During World War II, neutral ports like Spanish harbors and Portuguese Goa served as critical intelligence assets for both sides, with Germany using them for submarine resupply and observation networks while the Allies conducted covert operations to destroy these intelligence capabilities, demonstrating how neutral territories became strategic weapons in the intelligence war rather than safe havens.
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U-Boats Thought Neutral Harbors Were Safe Until They Became Intelligence TrapsAdded:
March 9th, 1943.
Mormugao Harbor, Portuguese Goa.
Lieutenant Colonel Lewis Pugh stood in the darkness on a river barge, watching middle-aged bankers and solicitors check their weapons and wait for the signal.
The men around him were members of the Calcutta Light Horse, an auxiliary regiment that hadn't seen real action since before most of them were born.
They were overweight. Some wore spectacles.
One had left his insurance office 3 weeks earlier without being able to tell anyone where he was going or why.
They were here to sink a merchant ship that had been sitting quietly in a neutral harbor for 4 years. No one was supposed to know they [music] had done it. If it ever came out, the British government would deny everything.
On shore, another Light Horse member named Jock Cartwright had spent the previous hours bribing brothel operators and organizing a carnival party large enough to draw the ship's officers away from the harbor, the lighthouse, and the navigation buoy had both gone dark.
The harbor was black water and silence.
Below decks on the German merchant ship Ehrenfels, the most powerful secret radio transmitter in the Indian Ocean waited.
Out at sea, 13 German submarines were waiting for their next set of coordinates.
To understand what happened in that harbor on March 9th, you need to understand something about how both sides had been using neutral territory since the war began and what the stakes were by the third year of the campaign.
Neutral ports had been part of warfare's hidden architecture since before either World War.
Germany understood this better than most.
In 1911, German naval planners created a secret organization called the Etappendienst, translated roughly as the secret naval supply service. Its purpose was simple: plant agents posing as businessmen in ports around the world years before any war began, so that when the shooting started, those agents would already be in position to supply German warships.
The people selected for the Etappendienst were not military men in any obvious sense. They were shipping company employees, fuel oil traders, chandlers, port officials, customs men who knew the docks, men who could spend years in a foreign city doing ordinary commercial work, waiting.
Some waited a decade and a half from the organization's founding until the war began.
When the Second World War started in September 1939, the Etappendienst activated.
Four German supply ships were already in Spanish ports.
The Thalia at Cadiz, the Bessel at Vigo, the Max Albrecht at El Ferrol, and the Corrientes in the Canary Islands.
Germany had also pre-positioned fuel tankers in the Canary Islands holding over 20,000 tons of diesel and fuel oil.
It had all been arranged years in advance under cover of legitimate shipping company operations.
Spain was sympathetic to Germany in 1939. With Franco in power and in debt [music] to Hitler for help during Spanish Civil War.
The arrangement was politically convenient for everyone. Between January 1940 and early 1942, 25 or 26 German submarines received fuel, food, water, lubricants, navigation charts, and in some cases torpedoes at Spanish ports.
All while Spain officially maintained neutrality.
The operations ran almost entirely at night.
The boats would come in after dark, moor alongside the supply ship, take what they needed, and be gone before first light.
Almost all of them were clear before sunrise. In a few cases, operations ran long, attracted attention, even drew crowds on the shoreline watching from the dark.
Those attracted British protest to Madrid.
The supply ships themselves had been sitting in Spanish ports since the war began.
They were legally marooned there.
The moment they left, British warships in the Atlantic would sink them.
So, they stayed.
Their captains [music] and crews had nothing to do but wait. And when a submarine came in at night with its fuel gauges low, they were ready. It was the sort of arrangement that looked chaotic from a distance and ran with quiet efficiency up close.
U-52 refueled at Vigo in July 1940. U-96 refueled there in November 1941.
U-4 3 4 received 100 tons of diesel, food, and medical supplies at Vigo in December 1941. Then sailed for patrol waters >> [music] >> near Gibraltar.
That last refueling would matter very soon, and not in the way Germany intended.
