For Britain Scapa Flow U-Boat attack was a terrible ‘feat of arms’

On 12 October 1939, a Luftwaffe reconnaissance flight confirmed the Home Fleet of the Royal Navy was in Scapa Flow and ripe for attack. The Germans had previously spotted a gap in the sea defences of the RN’s main war base and so kept a keen eye on things there.

The British war anchorage at Scapa Flow, at the end of WW1, with the interned German battle fleet enclosed. Photo: NHHC.

After sunset, however, the majority of the British vessels departed, with battleship Rodney and rest of the fleet heading for Loch Ewe on the west coast of Scotland. Yet the battleship HMS Royal Oak, which had been detached to patrol waters between the Orkneys and Shetland, remained at Scapa. Her job was also to act as anti-aircraft guardship for Kirkwall.

U-47, under the command of Kapitanleutnant Gunther Prien, had been sent to exploit Scapa’s defensive vulnerability and achieve something his forebears during WW1 had failed to do – sink a British battleship in the anchorage. As he took his boat north, Prien followed a pattern or running that aimed to ensure maximum stealth and survivability. U-boats, like all diesel-electric submarines, were much faster on the surface than dived.

The famous German submarine U-47 departing on patrol in 1939. Photo: US Naval History and Heritage (NHHC).

However, in seas where the enemy had dominant air cover – and with plenty of British patrol vessels also present – it was madness to try and cruise on the surface in daylight. Therefore, U-47 stayed submerged and rested on the seabed during the day, keeping the draw on battery power to a minimum. Most of U-47’s men got some sleep. After dark the boat surfaced and made speed towards Orkneys, her diesels driving hard – the batteries recharging and the engine fumes venting from the boat.

Prien had volunteered for the mission after being asked by Donitz, if he thought he could handle it. Had he refused, so Donitz maintained, there would be no stain on his record, but the ambitious Prien did not shirk the task. In WW1 the boats U-18 and UB-116 had been sent to penetrate Scapa, but had themselves been destroyed. Could Prien pull it off in the new war with Britain, his tiny craft delivering a devastating blow against the goliath of the seas that was the Royal Navy?

Until October 13 the crew of U-47 did not know exactly what their mission was about, though they guessed something big was imminent. When Prien gathered them in the forward torpedo room to reveal their objective, his men seemed to accept it with equanimity. The silence as they contemplated the enormity of the undertaking was broken only by ‘a soft gentle crunching sound as the boat shifted on the sea bed,’ as one account of the moment later described it.

U-47 rested on the bottom all that day, the boat surfacing at 7.15pm, when a hot meal was served – roast ribs of salt pork with cabbage. Making speed on the surface, there was a heart-stopping moment at 11.07 pm when the black mass of a ship materialised out of the night. It was only a merchant vessel, but Prien still dived U-47, to guarantee slipping by unobserved. When the U-boat again surfaced, Kirk Sound was visible ahead and Prien was presented with what he described in his patrol report as ‘a very eerie sight.’

In WW2 U-47 would penetrate Scapa Flow to attack Royal Navy warships and sink HMS Royal Oak (seen above in a floating dock between the wars). Photo: AJAX Vintage Picture Library.

He added: ‘On land everything is dark, high in the sky are the flickering Northern Lights, so that the bay, surrounded by English [sic] mountains, is directly lit up from above. The blockships lie in the sound, ghostly as the wings of a theatre.’ Deciding to squeeze past those blockships on their northern side, from the bridge of his boat Prien spotted the big, bulky silhouettes of ‘two battleships’ along with seemed to be destroyers lying beyond.

At 12.58am, with just 22ft below the boat’s keel, Prien fired one torpedo at what he referred to as ‘the northern’ ship and two at ‘the southern.’ All had impact exploders. ‘After a good three minutes, a torpedo detonates on the northern ship,’ reported Prien, ‘of the other two nothing is to be seen.’

Disappointed, but with no interference so far from the enemy, Prien swung U-47 around and launched a torpedo from the stern tube. He then turned the boat to fire three more torpedoes from the bow tubes, some with magnetic exploders. ‘There is a loud explosion, roar, and rumbling,’ recorded Prien of what happened next. ‘Then come columns of water, followed by columns of fire, and splinters fly through the air. The harbour springs to life…A battleship has been sunk, a second damaged…All the tubes are empty. I decide to withdraw…’

U-47 made off at high speed – still on the surface – exiting Scapa by Skildaenoy Point. Breaking through into the open sea, U-47 went as fast as she could, heading south-east and for home. With daylight fast approaching, Prien decided U-47 would be best advised to dive and sit on the seabed for a few hours to let the fuss die down. As he left the bridge Prien took a last look over his shoulder: ‘The glow from Scapa is still visible… Apparently they are still dropping depth charges.’

