submarines had been first suggested, an exceptionally speedy introduction to service for a new weapon.
While HX238 had a trouble-free passage, the same could not be said of SC130, escorted by Gretton’s B7 group, which had barely recovered from the westbound battle around ONS5. SC130 left Halifax on 11 May and, as well as B7, had 1st Support Group protecting it; the Canadian corvette HMCS Kitchener was detached from the local escort to join B7, which was a ship short. B7 met the convoy on the 14th when, during the handover of papers, Gretton informed the commodore that he was due to be married soon after his scheduled arrival in Londonderry. The commodore, Captain H. C. C. Forsyth RD, agreed that the convoy would maintain or, if possible, improve upon its rated speed. Although no fewer than four wolfpacks were sent to attack, not a single ship was lost. All attacks were repelled, the attackers losing heavily as they assailed the convoy between the 15th and 20th. A Liberator of No.120 Squadron, flown by Flight Sergeant Shores, attacked U-731, forcing her and five other boats to dive; subsequently, one of these, U-952, was damaged by depth charges from Tay. U-954 was sunk by depth charges from Sennen and Tay while Duncan damaged U-707 with Hedgehog. Peter Dönitz, the 21-year-old younger son of Admiral Dönitz, was among the dead of U-954. Another Liberator from No.120 Squadron, with Vidette, forced a further six boats down, while two more Liberators from the squadron did likewise with groups of four and two boats, three of which were bombed. Jed and Spey drove off the final spotter and a Liberator from 120 sank U-258. In all, five boats were lost, the others being U-209, sunk by Jed and Sennen, and U-273 by a Hudson of No.269 Squadron; U-381, believed to have been sunk by Duncan and Snowflake, had fallen victim to an unknown cause.
SC130 survived intact through the presence of daytime air cover during the critical period, although there was no carrier with the convoy, the assistance of 1st Support Group ‘and the discipline of the convoy which executed numerous emergency turns with the precision of a battle fleet’. Peter Gretton got to the altar in time, where he and his bride were married before the Reverend Willie Devine MC CdG, Catholic chaplain to the Londonderry Escort Force.
Dönitz now finally admitted that his boats were losing in the Atlantic. Recognizing the skill of the escort and support groups, the continuous air cover available, and the fact that most long-range aircraft were ‘equipped with the new radar’, he accepted that large-scale operations in the Atlantic could resume only if it proved possible to increase substantially the U-bootwaffe’s fighting power. Dönitz decided to withdraw his boats from the North Atlantic, issuing an order on the 24th that they should move with ‘the utmost caution’ south-west of the Azores. ‘We had lost the Battle of the Atlantic.’
May was the bloodiest month for the U-boats with forty-one lost. Added to the sixteen lost in April, this underlined the folly of continuing with the campaign as it had been fought until then. New weapons or new tactics, or a combination of both, were essential to continue the fight with any hope of success. And yet it is almost incredible that not until this point was a Naval Headquarters scientific directorate established with its most urgent task being the production of a new search receiver operating on a wider range of frequencies to detect Allied locating signals and so provide more timely warning of attack.
Other weapons were being developed; Dönitz sought the support of Albert Speer, Minister of Armaments and War Production, to accelerate work on the next generation of torpedo. Speer’s co-operation ensured that deliveries of the acoustic torpedo began in August 1943 rather than the projected date of autumn 1944. Meanwhile, schnorkel equipment was being fitted to existing boats and designed into new boats although no schnorkel-equipped boats would be in service until 1944. However, Germany was lagging well behind in the development of weaponry and technology in comparison to the Allies.
The accounts of the convoy battles of spring 1943 indicate some of the advances the Allies had already made. Evelyn Chavasse’s comments about talking to other ships by radio telephone and communicating directly with Coastal Command aircraft marked an important feature of operations at this stage. Similar comments were made by Commander Martin James Evans, senior officer of B3 in Keppel, who reported that air coverage from both sides of the Atlantic was good, as was ‘visual and telephonic communication … and no time was wasted in passing to aircraft the particular patrol that was required’. The American VHF radio telephones allowed speedier and clearer communication between ships which, combined with the ability to speak directly to the pilot of an aircraft, made co-operation between sea and air units much more effective; the R/T system was known as Talk Between Ships (TBS). Some U-boats sunk in recent months had been destroyed by ships and planes acting in concert; this included shore-based Coastal machines and carrier-based FAA and USN aircraft. The small escort carriers, known as ‘Woolworth carriers’ in the Royal Navy, and MAC-ships would prove invaluable, as shown by the comment from Keppel’s captain that ‘HMS Archer more than filled the thirty-six hour gap between the departure of the last aircraft from Newfoundland and the arrival of the first home-based aircraft’.
