Hierarchy survey vessel
The Hierarchy survey vessel was a type of starship utilized by the Overlookers. 

The ship was armed with polaron-based weapons including torpedoes and directed energy weapons powerful enough to disable a  shuttlecraft. It was equipped with a warp drive, transporters, tractor beams and a cargo hold large enough to hold an  warp core. The ship was protected by auto-regenerative shielding, that was not strong enough to protect the ship for long against an assault by two Starfleet shuttlecraft armed with phaser emitters. 

In 2378, Zet and Nar stole one of these ships and used it to kidnap Captain Kathryn Janeway and The Doctor on their return to the  from a medical symposium. Zet then ordered The Doctor to steal Voyagers warp core or he would kill the Captain. The Doctor, after impersonating various crew members, returned to Zet's starship with the core, however, Zet refused to live up to the deal, and imprisoned The Doctor with Janeway in a holding cell located just off the bridge. Zet later abandoned the core when Voyagers crew discovered the plan and engaged in a rescue effort which was ultimately successful. ()

de: Hierarchie-Raumschiff
Starship classes