A few weeks after sinking the Royal Oak, U-47 sails back into Kiel with her crew arranged on her casing. The battle-cruiser Scharnhorst is in the background. Photo: US Navy/NHHC.

On October 15, Prien sent a signal to U-boat headquarters: ‘Operation successfully completed. “ROYAL OAK” sunk. “REPULSE” damaged.’ He was not quite accurate – Repulse was not there – but he had put three torpedoes into Royal Oak, the old British battleship turning turtle and taking 800 men with her, devastating the families and loved ones of those lost.

The Deadly DeepWinston Churchill observed: ‘This episode, which must be regarded as a feat of arms on the part of the German U-boat commander, gave a shock to public opinion.’ It would be six months before Scapa Flow’s defensive gaps were plugged and the Home Fleet could return in safety to its principal war anchorage. Meanwhile, Prien and the crew of U-47 reached Wilhelmshaven on October 17 to be acclaimed national heroes. During an audience with Adolf Hitler in Berlin, U-47’s commander was presented with the Knight’s Cross. The Fuhrer hailed Prien’s achievement as ‘a unique triumph.’

More on the pursuit of submarine warfare in WW2 and other conflicts is to be found in Iain Ballantyne’s book ‘The Deadly Trade’ (Weidenfeld & Nicolson) It is published in the USA as ‘The Deadly Deep’ (Pegasus Books)

First blood in longest struggle of WW2

When a state of hostilities between Germany and Britain was declared on 3 September 1939, the Royal Navy battleships HMS Nelson and HMS Rodney, along with other units of Home Fleet were spread along the most likely breakout routes for commerce raiders. However, the German pocket battleships Graf Spee and the Deutschland had already broken out into the Atlantic while Kriegsmarine U-boats were also on their war stations.

The Germans were not then operating a policy of unrestricted U-boat warfare and, when first blood in the new struggle for the Atlantic was taken by Oberleutnant Fritz-Julius Lemp (in command of U-30), it proved one of the most controversial episodes of the conflict.

A Type IX U-boat out on patrol in the early part of WW2. The first submarine lost during the conflict would be a vessel of this type. Photo: US Naval History and Heritage (NHHC).

U-30 attacked the liner Athenia, of 13,581 tons, on the evening of September 3, to the west of Ireland. She was carrying 1,013 passengers, including refugees, among them 246 American citizens attempting to reach home. Despite Athenia steaming at 12 knots and zigzagging to try and deter submarine attack, Lemp still caught the liner in his periscope.

The ship he was studying while trying to make up his mind was large, showing no lights and also outside the usual transatlantic liner route. Lemp decided she was an Armed Merchant Cruiser (AMC) and therefore a permitted target. He fired two torpedoes, inflicting a single mortal wound.

British warships and various merchant vessels made haste for the scene after a distress signal was picked up, but 119 people had lost their lives, including 28 Americans. This was very unwelcome news, for the Germans were keen to keep the USA neutral in the new conflict. The deaths of its citizens in similar incidents during WW1 had helped to bring America into that war.

Berlin maintained it could not have been a U-boat that was responsible, as such acts were forbidden by Adolf Hitler but even they privately suspected that it may, in fact, be the case. Athenia was the first Allied vessel sunk in WW2, during what would be the longest struggle in the latest global war. On U-30’s return home, Oberleutnant Lemp was flown to Berlin to brief the naval high command, confirming he had, indeed, sunk Athenia. Lemp was not court-martialed, for it was felt he had acted properly and in good faith.

HMS Ark Royal, which led an anti-submarine hunting group. Photo: NHHC.

Even so, U-boat force boss Admiral Karl Donitz was told the episode must be kept secret. Donitz ordered the relevant page of U-30’s log removed and replaced with a doctored one, which confirmed attacks on the enemy merchant vessels Blairlogie and Fanad Head. However, on the day Athenia was sunk the fake log book page recorded U-30’s position as 100 miles away from the scene.

Less than a week after Athenia’s sinking, newly appointed First Lord of the Admiralty Winston Churchill issued orders for a convoy system to be introduced. To their credit, whereas in WW1 shipping companies were reluctant to tie themselves to the Royal Navy’s apron strings, in the new war they acquiesced immediately. For all that, in those early days there were still many ships sailing solo as they headed for friendly ports and which became victims of the so-called ‘grey wolves’ of Germany’s U-boat force.