But before that reckoning, consider what neutral ports provided to Germany beyond the fuel and food.
They provided extension.
A Type 7 submarine operating out of Brest had about a 3-week patrol radius to the North Atlantic convoy routes.
One refueling stop at a neutral Spanish port could add 10 days or 2 weeks to that range.
A submarine that had spent its offensive capacity and was running low on diesel no longer had to make the long run back to France and wait for the next patrol cycle. It could resupply and continue.
This was the quiet advantage that neutral ports gave Germany. Not dramatic, not a single battle-winning capability, but a steady multiplier.
More days on station, more chances to find convoys, more tonnage sunk per submarine per patrol.
The British understood this.
They watched the Spanish ports and the Canary Islands from a distance, gathered what evidence they could, and filed protests with Madrid.
For most of 1940 and 1941, they had strong suspicions, but lacked ironclad proof.
Then U-434 gave them all the proof they needed and something else besides.
There was a second dimension to neutral ports that neither side advertised, but both sides understood.
It wasn't just what you could take from a neutral port. It was what you could see there.
The Strait of Gibraltar is 9 mi wide at its narrowest point.
Every Allied convoy moving between the Atlantic and the Mediterranean had to pass through it. On both sides of the Strait, in Spanish territory, Germany had maintained advert observation posts since early in the war.
Teams of watchers with binoculars and radio equipment sat in cafes [music] and fishing villages and unofficial offices looking out at the water and reporting what they saw.
Every ship that passed, every convoy that entered, what time it sailed, what direction, how many escorts, what classes.
The Germans tracked Allied shipping movements in and out of the Mediterranean with the same systematic patience that had made the "Etappendienst" possible in the first place.
This information reached U-boat headquarters within hours via coded radio transmissions.
Submarines operating west of Gibraltar received position reports on convoys that were currently in transit, allowing them to set ambush positions ahead of the approaching ships.
The American naval historian's post-war analysis of German naval communication intelligence captured in the 1945 Battle of the Atlantic study put it plainly, "Information from agents, as seen through U-boat traffic, was confined largely to the Gibraltar area.
The Germans followed all ship movements in and out of the Straits.
There was a similar operation further east in a setting so unlikely that nobody initially thought to look for it."
The German merchant ship Ehrenfels had taken refuge in the neutral Portuguese harbor of Mormugao in Goa, British India's coastal neighbor, in 1939.
International law entitled neutral ships to shelter in neutral ports during wartime.
The Ehrenfels, along with two other German freighters called the Drachenfels and the Braunfels, and an Italian vessel called the Anfora, simply anchored in the harbor and stayed there.
Portuguese colonial officials looked the other way.
The ships were technically interned, >> [music] >> their radio equipment officially removed.
There was supposed to be nothing for them to do but wait out the war.
Officially, the Ehrenfels had no radio equipment. Unofficially, the Ehrenfels had a concealed transmitter of extraordinary power capable of reaching far out to sea. A German spy named Robert Koch, living ashore in Goa with his wife Gretta, collected intelligence about Allied merchant shipping movements from a network of agents with access to port schedules, cargo manifests, and convoy timetables.
Koch passed this information to an officer on the Ehrenfels. The transmitter relayed it to German submarines operating in the Indian Ocean.
In the autumn of 1942, 46 Allied merchant ships were sunk by U-boats in the Indian Ocean over a 6-week period.
In the first week of March 1943 alone, 12 more.
At that rate, the Indian Ocean shipping lanes that supplied Britain's forces in the Middle East and North Africa were in serious danger.
The intelligence coming out of Goa was not a side story.
It was directing operational attacks.
British intelligence in India began intercepting the radio signals. They traced them to Mormugao Harbor.
They sent two agents overland into Goa in November 1942 who kidnapped the Kochs >> [music] >> and brought them across the border for interrogation.
The Kochs were questioned and then vanished from the official record.
What exactly happened to them is not [music] documented.
But removing the Kochs did not stop the transmissions because enough of the network remained intact to continue funneling information to the ship.
