Fighting with Hedgehogs

USS England off San Francisco, 9 February 1944.

Hedgehog thrower on HMS Westcott, November 1945.

Secretary Margaret Jackson was able to provide Colin Gubbins, Special Operations Executive, with remarkably accurate briefs on the success or failure of the sabotage missions that were by now taking place on a nightly basis. Wireless transmissions were received by the various country sections, where they were collated and forwarded to her. She, in turn, handed them to Gubbins when he arrived for work at Baker Street.

The situation at the first was rather different. It was a source of continual frustration to Stuart Macrae not to have any idea as to how and when their weapons had been used. In part, this was because they were too busy to enquire. As summer yielded to autumn that year, 1943, they found themselves working on ‘all manner of remarkable projects’. There were ‘bombs which jumped about on the ground, bombs which leaped in and out of the sea and rockets which fired bridges over roads’ – the latter being the latest invention from the drawing board of Cecil Clarke. Yet news of operations hardly ever reached the sheds and workshops at the far end of the lower lawn.

Macrae tried to keep tabs on successful limpet attacks, but even this proved difficult. Unlike Gubbins, he was not in regular contact with the army high command. As for Jefferis himself, he didn’t seem to care. Macrae increasingly found himself in the role of ‘a theatrical producer who had found an unwilling star’ – Jefferis – ‘and forced him to fame’. He felt rather guilty, for ‘whereas I had succeeded in making myself happy, it was obvious that I had done the opposite for Millis’. Jefferis wanted nothing more than to be left with his mathematics, his coloured chalks and the occasional tumbler of whisky.

His most complex invention, the anti-U-boat Hedgehog mortar, had started life when the two of them were still working in the War Office back in the early days of war. It had originally been intended as a sabotage weapon to be used in the event of a Nazi invasion of Britain, but had slowly been transformed into an instrument of such complexity that it had required more than two years of fine tuning. The principal difficulty had been to calculate the recoil accurately, essential to the stability of any ship. One newly recruited engineer who found himself travelling in the company of Jefferis said that he ‘spent most of one train journey between Bath and London sketching furiously on empty cigarette packets’. As the train pulled into Paddington, Jefferis gave the hint of a smile: the mathematics finally made sense. And by the time the sea trials took place, the Hedgehog was near perfect. The mortars dived downwards in their streamlined casings and then homed in on their underwater foe.

This all took time and it was not until the spring of 1943 that the first Hedgehogs were being installed on Royal Navy vessels. When Commander Reginald Whinney took command of the HMS Wanderer , he was told to expect the arrival of a highly secret piece of equipment. ‘At more or less the last minute, the bits and pieces for an ahead-throwing anti-submarine mortar codenamed “hedgehog” arrived.’

As Whinney watched it being unpacked on the Devonport quayside, he was struck by its bizarre shape. ‘How does this thing work, sir?’ he asked, ‘and when are we supposed to use it?’ He was met with a shrug. ‘You’ll get full instructions.’

Whinney glanced over the Hedgehog’s twenty-four mortars and was ‘mildly suspicious’ of this contraption that had been delivered in an unmarked van coming from an anonymous country house in Buckinghamshire. He was not alone in his scepticism. Many Royal Navy captains were ‘used to weapons which fired with a resounding bang’, as one put it, and were ‘not readily impressed with the performance of a contact bomb which exploded only on striking an unseen target’. They preferred to stick with the tried and tested depth charge when attacking U-boats, even though it had a hit rate of less than one in ten. Jefferis’s technology was too smart to be believed.

The Americans proved quicker at embracing the Hedgehog, equipping large numbers of their ships in the final months of 1943. Among them was the USS England, which went into service in the Pacific shortly afterwards. She was soon to find herself caught in the opening shots of Operation A-Go, the Japanese quest for the total destruction of the American Pacific fleet in the spring of 1944. It was an operation driven by Admiral Soemu Toyoda, who knew that submarines would play a central role in the battle ahead. Indeed he said that ‘the success or failure of Operation A-Go depends on the submarines’. What he didn’t know is that he would be pitting his fleet against Jefferis’s mathematical genius.

