"Drei Mann in einem Boot" or "Three Men in a Boat" is a West German movie from 1961, so this one here has its 55th anniversary already this year. The director is Helmut Weiss and the writer is Wolf Neumeister who actually adapted a novel for the screen here.
I rated this one quite high and above current average. And this is because all that was intended here, was light heart escapist entertainment, no depth, no message beyond and above.