Ein Kolumbus auf der Havel (TV 1978)
aka A Columbus on the Havel
I'd forgotten about this little gem until it was mentioned in another thread. This is a cute movie, and a real "first-love" film.
Susanne Schulze plays Nana. Her dad is a photographer and had been on a large sailboat, so he decides he'd like to rent a small sailboat for the family vacation . Unfortunately, he's no sailor and there are some humorous mishaps along the way. Mischa, a boy she knew, was also sailing with his family and helps them out of some scrapes, and of course young love blossoms.
Not Academy Award material, but still enjoyable. I couldn't find any subtitles but you don't really need them.