It’s 1986. Professional diver Stathis Baramatis begins a long exploratory dive. The bright sapphire colours soon darken into ever-deepening blue hues, his survival depending on a trailing umbilical.

Despite the restricted view from his mask, he is trying to follow a stream of sporadic air bubbles and slowly ascending blobs of thick, dark yellow oil.

Curiosity has brought him and fellow-diver Theophilos Klimis to this spot, after noticing an oil-slick at the surface the previous day. Their years of experience suggest that they must be coming from a shipwreck. While junk-bonds and conspicuous lifestyles characterise the yuppie era elsewhere, sponge diving and the occasional commissioned recovery dive are how these two eke out a living. The scrap-metal riches they might extract from the new find could be considerable.

Thirty-six metres, forty-five – Baramatis plummets further. Below the thermocline it’s increasingly cold and foreboding. Visibility is poor as suspended particles whoosh by in the strong current. It’s nothing alarming for such a seasoned diver, but he remains prudently respectful of his surroundings as he presses on.

A cigar-shaped form can now be discerned in the eerie gloom, and at a little over 70m he finally reaches the wreck. Heavily encrusted with barnacles and other marine life, it’s frustratingly difficult to determine what he has found. Apart from the poor visibility and gloom, much of the prize is obscured by a recently entangled trawl-net.

As Baramatis will later learn, a trawler had snagged on something at the location a day or two earlier. Despite repeated attempts to break free, the net and tackle had refused to budge. When blobs of oil appeared at the surface, it was clear that something in the deep had been disturbed. Fearing trouble from the authorities, the fishermen had cut the net and fled.

Professional divers Efstathios “Stathis” Baramatis and Theophilos Klimis were the ones who discovered the wreck in 1986. Efstathios Baramatis, on the left of the photo, was the first person to dive and see the wreck post-war, 44 years after it sank. Photo: Archive of Efstathios Baramatis

Now Baramatis finds himself gazing at the source of the disturbance. The marine growth tells him that it’s metal and sank some time ago, but that’s all. “I was truly mystified,” he recalls. “The bow seemed to be missing and there was something like a turret that rose up from the hull, so I went to investigate. Behind it, I was eventually able to make out the barrel of a machine-gun – this was the moment I realised it must be a submarine.

“My heart skipped a beat as my thoughts immediately went to her crew. Submarines rarely sink without them, and it immediately changed my perspective.”

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After decompression (just over half an hour after 25 minutes beyond 70m – incredibly, such short times were routine for him), Baramatis surfaces and excitedly recounts his discovery to his old friend. They agree that further investigation is required.

The net proves a problem, but work to remove it on ensuing dives eventually reveals a compass on the conning tower. Encased in brass, it is mounted on a long-since jammed and overgrown gimbal.

While trying to remove the growth and grime from the glass dome, it bursts in a confusion of erupting bubbles.

“Down there, in the silence of the deep… all alone but for your own rhythmic breathing, an unexpected explosion is startling, even terrifying,” says Baramatis. “It took me a few moments to recover and work out just what had happened.”

The ordeal soon pays dividends. “Looking at the newly exposed compass dial, I noticed an unmistakable symbol. Emblazoned there as clear as day was a war eagle, its powerful claws clasping a Nazi swastika. I was standing on a WW2 German submarine!”

The diver quickly informs the German embassy in Athens, but little interest is shown. This is unexpected, given that bodies of the U-boat’s officers and crew are likely to remain aboard. Baramatis files a joint recovery application with salvage-company owner Yiannis Panagos, but the Greek authorities reject it. Panagos later lodges a separate request to buy the submarine for scrap, but this also fails. Baramatis is forced to drop the matter and look elsewhere to provide for his family.

The discovery of the virgin U-boat wreck appears to have been buried by indifference and bureaucracy, but in 1991 a newspaper article by journalist C. Karagiorgas is published. The U-boat’s exact location is not disclosed, but now the technical-diving community is aware of it. Recreational diving has yet to be deregulated in Greece, so only a hardy few professionals dive local waters at that time, but the allure of a U-boat sees the wreck relocated and several dives undertaken in the mid-1990s. The race to identify the vessel begins in earnest.

It is wreck-hunter Costas Thoctarides who first identifies it as U-133, a decade after its discovery. Since then, more information has come to light, and the complete story can be told.

Britain was almost brought to its knees by the havoc U-boat “wolf- packs” wrought on Allied convoys and transatlantic supply routes, but less is known about the crucial role these submarines played for the Germans in the Mediterranean.

U-133 anchors at the German submarine base on the Greek island of Salamis, after the completion of its second war patrol, at 10:45 in the morning of 22 January 1942. Photo: The U- Boot Museum Cuxhaven

A strong British naval presence in the region and the general ineptitude of the Italian navy had severely compromised Axis supply lines from Europe to the Afrika Korps in North Africa. This threatened General Rommel’s push east towards Egypt, his prize access to the Arabian oil fields that lay beyond the Suez Canal. So Hitler ordered six Type VIIc U-boats to run the gauntlet of the British-controlled Straits of Gibraltar in September, 1941.

