Operation Hannibal was a German naval operation involving the evacuation by sea of German troops and civilians from the Courland Pocket, East Prussia, West Prussia and Pomerania from mid-January to May 1945 as the Red Army advanced during the East Prussian and East Pomeranian Offensives and subsidiary operations. The operation was one of the largest evacuations by sea in history. Operations The East Prussian Offensive by the Red Army's 3rd Belarusian Front under General Ivan Chernyakhovsky commenced on January 13, 1945 and, with Marshal Konstantin Rokossovsky's 2nd Belorussian Front, subsequently cut off East Prussia between January 23 and February 10, 1945. German Grand Admiral Karl Dönitz ordered General Admiral Oskar Kummetz, as Naval High Commander, Baltic, and Rear Admiral Konrad Engelhardt, head of the Kriegsmarine's shipping department, to plan and execute the Rettungsaktion (evacuation operation). Dönitz radioed a message to Gdynia in occupied Poland on January 23, 1945, to begin evacuations to ports outside of the Soviet area of operations. The operation was codenamed Hannibal. The flood of military personnel and German civilians eventually turned the operation into one of the largest evacuations by sea in history, even larger than the far more widely known British evacuation of Dunkirk five years earlier. Over a period of 15 weeks, somewhere between 494 and 1,080 merchant vessels of all types, including fishing boats and other craft, and utilizing Germany's largest remaining naval units, carried between 800,000 and 900,000 German civilians and 350,000 soldiers across the Baltic Sea to Germany and German-occupied Denmark. Operation Hannibal commenced on January 23, 1945. On January 30, Wilhelm Gustloff, Hansa, and the whaling factory ship Walter Rau left the harbor at Gdynia in occupied Poland, bound for Kiel. Hansa was forced to return to port with mechanical trouble, but the Gustloff, overcrowded with more than 10,000 civilians and military personnel aboard, continued. She was torpedoed and sunk by the Soviet submarine S-13 off the Pomeranian coast, with possibly as many as 9,500 deaths, the largest loss of life in a single ship sinking in history. Those on Walter Rau eventually reached Eckernförde. On February 9, the SS General von Steuben sailed from Pillau with between 3,000 and 4,000 mostly military personnel on board, heading for Swinemünde. She was also sunk by the S-13, just after midnight, with 650 survivors. In early March, a task force composed of the German cruiser Admiral Scheer accompanied by three German destroyers