That left the transmitter itself.
And the transmitter was sitting inside a neutral harbor the British had no legal right to enter.
Consider what the 18 men of the Calcutta Light Horse and Calcutta Scottish were asked to do on March 9th, 1943.
They were civilians.
Their regiment was a part-time reserve unit that functioned as much as a social club as a military organization.
They met regularly, trained occasionally, and had last seen action in a conflict most of them had been too young to remember. Many of them had been rejected for active service because of their age.
They were bankers and merchants and solicitors in their 40s and 50s who had spent 3 years watching the war from the sidelines.
Lieutenant Colonel Lewis Pugh of the Special Operations Executive had come to them in late February because there was no one else.
Regular British Armed Forces could not enter Portuguese neutral territory. A formal military operation would constitute a violation of Portuguese sovereignty, create an international incident, and potentially push Portugal into Germany's arms.
Portugal's neutrality was valuable to the Allies.
The Anglo-Portuguese Alliance of 1373 was in active use, and Britain [music] needed to preserve that relationship for other strategic reasons, including the Azores.
So, the mission needed deniability. It needed men who could plausibly [music] be described as civilians engaged in some sort of private adventure that the British government had nothing to do with. It needed people who could not officially exist as combatants.
Pugh gave the Light Horse members a few days of training, showed them blueprints of the Ehrenfels that SOE agents had obtained, and asked for 14 volunteers.
More than 30 came forward. The plan had a specific detail that separated it from pure improvisation. Cartwright had been sent ahead to Goa. His job was to make sure that on the night of March 9th, the crews of the ships in the harbor would not be on their ships.
SOE funds were used to organize a carnival party for all the sailors in the harbor, timed to coincide with the town's actual carnival celebrations.
Cartwright also arranged with local brothel operators to make their services free that night. Again, funded by the British government.
On the night of the raid, the harbor's lighthouse and its navigation buoy were both dark. By arrangement or coincidence, the records don't fully clarify.
Pugh's team arrived at Mormugao on the river barge Phoebe piloted by a Royal Navy officer who found himself commanding what was, by any measure, the most improbable assault craft in naval history. Some of the team had sailed from Calcutta around the southern tip of India to reach Goa. Others had taken the train across the continent to Cochin and boarded the barge there.
The journey itself was an act of improvisation. There was no proper assault vessel available. The SOE used what existed and made it work.
Around midnight, Phoebe entered the darkened harbor. The boarding party >> [music] >> found a skeleton crew on Ehrenfels. The carnival had done its job. There was a brief, violent struggle. The ship's captain reached for a weapon. He was shot. Four other German sailors died in the fighting. The radio transmitter, which was the primary target, was disabled. As the boarding party began planting explosives, they heard the sound of the ship's seacocks being opened. The surviving crew was scuttling her rather than let the British take her intact.
Within 20 minutes of the attack beginning, Davis on the Phoebe saw Ehrenfels beginning to list. He pulled the recall signal three times on the ship's horn. Every one of the raiders made it back to the barge with minor injuries.
Then the darkness filled with the sound of additional explosions from the other Axis ships in the harbor.
The captains of the Drachenfels, Braunfels, and Ehrenfels, hearing [music] the attack on Ehrenfels and receiving a fake British radio broadcast warning of an imminent invasion of Goa, scuttled their ships before the raiders could reach them.
The British bluff had worked better than expected. As Phoebe cleared the harbor and reached open water, someone transmitted a single codeword, Longshanks. The mission was complete.
After the raid, the 13 German submarines operating in the Indian Ocean sank exactly one ship for the remainder of March.
In April, they managed two.
The intelligence network that had directed 12 killings in a single week had been destroyed. The mission stayed classified until [music] 1978.
Nobody got a medal.
The men went back to their offices.
Think about what that means from a different angle.
Somewhere in Germany in the spring of 1943, the families of submarine crews waiting for news from the Indian Ocean eventually stopped receiving letters.
A boat that had been sinking ships in January and February went silent in March.
