Tough to Sink

S.S. Laurentic before her conversion to armed merchant cruiser in 1939 (u-boat.net)

S.S. Laurentic before her conversion to armed merchant cruiser in 1939 (u-boat.net)

It has long been the practice in wartime for the British government to requisition civilian vessels for war service. Often these vessels are used in the logistics role supporting the Royal Navy at sea or the British Army and Royal Air Force in foreign lands. The practice has been used as late as the 1982 Falklands War where perhaps most famously the ocean liner Queen Elizabeth II was used to ferry over 3000 troops to the South Atlantic. Using civilian ships in wartime is a precarious business at best. They are seldom designed with the same level of protection a warship is afforded making them very vulnerable and their vital role in supporting the war effort makes them highly prized targets for the enemy.

One such civilian ship taken over for use by the Royal Navy was the Cunard White Star Line passenger ship the Laurentic. Requisitioned by the Admiralty a week before Germany invaded Poland on September 1st 1939 the vessel was put in to dock for conversion to an armed merchant cruiser which was completed in a remarkably short space of time. HMS Laurentic F51 was accepted in to service on October 15th 1939. As part of her conversion she was armed with seven Breech Loading 5.5inch (140mm) Mk I guns and three QF 4inch (102mm) Mk.XVI naval guns. She was also fitted with a quantity of depth charges for use against submarines.

The vessel was, like many of her kind, primarily employed on patrol and escort duties; armed merchant cruisers were effectively the last line of defence with the Royal Navy’s main fleet and aircraft being the first. Her start to the war was relatively uneventful but all that changed on the evening of November 3rd 1940. A little after 2140 hours her commanding officer, Capt E.P. Vivian RN, was informed that the radio room had received a distress call from an unescorted merchantman, the Casanare, stating it had been attacked by a U-Boat. Along with another armed merchant cruiser, HMS Patroclus, Laurentic raced to the scene west of Ireland at a place called Bloody Foreland.

A sister-ship to Casanare (wrecksite.eu)

A sister-ship to Casanare (wrecksite.eu)

Unknown to Captain Vivian and his men they were about to face off against one of Germany’s greatest U-Boat aces, the brash and skilled Kapitänleutnant Otto Kretschmer (known as “Silent Otto”) and his crew of U-99. Kretschmer’s attack had been a textbook example of U-Boat warfare, catching the Casanare completely by surprise. The torpedo struck just aft of the vessel’s bridge and she began to list heavily enough for the crew to begin abandoning ship. The wireless operator aboard U-99 suddenly found his headset alive with messages between their victim and the two approaching ships all of which were transmitted uncoded and in plain language.

Kretschmer continued to shadow the sinking Casanare while surfaced and it was not long before he detected the two ships coming to its aid. Picking his moment carefully, Kretschmer waited for the Laurentic to come in to his sights and at 2250hrs he unleashed his deadly arsenal on his second unsuspecting victim of the night (this early in the war few ships had radar to detect a surfaced U-Boat at night but by 1945 this kind of operation would have been suicide for a U-Boat commander). Launched from a distance of one and a half kilometres and incredibly while the U-Boat was turning the torpedo struck the Laurentic amidship near the boiler room tearing open a gaping hole in her side. Kretschmer watched the ship expecting it to sink and indeed a number of her crew had leapt overboard in the chaos of the blast but as the smoke dissipated the Laurentic proved that she was not done for yet and remained stubbornly afloat.

Kretschmer made two more attacks on the Laurentic, one at 2320hrs and another at 2330hrs with the range now having decreased to just 250m. The crew of the Laurentic briefly spotted the U-Boat on the surface and began shelling the submarine which quickly slipped away. The Laurentic was now heavily damaged and was riding much lower in the water than it should be convincing Kretschmer that the ship was finally done for and so he turned his U-Boat away to assess his situation.

hms patroclus

HMS Patroclus (u-boat.net)

In the meantime, HMS Patroclus had arrived on station and began efforts to rescue the crew of the Laurentic many of whom were abandoning the ship. The Patroclus’ Captain, William Wynter, ordered that two depth charges be launched over the side in an effort to frighten the U-boat away. He couldn’t have known that Kretschmer was still on the surface unseen in the night. Believing he had successfully drove off the U-Boat, Wynter’s crew began to rescue their comrades but Kretschmer had come about and at 0022hrs the Patroclus was hit by a torpedo from U-99 killing an unknown number of men aboard a lifeboat from the Laurentic that was being hauled aboard at the time. Like the Laurentic the Patroclus refused to sink and twenty minutes later at 0044hrs a second torpedo was launched in to the ship. The torpedo malfunctioned and missed its aim point hitting below the foremast. No doubt gritting his teeth Kretschmer fired a third torpedo at 0118 hrs but as he did so the British lookouts spotted the U-Boat and Kretschmer found his vessel taking fire forcing him to flee yet again.

Dumbfounded by his enemy’s refusal to sink, Kretschmer searched for his first target, the Casanare, to confirm it had indeed sunk. Two lifeboats bobbing in the water at her last known position offered the proof he was looking for when suddenly the air around him growled with the sound of aeroengines as an RAF Shorts Sunderland flying boat appeared over the scene. Kretschmer ordered his U-Boat to dive and the RAF aircraft was unable to launch its weapons but remained on station trying to locate the submarine.

