Operation Weserubung, the Nazi invasion of Denmark and Norway in April 1940, involved multiple aerial and naval thrusts up and down the Norwegian coastline. From Oslo in the south to Narvik in the north, German paratroopers and naval task forces worked in concert to establish footholds in Norway’s strategic centers. Kriegsmarine Group 5 was tasked with sailing through the Oslo Fjord to the Norwegian capital of Oslo where it was to secure the seat of government along with the Norwegian royal family.
The flagship of the naval task force was the newly completed heavy cruiser Blucher which also had embarked 1,500 assault troops for the capture of the capital. As the ships sailed through the narrow confines of the Oslo Fjord, alert Norwegian patrol vessels sounded the alarm and gave troops in the Oscarsborg Fortress precious minutes to prepare their defenses. In a double irony, the two 11-inch guns in the Norwegian fortress were named after Jewish heroes Joshua and Moses and had been built by Krupps in Germany in the late 1890s. Although each gun only fired a single shell, both struck home and inflicted enormous damage on the Blucher. As the cruiser labored further up the fjord, a shore based torpedo battery engaged the ship and struck home with two antique torpedoes.
The ship capsized and whisked nearly 1,000 sailors and soldiers to the bottom of Drobak Sound. With the loss of Blucher, the German task force withdrew and the capture of Oslo was left to Nazi airborne troops. Additionally, the sinking allowed the Norwegian royal family and other key members of the government to escape Oslo and organize resistance in other parts of the country and abroad. For the Kriegsmarine, Blucher would not be the only capital ship lost in Norwegian fjords during the war as Tirpitz would later succumb to Royal Air Force and Navy attacks.