No confirmed sinking. No signal.
The boat was at sea, presumably operating.
>> [music] >> Then weeks passed, then months, then the telegram. The men on those submarines had been guided to their targets by intelligence that came off a ship sitting in a Portuguese harbor in India.
A ship that appeared to all official records to be doing nothing.
When the ship went dark, the guidance went dark with it. The submarines didn't know why their targeting intelligence had stopped. They couldn't know. They just found fewer targets. The families waiting at home couldn't know any of this either. The official record of what ended the Ehrenfels wouldn't exist for 35 years. The intelligence game in neutral ports ran in both directions.
Germany was not only receiving help from Spain and Portugal.
Germany was watching from them.
Think about what it meant to command a U-boat heading south toward the Gibraltar approaches in 1942.
You have a submarine that needs to enter the Mediterranean. You need to cross 9 mi of heavily patrolled water.
Every hour, ships are passing through that strait. And on both banks, in Spanish territory, German eyes are watching them.
Before you make your approach, headquarters has sent you a message. At 3:15 in the afternoon, a convoy of 14 merchant ships with four destroyer escorts departed Gibraltar heading west.
At 5:40, a tanker group of six vessels sailed east toward Algiers.
The message contains the exact counts, the types of vessels, the timing.
Your headquarters is not guessing at this.
Watchers in Algeciras on the Spanish shore and in Ceuta on the Moroccan side saw this with their own eyes and radioed it within the hour.
You know what's in the water.
Your adversaries on those ships don't know you're coming.
This was the strategic gift that Spanish neutrality provided Germany throughout the first half of the war.
The Abwehr had built observation networks not just at Gibraltar, but at ports across North Africa and West Africa, in the Canary Islands, and in Lisbon.
A detailed analysis of captured German naval communication intelligence, part of the post-war Battle of the Atlantic study by American naval historians, documented the flow explicitly.
German agents in neutral Lisbon were collecting information on transatlantic convoy departures from the United States, some of it originating from Allied attache offices in the same city.
The Japanese military attache in Lisbon, whose traffic was being intercepted and decoded by Allied intelligence, was simultaneously relaying convoy departure data from American ports to Berlin.
Neutral Lisbon was both an Allied intelligence hub and a German one. And the information flowing through it went in multiple directions at once.
The Germans in the Canary Islands and along the Spanish coast were not amateurs doing rough estimates. They were trained observers filing systematic reports.
The German intelligence apparatus in Spain, known as the Abwehr station KO Spanien, was one of the largest German intelligence operations outside Germany itself. It ran agents at ports, at airports, at borders. It tracked not just military convoys, but merchant shipping patterns, fuel prices, cargo movements.
Anything that suggested Allied operational intentions was collated and forwarded. What made this dynamic particularly dangerous was the time sensitivity of the intelligence. A convoy that sailed from Gibraltar at 3:00 in the afternoon had to pass through the open Atlantic approaches before dark. A submarine that received the sighting report within 2 hours could be in position to intercept before the convoy reached deep water. The German observation network turned neutral Spanish geography into a tactical weapon.
When Operation Mincemeat was planned in 1943 to deceive Germany about the Allied invasion of Sicily, the planners specifically targeted a German agent in Cadiz as the reception point for the planted documents.
A dead man in a British military uniform was floated ashore on the Spanish coast carrying papers suggesting the invasion target was Sardinia and Greece rather than Sicily.
The documents were passed to the German agent in Cadiz within days and from there to Berlin.
The planners chose Cadiz not at random but because they knew the German intelligence network that was active, trusted, and fast. They were right.
The documents reached Hitler. He redirected German forces away from Sicily.
The invasion succeeded.
The same network that had been providing intelligence to U-boats was deceived into killing them.
The individual accounting behind the neutral port intelligence war is hard to pin down in numbers because intelligence that prevents attacks doesn't leave tonnage records the way attacks that succeed do. But some figures are clear.
