No time was wasted. On Monday 2nd February 1942 the first group of naval officers arrived at the top floor of the smoke-blackened Derby House, fresh from the ocean.1 They passed through the heavy oak door to undergo a week-long training course on ‘The Game’, as it came to be known. The Wrens ran the show. Some, like Okell, moved the game pieces around the floor. Others were responsible for manoeuvring U-boats, while the most personable women, like the pristinely presented Bobby Howes, guided the men through the process, often proffering gentle but incisive advice on what moves to perform and when.
For the officers playing as escort commanders behind the canvas peepholes the games were keenly intense. From his position behind the canvas sheet, the lieutenant would survey the ocean floor, then report back to his CO, who sat at a plotting table behind the screen, as though he was working in the charthouse up on his ship’s bridge. As well as listening to the situation report from his lieutenant, the senior officer would receive constant new information from his assigned Wren, designed to mimic the flow of information arriving from the ship’s ASDIC radar operator.
‘Star shell fired here,’ she would tell him. ‘Explosion heard there.’
She might explain that another ship was trying to make contact on the radio, or that a destroyer had opened fire but that the splashes were not observed. From this information, the CO would have to make quick judgement calls on what to do next, based on what he understood the other escort ships to be doing. Naval officers would then write their instructions on a small square of paper known as a chit. They might choose to alter their vessel’s speed or direction, fire star shells or drop a depth charge–any of the actions that were open to them in an actual sea battle. The chit was posted into a little box and duly collected by one of the young women, who passed the instruction to her fellow Wrens, who would proceed to shunt the models around the make-believe Atlantic Ocean accordingly, while kneeling on the floor and carefully marking off each instruction in pencil.
In an adjacent room Bernard Rayner and another clutch of Wrens would collect, decode, decipher and transmit signals to and from the naval officers behind the screens. These messages would be delivered to each officer, presenting an almost overwhelming amount of information on which instantaneous decisions had to be made. To mimic the chaos of battle, Roberts and the Wrens would introduce unexpected diversions to proceedings: a lone freighter, for example, spotted by an aircraft and reported to be blazing just over the horizon.2 In this instance, one of the Wrens would gingerly walk across the floor and place grey cotton wool around the miniature ship to indicate billowing smoke. Another Wren, meanwhile, might suggest to her captain that he should send an escort ship to investigate and search for survivors.
The pressure of the two-minute intervals between turns mimicked the stress of action against U-boats at sea, and each officer would often be caught up in the fiction, no longer viewing the chalk lines and wooden models as game pieces, but as the real ships, wakes and explosions they represented. The game occupied an unusual position between reality and make-believe. No limbs or lives were lost here on the linoleum ocean. But neither was the game fully abstracted, in the way that Monopoly is based on, but distinct from, the property business. For the men who played WATU’s game, who had often returned from sea only a few days earlier, and who were often due to sail again a few days later, the game had an unsettling quality. The choices made on the floor reflected an officer’s current tactical thinking; if his ship was lost in the game, he had to cope with the knowledge that had the same situation arisen at sea, and had he acted the same way, he may well have died.
‘Make your mistakes here and you won’t make them at sea,’ Roberts was fond of saying, a euphemistic way of pointing out the scale of risk against which the game was attempting to insure its players. For all Roberts’ engaging presentation, a man who failed to drive off the U-boat or, worse, who lost his ship in the game, would leave WATU feeling sternly chastened. In this way the psychic link between Derby House and the Atlantic Ocean became fearfully strong.
‘We destroy U-boats out in the oceans,’ wrote one observer who sat in on a round of the game. ‘But the death sentence is delivered, miles away, in the assize court, in that old building erected on the banks of the River Mersey above the old dungeon haunts of the slave-traders.’3
Each course, which lasted from Monday to Saturday*, and which ran weekly without interruption from the first week of February 1942 to the last week of July 1945, involved up to fifty officers at once. It consisted of four game scenarios, which each varied details such as the weather conditions, visibility, time of day and the size, speed and start point of the convoy.
