Volunteers from some branches of the Royal National Lifeboat Institution (RNLI) have been fund-raising outside cinemas screening the film. Other branches have placed collection boxes in cinema lobbies.
Mary Jenner, area organiser for the Devon region of the RNLI, said watching the film about the 1912 Titanic disaster, in which hundreds of passengers died, made viewers aware of the horror of death by drowning.
She said: "I think that people have a real fear of drowning. Perhaps its something to do with being an island race. Titanic makes them confront the reality of drowning. When they see the film they start thinking about it."
Cinemas in Devon, the north east, Wales, Oban and Belfast have been taking part in the project and organisers hope to collect several thousand pounds by the end of the film's run.