Admiral Toyoda issued his pre-battle orders to Rear-Admiral Naburo Owada on 3 May 1944. Owada was commander of the Japanese submarine force, Squadron Seven, and he was instructed to launch ‘a surprise attack against enemy task forces and invasion forces’.

The Americans were quick to intercept the Japanese wireless transmissions: one of the first intercepts revealed that a lone Japanese sub, I-16, was heading towards the Solomon Islands. The I-16 was an enticing prize, one of the largest submarines ever built in Japan. She was almost 350 feet long and heavily armed with eight 21-inch torpedo tubes. She was so big that she could carry a small supplementary sub in her deckhouse. Moreover, she was commanded by the brilliantly gifted Yoshitaka Takeuchi.

American intelligence discovered not only the sub’s destination, but also her intended route and speed. This was immediately forwarded to the USS England, which set out in hot pursuit.

The England ’s executive officer, John Williamson, was one of the new breed of navy men: savvy, clean-shaven and passionate about the latest gadgets. With his large ears and goofy smile, he looked like a typical college geek. But he was a geek who was hungry for victory. And in Jefferis’s Hedgehog, he smelled triumph. Long before his vessel set sail from San Francisco, he had instigated a series of test firings in the harbour. ‘If it hit,’ he noted, ‘the concentrated power of its thirty-five pounds of TNT was enough to blow a two- or three-foot hole in a submarine’s three-quarter-inch rolled-steel hull.’ Unlike the depth charge, the Hedgehog only detonated on making contact with the submarine. ‘You knew you had scored a hit, and a devastating one.’

Now, as Williamson went in search of the Japanese sub, he felt ‘a heady mixture of excitement, eagerness and trepidation appropriate to new boys on the block’. One slip on his part and the England herself would come under attack from Commander Takeuchi’s torpedoes.

At exactly 1.25p.m. on 18 May, the England ’s soundman, Roger Bernhardt, gave a shout from the bridge. ‘Echoes sharp and clear, sir!’ The echo detection equipment revealed that the submarine was just 1,400 yards away. The chase was now on and the vessel began to shudder as the engines were cranked to full throttle.

Williamson was impressed by Takeuchi’s reactions, for he proved a skilled quarry. ‘At four hundred yards, the target turned hard left and kicked his screws.’ Takeuchi was making his escape, using a procedure known as ‘kicking the rudder’. This threw up disturbances in the water, distorting the sonar echoes and making the sub’s position impossible to pinpoint with accuracy. But Williamson had made it his business to locate subs, even in turbulent water. He studied the Doppler machine intently as he tried to calculate the exact depth of Commander Takeuchi’s sub. At precisely 2.33 p.m., he got a fix. A split-second later, he fired his weapon and the Hedgehogs roared away from the ship and upwards into the clear blue sky, forming themselves into a perfect ellipse and then entering the sea in symmetry, just as Millis Jefferis had intended.

‘No one said a word. All eyes were fixed on the water’s surface, everyone imagining the huge steel fish below.’ Everyone knew that unlike the old depth charge, the Hedgehog would only explode if it hit the sub.

Silence. Tension. And then – ‘V-r-r-oom ! We heard it again and again, in rapid-fire succession, four to six hits coming so fast on top of one another as to seem almost simultaneous.’ Williamson had just one word in his mind: ‘Bull’s-eye!’

Deep below the surface, Commander Takeuchi had been engaged in a desperate struggle to evade the England when his submarine was hit by six shattering explosions. Jefferis had spent months calculating the mathematical equation that would ensure his Hedgehog would strike with deadly precision. Now, that mathematics reaped dividends. As the I-16’s steel hull was punctured by multiple spigots, the rigid hull instantly and violently crumpled in on itself like a tin can crushed by a giant fist. Commander Takeuchi and his crew were engulfed in a catastrophic decompression that sucked in a high-velocity avalanche of water, along with twisted shrapnel from the crippled outer shell. Death was mercifully quick. There was no hope of escape.

