One of the most closely guarded secrets of the war, a Q-ship was a heavily armed merchant ship with concealed weaponry designed to lure German submarines into making surface attacks and then open fire and sink them. The idea was to be a wolf in sheep's clothing. Their codename referred to their home port of Queenstown (now Cobh) in County Cork, Ireland.
According to film director Victor Saville's autobiography, the part of Madeleine Goddard was first offered to Miriam Hopkins.