A type of ship powered by a large group of oarsmen, in addition to, or in the place of, sails. The standard image is dirty rowers seated two-by-two down either side of a narrow aisle, like an even-more-sadistic school bus, overseers with whips, and a coxswain with a drum beating out a steady rhythm. Showing a character as a galley slave is a quick-and-easy way to depict their suffering, as it combines all the bad parts of being a sailor with all the bad parts of slavery - that is to say, all of it.