Based on the standard Starfleet design tree and hull components of the time, the Ptolemy-class replaced the engineering hull of the Template:ShipClass with a connector at the base of the connecting neck, which could accept a variety of transport containers.
Ships of the class
The Ptolemy-class starship was originally seen on a display in the Starfleet Academy's training simulation in Star Trek II: The Wrath of Khan. The display was literally a page pulled from Franz Josephs' Star Fleet Technical Manual.
Intended to be merely background decoration, freeze frames and close examination have inconclusively shown that the images used were taken from the Joseph book with little or no modification. This would be confirmed later by Rick Sternbach on a few occasions at TrekBBS.com. The Saladin-, Hermes-, and Federation-classes appear as part of the loop. (citation needed • edit)
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.
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.