More followed, and the 23rd and 29th Kriegsmarine Submarine Flotillas were established – the 23rd being located at a commandeered naval base on the Greek island of Salamis. The U-boats were soon disrupting vital supply-lines from Alexandria and Port Said to the British and Commonwealth forces in besieged Tobruk, and one of them was U-133.

The U-boat had been redirected from the Atlantic at the start of its second war patrol and, despite being seen and chased down, Lt-Cdr. Hermann Hesse made it through the British picket at Gibraltar on the night of 21 December, 1941.

After being laid up for a time in Messina, Italy, by propshaft problems, U-133 was in its designated hunting ground off Egypt on 17 January, 1942, when its hydrophone picked up an Allied convoy heading from Alexandria to the besieged island of Malta. Hesse fired a full salvo of torpedoes at one of two destroyer escorts, sinking HMS Gurkha. Miraculously, the second destroyer managed to save all but nine of the crew.

U-133 finished its patrol at Salamis and was incorporated into the 23rd Flotilla. Hess relinquished his captaincy, and the mascot of a kicking donkey – referring to the island’s large wild donkey population – was painted onto the conning tower. Command of U-133 was given to Lt. Eberhard Mohr, 26, even though had no combat experience. The submarine set off on its third war patrol just before dusk on 14 March and, within an hour, it would be lost with all hands.

U-133 on the departure for its third war patrol. Just an hour later it would sink off the northeast coast of Aegina after being struck by a mine from the old Greek Tourlos-Phleves minefield. Commander Eberhard Mohr and first officer Harald Preuss are distinguishable on the conning tower. Near the anti-aircraft gun, the chief of the Salamis Naval Base Machinery and Repair Department, Kptlt. Otto Erich Zürn, flanked by second officer Hans-Joachim Schale (left), and the chief engineer Eugen Pöhlmann (right) can been seen. Photo: The U-Boot Museum Cuxhaven

The event was witnessed by look-outs of the Kriegsmarine 603rd Coastal Artillery at Cape Tourlos on the island of Aegina and dispassionately recorded in their war diary: “18:55 hrs: The lookout at Tourlos reports a vessel heading south. It is identified as a submarine. 18:57 hrs: A flash and eruption of water, an explosion is heard immediately afterwards. The submarine has disappeared.”

What caused such sudden destruction?

To safeguard strategic areas including Athens and Piraeus, the Royal Hellenic Navy had laid minefields in the Saronic Gulf days after the Italians declared war on Greece on 28 October, 1940.

The largest was between Cape Tourlos and the islet of Phleves just off the mainland. It created a formidable east-west barrier across the Gulf, though it failed to stave off Germany’s war machine.

After Greece was occupied in April, 1941, the minefields were incorporated into Axis defence plans, but proved problematic. Mines would shift or even detach from their moorings and wash up on the beach, or drift at the surface, endangering all concerned. On 29 March, 1941, just days before the Germans arrived, the Royal Hellenic Navy salvage tugboat Mimis fell prey to the mines with the loss of 23 men, as did a hapless Greek caique on 18 January, 1942.

Confirming that had suffered the same fate required the help of the Royal Italian Navy. Submarines were highly valued weapons, and any chance of retrieval had to be investigated. Lt. Enzo Biagi descended in a diving bell on 4 April, 1942, and reported extensive damage by an explosion consistent with that of a shipping mine. U-133 was beyond recovery.

Although newly arrived in Greece, Lt. Mohr must have known about the quirky minefield, so was blamed for wandering into the hazardous area. However, “it’s only when things go horribly wrong that they start handing out medals,” as they say in military circles, and Lt. Mohr was posthumously promoted to Lt-Commander soon afterwards.

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Deeper investigation into Attica’s German Naval Defence Administration records has since revealed that 12 days before the demise of U-133, a cargo ship had inadvertently hit a buoy off Cape Tourlos, destroying the signalling lamp that indicated safe passage through the minefield. However, it was not replaced for six days, and then only with a simple surface marker. Given that the sun had set 40 minutes before the disaster, and it was two nights before the next new moon, it seems that Lt. Mohr and/or his look-out simply failed to see this marker in the dark. They paid for this understandable omission with their lives.

A little earlier the same day, reports of an Allied submarine in the Saronic Gulf had prompted the Germans to send two coastal patrol vessels to the area. They had been waiting for U-133 approximately 1.5 nautical miles away on the other side of the minefield, intending to safeguard the submarine’s passage out of the Gulf and into the wider Aegean. So had there been any survivors after the disaster, they could have been rescued in minutes. But it was not to be.

The crew of a German Type VIIC submarine during the Battle of the Atlantic. Note the difficult living conditions due to the confinement of the space and the long duration of the war patrols. Photo: The Bundesarchiv

U-133 is a designated war grave so has not been promoted as a diving location. In any case, it lies nearly two nautical miles off Cape Tourlos at 70m-plus in an area known for currents, so is a serious dive.