Kretschmer used his time submerged wisely and reloaded the torpedo tubes. With the sound of the Sunderland’s engines dissipating he felt confident enough to surface at 0330 hours. Rather arrogantly he went back to the site of his attack on the two armed merchant cruisers and saw that Laurentic and Patroclus had still yet to sink! At 0435hrs he fired a fourth torpedo at Laurentic which struck astern. The blast ignited the depth charges stored in that area resulting in a huge explosion. The Laurentic’s luck ran out and the ship began to sink by the stern disappearing forever.

Kretschmer then turned on the Patroclus but as he did so his own lookouts spotted a destroyer, HMS Hesperus, approaching on the horizon. Rather than be satisfied with sinking the Casanare and the Laurentic he made a hasty attack on the Patroclus. At 0516hrs a fifth torpedo struck the ship fired from U-99 but the British ship refused to go down one last time prompting Kretschmer to fire a sixth torpedo. That was the end of the Patroclus and the hull crumbled into pieces before finally sinking. 114 sailors had been killed in the whole incident.

Kretschmer and the crew of U-99 celebrate in late 1940 (commons.wikimedia)

Kretschmer and the crew of U-99 celebrate in late 1940 (commons.wikimedia)

Kretschmer immediately ordered his U-Boat to dive as the destroyer zeroed in on him. Kretschmer and his men now paid for their victory as they were repeatedly depth charged by the Hesperus but the destroyer failed to score a direct hit and Kretschmer returned to Germany a hero.

So just what was the secret behind the Laurentic and the Patroclus that kept them afloat for so long? Was it excellent damage control techniques? Perhaps it was superb craftsmanship in the construction of the two vessels? Actually it was neither. It was in fact the placing of thousands of empty oil drums inside the hull of the ship. This dramatically increased the overall buoyancy of the vessels which meant that despite several gaping holes in the hull the barrels kept the vessels afloat making them very tough to sink.

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The scale of the U-Boat threat on 18th October 1942

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This image was sourced from U-Boat.net and shows just how widespread the U-Boat threat was in the North Atlantic on just one day in 1942. It is easy to see how so many ships fell victim to this unseen threat but by this time in the war the wheels of fortune were turning against them as new technologies such as airborne radar meant that not even night provided cover for the U-Boat anymore. Nevertheless Allied losses continued right up to the end of the war and the lessons of the U-Boats were not lost on military planners in the Cold War.

HMS D3 – A Case of Mistaken Identity

HMS D3 (histomar.net)

HMS D3 (histomar.net)

The First World War changed the nature of military conflict beyond recognition. Not since the Battle of Agincourt where French Knights in armour found themselves rendered obsolete by new weapons had war been revolutionised so quickly. The new wars being waged under the sea and in the air both came of age and on a handful of occasions these two arenas clashed. Unfortunately this led to tragedy in March 1918.

HMS D3 was commissioned on August 30th 1910 at a time when the infantile Submarine Corps was still considered something of a pirate branch of the Royal Navy being viewed in a similar fashion to how regular servicemen once viewed British privateers. The third of the D-class submarines, an improved version of the previous C-class, HMS D3 operated in northern waters for the bulk of the war helping to enforce the blockade against Germany and contain the Imperial German Navy. Her first taste of combat was anything but glorious however when the submarine fired on another submarine believing it to be a German vessel when in fact it was HMS E48. Fortunately the torpedoes missed but the incident would have ghostly echoes upon the story of HMS D3.

On March 7th 1918 the submarine set off for another war patrol of the English Channel under the command of Lieutenant William McKinstry Heriot-Maitland-Dougall of the Royal Canadian Navy. The situation at sea as well as on land had swung well in favour of the Allies although the German surface fleet remained alive it refusing to come out of port in force for the Royal Navy, now supported by the US Navy, to destroy it. This left the Imperial German Navy’s U-boat fleets to keep the fight alive and they had proven dramatically that they had the power to alter the course of the war first by demonstrating how vulnerable the Royal Navy was to submarines when three Cressey-class cruisers were sunk in a single engagement by just one submarine and then by sinking the liner Lusitania which effectively brought the United States in to the war on the side of Britain and France. U-boats therefore became high priority targets for the anti-submarine forces of the Allies.

The crew of HMS D3 (histomar.net)

The crew of HMS D3 (histomar.net)

After being escorted to the patrol area by a British destroyer so as to allow the submarine to pass through British defences without being mistaken for a German vessel the destroyer turned back for the Isle of Wight leaving D3 to begin hunting for German vessels. A World War One submariner’s life was a tough one even more so than later in the Second World War. Their vessels themselves were just as likely to kill them as the enemy and so just volunteering for the Submarine Corps was an act of courage alone. Even when everything was running smoothly as far as the submarine was concerned life was cramped, uncomfortable and lacking in privacy as the crew almost literally lived on top of one another. Officers and crew transferring from big ships were often amazed at how lax the discipline on submarines were in comparison for there just wasn’t the room for the usual pompous nature of life in the Royal Navy but this in turn bred new types of crew. Submarine crews were tighter teams and the feeling of brotherhood amongst those who served in the underwater branch of the Royal Navy was unparalleled so losses, and there were many, were felt throughout the force.

On March 12th 1918 HMS D3 was just two days from being relieved of her duties by another submarine when at shortly after 1400hrs the lookouts on the coning tower spotted an object above the horizon to the south-west of their position. They quickly identified it as an airship and reasoned that it must be an allied aircraft given that by this point in the war German airships seldom ventured beyond the Western Front in France. The officer of the watch saw the airship turning towards them and having identified French roundels on the aircraft ordered that recognition rockets be readied to signal that they were a friendly vessel. A series of signal rockets were set up aft of the coning tower and the order was given for them to be fired. The brightly lit rockets shot upwards and in the wind arched over in the direction of the airship passing ahead of it as it droned forward towards the submarine.

