What is the prison hulk?

Prison hulks were old, decommissioned vessels moored in British harbours to house prisoners from what were then overcrowded gaols. Many prisoners awaiting transportation (as a punishment, often in lieu of the death penalty) to the colonies (usually Australia, especially after the War of Independence removed the American colonies from British control) we sent to the hulks before starting their journeys to the colonies on (hopefully) more seaworthy ships.