Finally, when the game finished the officers would step from behind the canvas screens and, along with the Wrens, sit in a square of chairs around the room. Then, with a ten-foot wooden pole Roberts would commentate on the preceding battle, blow by blow, like a sports pundit delivering a post-match verdict. He would draw attention to moments of particular brilliance, moments of particular disaster and the turning points of each game. These summations were, for Roberts, the most enjoyable aspect of the work. He relished the opportunity to create a picture of the battle far more vivid and engaging than the reports written by officers returning from earnest action at sea.
‘As we listened to him, he made the most difficult situation appear simple,’ said Vice Admiral Gilbert Stephenson, of Roberts’ flair. ‘He appreciated the difficulty that hundreds of commanding officers had in deciding what to do when faced with any of the surprises that war at sea was constantly presenting, and he taught them how to meet these surprises till they were ready for anything.’
Although ‘much lacking in physical health’, Roberts ‘made up for this shortcoming’, as Stephenson put it, with ‘enthusiasm and obsession’.4 Men entered WATU dubious of what they were about to experience and left a week later as exhilarated converts. Roberts for his part believed that he, and especially the Wrens, had a pivotal role to play, not only in teaching tactics to men before they went to battle at sea, but also in infusing those men with self-assurance and vigour.
‘It is of paramount importance… that the staff are always enthusiastic, in order to transmit enthusiasm and zest, and therefore also confidence to those who are at sea,’ he wrote in an annual report of the unit’s work.5 Favourable word of WATU began to spread, a flicker of good news at a time when, as the First Sea Lord Sir Dudley Pound put it, the war at sea was in grave danger of being lost, and the wider war with it.*
On 18th April 1942, the Admiral of the Fleet and the most senior member of the navy, Sir Dudley Pound, wrote to Sir Percy Noble to enquire how Roberts and the Wrens were doing. A week later Noble, who had been so sceptical of Roberts and his game ideas just a few weeks earlier, sent a shimmering response.
‘This unit has now been in existence for two and a half months,’ he wrote, ‘and is a valuable going concern.’6
In just ten weeks, scores of captains of escort vessels had, Noble informed Pound, taken Roberts’ course. They had included two Royal Indian Navy officers, who had since returned to the Indian Ocean to implement what they had learned on their Bangor-class vessels, two Norwegian officers and one American.
‘I would like it to be made a rule that as many officers as possible… belonging to Western Approaches ships should be appointed to Derby House for a week’s course, before joining their ships,’ Noble continued.
The commander-in-chief of Western Approaches had particular praise for the ten Wrens working alongside Roberts: officers Drake, Howes, Laidlaw and Wales, and six junior ratings including Okell, who, Noble informed Pound, ‘are becoming surprisingly adept at handling ships themselves for investigation, and working by general instructions for the conduct of the affairs they handle’.
Still, the combination of ministration and expertise was not always welcomed by the experienced officers on the receiving end of the Wrens’ advice. Often the men would resent being told what to do, no matter how gently, by women who were barely out of school and who, in most cases, had never been to sea in peacetime, let alone during a war. During one 1942 game, Bob Whinney, who captained the destroyer HMS Wanderer, in which he sank three U-boats, handed his chit to one of the Wrens, Judy Du Vivier, a ‘particularly clued-up girl’ whom he had been assigned.
‘No, sir,’ she said, of Whinney’s chosen move. ‘I do not think that you should do that.’7
‘Good God,’ he later recalled thinking of her ‘firm and polite’ request. ‘What on earth does this girl know about it?’
So confident and tactful was Du Vivier’s tone, however, that Whinney chose to hear her out. He listened to the Wren’s ‘convincing’ explanation in astonishment. From his perspective, a battle-worn captain was being tutored on the finer points of U-boat warfare by an inexperienced girl. For Roberts, the exchange vindicated a long-held belief: with careful design, games had the capacity to make experts of amateurs, to instil in players invaluable, potentially life-saving, battle-winning experience.