For anyone lucky enough to experience this time-capsule for themselves, the conning-tower is an obvious starting point. The air observation and attack periscopes, both lowered in their protective sheaths, can be clearly seen on approach. They are not vertical, which accentuates that the submarine is resting port side-down at an angle of about 30°.

Hovering above the conning tower, the base of the UZO (U-Boot-Zielobjektiv) is still distinguishable, despite thick encrustation. Special binoculars with night-vision capability mounted on the UZO were, like both periscopes, linked to an onboard electro-mechanical torpedo data computer manufactured by Siemens. This worked out solutions for the firing control system and was cutting-edge in its day. Type VIIc U-boats also had radio direction-finding capability, and the scant remnants of the loop aerial base can be seen.

Above the conning tower of U-133. The observation Periscope (Navigationsperiskop) on the right is visible, and the attack Periscope (Angriffsperiskop) on the left. Photo: Archive of Dimitri Galon

The compass is missing from its encrusted gimbal – it was removed by Baramatis in 1986 as proof of discovery. The hatch on the conning-tower deck is open, confirming that U-133 had been at the surface when disaster struck.

Moving aft of the conning-tower, the ”Wintergarten” area is barely discernible. This is where the 20mm Flak 30 anti- aircraft gun was located. However, the railings have corroded away and only the encrusted mounting remains. Sadly, the gun itself seems to have been pilfered by some unscrupulous diver.

In front of the conning-tower is the 88mm deck-gun, covered with a large piece of that trawl-net that snagged it in 1986. Now one continuous mass of marine life, the gun is barely distinguishable.

Along the hull the wooden decking has long since disintegrated, leaving big gaps through which the space between the casing and pressure hull is visible and fish dart about.

Forward of the deck-gun, the entire bow section – about a quarter of the submarine’s 67m length – is missing. The mine struck under the forward torpedo room, which was also the crew’s quarters. With water being such a dense, incompressible medium, the main force of the blast had been directed upwards and onto the hull, blowing the front of the submarine off and leaving a cross-sectional hull breach.

However, the twisted metal and marine growth rule out any misguided notion of wreck-penetration.

Swimming back down to the stern reveals both three-bladed propellers, the port one resting on the seabed. The course rudders, vertical support shaft and rear hydroplanes are also distinguishable, although thickly overgrown.

But an unexpected surprise is that beneath all this, and perpendicular to the main body of the submarine, is the missing bow section. Following the explosion, the detached bow had settled on the seabed shortly before being followed by the rest of the submarine. Perversely, the stern came to rest on top of it.

Closer inspection of the starboard side of the bow section (the port side being partially buried in sand) reveals that torpedo-tubes one and three are closed. U-133 had just been embarking on a war patrol, so would have been fully laden with fuel, food and munitions. Fourteen torpedoes must have been on board, none of them loaded into the bow tubes because the submarine had been cruising in friendly waters. Most were stored precisely where the mine struck. Whether or not these contributed to the powerful explosion will never be known. Type VIIc boats also had an aft torpedo tube that could be loaded externally only at the surface. A single torpedo loaded in 1942 probably remains there.

Various objects are scattered on the sandy seabed around the site. Most notable is a torpedo-like compressed-air cylinder in front of the breach. This had been located directly above the forward torpedo-room and living quarters, but became separated in the explosion. One of the anchors can be found near the stern, but most other objects have been rendered indistinguishable by the force of the explosion or marine encrustation and corrosion.

This war-grave is protected by law. Special permission was required to dive it until June when this was rescinded, but no dive-centre in the area facilitates access.

A propaganda poster from the Kriegsmarine to solve moral problems that sometimes arose during the war patrols on German submarines. The poster reads: “An 8,000 ton cargo ship can carry 11,550 tons of fuel. That fuel is enough to equip 11,550 modern aircraft on four missions.” Photo: Bundesarchiv

U-boats might have had the upper-hand in the first years of the war but the eventual losses were staggering. Of the 65 sent into the Mediterranean, none survived. To serve on a Kriegsmarine U-boat in any theatre of war was a virtual death sentence. Of the 40,000 men who enlisted or were recruited, 30,000 were lost. Of the 863 U-boats sent on war patrol, 784 met a catastrophic end.

There are five other U-boat wrecks in Greek waters but U-133 is the only one accessible to divers, and the only one unequivocally identified. It is a rare and important artefact because it embodies events that took place in Greece and the wider Mediterranean in WW2, but it is more than an object of historical interest because it also entombs its young crew.

Seventy-eight years later, the wreck is a reminder of the needless bloodshed caused by promoting intolerance and manipulating beliefs. As such, it’s a dive far deeper than anyone who makes it expects.

♦ This article previously appeared in UK Diver Magazine, September, 2020. and is reproduced with permission.

Over the stern of U-133. On the left the detached bow of the submarine can be distinguished. It is located directly under the stern. Photo: Archive of Dimitri Galon