The Ptolemy-class was a type of Federation transport/tug utilized by Starfleet during the latter half of the 23rd century. Based on the standard Starfleet design tree and hull components of the time, the Ptolemy-class replaced the engineering hull of the Constitution-class with a connector at the base of the connecting neck, which could accept a variety of transport containers. A graphic displaying a vessel of this class appeared on the Starfleet Academy bridge simulation in 2285. (Star Trek II: The Wrath of Khan)