Speleonaut, is the submersible used by the cave diver Jochen Hasenmayer, after the 1989 decompression accident that left his legs paralyzed, Hasenmayer designed the "Speleonaut" with his friend Konrad Gehringer in order to continue exploring the Blauhöhle cave system, which begins at the base of which spring that serves as the source of the river Blau in the karst landscape on the Swabian Jura's southern edge, in Southern Germany?