The 12 Allied ships sunk in the Indian Ocean in the first week of March 1943 had a combined displacement of [music] roughly 80,000 tons based on the estimates in post-war British assessments.
Those 12 ships carried cargo.
Some of them carried people.
The crews of merchant vessels in the Indian Ocean in early 1943 were not generally naval personnel.
They were merchant sailors with no weapons and minimal protection.
When a torpedo found their ship, they had minutes to get to lifeboats in some of the most isolated waters in in war.
After the Ehrenfels went down on March 9th, the same 13 U-boats that had been sinking a ship or more per day managed only one kill in the last 3 weeks of the month. Then two in April. The math is not subtle.
Something that had been working stopped working on the night of March 9th.
The families of the 200-odd crew members on the Axis ships in Goa eventually got their men back, though not until the war ended.
The Portuguese kept the survivors in Aguada jail after the scuttling.
The local newspaper reported that the German crews had mutinied and sunk their own ships.
This was technically accurate enough not to raise further questions.
The families of the 18 raiders from the Calcutta, [music] Lighthourse, and Calcutta Scottish went 35 years not knowing what their fathers and husbands had done.
Not because the men were dishonest, but because they had been told not to speak.
Some of them had never told their families anything.
When James Leasor published his account in 1978, some of the surviving raiders' children learned for the first time what the missing weeks had been about.
Jack Breen, one of the raiders, returned to his insurance firm's offices the week after the mission. His business partner showed him a newspaper article about the mysterious scuttlings in Goa harbor and the inexplicable loss of four Axis ships. His partner was worried. He had insured the Ehrenfels and the other vessels. There would be claims. [music] Breen looked at the article and said nothing.
The insurance company paid out.
U-434 and the intelligence windfall Wolfgang Heyda, who commanded U-434, had refueled at Vigo in December 1941 as part of Group Stuben's operations in the [music] Atlantic.
Low on fuel and provisions after an unsuccessful sweep near Newfoundland, he brought his boat into the Spanish port overnight, took on supplies from the interned German supply ship Bessel, and sailed for patrol waters near Gibraltar.
He was assigned to Group Sierra Alba targeting convoy HG76, a Gibraltar homebound convoy that would prove to be one of the most consequential battles of the early war.
Convoy HG76 was escorted by Commander Frederick John Walker's 36th Escort Group, and it had something Germany had not yet encountered at sea, the escort carrier Audacity, carrying Martlet fighter aircraft.
Walker's group was experienced, [music] well coordinated, and looking for a fight.
Group Seeräuber found one.
On December 18th, Walker's Escort Group caught U434.
50 depth charges drove the boat to the surface.
The crew abandoned ship.
42 men, including Heider himself, were pulled from the water and taken prisoner.
In late 1941, British intelligence had been trying to prove what it already suspected about Spanish port resupply operations.
The crew of U434, fresh from Vigo, and the resupply that had sent them back to sea, provided the irrefutable evidence the British had been seeking. The interrogation of the prisoners confirmed not just that the refueling had happened, but the details, the ship used, the quantities, the procedures, the coordination with German and naval command. The British Embassy in Madrid had filed a formal protest in July 1941.
The capture of U434 in December provided the documentation to back it.
By late 1941, Spain began scaling down its support of U-boat operations in the Canary Islands.
By late 1942, the Spanish formally reduced the program to emergency only cases.
The intelligence from U434 had directly contributed to closing one of the most effective covert supply networks Germany had established.
Heider went to a prisoner of war camp.
He later attempted a daring escape from a Canadian facility and was recaptured on the beach.
U434 was the last boat [music] he ever commanded. U760, and the boat that Spain kept. [music] In August 1943, U-760 was on patrol south of Newfoundland when it was caught on the surface by a United States Navy Liberator bomber from Patrol Squadron V-B-103, piloted by Lieutenant Junior Grade Thueson.
The aircraft attacked with depth charges and cannon fire, damaging the submarine severely. The boat managed to submerge and survive the immediate attack, but her diesel engines had been damaged.
Both eventually failed west of Cape Finisterre.