ASV III made Coastal Command aircraft even more deadly, an effect further intensified by the new weapons available to the aeroplanes fighting the U-boats. We have noted the fitting of rocket rails to Fleet Air Arm Swordfish, which had required replacing their fabric-covered lower wings with metal-skinned undersides. In addition, Swordfish were also adapted to carry ASV III, the machines fitted with this and rockets being Swordfish Mark II, which also had a more powerful engine. The later Swordfish Mark III had ASV XI which could detect a ship or, in good conditions, a surfaced U-boat at a range of twenty-five miles and, in calm sea conditions, a schnorkel at up to five miles.
In the account of the passage of SC129 reference was made to a No.86 Squadron Liberator using a homing torpedo. Although unsuccessful that attack represented another increment in the battle. The ‘homing’, or acoustic, torpedo was an American innovation, known officially as the Mark 24 Mine to conceal its true nature, which entered US Navy service in March 1943 and was also supplied to the UK and Canada. With a warhead of 92lb of HBX (High Blast Explosive), derived from Torpex, the weapon, weighing 680 pounds, had a preset circular search pattern when dropped into the water. Once its hydrophones detected a signal, the homing guidance system took over. With a speed of 12 knots, the torpedo could not overtake a surfaced submarine but could catch a submerged boat. Also known as Fido, Wandering Willie or Wandering Annie, its first kill was achieved in mid-May, two months after its entry to service. On 12 May a Liberator of No.86 Squadron launched a Mark 24 at U-456 which damaged the boat severely and probably contributed to its subsequent sinking by HMS Opportune (see page 204). Two days later a US Navy Catalina of VP-84 sank U-640 with a Mark 24.
Horton continued paying close attention to training with many more escort group officers undertaking courses on Philante. He was also aware of the expanding needs of the Fleet Air Arm in its anti-submarine role. Thus on 1 May 1943 two RAF stations in County Londonderry, close to HMS Ferret, RAF Eglinton and RAF Maydown, its satellite, were handed over on loan to the Admiralty, being commissioned two weeks later as ‘stone frigates’. Eglinton became HMS Gannet, a base for the formation and training of fighter squadrons, while Maydown became HMS Shrike, the home for No.836 NAS, the pool, or parent, squadron for the MAC-ships then entering service.56 Although the Admiralty had intended to make HMS Gadwall (Belfast) the headquarters for MAC-ship flights, it was decided that Maydown would be more suitable. HMS Shrike, or RNAS Maydown, later became home to the Dutch No.860 NAS, operating Swordfish from MAC-ships. Eventually Shrike was the base for about 100 Swordfish; No.744 NAS re-formed there to train MAC-ship Swordfish crews. Swordfish would land on a MAC-ship as it steamed off Ireland’s north coast on its westbound voyage. Nearing the end of the return journey the Swordfish would fly off and return to Shrike. In between, the crews may have been involved in action against U-boats, in which some aircraft may have been lost, or simply spent the voyage flying ahead of and over the convoy, forcing submarines to remain submerged. The Swordfish played an important part in ensuring the safety of convoys. It was these flimsy-looking biplanes rather than the large robust land planes that closed completely the mid-Atlantic air gap.
Another factor in expanding Allied air cover was the Portuguese government’s agreement to allow British aircraft to operate from the Azores. In Operation ALACRITY British forces landed in the Azores in October, to pre-empt an anticipated German invasion, and an air base was established at Lajes, known as RAF Lages; US Navy aircraft also operated from there. North of the Azores three British escort carriers worked with convoys, while US Navy carriers ‘continued their good work south of the Azores’.
Although many writers have chosen to define May 1943 as the ‘end’ of the battle, it still had many months to run and would not conclude until the end of the European war.