Mystery of the WWI U-Boat and the 'sea monster' solved: How bungling German captain sank his own vessel after demanding a heater in his cabin - and then blamed the leak on a creature of the deep 

• UB-85 was patrolling the Irish Sea when captain claimed monster attacked
• Captain said damage forced them to surface and surrender to British
• Sub was recently found by Scottish Power when laying undersea cables
• German navy logs reveal sub sunk after issues caused by captain's heater

The North Channel that connects the Irish Sea with the Atlantic Ocean has long been a haunt of those wishing to prey on Britain’s shipping.

At its narrowest point, the channel is just 12 miles across, creating an ideal bottleneck for the pirates and privateers who for centuries targeted ships passing between Ulster and south-western Scotland. 

In the early hours of April 30, 1918, a particularly deadly pirate emerged stealthily from the depths of the channel. Painted on its side was the name UB-85. This hunter was a German submarine, a feared U-boat.

For the previous two weeks, ever since it left its secret pen on the German island of Heligoland, UB-85 had been patrolling the Irish Sea, looking to unleash its ten torpedoes on merchant ships bringing vital supplies to Britain from the US and Brazil.

Much to the frustration of her commander, Kapitänleutnant Günther Krech, UB-85 had not had much luck.

Although U-boats had sunk nearly 280,000 tons of Allied shipping that month, not one had been dispatched by Krech.

Accompanied by a few of his officers, he stood in the conning tower, scanning the waters through his binoculars by the light of the full moon – perhaps this would be the day he would finally start his scorecard.

But before he could continue his hunt for a victim, UB-85 was rocked by an almighty surge on the starboard side, followed by a terrific thud as something landed on the deck. Krech looked down, and to his bewilderment and horror saw a huge sea monster emerging from the water and climbing on to the side of the submarine.

‘This beast had large eyes, set in a horny sort of skull,’ Krech is reported to have said. ‘It had a small head, but with teeth that could be seen glistening in the moonlight. Every man on watch began firing a sidearm at the beast, but the animal had hold of the forward gun mount and refused to let go.’

The weight of the monster was so great that it was forcing the 730-ton submarine down into the water and, with the hatch still open, there was a very real risk that the U-boat would sink. Krech therefore ordered his crew to keep firing.

Eventually, with its mighty body stung by one too many bullets, the monster let go of the now-mangled gun mount and slipped back into the depths. Although the crew were safe from immediate peril, it soon became apparent that the creature had severely damaged the forward deck, leaving the U-boat incapable of diving.

As dawn rose, UB-85 became a sitting duck for the many ships of the Royal Navy patrolling the channel. Among them was an armed drifter called the Coreopsis, which cautiously approached the damaged submarine as it bobbed up and down. To the astonishment of the British ship’s crew, the Germans were standing on the deck with their hands up, and were willing to surrender without a fight.

It had a small head, but with teeth that could be seen glistening in the moonlight.

It was only when the trembling seamen were on board, and Krech told his tale, that it became apparent quite why the Germans seemed so grateful to be taken prisoner.

Even if the crew members of the Coreopsis were not sure whether to believe their captives, the story of the sea monster and UB-85 has endured. As the Navy is said to have sunk the submarine shortly afterwards, there has never been any evidence to show if it had indeed been attacked by some inexplicable force.

But now, nearly a century later, it looks as if the secrets of UB-85 may finally be revealed. Last week it was announced by energy firm Scottish Power that engineers laying undersea cables had discovered the wreck of a U-boat lying close to the last position of UB-85 reported by the Coreopsis.

Although no photograph of the submarine has been taken, a remarkably clear sonar image certainly shows the unmistakable form of the 180ft craft lying 340ft below the surface.

Unfortunately, the image is not sufficiently defined to show whether the foredeck has been damaged by the monster in the way supposedly described by Krech.

Despite the apparent absurdity of the German commander’s claims, plenty of locals have maintained that UB-85 could well have been set upon by a savage sea serpent.

Among them is Gary Campbell, the keeper of the Official Sightings Record for the Loch Ness Monster. ‘The area of sea where the attack took place has a history of sea-monster sightings – they have ranged from the north coast of Wales to Liverpool Bay,’ he said. ‘What the captain said could well be true. It’s great to see how Nessie’s saltwater cousin clearly got involved in helping with the war effort – she even managed to do the damage without anyone being killed.’

Unsurprisingly, such claims have been scoffed at by others. Peter Roper, of Scottish Power, said: ‘I am probably on the side of the historians who believe that the capture of the vessel was more straightforward than a sea monster attack. “A sea monster attacked my submarine” may be one of the most fanciful excuses of all time.’