Usborne also wrote to the First Sea Lord with news of Raspberry, the night-time countermeasure against a U-boat attack from within the convoy, and Gooseberry, its daytime equivalent.8 In the same letter, Usborne made his feelings about Walker’s Buttercup clear.
‘One of the first problems that C.-in-C. Western Approaches set… was to investigate an alternative to “Buttercup”,’ he wrote, before describing, in brief, Roberts’ two manoeuvres, which were to replace Walker’s flawed tactic.
WATU’s two brand-new countermeasures, Usborne explained, were being included in the latest edition of the Western Approaches Convoy Instructions, a bible for escort officers that explained best practices for all manner of potential scenarios encountered while protecting the convoy ships. He further urged the need to find a way to train escort ships in their deployment as quickly as possible. One suggestion was for Roberts, the Wrens and all of their equipment to be put onto a ship and sent to Londonderry for a month, where they would be better placed to instruct captains who were working up their crews in the North Atlantic. This plan, Usborne wrote, ‘would have the advantage that American Escort Groups will be able to see the Table at work and use it themselves if they wish to’. Usborne hoped that, if this were to happen, it would ‘stimulate a desire for a similar instruction unit in the USA’.
Further vindication for the theory behind Raspberry came when Roberts was ordered to report to Usborne in London. There Usborne played him a recording of two German POWs who had been secretly taped while whispering in their cell while awaiting interrogation. One was a U-boat crew member, the other a tank commander who had been captured in Egypt. The U-boatman was describing an attack on an Allied convoy and used the words, in German, ‘And then no man may move, or anything.’
Roberts played these words over and over again.
‘What did it mean?’ he wrote in his diary. It could not be that the men had to be quiet while fleeing a battle on the ocean’s surface.
‘Oh no!’ Roberts wrote, his glee betrayed by every exclamation point. ‘It was when the U-boat had fired its torpedoes, gone deep, and was coming out of the stern of the convoy, deep and quiet in order to not be heard by the British ASDIC: what a proof for Raspberry!’
Before he returned to Liverpool. Roberts met the broadcaster Richard Dimbleby, who was recording commentary for a Disney film.* Roberts and Dimbleby discussed WATU’s work, and Dimbleby made the masterstroke suggestion that Roberts have the Raspberry manoeuvre illustrated and made into a flick-book, so that officers undergoing training could see at a glance how it worked.
When he returned to Liverpool, Roberts commissioned the design and printing of these flick-books, which showed not only Raspberry, but all of the searches and operations designed by WATU.* These instructive booklets were routinely stolen and taken to sea by Officers undergoing the course.
(These were not the only items purloined from WATU, where a notice addressed to Course Officers had to be posted to the door. ‘We have great difficulty in getting soft pencils here,’ it read, ‘and India-rubbers are scarcer than rubies. Please don’t give them wings.’9)
WATU’s tactics, once tested and proven in the game, were written up and added to the Western Approaches Convoy Instructions.
Soon enough, reports from graduates of the training school, now back at sea, began trickling back to WATU. These verified that Raspberry and the other tactical manoeuvres were working just as Roberts and the Wrens had hoped. Following the battle to defend convoy NS.122, for example, which commenced on 22nd August 1942, six months after the first training courses began, the senior escort officer said: ‘Raspberry went like clockwork and whenever, during the night, the cry of “Tally-ho” was heard on the scram, I only had to check the bearings to know where a U-boat was being hunted.’10
Roberts’ workload, meanwhile, had increased to an almost unbearable degree. As well as teaching, devising new scenarios for the game and testing new tactics on the plot, Roberts met incoming escort commanders for operational debriefs and, many nights, worked in the main Operations Room at Derby House, where the markers on the map no longer represented hypothetical ships, but real vessels, crewed by real men.
Still, the work was exhilarating, especially when the first fruits of WATU’s work began to be seen in summer 1942, when escort ships sank four times as many U-boats as the previous month,11 beginning an upward trend that would continue, broadly, for the rest of the year.