In just a few seconds all hell broke loose on the deck of the submarine as bullets raked the hull from a machine gun mounted on the French airship. It was immediately obvious that the French had mistook the signal for an attack and were retaliating. Knowing the airship had bombs onboard Lieutenant Heriot-Maitland-Dougall gave the order to dive and the crew tried desperately to clamber inside their vessel as the airship droned closer, its machine gun still spewing bullets at the exposed crewmembers. As the submarine disappeared beneath the waves the airship was almost overhead and dropped two of its four light bombs which fell around 20m from the submarine.

The airship then made a second attack and dropped four bombs around the last known position of HMS D3. One by one the bombs exploded sending huge plumes of spray up in to the air before suddenly the coning tower broke the surface again. Heavily damaged from the French attack the crew made an effort to abandon their vessel but only four crewmembers made it off before the submarine disappeared below the surface for one last time.

The French airship cut its engines and began to descend in an effort to rescue the men and take them “prisoner”. Without the noise of their engines they heard the men speak as one of them shouted in English, “You’ve got us!” It was only then the French realised their mistake and made frantic efforts to organise a rescue for their Allies but it was all in vain. The French were unable to radio for assistance nor offer assistance themselves and by the time a vessel did reach the area the survivors had joined their comrades in the watery grave of HMS D3.

Naturally an investigation was launched and the commander of the French airship designated AT-0, Lieutenant Saint-Remy, was initially blamed by the British for the loss. However the investigation revealed that there was a certain degree of blame for both sides to accept. Attention was brought on the signal rockets fired by D3 which Saint-Remy took for an attack. It seems that the rockets were somehow rendered ineffective for the purposes of identification either because of atmospheric reasons such as haze or that the French crew, busy flying their airship, failed to properly identify them before they passed nearby leading them to the conclusion that they were under attack.

The investigation placed some blame on the British crew also. Signal rockets were common practice for the Royal Navy but the French Navy operated on the tactic of using smoke markers on the rear of their ships to identify them to Allied aircraft. The French argued that had the British crew done this instead of firing rockets then the attack would never have happened. But even they conceded that both sides should have been aware of their opposite number’s methods of identification. In the end Lieutenant Saint-Remy and his crew were exonerated of blame.

29 men died when HMS D3 sank in an example of what is now termed as friendly fire. The vessel has the somewhat sad distinction of being the only submarine to have been successfully engaged and sunk by a French aircraft in World War One.

The Only Underwater Submarine-to-Submarine Kill in History

HMS Venturer

Even in the 21st century the submarine remains one of the stealthiest weapons of war. Advances in sonar technology and magnetic anomaly detectors have done much to improve the chances of detecting submarines but the advantage is still very much on the side of the submariner even when he is facing another submarine. Submarines are in a much better position to detect other submarines than surface vessels as their hydrophone detectors can take advantage of underwater currents carrying the sound or sonar ping from a nearby submarine. Nevertheless, one of the most difficult missions in warfare remains sub-versus-sub combat whilst both are submerged. In the history of submarine warfare there has so far only been one occasion where a submarine successfully carried out an attack on another while both were underwater.

While the story of anti-submarine warfare is remembered as akin to a game of chess between surface ships and their elusive elusive quarry, submarines have actually fought one another ever since the type went to war in 1914. British submarines were heavily involved in providing a defensive screen against German submarines that tried to attack the troop ships crossing the English Channel at the outbreak of war. The Germans spotted the British submarine screen and the two sides tried to lure one another in to combat but all in vain. Nevertheless, the British submarines still achieved their mission by keeping the Germans away from the vital troop ships carrying the British Army to France.

HMS E3

HMS E3 (commons.wikimedia)

On the 18th of October 1914 the British submarine HMS E3 under the command of Lieutenant Commander George Cholmney was conducting a patrol in the North Sea off Borkum, an island off North West Germany. During the course of the day the E3 spotted a small flotilla of German destroyers and began stalking them however the destroyers had the advantage of speed and the E3 was not able to get in to a good firing position. Cholmney therefore elected to hide his submarine in a nearby bay believing the German destroyers would either return or disperse thus allowing him a second chance to engage.

Unbeknown to Cholmney the bay was already occupied. The sleek lines of U-27 under the command of Kapitänleutnant Bernd Wegener slid through the waters with its lookouts atop the coning tower scouring the horizon. They quickly spotted what they suspected to be a buoy floating by in the distance but there wasn’t supposed to be one there and on closer inspection Wegener realised that it was in fact a British submarine. He immediately ordered his crew to diving stations and he closed on the target expertly positioning his submarine between E3 and the afternoon sun in order to make spotting his periscope more difficult to see in the glare on the water.

Having pursued the E3 for nearly two hours the distance between the U-27 and the still oblivious E3 had closed to 656 yards (600m) and Wegener decided it was time to engage the enemy vessel. He dispatched two G6 torpedoes at the British submarine and after travelling for twelve seconds they struck the stern of the submarine blowing it clean off from the rest of the submarine’s forward hull. There were no survivors from HMS E3 which has the unfortunate distinction of being the first submarine to be sunk in action by another.

Throughout World War I and World War II submarine versus submarine actions were infrequent and often resembled that of the sinking of E3; one submarine spots another on the surface and fires at it. While naval Anti-Submarine Warfare (ASW) technology advanced on both sides it was the aircraft that would prove the biggest threat to submarines and remains so to this day. The thought of using submarines to hunt down other submarines while submerged however was a concept that still appeared to remain confined to the realms of fiction.