With no diesel power and batteries running down, U-760 had two options. She could try to reach her home port in France on electric motors, which might not hold long enough for the crossing, or she could put into the nearest neutral port.
Commander Heinrich Hans Graf brought his boat into Vigo on September 8th, 1943.
Under international law, a warship that entered a neutral port for repairs >> [music] >> had 24 hours to leave or be interned for the duration of the conflict.
It took more than 24 hours to repair both diesel engines. The Spanish naval authorities placed U-760 under the supervision of the Spanish cruiser Navarra, and then transferred the boat to El Ferrol, where it stayed until Germany surrendered.
52 men spent nearly 2 years in neutral Spanish internment rather than finishing the war.
From Germany's perspective, this was 48 men and a working submarine removed from the order of battle.
The Allies tracked the boat.
Allied intelligence noted its location.
The records of captured submarines and interned vessels contributed to the broader picture of German operational capacity that Allied planners monitored throughout the war.
The Abwehr watchers and their blind spot. Germany's observation networks in Spain were genuinely effective at tracking convoy movements.
The Abwehr teams at the Strait of Gibraltar, >> [music] >> on both the European and African sides, reported ship movements with a regularity and precision that made them operationally valuable to U-boat commanders.
But the network had a blind spot built into its own success.
The information it generated was valuable enough that transmitting it required radio communications. Radio communications could be intercepted.
Germany's Enigma encoded radio traffic was being read by British intelligence at Bletchley Park from June 1941 onward with varying levels of access at different periods of the war. The network of agents in neutral Spain was not running on a separate secure channel. Their reports reached Germany via the same diplomatic and military communications that Allied intelligence monitored and sometimes decrypted. The result was a situation where Germany's neutral port intelligence network was simultaneously providing Germany with operational convoy data and providing Allied intelligence with a window into German intentions.
When specific convoy sightings generated specific U-boat movement orders and those orders could be tracked against subsequent Allied convoy routing decisions, the information flow could sometimes be reversed to identify what Germany had seen, when it had seen it, and from where. This was not a simple advantage that the Allies held consistently. The intelligence picture was messy, contested, and sometimes dangerously delayed. But the principle held, a network [music] that depended on radio communication was a network that produced interceptable signals. The neutral port, which provided physical shelter and supply, also generated the radio traffic that became the target of counterintelligence work.
The Azores and the closing gap.
The most strategically consequential neutral port story of the Atlantic campaign wasn't about submarines at all.
It was about aircraft. Germany had been using the Azores through the Etappendienst station at Horta on the island of Faial for submarine provisioning since the early stages of the war.
The island sat in the middle of the Atlantic, roughly 800 miles west of the Portuguese coast at a position that made them useful to anyone conducting operations in the Central Atlantic.
They were equally useful to the Allies.
Aircraft based in the Azores could patrol a vast stretch of the Mid-Atlantic that no land-based aircraft from Britain or North America could reach. This was the gap that wolf packs had exploited. The zone where convoys crossed without air coverage and where submarines could attack with relative impunity. Britain had been trying to negotiate access to Azorean bases since early in the war. Portugal refused, afraid that granting bases to the Allies would provoke Germany into invading the Portuguese mainland. The negotiations continued for 2 years.
In August 1943, with the Battle of the Atlantic turning in the Allies' favor and Germany weakening on multiple fronts, Portugal's calculation changed.
On August 17th, [music] 1943, the British and Portuguese governments signed an accord granting Britain unrestricted use of the port [music] of Horta for resupply, full use of airfields at Lajes on the island of Terceira, and associated facilities.
Britain had invoked the Anglo-Portuguese Alliance of 1373, the oldest formal alliance in the world still in effect, to make its request.
Salazar had agreed. The German Etappendienst station at Horta, which had been providing provisioning [music] support for German submarines, was now in a port where British aircraft were landing and British warships were refueling.
The same harbor that had helped extend German U-boat patrols now anchored Allied anti-submarine operations. Allied aircraft operating from Lajes covered the Central Atlantic gap that had protected wolf pack assembly areas for 3 years.