The improvements in tactics were timely as they helped compensate for the fallout from an internal battle being waged between the navy and air force in London. The major source of contention between the Admiralty and the Air Ministry related to the deployment of long-range bombers. In Captain Walker’s battle of HG.76 in December 1941, a lone bomber had played a decisive role in scattering a wolfpack. This led Walker to formally advise that aircraft were ‘absolutely invaluable’ to the protection of convoys. Following Walker’s report, the Admiralty repeatedly requested an allocation of bombers to provide air support (at one point the First Sea Lord Sir Dudley Pound requested 2,000 warplanes12). The Air Ministry repeatedly refused.
In part, this was because Churchill had long asserted his belief that the only ‘sure path’ to victory lay in ‘an absolutely devastating, exterminating attack by very heavy bombers… on the Nazi homeland’.13 Knowing his rejection of the Admiralty’s request would be supported by the prime minister, Chief of the Air Staff Sir Charles Portal wrote: ‘To divert [the RAF’s bombers] to an uneconomical defensive role would be unsound at any time. It would be doubly so now when we are about to launch a bombing offensive… which will enable us to deliver a heavy and concentrated blow against Germany.’14
Pound, who was at the time ill with the brain tumour that would kill him in 1943, was wearied, often falling asleep in meetings and therefore unable to effectively challenge the Air Ministry’s specious assumptions and infuriating defiance. In May 1942 Pound again demanded–this time ‘with all urgency’ and the support of three of his most senior colleagues, admirals Forbes, Cunningham and Tovey–an increase in the number of planes ‘necessary to guard our vital sea communications’. The U-boat situation in the Atlantic was ‘so grave’, Pound wrote, that a stand had to be made, even if it led to ‘the extreme step of resignation’.15 Again his pleas were rejected. Despite Churchill’s personal ties to the navy, and belief that the safe passage of convoys was key to Britain’s survival, the prime minister was enamoured with Air Chief Marshal Sir Arthur Harris, the commander-in-chief of Bomber Command. Harris had a talent for public relations and, in modern parlance, optics. When he sent a fleet of bombers to attack Cologne on 30th May 1942, the figure of 1,000 aircraft was chosen not for any strategic benefit, but in order to capture the public imagination via newspaper headlines.
Harris had the prime minister’s ear in a way that Pound did not, often sidestepping protocol to make private appeals for Bomber Command against the Admiralty. The Air Ministry’s political superiority was made clear in the autumn of 1942 when the Admiralty’s chief of operational research, Professor Patrick Blackett, a distinguished scientist who later won the Nobel Prize for Physics, presented a comparative statistical analysis of the situation. His research showed beyond all reasonable dispute that a force of 200 long-range bombers would make a decisive contribution to the Battle of the Atlantic. Moreover, using aircraft in this way would have a far more meaningful effect on the broader war than in their current deployment, bombing German cities.
Even with meticulous statistical analysis Blackett struggled, as he later put it, ‘to get the figures believed’. By January 1943, just one squadron of twelve bombers supported the escorting of convoys. As Churchill’s chief of military operations later concluded, the prime minister’s ‘obsession for bombing Germany’ resulted in ‘the navy being very short of long-range bombers’, which was ‘the only well-founded ground for criticism of our central war direction’.16 All of this was not lost on those who had to fight at sea. The convoy commander Peter Gretton, who became one of WATU’s most distinguished students, later said that ‘co-operation between the Navy and the Air Force in the field was very bad indeed, mainly due to stupid quarrels between senior officers in Whitehall.’