ASDIC

ASDIC

There were a number of obstacles that stood in the way of World War II submarines trying to hunt each other down in the depths of the world’s oceans. First of all detecting the other submarine was still a challenge. Hydrophone technology was still very primitive and while they could give advanced warning of a surface vessel pushing its way through the waves above, a submerged submarine made less noise and so was less detectable. The sea did more than keep a submarine hidden from view as well. Sound waves don’t travel very well in colder waters making the passive hydrophone system less effective in hearing the enemy sub. ASDIC, an early form of sonar, sent out a sonic pulse to detect an object but again low temperatures hindered its effectiveness. Unsettled water also disrupted the pulse degrading its strength but the biggest problem with ASDIC was that while it could give a direction it couldn’t give a depth.

Even if a submarine could detect another submarine engaging it in combat presented its own problems. Firstly the torpedoes themselves had to be set to a neutral buoyancy rather than their usual run depth which in World War II was just below the waterline of a ship. If this wasn’t achieved then the launched torpedoes would rise upwards rather than straight on towards the target. By World War II the first primitive targeting computers were being installed in submarines for aiming the torpedoes but these were designed for attacking surface based targets. They therefore operated in a two-dimensional capacity (forward and to the left/right of the attacking submarine) as opposed to the three-dimensions required for fighting below the surface (forward, left/right and above/below the attacking submarine).

Given all these factors it is no wonder that only once has a successful attack on a submerged submarine by another submerged submarine been carried out in military history. The story begins in the twilight of World War II and has all the hallmarks of a Tom Clancy thriller. As 1945 dawned the fate of Nazi Germany seemed sealed. The allies were now marching eastwards across western Europe and north through Italy while in the east the massive juggernaut of the Soviet Union was bearing down to complete the ever tightening noose around the neck of Hitler’s Third Reich. In the Pacific theatre the almost paper ally of Germany, Japan was in a similarly dire state but unlike Germany Japan still had distance on its side. It was clear that Japan was not going to be defeated before Germany and that the war in the Pacific would likely last another few years as only a handful of people knew of the awesomely destructive weapon the Manhattan project was developing that would ultimately bring about peace. As part of the alliance with Japan, Germany promised to supply advanced weapons and technologies to its Far East ally that would help keep the Americans at bay. This policy continued throughout the war and even in the dark days of 1945 the Germans were sending this advanced technology to Tokyo.

U-boat pen like that at Bergen, Norway (uboataces.com)

U-boat pen like that at Bergen, Norway (uboataces.com)

Naturally, intercepting these shipments became a high priority for the allies and in December 1944 British codebreakers intercepted communications between Germany and Japan of an upcoming shipment expected to leave Norway via U-boat. The overwhelming strength of allied air and naval power meant that U-boats now offered the only chance of getting through to Japan as merchant ships would almost certainly be detected and sunk. On the 5th of February 1945 U-864 slipped its moorings at the Bergen U-boat bunker in Norway under the command of Korvettenkapitän Ralf-Reimar Wolfram with its destination being Japan. The departure had been repeatedly delayed due to first a faulty snorkel and then again after the U-boat ran aground attempting to leave Kiel in Germany forcing it to Bergen for repairs. Whilst in Bergen it was again damaged this time in a visit by the Royal Air Force’s famous No.617 Squadron and their Lancasters carrying 12,000lb “Tallboy” bombs. The U-boat pen was damaged and this in turn damaged U-864 and delayed repairs further. Now however despite the fact that Germany’s situation was growing ever direr in Europe the mission, codenamed Operation: Caesar, was to go ahead.

Wolfram’s U-boat was crammed with material destined to aid Japan’s fight against the allied nations in the east. This included 61 tons of metallic mercury which was a material growing increasingly scarce in Japan and used in bomb trigger construction. Perhaps of greater concern to the allied cause were numerous boxes containing engine parts for the Junkers Jumo 004 jet engine that powered the Messerschmitt Me262 jet fighter. The intention was for Japan to reverse engineer these components in order to build their own jet fighters that could counter the devastating B-29 Superfortress raids that were bringing Japan to its knees. Other boxes contained guidance systems for the V-2 rocket again for use by the Japanese in developing their own rocket program although this was at a significantly less advanced stage than in Germany.

U-864 was carrying personnel and equipment for Japan's jet fighter program

U-864 was carrying personnel and equipment for Japan’s jet fighter program

The U-boat also included four passengers. Tadao Yamoto was a Japanese acoustic torpedo expert who had travelled to Germany to compare notes and inspect German efforts in developing the first guided torpedoes. Toshio Nakai was an expert in the manufacture and employment of different fuel and was most likely involved in examining the fuel systems of the Me262 for use in Japan’s jet fighter project. Finally, emphasizing just how important the jet fighter project in Japan was to the Japanese, two Messerschmitt engineers were also aboard. The U-boat’s mission therefore was given the highest of priorities and conducted in the strictest secrecy.

Somewhat ironically it was this level of secrecy that betrayed the U-boat for the codebreakers at Britain’s famous Bletchley Park intelligence operation had cracked the German codes and learned of the mission. The Admiralty was immediately alerted about the U-boat and quickly went in to action to intercept it. Among the assets available was HMS Venturer, a V-class patrol submarine, under the captaincy of Lieutenant Jimmy Launders. Launders was known to have a brilliant mathematical mind that made him an ideal submarine commander and in the coming engagement this mathematical prowess would manifest itself in spectacular fashion. Venturer had already made a name for itself when it came to fighting other U-boats having sunk U-771 the previous November with torpedoes while it recharged its batteries on the surface.