There was jubilation aboard the England at the sound of the underwater explosions. The crew ‘broke out in cheers, everyone jumping and slapping one another on the back like a team that had just won a tournament game’. The cheering continued for fully two minutes, ‘and was just beginning to die down when all of a sudden we heard a giant wham !’ The sea erupted into angry wavelets and the England ‘shuddered violently and started rocking and reeling’.

Williamson’s first thought was that they had been torpedoed. He feared that Commander Takeuchi had somehow detonated his on-board torpedoes as a final, desperate act of revenge. In fact, it was the violent implosion of the submarine that caused the shockwaves. The men on the England were nevertheless terrified. The fantail of the ship ‘lifted as much as a foot, plopped heavily back in the water, while men throughout the ship were knocked off their feet and deck plates sheared loose in the engine room’. Williamson concluded that the aftershock marked the ‘cataclysmic certainty that we had heard the last of the Japanese submarine’. It left the men ‘sobered and subdued’. The Hedgehogs had made their job of killing very easy.

The submarine had been sunk at more than 500 feet below the surface and almost twenty minutes were to pass before the first wreckage began to appear. Williamson was staring intently at the sea when he saw some shredded cork insulation pop to the surface. It was followed by deck planking and the remnants of a filing cabinet. Next to float up was a prayer mat decorated with Japanese characters, a lone chopstick and a large rubber container holding a seventy-five-pound bag of rice.

There was increasing excitement on deck as more evidence of their ‘kill’ started floating to the surface. Everyone was awaiting the inevitable appearance of human remains. Ten minutes passed, then twenty, but they never arrived. John Williamson peered into the water and was quick to see why. ‘Soon a dozen or so well-fed-looking sharks were milling around the vicinity.’ Commander Takeuchi and his crew had fallen prey to two different enemies, one above water and one below.

A small oil slick soon appeared on the surface, evidence that the Hedgehogs had ruptured the sub’s fuel tanks. ‘The slick grew steadily in size until profuse amounts of oil were bubbling to the surface, along with more debris.’

All the detritus needed to be collected, for the US Navy would only confirm a ‘kill’ if there was evidence. One of the England ’s whaleboats was lowered and a few of the crew began collecting relics of the sub. Williamson was concerned for the men’s safety, for ‘there were a dozen or more huge sharks swimming excitedly through the floating debris, looking for blood and shredded limbs.’

Over the course of the next twelve days, Williamson achieved a record unbeaten in the history of naval warfare. He and his men sank a further five submarines, all destroyed by Hedgehogs. Each time, the effect was the same: a deep-water vroom, an oil slick on the surface and dozens of marauding sharks. One young mariner aboard the England confessed to being upset at the ease with which their Hedgehogs were destroying the subs. Williamson had a ready answer. ‘Son,’ he said, ‘war is killing. The more of the enemy we can kill, and the more of his ships we can sink the sooner it will be over.’ He added that ‘we are in a war that we must win, for to lose it would be far worse.’ It was a sentiment that could have come straight from the mouth of Millis Jefferis.

At the naval headquarters in Japan, Admiral Soemu Toyoda was still unaware of the catastrophe that had befallen Squadron Seven. He was eagerly anticipating the onset of Operation A-Go, aware that his submarines had a unique role to play. At 9 a.m. on 15 June he gave the order for battle, using exactly the same words as Admiral Togo had used to address his fleet on the eve of the famous Battle of Tsushima, thirty-eight years earlier. ‘The fate of the empire rests on this one battle. Every man is expected to do his utmost.’

As part of the general deployment, he sent an urgent directive to Admiral Owada: ‘Submarine Squadron Seven is to be immediately stationed east of Saipan, to intercept and destroy American carriers and transports, at any cost.’ Admiral Owada’s reply was succinct. Squadron Seven, he said, ‘has no submarines’. Jefferis’s Hedgehogs had claimed the lot.

Stuart Macrae was delighted when he was brought the news: indeed, it would remain with him for years. ‘The hedgehog was an out and out winner,’ he wrote. ‘It went into service rather late in the day, but was credited with thirty-seven confirmed submarine killings.’ What had begun as a sabotage mortar for use against the Nazis in Kent had been transformed by Jefferis into a devastating weapon of destruction.


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