In around 1947, rather than go to university, she applied for and got the job of secretary to biologist and diving pioneer, Hans Hass (1919–2013), at the International Institute of Submarine Research in Vienna.

[8] In the 1950s, Hass received several film offers from Hollywood but turned them all down because she wanted to continue supporting her husband in his research.

Firstly, the company Sascha-Film who were producing the documentary, decided that the film would appeal to a wider audience with the inclusion of an attractive female lead.

[17] Secondly, while testing the diving gear in the Port Sudan hotel pool, the expedition’s cameraman collapsed from the heat and was removed from the team.

[18] During dives with Hass, she continued to act as his secretary, taking notes with a stylus on wax “sitting calmly on a rock, several fathoms down.”[19] The resulting documentary Abenteuer in Roten Meer was released in 1950 with Lotte starring under her maiden name.

Hass was unable to join part of a subsequent 1957-8 expedition because she was pregnant, so she asked the on-board zoologist Wolfgang Klausewitz to name a new species of fish in her honour.

He chose a whitecap goby, naming it Lotilia graciliosa, Lotilia meaning “belonging to Lotte.”[24] Hans made over 100 films between 1948 and 1960, with Hass appearing in, and later producing “almost all of them”[25] including: In 1976, she had a supporting role, playing the character Frau Parenge, in episode 29 (The Man from Portofino) of the German detective series Derrick (TV series) [28] In 1970, Hass published her autobiography, Das Mädchen auf dem Meeresgrund: Die Geschichte der Tauchpioniere Lotte und Hans Hass.