As an author, his first big success was a book about his solo journey down the Amazon, Ganz allein zum Amazonas. He is also the author of Neue Schule des Kanusports, the new school of paddling.
His travels took him to rivers in China, Japan, Australia, and Greece, South America and Africa, paddling both whitewater and flatwater. His writings about those travels brought him considerable fame beyond his own country’s borders, serving as an early advocate for all paddlesports.
He holds first descent of rivers in Kurdistan (Turkey) and Romania (1932-1933), and the first solo descent of the Amazon in South America from the Andes to the ocean in 1936-37. He completed a descent of the Blue Nile in Africa in 1953. He also holds first descents of rivers in Mexico and Guatemala including the Azul in 1958, among uncounted other first descents.