A Black Hole Carrier was a type of craft used by the Time Lords in what was their ancient history by the time of the Last Great Time War. During that conflict, fought against the Dalek Empire, the Time Lords Time Scooped Black Hole Carriers, along with Bowships and N-Forms, to their present, creating a fleet to use against the Daleks. (PROSE: A Brief History of Time Lords)
Behind the scenes
The Black Hole Carriers were first mentioned in Russell T Davies's short story Meet the Doctor.