HMS Venturer crestRoyal Navy Submarine Command, using the best information it had available to it, ordered Launders and the Venturer to patrol near the island of Fedje off Norway’s southwest coast in the belief that this was the most likely place where U-864 would be transiting in its attempt to break out. Venturer was one of an increasing number of British submarines that had been fitted with its own ASDIC system but the calculative Launders reasoned quite correctly that if Venturer went about sending out ASDIC pings to hunt for the U-864 it would alert the Germans to his presence and even invite attack. Venturer therefore stalked the waters around the island silently listening for the sound of a U-boat with its hydrophone equipment. Unfortunately for Venturer U-864 had already passed the island and had apparently escaped but as often is the case in war luck was about to play its part.

Wolfram was having problems with U-864’s engines. While they appeared to be functioning properly they were generating a great amount of noise indicating there was a problem deep inside the engine block. Afraid of breaking down hundreds of miles from a friendly port Wolfram elected to reverse his course and cancel the mission yet again. It must have been extremely frustrating for Wolfram and his men who unknown to them were now sailing back towards Venturer’s hunting ground.

Given his calculating mind Launders had begun to reason that they had indeed missed U-864 as he continued his patrol on the morning of February 9th 1945. Then suddenly he was informed by his hydrophone operator that he was detecting a sound in the distance. When asked what the sound was the hydrophone operator responded by saying that it sounded like a fishing boat’s diesel engine had started up. Launders suspected that it was more than a simple fishing boat’s engine. He reasoned that it was quite likely to be a submarine surfacing to charge its batteries since the noise seemed to appear out of nowhere. He therefore ordered his submarine to head for the sound of the diesel engine.

U-boat snorkelling (weberswarships.ca)

U-boat snorkelling (weberswarships.ca)

As they closed on the source of the noise the officer of the watch aboard Venturer raised the periscope and reported sighting another periscope cutting through the water. In actual fact he had spotted U-864’s snorkel which allowed the U-boat to run its diesel engines while submerged by feeding in outside air and ejecting the exhaust fumes. Snorkels were a relatively new invention and were only on German U-boats at this point hence the officer’s mistake. Launders now formulated a plan of attack. While the noisy diesel engines aboard U-864 were running he knew that the U-boat’s own hydrophone system would have a difficult time detecting his vessel and so the element of surprise was still on his side. Launders believed that the U-boat would have to surface soon not realizing what the snorkel was and the advantage it offered to the U-boat. He planned to stalk the U-boat until it surfaced and then attack it with torpedoes as it had done when attacking U-771 in the previous November.

For several hours Venturer followed U-864 which was zig-zagging from side to side as it made its way back to Norway; a common tactic to reduce an enemy submarine’s ability to acquire a firing solution with a high chance of scoring a hit. Time was quickly running out for Launders however as his own engine room reported that Venturer’s batteries were being drained rapidly by the pursuit and she would have to surface to charge them before long. Realizing that U-864 was not about to surface anytime soon Launders was faced with a choice; attack while the U-boat was submerged or break off the pursuit.

Launders’ mind began running numbers as he contemplated the chances of a successful engagement. He had a rough estimate of how deep the U-boat was thanks to the fact he could see its periscope (snorkel) but that didn’t guarantee accuracy. Launders reasoned that his best chance of success was to ripple fire all four of his forward torpedoes in to a kill-zone around the U-boat’s estimated position. Each torpedo would be fired independently at 17;5 second intervals and each successive torpedo would be directed differently assuming that if the first torpedo missed then the U-864 crew would be alerted to Venturer’s attack and take evasive action. Launders was calculating the first three dimensional submarine attack in history.

He had precious little battery life left and so he moved his submarine in to the most optimal attack position he could attain. Launders and his men knew their chances of success were low but they pressed on anyway determined, in that defiant spirit of the submarine service, to give it their best shot. The first torpedo left its tube and began its run while Launders counted down on his stopwatch towards the launching of the second torpedo. The frantic sounding whirl of the torpedo did indeed alert the crew of U-864 which quickly began efforts to take evasive action but the large U-boat was no ballerina and in order to submerge further to the protection of the deep the diesel engines had to be shut down and the electric motors started up all of which took time. Nevertheless the first torpedo was off target and missed as did the second.

After 53 seconds the third torpedo raced out of its tube and began its run. The fourth and final torpedo left the submarine 17.5 seconds later and with none left to fire Launders ordered his submarine to go deep to avoid counter attack. The submarine began a steep dive down in to the depths below as Launders watched the seconds tick by. He knew that if the third torpedo had found the target then they would have heard the explosion by now and so he assumed that it had missed. Everything now lay on the final torpedo.

There was a deep booming sound in the ocean outside. The explosion sent a shockwave familiar to the crew of a successful submarine as that of an enemy vessel exploding. Through the hydrophones Launders could hear the sound of popping rivets and breaking bulkheads confirming that he had hit the target. U-864, in taking evasive action to avoid the third torpedo had actually turned in to the path of the fourth just as Launders had predicted and now both the U-boat and its precious cargo were being sent to the ocean floor below. It remains the most unique submarine action in history.

NEWS: Did HMS Turbulent sink a French trawler in 2004?

