The U-735, a German submarine, sank on December 28, 1944, after being bombed by Allied aircraft near the island of Mølen in the Oslofjord, according to official sources. According to NRK Vestfold og Telemark, Kai Steenbuck, an expert at the German submarine museum in Cuxhaven-Altenbruch, said the submarine could not dive in time because its compressed air tanks were not filled before it was hit. Only one of the 40 crew members survived, official sources said.
The wreck is now leaking old diesel fuel, which rises to the surface drop by drop, according to official sources. Along the Norwegian coast, there are approximately 2,400 wrecks, of which about 800 are German ships, including Norwegian boats confiscated by the occupation forces. Many wrecks contain tons of lead, diesel, mercury, and ammunition in increasingly rusted hulls, posing environmental risks, official sources said. Coordinates and positions of the wrecks are withheld from the public. There is disagreement about whether to urgently empty the rusting wrecks or leave them as they are, according to official sources. The exact volume of diesel and other pollutants still inside the U-735 wreck remains unknown, as does the timeline for potential major leaks.
They didn't manage to fill the boat's tanks with compressed air in time.