So what is the truth behind the sinking of UB-85? I have some professional interest in the matter, as I am a contributor to a forthcoming series on television channel Yesterday, called World War Weird. The series covers a bizarre series of wartime phenomena, ranging from the appearance of seemingly pro-Nazi crop circles in the British countryside to bombs carried by bats, UFOs over Canada and Los Angeles, and Stalin’s mine-carrying dogs.

The tall tale that really stoked my interest was that of UB-85 because stories of sea monsters attacking human beings during modern times are fantastically rare.

Typically, when we think of creatures such as krakens and leviathans, we are taken back to ancient times, to the world of myths and legend, not to a time of modern warfare.

But war is often associated with the supernatural, as the fevered and hopeful minds of scared and impressionable young soldiers, sailors and airmen can witness apparitions such as ghosts and angels in the chaos of battle.

However, the notion of a sea monster appearing off the Irish and Scottish coasts in the latter days of the First World War seemed far too unusual and intriguing a story not to dig further into. 

Yes, it seemed like a hoax, but where had it come from, and why was a more plausible story not readily available? What quickly became apparent as I began to investigate was that there was no obvious source of the tale.

 Normally, when researching episodes from either of the world wars, the plethora of books, articles and documents soon yields enough clues as to a story’s origins. In this instance, there is no clear foundation.

More troubling still was the lack of any original document or newspaper report that contained the words supposedly spoken by the U-boat’s captain. Krech himself left very little trace. He died of unknown causes at the age of 33 in March 1919, his career as a submarine captain relatively undistinguished. However, his early death naturally meant that words could be put in his mouth. So, if it was impossible to find the source of the sea monster story, where could the truth be found?

The answer lies deep in the vaults of the National Archives and Records Administration (NARA) in the United States. At the end of the Second World War, the Allies captured the entire records of the German Navy from 1850 to 1945, and copied them on to 4,317 rolls of microfilm, now stored at NARA’s site in Maryland. Hopefully, somewhere among them would be accounts given by the U-boat’s crew members after the war.

Spooling through hundreds of miles of microfilm was clearly an investigative step too far. Fortunately an American naval historian and retired detective from the San Jose Police Department in California called Dwight R. Messimer had already done all the hard work, and had presented it in an obscure 2002 tome called Verschollen [Missing]: World War I U-boat Losses. The files contain at least four interviews with crew members, including Krech himself.

But did any of them mention a monster? And if they did not, did any of them report anything strange or outlandish?

In his account, Krech recalled how he decided to crash-dive the U-boat after he spotted Royal Navy patrol boats. ‘The navigator reported the conning tower hatch closed,’ he said, ‘but as we went under, heavy flooding occurred through the hatch.’

Now unable to close the hatch, the submarine was clearly in trouble. Water poured from the conning tower into the U-boat, causing the pumps, batteries and electric motors to fail. To make matters even more dangerous, the air was starting to fill up with chlorine gas emitted by the flooded batteries, which meant the crew were either going to drown or be poisoned to death.

The only option was to surface, and quickly. Krech ordered the ballast tanks to be blown, and the U-boat rose slowly. However, that did not mean the crew was safe.

Senior stoker Julius Göttschammer reported: ‘We opened the watertight door into the control room and managed to make our way against the in-rushing water into the control room and exit the boat through the conning tower.’

In fact, it is Göttschammer who held the key as to why water had managed to enter the boat from the conning tower – and he laid the blame squarely on Krech.

Göttschammer said Krech had insisted on the installation of a heater in the officers’ compartment. He said the cables to power it had to be run into the control room through the conning tower, compromising its ability to be completely sealed. ‘The result was that the new cables allowed water to flow unhindered from the conning tower,’ said Göttschammer.

Had these new cables not been in place, only the conning tower would have flooded, which would have posed no danger to the submarine.

At the surface, the submarine came under heavy fire from the Coreopsis. ‘We could not return fire because our ammunition was underwater and the water was rising in the boat,’ said Krech. ‘The crew was taken off in rowboats.’

The Navy soon picked up the crew. The last to leave were Krech and his navigator, who scuttled UB-85 rather than allow the satisfaction of a kill to the enemy. ‘The UB-85 along with all the secret documents and codebooks sank in 260ft,’ Krech recalled.

So UB-85 lies at the bottom of the North Channel because its commander wanted to keep warm in his quarters, and not because of a mysterious sea monster.

Had that cable not been installed, it is likely that the submarine could have made its escape.

It is not known how Krech’s superiors reacted.

Perhaps the source of the myth was Krech himself, who felt unable to admit that he had lost his boat for such a stupid and trifling reason.

Far better, perhaps, to lay the blame on a sea monster than on a desire to keep his toes warm.