Just to clear this one up for ya:
A galley slave is a slave rowing in a galley, either a convicted criminal sentenced to work at the oar, or a kind of human chattel, often a prisoner of war, assigned to his duty of rowing, or
A person who works very hard, typically performing menial or thankless tasks.
Nothing to do with what you mighta had in mind.
Oh yeah! I see it now! Always thought of Morrissey as a multimillionaire "galley slave". I'm such an idiot! Apologies!