HMS Turbulent S87 submarine

HMS Turbulent (militaryimages.net)

Five fishermen died in 2004 when their trawler, the Bugaled Breizh, sank off the coast of Cornwall under as yet unclear circumstances. While French authorities have failed to find a definite reason for why the vessel sank, family members of the five dead fishermen believe that either a British or French submarine operating on NATO exercises snagged the trawler’s nets and pulled the vessel under. They have two suspects in mind; the French submarine Rubis and the British submarine HMS Turbulent. A theory put forward in 2008 that it could have been an American submarine on a covert mission in the English Channel has largely been dismissed.

The Royal Navy and the Turbulent’s Captain Andy Coles have vigorously denied any involvement in the sinking of the trawler claiming that Turbulent wasn’t even at sea at the time of the tragedy. The Royal Navy have repeatedly stated that HMS Turbulent was in port at HMNB Devonport. The families claim that given the speed in which the trawler sunk which is estimated to have been just 27 seconds(!) coupled with traces of titanium believed to be from a submarine’s hull on the cables that enough evidence exists to point blame at a submarine for dragging the trawler down.

Earlier this week a French court hearing the case quashed an effort to force the French authorities to reopen the investigation. While French investigators failed to reach a conclusive answer as to why the trawler sank so quickly they did publish their belief that the most likely cause was that the nets snagged rocks and that the fishermen were unable to stop their engines before the vessel was pulled under the water.

Lawyers representing the families have said that they will continue to fight on for another investigation in to their claims and have threatened to take the case to Europe and even the UK.

Denying Dönitz the Dark

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Oberleutnant zur See (Lieutenant) Walter Köhler climbed the ladder from the control room of U-451 on December 22nd 1941. Climbing through the hatch atop the conning tower he was greeted by the calm night air of the western approach to the Strait of Gibraltar. The sound of the Type-VIIC U-Boat’s diesel engines chugged through the air as they charged the batteries used to power the submarine when submerged whilst under the cover of dark.

Karl Dönitz

Karl Dönitz

A World War II submariner’s life was often a singular one. There was very little news of the war outside the confines of the submarine’s hull and most crews didn’t know their country’s fortunes or failings until returning to port. One man in Nazi Germany’s U-Boat force who had an unparalleled view of the war however, at least compared to others in the service, was Konteradmiral (Rear Admiral) Karl Dönitz, the head of Germany’s submarines. The last quarter of 1941 had brought him cause for both celebration and concern. On November 13th one of his U-Boats, U-81, had torpedoed and sunk the British aircraft carrier HMS Ark Royal. As well as being a major combat loss for the British the vessel’s sinking was also a major hit on British morale.

This sapping of the British morale however would be shortlived because less than a month later the Japanese attacked the US Navy at Pearl Harbour and despite being advised against it by many of his top leaders, Adolf Hitler decided to honour the almost entirely “paper” alliance with Japan and declare war on America also. With German forces heavily committed to the war in the Soviet Union it was seen by nearly everyone as an almost suicidal move. For Dönitz this meant his U-Boats were now subject to attack by American warships anywhere in the world but he was still confident in his men and their submarines.

In truth he had every right to be. His U-Boats were still an elusive enemy and were inflicting savage losses on the Allied effort to keep Britain in the fight. The convoy system had done much to improve the odds in the favour of the Allies but they were still taking losses especially when the U-Boats operated at night. Contrary to popular belief, World War II submarines spent around 80-90% of their time on the surface to make sure their batteries were fully charged for the attack or for when they in turn were attacked. This was always safest at night and it also gave the German lookouts more of a chance of finding a target. It was always easier for a U-Boat lookout to spot a ship’s large silhouette on the horizon than vice-versa because like an iceberg most of a surfaced U-Boat remains below the waves. A crew on a destroyer or an aircraft might be lucky enough to spot the wake of a surfaced U-Boat in the moonlight but the chances were very slim. The night had been the refuge of the U-Boat since the war began.

With that in mind, Walter Köhler spent most of his watch scanning the horizon looking for a target confident that U-451 was as good as invisible and they would have plenty of time to react should they come under attack from a roaming Allied warship. An aircraft flying overhead might spot the wake of the submarine but Köhler and his lookouts would hear any multi-engined aircraft before it had time to attack and thus allow them time to dive away. Even radar hadn’t helped the RAF and Royal Navy hunt U-Boats at night…yet. The problem was that while ASV radar could vector an aircraft to within a mile of the U-Boat the pilots often couldn’t see the target especially if the U-Boat had dived. The radar sets simply weren’t sensitive enough to give a truly precise location of a U-Boat for an effective attack.

U-451 was operating in a rich hunting ground with the Strait of Gibraltar acting like a bottleneck for Allied ships in to and out of the Mediterranean. Gibraltar itself had a very heavy British military presence including a large number of aircraft. As Köhler’s watch continued a strange sound appeared to come from the diesel engines. Maybe it was a cylinder misfiring?

“Flugzeug!”

One of the lookouts screamed at the top of his voice; aircraft! The British Swordfish torpedo-bomber, an almost antiquated design, with it’s single engine being drowned out by the U-Boat’s own diesel engines had sneaked up on the surfaced submarine. Its ASV radar had got them into the area and its crew had plotted the direction their target was travelling in and worked out where it would be when they arrived in it’s immediate vicinity. It was a mix of radar information coupled with a highly educated guess. The Captain of U-451 ordered the submarine to dive quickly and Köhler along with the three other lookouts rushed for the hatch. The buzz of the Swordfish’s engines was now a roar and he glanced upwards, his night-oriented eyes spying the Swordfish for the first time as it’s depth charges began to drop from under it’s wings.