The bombers may have been absent, but WATU’s work was aided in other ways. There was the invention and introduction of the ship-mounted high-frequency direction finder (HF/DF), a piece of equipment known to sailors by the nickname ‘huff-duff’. Two ships equipped with this vessel-mounted direction-finding gear could pinpoint a U-boat location by detecting and triangulating the source of the high-frequency radio transmissions it was sending, either to other U-boats or to U-boat headquarters.* Then there was the fact that, after September 1942, the Western Approaches Convoy Instructions, the bible issued to all British escort officers filled with WATU-coined tactics and signals, was published for Canadian and American ships too, under the new title Atlantic Convoy Instructions. This book ensured escort ships from different Allied navies now used the same anti-U-boat signals where, prior to this, the British were just as bemused by the American signal ‘Zombie Crack’ as the Americans were by the British signal ‘Pineapple’.17
Finally, there was the introduction of Hedgehog, a bow-mounted anti-submarine weapon that could spray a volley of mortar rounds directly ahead of the ship, toward a suspected U-boat location. The name derived from the weapon’s appearance: the twenty mortar rounds were bunched together at a near-perpendicular angle, giving the appearance of a hedgehog’s spikes. The projectiles were primed to explode not by fuse but on contact, and entered the war just as the U-boat captains had become adept at evading depth charges. By increasing the strength of U-boat hulls so that they could withstand the pressure at 600 feet, a U-boat captain could now listen on the hydrophones for the roar of a warship overhead, and the telltale splash of the depth charges, and immediately increase to full speed, turning sharply while diving. During the time it took for the depth charge to fall, the U-boat would have disappeared. The Hedgehog enabled the explosives to be hurled ahead, while the U-boat was still within ASDIC contact, and before it could turn and dive.18
In the months that followed the development of Raspberry, using information gleaned via debriefs, Roberts and the Wrens developed numerous other tactical manoeuvres to suit the expanding variety of wolfpack attacks. Most of these manoeuvres, which involved the escort ships performing different shapes and varieties of coordinated sweeps to find and hunt lurking U-boats, were given the memorable names of fruit and vegetables: ‘Pineapple’, ‘Gooseberry’, ‘Strawberry’, ‘Artichoke’ and a modification to the original manoeuvre, known as a ‘Half-Raspberry’. These new manoeuvres provided escort ships with the tactics needed to go on the offensive, hunting U-boats before they made an attack rather than, in the case of Raspberry, after a merchant ship had been lost. Some, such as ‘Umbrella’, explored what to do in the event of a battle with a German surface raider–a merchant ship that had been fitted with powerful guns–rather than a U-boat.
The workload soon took a toll on Roberts. Donald Macintyre, Kretschmer’s captor, recalled that Roberts was ‘never well’ and ‘constantly in pain’.19 The captain’s weight dropped to eight stone. The rigours of overwork were compounded when, in the late autumn of 1942, Roberts and the Wrens learned that their staunch advocate Sir Percy Noble was leaving Derby House. The commander-in-chief of Western Approaches had been transferred to Washington DC to work alongside the US Navy in protecting American convoys from the U-boat threat. It was a serious blow: Noble was beloved by all at Derby House and WATU would lose a powerful ally. Their sense of dismay was heightened when they learned the name of his replacement: the imposing Max Horton, submarine ace of the First World War famed, also, for his brusque manner and quick temper.
To bid Noble goodbye and welcome Horton in his place, the king and queen arranged a visit to Derby House. On 17th November 1942, the royals arrived accompanied by Vera Laughton Mathews, director of the Wrens, on her first visit.
On arrival, Laughton Mathews asked a naval officer if her Wrens were executing their duties well.
‘Well,’ he replied, ‘as they are doing the bulk of the work, I suppose they are.’20
Roberts, to his astonishment, learned that the royal party would be visiting WATU during their visit. And not only that, they had also requested a demonstration of the game. The morning of the visit the Wrens were, as Roberts later recalled, ‘all of a twitter’.21
Despite the pressure, the Wrens performed a perfect Raspberry manoeuvre on the plot, while Roberts brought life and colour to the scene with his usual theatrical embellishments.
Afterwards, the king, who recognised Roberts from their Christmas meeting on the London Underground platform two years earlier, approached him. He asked about Roberts’ health and admonished him for getting too thin.22 Finally, King George gestured at the floor, still littered with the remnants of the game, a shanty town of play.
‘This,’ he said, leaning in, ‘is the key to the Battle of the Atlantic.’