What the Lisbon connection meant, Lisbon was the spying capital of the war. Both sides had large, professional intelligence operations [music] running simultaneously in the same city, and both sides knew it. And both sides used this knowledge strategically.
British agents in Lisbon were monitoring German diplomatic and military communications.
German agents in Lisbon were collecting Allied shipping intelligence.
Some of it from Allied attaché [music] offices in the same city.
The Japanese military attaché's office transmitted convoy departure information from American ports to Berlin via Lisbon.
Allied intelligence decoded this traffic and learned both what Germany knew and sometimes when Germany had learned it.
The British also ran double agents through Lisbon.
An agent >> [music] >> established as a reliable source for Germany could pass information deliberately shaped to mislead. If a German agent in Lisbon received and forwarded [music] false convoy routing data, and German submarines positioned themselves based on that data, the submarines would be in the wrong part of the ocean.
The double agent operation wasn't simply about passing false information once and hoping it worked. It required maintaining the agent's credibility with German handlers over months [music] and years.
The agent had to provide a steady stream of information, most of it genuine, but carefully selected so that the occasional piece of deliberate misinformation would be trusted.
Too many inaccuracies and the Germans would suspect the source.
Too much genuine intelligence and the Allies were simply handing Germany real convoy data.
Getting this balance right was painstaking work.
The records of the double cross system, which ran British double agents throughout the war, show how carefully each piece of information was evaluated before being approved for passage.
An intelligence officer had to weigh whether giving Germany an accurate convoy departure time would sink more ships than it would protect in the long run by preserving the agent's credibility.
These were not abstract calculations.
Real ships were sailing those routes.
Real sailors were aboard them. This was sophisticated work, harder to maintain than the operation in Goa had been.
The Ehrenfels problem had a physical solution, destroy the transmitter.
The Lisbon intelligence war had no physical solution.
It was an ongoing contest of deception and counter deception running through the same neutral city simultaneously on both sides. The measure of how seriously both sides took this environment was the level of talent committed to it.
German intelligence sent experienced capable officers to Lisbon.
British intelligence under Stewart Menzies and the Secret Intelligence Service >> [music] >> ran multiple active networks there.
The Office of Strategic Services, the American wartime intelligence organization, competed and sometimes clashed with British intelligence in the same city.
For the families of merchant sailors in the North Atlantic and Indian Ocean, this contest of professionals in Lisbon cafes had direct consequences.
An agent who successfully passed false departure times to German headquarters could mean that a convoy crossed safely because the submarines were positioned wrong.
A German agent who successfully obtained real departure data could mean a submarine found a ship that had been at sea for 3 days.
The intelligence flowed directly to operational outcomes with a speed that made neutral ports not just logistical assets, but active weapons. The invisible crew of U-760, the men of U-760 spent almost 2 years in El Ferrol, northern [music] Spain waiting. They were not prisoners of war in the formal sense. Spanish internment was a legal status under the laws of neutrality different from capture by an enemy. They were confined, supervised, and [music] not permitted to leave.
But they were in a neutral country rather than an enemy one.
They knew the war was continuing without them.
They could not participate in it.
They heard news at varying degrees of reliability of how the campaign in the Atlantic was going.
They were there when Germany surrendered in May 1945.
They went home as survivors rather than casualties.
Their submarine stayed in Spanish hands after the war. Spain had purchased the Corrientes supply ship from Germany in 1942 as the price of continued silence about the refueling operations. The interned U-boats became a kind of currency in the same diplomatic transaction.
Spain had taken custody of them under neutrality law, but possession had consequences that lasted beyond the armistice. By late 1942 and through 1943, the neutral port network that Germany had constructed with such patience was closing down station by station.
Spain's willingness to facilitate German submarine operations had begun declining in mid-1941 when it became clear that Germany was not going to win quickly and that British protests about neutrality violations were backed by economic leverage.