Fairey Swordfish

Fairey Swordfish

The weapons detonated ahead of the submerging U-Boat mortally wounding the vessel. The explosions sent pillars of water in to the conning tower forcing the captain, unaware that his vessel was already doomed, to take the drastic action of closing the hatch before Köhler could get inside to prevent further flooding. The unfortunate German officer found himself alone outside of a sinking submarine in a torrent of swirling water and so with little choice left to him he leapt in to the sea and started swimming away so as to not get caught in the swell of the sinking U-Boat. Within a few minutes U-451 was gone although he was unsure if it had dived or had been destroyed. Indeed he would not know for certain the fate of his shipmates until some time later. It would be nearly an hour and a half before a British ship found the exhausted Köhler and took him prisoner. Under interrogation he displayed hostility towards U-451’s captain unaware that the captain’s order to close the hatch effectively saved Köhler’s life.

Reports of the attack filtered back to London and Berlin. While it has to be taken in to account that the Swordfish crew’s skill and a certain degree of luck had a part to play in the sinking, the possibilities ASV radar offered could not be ignored. Interestingly, the radar used by the Swordfish crew had not been designed for this role but in the following year new radar sets built specifically for hunting submarines at night meant that Dönitz’s U-Boats had lost the cover of the dark. This would eventually force the Germans to introduce primitive radar warning receivers to give the U-Boat crews advance notice but it was a short term solution and this resulted in the development of the snorkel to allow the U-Boat to charge it’s engines while remaining at periscope depth; a slow and frustrating process.

By the end of the war a U-Boat on the surface  could expect attack in either day or night from overwhelming Allied air power that had both a numerical and qualitative superiority. One final note; the Swordfish that sank U-451 was attached to No.812 NAS operating out of Gibraltar. The only reason the squadron was flying from there was because their carrier, Ark Royal, had been sunk by a U-Boat the previous month. The Swordfish crew had taken their revenge.

A U-Boat in the Royal Navy (Part 3)

< A U-Boat in the Royal Navy (Part 1)
< A U-Boat in the Royal Navy (Part 2)

HMS Graph

Part 3 – HMS Graph is born.

Few vessels were ever tested as thoroughly as the captured U-570. Efforts were made to make her fully submersible again so as to fully evaluate the performance of the Type VII U-Boat. At the same time moulds were taken of the hull to test different shaped explosive charges for new depth charge designs. Just when the repair work was ready to go ahead Winston Churchill stepped in and began an effort to convince the Admiralty to hand the vessel over to the Americans. Churchill’s motives for this was that firstly the neutral Americans had the infrastructure to complete the repairs while Britain could barely spare a bolt it was so geared for war. He also believed that by handing over the vessel he would be further drawing the US into the Battle of the Atlantic and perhaps even the war itself.

The Admiralty successfully resisted his efforts although they did allow almost unrestricted access to the US Navy intelligence officers who arrived to inspect the vessel. Churchill’s interest in the vessel was not lost however and he then proposed that the vessel be given to the Yugoslavians to operate in the Mediterranean. This second plan died a quick death for many reasons, some technical and some political, but above all the lack of a skilled Yugoslavian crew who could man it meant the idea had to be dropped. Finally, Churchill conceded to the Admiralty’s desire to repair and test the vessel itself with the ultimate intention of putting the vessel in to frontline service against the Germans.

With that in mind a new name was needed as “HMS U-570” was not going to be looked upon favourably by anyone. To help identify her she received the pennant number “P715” which was painted on the sail but a name beginning with “G” to signify she was of German origin was needed. Just how the name HMS Graph was selected is disputed with some believing it is a play on the German word Graf meaning Count. Given its spelling however the real explanation is probably that it reflected the extent of the testing carried out that used literally miles of graph paper. Either way, HMS Graph was born.

HMS Graph interior

RN officer at U-570/HMS Graph’s chart table

Trials were conducted under the command of Lieutenant Commander E.D. Norman and between September 1941 and June 1942 every aspect of the vessel’s performance was examined. The trials proved just how good German submarine design really was compared to the Allies. It seemed that the Germans had a better understanding of keeping a submarine undetected than the Americans or British did with features such as rubber padded floors in the machine room that suppressed the vibration of the electric motors when operating submerged. This made detecting the vessel by hydrophone very difficult and impressed the Allies so much that they immediately copied the system in their own vessels. One of the most secretive projects that involved the Graph was the copying of the control room’s layout. This was then used to train specialist boarding parties who would (in theory) be able to fight their way in and capture more U-Boats.

By Mid-1942 the Admiralty was satisfied that it had learned all it could from the U-Boat and therefore felt willing to put it in the frontline. HMS Graph was placed under the command of Lieutenant Peter Marriott who had served under Norman during the trial phase and had thus became well acquainted with the vessel. On October 8th 1942, the former German U-Boat set sail under the Royal Navy ensign to wage its war against its former master.

HMS Graph transited south to patrol the west coast of France to attack any U-Boats or German surface raiders attempting to break out in to the Atlantic to intercept the convoys between Britain and North America. Just like their German counterparts, British submarine crews had to contend with harassment from the air which for the British meant keeping a watchful eye for the German Focke-Wulf Fw200 Condor. This large four engined aircraft had built an enviable reputation for successfully tracking convoys and directing U-Boats to their position. It was also able to attack submarines with bombs and depth charges.

