This version is one of the most popular versions of the song, recorded by Dock Boggs in 1927. It’s based on a British folk song of the same name, or The Cruel Ship’s Carpenter. Many versions pin the narrator as a ship’s carpenter, the titular Polly’s lover. He promises to marry her, but instead kills her and returns to the sea. When he does, he’s haunted by her ghost, which drives him to insanity.