A series of British diplomatic efforts backed by the threat of economic sanctions and reinforced by Germany's failure to deliver on promises made to Franco about Spanish territorial ambitions in North Africa gradually squeezed the supply operations.
By late 1942, the Spanish operations were nominally restricted to emergencies only.
The last documented refueling in Spanish ports took place in February 1944.
It's worth noting what was not lost when the supply network closed. The submarines themselves didn't become less capable in a single moment. The boats still had French bases in Lorient and Brest and Saint-Nazaire. They still had the milk cow submarines, modified type 14 boats that could refuel and resupply attack submarines at sea, but the milk cows were themselves priority targets.
Allied intelligence prioritized them specifically because eliminating them hurt multiple submarines.
By mid-1944, all 10 of the milk cows had been sunk.
Every layer of the supply and intelligence network that had extended German submarine operational range was being systematically peeled away.
The Azores deal in August 1943 closed the final major gap in Atlantic [music] air coverage.
With British aircraft operating from Lajes, and subsequent American access to the islands in the following months, submarine wolf packs could no longer assemble unmolested in the central Atlantic.
The air gap that had been the geographic foundation of the wolf pack strategy ceased to exist.
Operation Creek in March 1943 had already shut down the Indian Ocean intelligence network that had been directing submarine attacks against shipping in those waters.
The 13 U-boats operating there in early March had lost their eyes within a month.
The Abwehr networks in Spain continued operating, and they continued providing some intelligence on convoy movements through the Gibraltar Strait.
But by late 1943, those submarines that received the data were operating in an environment so hostile that the information often couldn't be acted upon.
A submarine that positioned itself based on a Gibraltar sighting report was a submarine that had to transit waters covered by air patrols from Morocco and Gibraltar itself, potentially detected by centimetric radar before reaching the reported convoy position.
The intelligence had not stopped flowing, but the force that was supposed to use it had been degraded to the point where the information arrived faster than the submarines could act on it. Germany had spent years constructing a network that extended its submarine reach through neutral territory, neutral ports, and neutral complicity.
The Etappendienst had been built starting in 1911, refined through the 1920s and '30s, activated in 1939.
30 years of institutional work.
It had worked for a time with real effectiveness.
The Allies had dismantled meaningful pieces of it in 1941, in March 1943, and again in August 1943 through a combination of military capture, covert operations, and patient diplomacy.
Each dismantlement had taken months or years to achieve, but each one was permanent.
You couldn't rebuild the Ehrenfels. You couldn't un-capture U-434.
You couldn't un-sign the Azores Accord.
In April 1945, with Germany collapsing on every front, >> [music] >> Admiral Karl Dönitz ordered the last remaining operational submarines to the American coast for a final harassment campaign.
The boats that went out had young commanders with one or two patrols behind them.
The Etappendienst stations that might have supported them were gone.
The agents in Spain who had once reliably reported on convoy departures were now in a country that was cautiously edging toward the Allied side.
The infrastructure that had extended German submarine reach across two oceans and four years of war had been dismantled port by port, ship by ship, one covert operation at a time. 30,000.
That's how many German submariners died in World War II out of roughly 39,000 who served. Three out of four.
The men who benefited from the Spanish ports, the Etappendienst fuel that extended their patrols, the Gibraltar observations that showed them where the convoys were, they are included in those numbers. They had advantages their adversaries worked for years to eliminate.
When the advantages were eliminated one by one, what remained was the same math that governed everything else in the Atlantic, whether the boat came back or didn't.
Wolfgang Heyda, whose U-434 helped end the Spanish refueling operations with his capture in December 1941, tried to escape from a Canadian prisoner of war camp in 1943. He got as far as a lighthouse on the New Brunswick coast, where the Canadians were waiting for him.
He was returned to captivity. He survived the war. He went home.
The 18 middle-aged bankers and solicitors who killed the Ehrenfels >> [music] >> went back to their offices and said nothing for 35 years.
The insurance company paid out the claims on the ships they sank.
The last one to die, who knew what he'd done, died knowing something most of them never got to know.
He made a difference, and someone eventually wrote it down.
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