It is one of the strangest mysteries of the World War I - a story of intrigue, drama and sea monsters large enough to destroy a submarine.
But now experts believe they may be a step closer to unravelling what really happened to a German ship that was sunk in curious circumstances by a British boat off the coast of Scotland.
A £1 billion ($1.7b) venture by ScottishPower and the National Grid to lay a subsea power cable big enough to connect Scotland and England has led to the discovery of the wreck of a German U-boat near Wigtownshire in south-west Scotland.
The submarine was sunk by a British patrol boat after it was caught on the surface of the water on April 30, 1918. However, its German crew surprised the British forces by surrendering without resistance.
According to an old sea tale, the ship's commander Captain Krech later revealed that they had been on the surface of the water while they recharged their batteries at night when a "strange beast" rose out of the deep.
He is believed to have described a monster with "large eyes, set in a horny sort of skull", adding: "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", he said, but in the battle the submarine had been so damaged that it could no longer submerge beneath the water.
"That is why you were able to catch us on the surface," the captain is said to have told the British.
Dr Innes McCartney, a historian, nautical archaeologist and honorary research fellow at Bournemouth University, has been examining the wreck, which is approximately 45m long and around 120m away from the centre of the planned cable route, and believes it could be the fabled UB-85.
"The features of this particular wreck, which is largely intact, confirm it as a UBIII-Class submarine, of which we know of two which were lost in the area - the more famous UB-85 and its sister boat UB-82," he said.
"While I can conclude that this wreck is likely to be one or the other, they would be practically impossible to tell apart, aside from the numbers painted on them in service, now obviously long gone.
"Unless a diver can find a shipyard stamp, we cannot definitively say but yes, we are certainly closer to solving the so-called mystery of UB-85 and the reason behind its sinking - whether common mechanical failure or something that is less easily explained."
Gary Campbell, the keeper of the Official Sightings Register of the Loch Ness Monster, says reports from 1917 made it clear that sailors were aware of sea monsters that could damage their vessels.
"It is entirely feasible that some large sea creature disabled the submarine," he said.
"History has shown that there have been consistent reports of large 'monsters' not just in lakes and lochs like Loch Ness but out in open waters as well.
"For many years the giant squid was known as the fearsome Kraken and given the size of the oceans, it wouldn't be a surprise if many large species were still to be discovered.
"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. What the German 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."