This film is based on a novel "Il était un petit navire" written by René Fallet who participated in the film for the adaptation.René Fallet was son of a railroadworker and was also born in Villeneuve, this very important place for the French railway company.This film has a very nice cast: Jean Gabin (who plays the uncle Victor Ploumaz, who says that he is a great adventurer of the seas),Ginette Leclerc, Jean Carmet, Jacques Marin and Claude Piéplu among others.
TS. René Fallet has participated in various cinematographic adaptations of his book and I recommand to see "La soupe aux choux" and "Le beaujolais nouveau est arrivé"