"Hessen" was thereafter converted into a target ship. The work involved cutting away most of the superstructure, removing the armament, and replacing the old propulsion machinery with steam turbines. Additionally, equipment to allow the ship to be operated via radio control was installed. Conversion work lasted from 31 March 1935 to 1 April 1937, when she was recommissioned as a target. She served in this capacity through 1945; during World War II, she was also occasionally used as an icebreaker to clear paths in the Baltic. After the war, she was ceded to the Soviet Union and renamed "Tsel". The Soviets also used the ship as a target and eventually scrapped the vessel in the 1960s. When "Preussen" was being dismantled in the 1930s, a length of her hull was retained for use as a target. The hulk was nicknamed "SMS "Vierkant" ("SMS Rectangle") and remained in use through World War II until Allied bombers attacked and sank it in April 1945.