Ghost Ship (1952)

A young couple buys a yacht and scoffs at the rumors that it is haunted. After a few incidents that ends their scoff they summon a professional ghost-tracker from the Institute for Investigation of Psychic Phenomena. He brings along a medium to assist him they learn, from her mumblings while in a trance, that the last owner of the ship---in its pre-haunted days---killed his unfaithful wife and her lover before they could do as much for him, and that their bodies are still concealed below the floor boards