The Fw200 Condor provided the U-Boats with vital intelligence

The Fw200 Condor provided the U-Boats with vital intelligence

On the afternoon of 21 October 1942 HMS Graph was operating 60 miles off Cape Ortegal when her lookouts atop the sail spotted the menacing shape of a four engined maritime patrol aircraft. The vessel immediately went to diving stations with the lookouts rushing down below frantically closing the hatches behind them. Soon the vessel was slipping beneath the protection of the waves but as it did the hydrophone operator detected a contact in the local vicinity. Weighing up all the information he had such as the location of where Allied submarines would be operating Marriott assumed, quite correctly, they had detected a U-Boat.

Marriott set about stalking his prey. After nearly a quarter of an hour of following the contact which was travelling on the surface he raised his periscope and spied the distinctive tail of U-333. Marriott plotted a firing solution and when he was satisfied he gave the order to fire a spread of four torpedoes. Several tense minutes passed. Then the hydrophone operator reported loud explosions as the torpedoes detonated followed by what appeared to be the sound of bulkheads failing. The crew of the Graph cheered as they celebrated their victory and a few days later returned to port to claim their kill which for Marriott meant receiving the Distinguished Service Order for his courage and skill.

U-333

U-333

Alas, history would steal the claim away from the Graph. Records obtained post war showed that U-333’s own lookouts spotted the torpedo tracks early enough for her to take evasive action. The U-Boat’s captain, Peter-Erich Cremer, later said that after the torpedoes passed by then detonated harmlessly in the distance. As for the sounds heard afterwards that the Graph mistook for collapsing bulkheads he believes that damage already inflicted on the U-Boat by a British escort ship that had rammed the U-333 on the surface could account for this. At the time it was detected by HMS Graph, U-333 was limping back to its base following the collision.

Unaware of this fact however, HMS Graph departed Holy Loch again on the 19th November 1942 hoping to repeat the “success” of the previous patrol. Marriott and his men thought the opportunity was presenting itself when they received a signal that an Italian transport ship, the Cortellazzo, had entered the area and it was to be sunk with the highest priority. Unknown to Marriott, British intelligence had discovered that the Cortellazzo was carrying over 2,000 tons of advanced machinery destined for Japan to help them improve their own equipment to use against the Allies in the Pacific. Later in the war these journeys were actually undertaken by U-Boats as surface vessels became increasingly vulnerable. Equipment given to the Japanese by the Germans this way included jet and radar technology the latter of which was fitted to the battleship Yamato. Marriott set up a search pattern but his efforts were to prove fruitless as the Cortellazzo slipped by undetected by the Graph only to be intercepted by HMS Redoubt, a destroyer-escort which sank the vessel after ordering her crew off and then rescuing them. The frustrated crew of HMS Graph returned to port on the 8th December 1942.

Any hope of a Christmas at home were dashed however when the crew were ordered to set sail again on Christmas Eve 1942 for a third patrol. This time they were operating with a British wolfpack of four submarines heading north for the Norwegian coast to intercept German warships and submarines attempting to interfere with convoys to Russia as well as North America. Upon arriving on station the wolfpack received word that the German heavy cruiser Admiral Hipper was expected to make a break for its port in Norway.

Admiral Hipper

Admiral Hipper

 The Admiral Hipper was one of the German Kriegsmarine’s main surface combatants and a very real threat to the convoys. However, on the 31st December the Admiral Hipper along with another cruiser and six destroyers attacked the convoy JW 51B heading north for Russia. In what became known as the Battle of the Barents Sea the German force faced disaster in the face of a potent British escort force who used superior tactics to circumvent the German’s superior firepower. The Germans lost one cruiser and one destroyer with the remaining force, including Admiral Hipper, being made to scatter and retreat. Unknown to British intelligence or the crew of the Graph Hitler had been so infuriated by the disaster that it effectively meant the end of any real attempt to attack convoys by surface vessels and priority was soon given to the U-Boats. Nevertheless, at 1am on the 1st January 1943 Marriott spied the menacing silhouette of the Admiral Hipper and prepared his attack. Frustration would once again curse the Graph as Marriott realized the Admiral Hipper was too far off and travelling too fast for any chance of a successful attack.

Unable to pursue, the Graph lost contact but as though fortune was smiling on them they suddenly ran in to two of the German destroyers that had taken part in the attack. While Admiral Hipper was relying on her great speed for protection the two destroyers were relying on their manoeuvrability and were zig-zagging; a common tactic to make a ship difficult to attack with a torpedo. At 4:23am, Marriott ordered the Graph to close within 7,000 yards of the two ships and prepared a spread of four torpedoes in a wide pattern in order to counter the defensive pattern the destroyers were taking. The torpedoes fired and after a few moments a loud explosion was heard through the hydrophones indicating a hit. The Graph then retreated from the area fearing depth charge attack from whichever destroyer hadn’t been hit. History would prove cruel twice to the crew of the Graph as again post war records proved that all four torpedoes missed their targets and the explosion must have been caused by a torpedo hitting rocks or malfunctioning.

HMS Graph returned to port on the 13th January. Her engineering log showed that she was beginning to look in poor shape as a number of breakdowns from a lack of spare parts was beginning to blight the vessel. It was therefore decided to take her off the frontlines to spend her last days as a target for air and surface battery crews to train their weapons on. Shortly after decommissioning in February 1944 she was taken undertow for scrapping on the River Clyde but during gale force winds her tow rope snapped and she was blown aground near Coul Point, Scotland. She was never recovered and broken up for scrap in situ over the following 20 years but some of it remains even today.

The legacy of U-570/HMS Graph lays in revealing to the Allies how much more sophisticated the German submarines were and how they could improve their detection methods. This went a long way to helping the Allies finally defeat the Germans in the Battle of the Atlantic.