Ein Kolumbus auf der Havel (1978)

Eleven-year-old Nana dreams of going on holiday with her family on a boat. Despite her mother's protests, she manages to persuade her father to buy an old sailing boat and so nothing stands in the way of a trip on the Havel. But her father's sailing skills are a bit rusty and a lot of unforeseen things happen that make the trip an exciting adventure. In Mischa, Nana finds a new friend with whom she can explore the Havelland.