Chula warship

Chula Warships were spaceships that could travel in time. Chula Warships were fully equipped with tractor beams and Nanogenes. These warships could also turn invisible, to avoid detection.

Jack Harkness used a warship as his time travel vessel for a short while when he was a con man. He used it to save the last Selkie from the ruins of her planet and deliver her to Earth. (TWC: Captain Jack and the Selkie)

Later, Jack used it to steer a Chula ambulance to attract the TARDIS, which he thought contained Time Agents. He used its tractor beam to rescue Rose Tyler from falling, and to stop a German bomb from hitting the stranded amublance. This warship was later destroyed by the bomb onboard. (DW: The Empty Child / The Doctor Dances)