Chula warship

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

Jack Harkness' ship
Jack Harkness used a Chula 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. (TM: Captain Jack and the Selkie)

Fellow con man Alexander Martin, posing as a customs official on the planet Balthazar, impounded Jack's ship as part of a con but gave it back shortly after as "it didn't suit his purposes". (TWN: The House That Jack Built)

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 (DW: The Empty Child) and to stop a German bomb from hitting the stranded ambulance. (DW: The Doctor Dances) Jack also had a remote control that operated a lot of the ship's functions, including the invisibility control, (DW: The Empty Child) the ship's teleport function and a music player. This warship was later destroyed by the bomb onboard. (DW: The Doctor Dances)