The death-ship was a mysterious vessel sailed by Voyager, a Lord of Life of untold power.
Though resembling an Earth sailing ship, it was not crewed by anyone but Voyager, who usually stood still on its deck. The ship could fly, or materialise from one time and place to another in a flash of light. Voyager was also capable of sailing it off the edge of the universe and into the Void, where not even a Time Lord like the Doctor could follow. (COMIC: Voyager)
It was not the only mode of transport available to Voyager, who would later confront Astrolabus for the final time while on the back of a camel. (COMIC: Once Upon a Time-Lord)
It was believed that "Life's Voyager" sailed "his creaking ship" into the War even after Life herself had fled from the Spiral Politic. (PROSE: Hark! The Herald Angels Sing)