Thielbek was a 2,815 GRT cargo steamship that was built in Germany in 1940, sunk in an air raid in 1945, refloated in 1949 and repaired, and was in service until 1974.

She was at anchor in the Bay of Lübeck with the passenger ships Cap Arcona and the Deutschland, which were sunk in the same air raid.

At the time Cap Arcona and Thielbek were crowded with prisoners from the Neuengamme, Stutthof, and Mittelbau-Dora concentration camps.

Human remains found aboard her were buried in the Cap Arcona cemetery at Neustadt in Holstein.

She remained in Knöhr and Burchard service until 1961 when she was sold, renamed Magdalene, and registered under the Panamanian flag of convenience.