For their part, the Germans suffered their first submarine loss on September 14, when Kapitanleutnant Gerhard Glattes of U-39 tried to attack HMS Ark Royal. Britain’s most modern aircraft carrier was leading a U-boat hunting group – but U-39’s torpedoes missed and escorting destroyers Firedrake, Faulknor and Foxhound pounced while Ark immediately exited the scene. The entire 44-strong crew of the U-boat was taken prisoner.

The aircraft carrier HMS Courageous, which was sunk on 17 September 1939 by U-29, a heavy blow for the British. She is seen here in summer 1937. Photo: AJAX VINTAGE PICTURE LIBRARY.

The loss of the carrier HMS Courageous three days later, sunk to the south-west of Ireland, proved the error of Britain sending out sub-hunting groups led by aircraft carriers. They were nothing but an ideal means to serve up much-prized targets on a plate, though the carrier-led hunting group concept would come to fruition for the Allies later in the war.

Kapitanleutnant Otto Schuhart of U-29 found Courageous after sighting one of her aircraft during a periscope look. He waited until the massive ship was compelled to follow a straight course to land an aircraft and torpedoed her. Within ten minutes of being hit, the Courageous was gone. Out of the 1,260 men in the ship’s company and embarked air squadrons, only 519 survived, picked up by destroyers and passing merchant ships. While the loss of Courageous and so many men was a bitter blow – also causing a change in direction for the British, who abandoned the hunting group idea – the real shocker was delivered the following month.

More on the pursuit of submarine warfare in WW2 and other conflicts is to be found in Iain Ballantyne’s book ‘The Deadly Trade’ (Weidenfeld & Nicolson) It is published in the USA as ‘The Deadly Deep’ (Pegasus Books)

Convoy Battles were as Important as El Alamein, Stalingrad or Guadalcanal

Seventy-five years ago saw what has often been lauded as the moment of victory for the Allies in the Battle of the Atlantic. The key clashes were staged across April and May 1943, with convoy escorts battling a U-boat force encouraged by an impressive score in March – sinking 107 Allied ships in the month’s first 20 days – to believe it could yet secure supreme triumph for Germany.

As was so often the case in war, such an upswing in fortune could so easily become a downturn and signs of the German decline to come were there even in March. The month had closed amid dreadful weather, with only 15 enemy merchant vessels sent to the bottom by U-boats during its final 11 days. The submarine crews were tired, the boats battered and in need of repair, while fuel and torpedo stocks were depleted.

A U-boat hunts for a convoy in the vast N. Atlantic. Image: Dennis Andrews.

Yet the resilient U-boat force soon sent its submarines back into action, to become locked in battle with escort groups, trying to break through and attack merchant vessels.

The first of the pivotal fights came in early April with the assault on convoy HX-231, of 61 merchant vessels, a battle stretching across hundreds of miles of ocean. The cutting edge of the wolf pack was blunted above all by the determined actions of the B7 escort group, led by the Royal Navy’s formidable Commander Peter Gretton. Six merchant vessels were sunk, for no boats lost, but the overall performance of the German submarines had been timid, the U-boat force War Log blaming it on ‘the inexperience of young Commanding Officers.’

A British escort charges off to tackle a U-boat to prevent it from sinking merchant ships in convoy across the Atlantic. Image: Dennis Andrews.

In fact, morale was so fragile in the U-boat force that some submarine COs eagerly embraced any mechanical defect to report their vessels non-operational. Kriegsmarine commander-in-chief Grand Admiral Karl Donitz responded by threatening stiffer penalties for those he perceived to be shirkers.

The B7 group was also sent out to protect the 41-ship convoy ONS-5. The U-boats were ordered by their boss to wait for nightfall on 5 May and then to attack with vigour in order to ensure ‘there will be nothing of the convoy left’. This was far from being the case, with just 13 merchant vessels sunk, a poor return for five U-boats and their crews destroyed.

When the U-boats tried to score big again in late May, they failed utterly, with four submarines lost during attempts to attack convoy SC-130. All 37 of its precious merchant vessels – carrying fuel oil, explosives, lumber and grain among other things – were delivered safely to Liverpool.

By this time in the contest Allied escort groups & aircraft were clearly achieving a measure of superiority in the open ocean war that stacked the odds heavily against Germany’s submariners. In the first five months of 1943, Allied warships and aircraft sank 81 U-boats. With that rate of losses Donitz felt he had no choice but to admit wolf pack operations were no longer possible – at least not for the time being. He therefore issued an order for U-boats to withdraw from the North Atlantic on May 24.

