While the mines and lights remained in place, security of the actual plant had slackened somewhat over the winter months. The team discovered at least 18 barrels of heavy water — a key ingredient in making nuclear weapons — on board the sunken ferry at the bottom of Lake Tinn, 100 miles outside Oslo. The only person they encountered in the plant was a Norwegian caretaker named Johansen, who was very willing to cooperate with them.The saboteurs then placed explosive charges on the heavy-water electrolysis chambers, and attached a fuse which allowed sufficient time for their escape. Analysis of the contents of one of those drums solved the longstanding mystery about the role that the Allies played in preventing a Nazi nuclear bomb. Even before Grouse landed in Norway, SOE had a Norwegian agent in the plant who supplied detailed plans and schedules. Scientists working with the program “Drain the Oceans” used advanced sonar technology to find out what’s inside the drowned ship. The winter river level was very low, and on the far side (where the ground leveled) they followed a single railway track straight into the plant without encountering any guards. The German army moved the remaining heavy water to a dock on Lake Tinn. A The raid was considered successful. In an attempt to avoid reprisals, a The raid was considered successful. In cooperation with NOVA, ProMare plunged 1,300 feet beneath a remote Norwegian lake to find the answer to “Hitler’s Sunken Secret. The allies and Norwegian resistance forces launched a series of operations to destroy the plant to help thwart Hitler’s nuclear ambitions. The next day when the boat was over the deepest part of Lake Tinn the bomb exploded, sinking the ship with the heavy water contents within minutes. âAfter the war, those involved in the German nuclear program said that the loss of the heavy water was absolutely decisive,” naval historian Professor Eric Grove told The National Geographic team believes the remains of more barrels of heavy water are strewn near the wreckage. The British were ecstatic at the success of the Norwegian team's insertion, and the next phase of operations commenced.On 19 November 1942, Operation Freshman followed with the planned glider-borne landing on frozen lake One of the Halifax tugs crashed into a mountain, killing all seven aboard; its glider was able to cast off, but crashed nearby, resulting in several casualties. The plant was repaired by April; SOE concluded that a repeat commando raid would be extremely difficult, since German security was considerably improved.The ferry and its cargo sank in deep water shortly after its departure around midnight on 20 February 1944. French research considered the production of Pu using reactors moderated by heavy water and graphite. With Kirk Douglas, Richard Harris, Ulla Jacobsson, Michael Redgrave. The team discovered at least 18 barrels of heavy water — a key ingredient in making nuclear weapons — on board the sunken ferry at the bottom of Lake Tinn, 100 miles outside Oslo. Norwegian resistance tries to stop German efforts to produce an … The Germans were using the ferry to transport a large quantity of heavy water to Germany, where it was to be used for nuclear weapon research. On Sunday, February the 20th in 1944, when the "Hydro" was half way across the lake, there was an explosion and the ferry sank within minutes, taking the vital heavy water down with it to rest at a depth of 460 metres. The British were ecstatic at the success of Grouse, and the next phase of the operations began.On 19 November 1942, Operation Freshman followed with a planned glider-borne landing on the frozen lake One of the Halifax tugs crashed into a mountain, killing all seven aboard; its glider cast off but crashed nearby, resulting in several casualties.