LONDON – The fate of a Nazi U-boat that was torpedoed en route to Japan with 70 people on board, including two Japanese men, hangs in the balance as officials debate what to do about a growing environmental threat.
Tadao Yamato and Toshio Nakai were among the passengers traveling with the German crew on the U-864 en route from Germany to Japan with aircraft parts and a toxic cargo of 1,857 flasks of mercury when the Royal Navy submarine Venturer torpedoed it on Feb. 9, 1945, off the Norwegian coast.
When the U-boat went down, some of its mercury cargo leaked and settled on the seabed, contaminating an area covering 30,000 sq. meters. Small creatures and fish from the area have been found to contain high levels of the heavy metal.
Norwegian authorities would like to cover the wreck and surrounding seabed with a thick layer of gravel to seal the mercury in.
But environmentalists claim that given the toxic cargo, the submarine should be raised, taken from the sea and properly sealed.
Officials fear the wreck is too fragile to be salvaged and such an operation could cause more mercury to be released. Oslo has ordered an investigation into whether raising the wreck is viable.
The U-864 contained plans and parts for the production of various Messerschmitt aircraft, submarines and radar. Facing imminent defeat, Adolf Hitler hoped that boosting Japan’s capacity would put greater pressure on the United States and weaken Britain. It is thought the mercury was to produce weapons.
Britain was aware of the U-boat’s voyage because the Japanese and German codes had been cracked. Some of the intercepted messages can be viewed at the National Archives in London.
Yamato was an engineer from Kobe who had been in Germany since 1940, and Nakai was a naval scientist who graduated from Tokyo Imperial University.
They had studied production techniques in Germany and were traveling home to help build German-designed aircraft. It was one of several secret submarine missions to Japan.
The bottom of the North Sea is a graveyard of shipwrecks. In 2003, the Norwegian Navy found the U-864 at a depth of 140 meters about 56 km from Bergen in northern Norway.
An exclusion zone was established around the wreck after a flask of mercury was found near the boat’s keel. There is continuing concern that some of the flasks still on board could leak after such a long time on the seabed.
Tor Sletner, a Norwegian coastal authority, said there had been attempts to raise the submarine, which split in two, but it was too fragile and the mercury flasks were at risk.
Underwater photos show the wreck covered in seaweed, the bow and stern sections 40 meters apart, and the stern plane in a crash dive position.
“We haven’t located the bodies because we haven’t been able to get inside the wreck,” Sletner said.
Some of the flasks had eroded, but it was not thought any had actually started leaking mercury, he added.
Hans Kjelstrup of the Norwegian Navy said the sub’s control room, which may contain mercury, has never been found. He said the sub would have contained several pressurized compartments, and there is a possibility that some of the 17 passengers, including the Japanese, may still be in these airtight units.
If the gravel blanket operation gets the go-ahead, the stones will be placed on the area in varying levels from as little as 50 cm to 12 meters, depending on the amount of pollution. This is designed to prevent small sea creatures that fish consume from taking in the mercury.
In his book “Hitler’s U-Boat War,” Clay Blair describes how the Venturer’s skipper, James Launders, tracked the German vessel by sonar while both subs were submerged about 56 km from Bergen.
“With uncanny skill, Launders set up and fired four torpedoes by sonar and guesswork at 18 second intervals from 3,000 yards (2,730 meters), their depth set at 40 feet (14 meters),” Blair wrote.
One or more of the torpedoes hit the U-864. Launders inspected the surface by periscope, seeing much oil and “wood” and what might have been a torpedo or storage canister. On his return to Scotland, he was commended and received a medal.
Karl Vandenhole, who produced a TV documentary on the U-864, said German relatives of the ill-fated crew were not opposed to their loved ones being entombed in the submarine forever. They hope to have a small ceremony at sea if the vessel is eventually covered in gravel.
He said the relatives knew the crew was on a secret mission to Japan but did not know the precise circumstances surrounding the loss of the U-864 until the discovery of the wreck in 2003 and subsequent research.
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