Ok, so this article is a little old, but still interesting:
Adolf Hitler's 'lost fleet' found in Black Sea By Jasper Copping
Last Updated: 2:36am GMT 03/02/2008
The final resting place of three German U-boats, nicknamed "Hitler's lost fleet", has been found at the bottom of the Black Sea.
In pictures: Hitler's lost U-boats The submarines had been carried 2,000 miles overland from Germany to attack Russian shipping during the Second World War, but were scuttled as the war neared its end. Now, more than 60 years on, explorers have located the flotilla of three submarines off the coast of Turkey.
The vessels, including one once commanded by Germany's most successful U-boat ace, formed part of the 30th Flotilla of six submarines, taken by road and river across Nazi-occupied Europe, from Germany's Baltic port at Kiel to Constanta, the Romanian Black Sea port.
In two years, the fleet sank dozens of ships and lost three of their number to enemy action. But in August 1944, Romania switched sides and declared war on Germany, leaving the three remaining vessels stranded.
With no base and unable to sail home - the Bosporus and Dardanelles were closed to them because of Turkish neutrality - their captains were ordered to scuttle the boats before rowing ashore and trying to make their way back to Germany. However, all three crews were caught and interned by the Turks.
Now the submarines' hulls have been discovered by a team led by Selçuk Kolay, a Turkish marine engineer, who will present his findings to a shipwreck conference in Plymouth this week.
Mr Kolay established the boats' positions through research in German archives, interviews with surviving sailors and by sonar studies of the seabed.
He has already completed successful dives to the wreckage of one vessel, U-20, two miles offshore in about 80ft of water. He believes he has discovered another, U-23, at twice that depth, three miles from the town of Agva, but bad weather forced him to suspend diving until the spring.
He thinks he is also close to pinpointing the third boat, U-19, thought to lie more than 1,000ft down, three miles from the Turkish city of Zonguldak.
"It's one of the least well known stories of the war but one of the most interesting, " said Mr Kolay.
"It is a quite incredible story. To get to the Black Sea these boats had to be taken across the land, and once they got there they had no way out."
All three U-boats had been operating against British shipping in the North Sea. U-23 gained notoriety for scoring one of Germany's earliest successes, sinking a British ship off the Shetland Islands days after war began. It was later commanded by Otto Kretschmer, known as "Silent Otto", the most successful U-boat ace.
In 1941, Germany invaded Russia and decided it needed a presence in the Black Sea to harass Soviet shipping there. Unable to use the Bosporus, the only shipping route into the Black Sea, the boats were dismantled at Kiel and taken by canal to the River Elbe, and upstream to Dresden.
Here, they were partly dismantled and taken by lorry to Ingolstadt, on the Danube, and then ferried downstream to the Black Sea and Constanta, where they were re-assembled.
When Romania switched sides the crews were ordered to scuttle out of sight of the Turks so the submarines' locations would remain a mystery. Mr Kolay was helped by a map drawn by Rudolf Arendt, 85, the former captain of the U-23, showing where his crew came ashore.
Mike Williams, secretary of the Nautical Archaeology Society, said: "This is a significant find because these U-boats were all scuttled, so they should be intact, like a sealed tube. They are unique survivors of the war."