The quality of Allied warships, not least their weapons and U-boat detecting equipment, had risen dramatically since German submarines had been able to wreak havoc on convoys (especially during 1940 – 1941). The senior leadership of the Allied escorts – the skill of junior officers too – was also greatly improved.

Gretton, along with other escort group commanders, including the equally lethally proficient Donald Macintyre and ‘Johnny’ Walker, were now getting into their stride. As they wielded their ships to great effect, long-range air patrols by Allied air forces bore down heavily on the enemy too, at times scoring a similarly devastating rate of kills.

An Allied aircraft attacks a U-boat as the struggle in the N. Atlantic continues during WW2. Photo: US Navy/NHHC.

Amid all the memorializing of the great victories on land at the end of 1942 and in the first half of 1943, the great turning of the tide against the Axis – via the British victory at the Second Battle of El Alamein, the Sixth Army surrendering to the Russians at Stalingrad, the capture of 275,000 Italian and German troops in Tunisia and Americans triumphing at Guadalcanal – the significance of the convoy battles in the Atlantic of April and May 1943 can become forgotten. Such critical events in the turn of the tide at sea risk being lost amid the amorphous term Battle of the Atlantic.

Those laurels that were awarded to the warship captains who beat the U-boats came in the form of paper slips on which were written decryptions of coded signals conveying congratulations from senior commanders. In the aftermath of the fight to get ONS-5 through there was at least a message of thanks from Prime Minister Winston Churchill signaled to escorts.

One post-war admiral – a junior officer serving in destroyers during 1943 – judged Allied victories in the Battle of the Atlantic to be as great as any land victory. According to Vice Admiral Sir Roderick Macdonald, they were vital in ‘preparing the way for the invasion of Europe’. Had it been fought ashore, or even a sea engagement in the age of fighting sail, the ONS-5 victory ‘would be [lauded] in the history books, like Salamis or Trafalgar’ for it was ‘no skirmish’ and the battle ‘to defend convoy ONS-5 was of more significance than Alamein.’

That may be stretching it a little, but the point is well made, for pitched battles at sea do not leave behind scarred buildings or pockmarked bunkers, or wrecked tanks littering the landscape. Nor do the casualties lie in lovingly tended war cemeteries close to the scene of the battle to offer an all too tangible reminder of sacrifice.

Those who perished in the battles for convoys HX-231, ONS-5 and SC-130 lie in unseen and unknowable watery graves, vanished under the sea either inside their sunken ships and submarines or swept away by the cruel sea until absorbed into the vastness of the ocean.


Each merchant vessel that reached a UK port was another victory for the Allies in the struggle against the U-boats in the Battle of the Atlantic during WW2. Photo: US National Archives.

Victory for the Allies was actually recorded in the ships the enemy never saw – the vessels that slid by the U-boats without a shot being fired and to enter a British port to offload their vital cargoes, all routine and largely unremarked. Each ship unloaded was, however, another small victory and diminished even further Germany’s chances of success.

Even though May 1943 is often regarded as the moment when the Battle of the Atlantic was won by the Allies – enabling the invasion of Normandy just over a year later – in reality the bitter struggle between Allied escorts/airpower and U-boats continued right until the end of the war in Europe. There were even fears the war at sea off Europe could still be lost by the Allies.

It morphed into a different kind of contest – in fact a series of contests stretching from the deep ocean to inshore waters around N.W. Europe – that at various times was arguably harder for the Allies to deal with, though the US Navy’s escort carrier hunter-killer groups reaped a devastating harvest in the mid-Atlantic, around the Azores. Tough as the fight may have become once again, British escort groups were relentless elsewhere.

The Allies feared the ‘U-boat peril’ (to borrow Churchill’s description) right up until the Reich’s total collapse, not just because of the looming (if troubled) introduction into service of the much-vaunted Type XXI and Type XXIII U-boats, but the Total Underwater Warfare concept.

Donitz hoped it could deliver final victory to Germany. So, in May 1943 the war of the transatlantic convoys may have peaked but now the battles had different objectives and the Allies’ hard won advantages were under threat of neutralization by Total Underwater Warfare.

 

How that German bid to achieve victory at sea unfolded – along with many other episodes in submarine warfare across the ages – is told in my latest book ‘The Deadly Trade: The Complete History of Submarine Warfare from Archimedes to the Present’, published by Weidenfeld & Nicolson (752 pages, hardback £25.00/eBook £12.99) which is available via Amazon and Waterstones plus other retailers and shops.

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