galley yarn

An obsolete piece of nautical slang for a fabricated or exaggerated story — essentially a tall tale spread among sailors. The 'galley' refers to the ship's kitchen, historically a place where crew members gathered to gossip and swap stories. A 'yarn' is itself a sailor's term for a long tale. The compound suggests a story so implausible it could only have been cooked up in the galley. Entirely archaic today, it would appear mainly in 19th-century maritime literature.