Ankari vessel

The Ankari vessel was a class of starship used by the Ankari in the late-24th century. Vessels of this type used a form of propulsion that was difficult for normal sensors to detect.

In 2376, Captain Kathryn Janeway of the USS Voyager managed to track down one of these vessels in order to gain help from the Ankrari in negotiating peace between them and nucleogenic lifeforms that threatened the ship. 

Ankari-Raumschiff