Rudolf Czeppan (1923-2003) was an ardent supporter of Jürgen Spanuth’s theory of Atlantis in the North Sea(a). Czeppan proposed that an impact by an extraterrestrial body south of Heligoland caused the sinking of Atlantis.
There have suggestions that Spanuth was more than a mere nazi ‘sympathiser’ and consequently had access to Ahnenerbe files relating to their Atlantis research. This might partly explain why Czeppan, a convicted neo-nazi, was so enthusiastic in his endorsement of Spanuth.
(a) https://www.vho.org/VffG/2001/4/Czeppan374-381.html (German)