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.
Ships of the class
According to Star Fleet Technical Manual from which the class is derived, NCC-3801 is the registry of the USS Ptolemy and is also the prototype of the class.
The tugs which are seen towing the damaged USS Enterprise in the Star Trek: Discovery episode "Brother" appear to be Ptolemy-class ships. They are not mentioned by name, nor are they seen up close, because to do so would require permission from Franz Joseph's estate as the class first appeared in the Technical Manual.Template:Minicite
In the CD-ROM game Star Trek: 25th Anniversary, the USS Enterprise was assigned to recapture a Ptolemy-class Starfleet tug, the USS Masada (NCC-293391) that had been hijacked by Elasi pirates. The ship was described as having a crew of seventeen, captained by Lt. Kevin Keeler.
The Ptolemy-class is also present in the Star Fleet Universe, in which it serves as part of the Federation's logistical network in peace and war. In Star Fleet Battles Module R8, a scenario is presented in which Ptolemy herself is tasked with transporting the crippled vessel Star Tiger out of danger in the early part of the General War.