The Cap Arcona was a large German luxury ocean liner, formerly of the Hamburg-South America line.  The Cap Arcona was a large German luxury ocean liner, formerly of the Hamburg-South America line. It transported passengers between Germany and South America until 1940 when it was taken over by the German Navy.

Late in the war, the steamer was used to evacuate German soldiers and civilians from East Prussia before the advance of the Soviet Army. While heavily laden with prisoners from Nazi concentration camps, she was sunk in May 1945 by the Royal Air Force. About 5,000 people died. The sinking of the Cap Arcona was one of the biggest single-incident maritime losses of life during the war and also one of the largest maritime losses of life in history.

Plans of the Cap Arcona.
The 27,561 gross ton Cap Arcona, named after Cape Arkona on the island of Rügen, was launched in 1927. She was considered one of the most beautiful ships of the time, was the largest German ship on the South American run, and carried upper-class travelers and steerage-class emigrants, mostly to South America.

Naval service
In 1940, the Cap Arcona was taken over by the Kriegsmarine (the German Navy), painted overall grey and used in the Baltic Sea as an accommodation ship in Gotenhafen (formerly Gdynia, Poland). During 1942, the SS Cap Arcona was used as a stand-in for the RMS Titanic, to supply exterior locations for the filming of the Nazi film version of the disaster in the harbour of Gdynia. The production was completed, although the first director, Herbert Selpin, was arrested and hanged on the orders of Joseph Goebbels, after he had complained about German military personnel molesting the actresses and made disparaging remarks about the German war effort.

On 31 January 1945, the Kriegsmarine reactivated her for Operation Hannibal, where she was used to transport 25,795 German soldiers and civilians from East Prussia to safer areas in western Germany. By now these trips were made very dangerous by mines and Soviet submarines. On 30 January, the MV Wilhelm Gustloff, carrying a total of 10,582 passengers and crew, was torpedoed by the Soviet submarine S-13 and sank in forty minutes. An estimated 9,400 people died. Early on the morning of 11 February, the same submarine torpedoed the 14,666-ton SS General von Steuben on its way to Copenhagen with military and civilian passengers; this time 3,500 lives were lost. On 20 February, the Cap Arcona's captain, Johannes Gertz, shot himself in his cabin while berthed in Copenhagen rather than face another trip back to Gdynia.

On 30 March 1945, the Cap Arcona finished her third and last trip between Gdynia and Copenhagen, carrying 9,000 soldiers and refugees. However, her turbines were completely worn out. They could only be partially repaired and her days of long-distance travel were over. She was decommissioned, returned to her owners Hamburg-Süd and ordered out of Copenhagen Harbor to Neustadt Bay.

As a prison ship
Towards the end of April 1945, the German Navy assembled a small fleet of ships in the Bay of Lübeck, consisting of the liners Cap Arcona and SS Deutschland, and the smaller vessels Thielbek and Athen. Since the steering motors were out of use in the Thielbek and the turbines were out of use in the Cap Arcona, the Athen was used to transfer prisoners from Lübeck to the larger ships and between ships. By the end of the month, these ships held more than 10,000 prisoners from the Neuengamme concentration camp and its subcamps, and two barges brought more from Stutthof and Mittelbau-Dora camps.