A rare German U-boat was found by explorers this month in the Skagerrak strait, which lies between Denmark, Norway and Sweden. The Sea War Museum Jutland in Thyborøn, Denmark found the submarine while continuing its search for shipwrecks in the North Sea and other waters surrounding the Scandinavian countries.
In early April, researchers aboard a vessel sponsored by the museum found the wreck of German U-boat U-3523, which was sunk by bombs dropped in the Skagerrak by a British B-24 Liberator bomber on May 6, 1945. Tragically for the submarine crew, it was on the day before that German forces in Denmark, the Netherlands, and northwestern Germany had surrendered.
But the ill-fated U-boat was not on the war path. It was probably on the run. While the entire crew of 58 perished along with the sub, rumors have been alive ever since about the sub’s intended destination and what it may be hiding in the depths of the sea. After the Second World War, rumors and speculation were rife about Nazis fleeing Europe and seeking refuge in U-boats carrying Nazi gold. The loss of U-3523 fed those rumors.
The U-3423 was of the new Type XXI submarine was the first that could travel submerged for a prolonged period of time. In the case of the U-3523, it had a range that would have allowed it to sail non-stop all the way to South America, where many Nazis did eventually find refuge. The mystery of the U-3423 is that no one knows the identity of those on board or if there is gold to be found in the ruined vessel.
"This was a very special U-boat. It was the most advanced submarine the Germans built during the [Second World] war. It was highly modern and far ahead of its time," Sea War Museum Jutland director Gert Normann Andersen told Denmark's TV2. "Why they were fleeing, and where they were going, no one knows. So it's exciting in a way," Andersen said.
Explorers found the sub at a depth of 123 meters (375 feet), some ten nautical miles north of Skagen, Denmark. A sonar scan of the depths revealed that nearly the whole forward section of the sub is buried into the seabed. The stern juts at an approximate 45 degree angle and stands more than 60 feet off the bottom. and the picture was very surprising. Most unusual the whole fore part of the U-boat lies buried in the seabed, while the stern is standing 20 meters above the bottom.
While it was previously thought that the sub was located at 57°52′N 10°49′E, the Sea War Museum Jutland found it 9 nautical miles (17 km; 10 mi) further west.
As part of its efforts, the Sea War Museum Jutland in Thyborøn has found, registered and measured so far about 450 wrecks in the North Sea and in the Skagerrak. Twelve of these are submarines: 3 are British and 9 are German. After the war, the United Kingdom, United States, France, and the Soviet Union seized a number of German Type XXI U-boats and added them to their fleets. In the case of the Soviet Union, the U-boats became known as the Whiskey class and continued in service into the 1980s. Currently, there is only one Type XXI U-boat that has been left preserved. It is a museum piece that is displayed at the German Maritime Museum in Bremerhaven, in northern Germany.
The U-3523 submarine or "Elektroboote" was launched on December 14, 1944 and was under the command of Oberleutnant zur See Willi Müller in January 1945. Like all Type XXI U-boats, U-3523 had a displacement of 1,621 tonnes (1,595 long tons) when at the surface and 1,819 tonnes (1,790 long tons) while submerged. She had a total length of 76.70 m (251 ft 8 in) (o/a), a beam length of 8 m (26 ft 3 in), and a draught length of 6.32 m (20 ft 9 in). The submarine was powered by two MAN SE supercharged six-cylinder M6V40/46KBB diesel engines each providing 4,000 metric horsepower (2,900 kilowatts; 3,900 shaft horsepower), two Siemens-Schuckert GU365/30 double-acting electric motors each providing 5,000 PS (3,700 kW; 4,900 shp), and two Siemens-Schuckert silent running GV232/28 electric motors each providing 226 PS (166 kW; 223 shp).]
The submarine had a maximum surface speed of 15.6 knots (28.9 km/h; 18.0 mph) and a submerged speed of 17.2 knots (31.9 km/h; 19.8 mph). When running on silent motors the boat could operate at a speed of 6.1 knots (11.3 km/h; 7.0 mph). When submerged, the boat could operate at 5 knots (9.3 km/h; 5.8 mph) for 340 nautical miles (630 km; 390 mi); when surfaced, she could travel 15,500 nautical miles (28,700 km; 17,800 mi) at 10 knots (19 km/h; 12 mph). U-3523 was fitted with six 53.3 cm (21.0 in) torpedo tubes in the bow and four 2 cm (0.79 in) C/30 anti-aircraft guns. She could carry twenty-three torpedoes, or seventeen torpedoes and twelve mines. The complement was five officers and fifty-two men. Any passengers would have been cramped.
The modern diesel-electric U-boats of the sort found recently off Denmark had flaws that prevented most from being used in combat. The Nazis built 118 of the Type XXI U-boats. However, due to poor quality control, only four were fit for combat before the end of hostilities. Just two were deployed, neither sinking any Allied ships.