The Northampton-class was a Federation class X frigate starship in Starfleet service in the 23rd century, with a mark I configuration becoming active on reference stardate 2/1905. An upgraded mark III configuration entered service on stardate 2/2002.
The Northampton vessels crewed 325 in the mark I design, with 328 crew in the mark III configuration, both arrangements with space to carry 200 SFMC troops. Additionally, the Northampton could carry 25,000 metric tons of cargo, rated at 500 SCU (standard cargo units). Unloaded, the mark I Northampton vessels weighed 154,600 metric tons, while the mark IIIs weighed 154,570. The Northampton-class and measured 300 meters in length, 150 meters in width and 75 meters in height.
The Northampton computers were of the M-6 type, and the vessels were loaded with six standard (6-person) personnel transporters, four 20-person transporters and two cargo transport stages. There were also six Federation shuttlecraft standard to these vessels' shuttlebays. These vessels were designed for deep-space stationing in all sensitive areas, to prevent alien aggression. The Northampton vessels were sought after assignments by crews and troops due to numerous recreation decks and spacious quarters for the crewmembers and marines. Swimming pools, gravball courts, and gymnasiums were all located in the lower hull adjacent to the shuttlebay and near the engineering section. Although the hull design incorporated the single-engine lock often found in Andorian designs, the Northampton was a Martian design.
The Northampton warp engines were FWG-1 type, rated to cruise at warp factor 8 and max out at warp factor 10 (on the OCU scale). The impulse engines were of the FID-2 type, and Northampton had six FH-11 phaser emitters, in three dual-mount phaser banks, with arcs of fire to fore and aft as well as port and starboard. The vessels had three launcher weapon emplacements, with FP-7 photon torpedo systems on the mark I and FP-6 systems on the mark III model. The Northampton weapons array was similar to that found on the Chandley-class frigate, with different arrangements. Both classes mount the same number of FH-11 phasers, but with differing fields of fire, with the Northampton having better aft-firing capabilities and the Chandley having better forward-firing capabilities. Unlike the Chandley, the Northampton has concentrated all three of its torpedo tubes forward, which makes it offensively powerful. Northampton was defended by FSO model deflector shields.
By the later part of the 23rd century, the Northampton was in full service production, with 39 mark I vessels and 28 mark III vessels having been built prior to the mid-2280s. At that point, all were in service save for one vessel detailed to Starfleet Intelligence, and new vessels were built at Mars in the Sol system at a rate of about twenty per year. (FASA RPG modules: Federation Ship Recognition Manual, Starship Tactical Combat Simulator)
Presumably, the first ship of this series would have been called USS Northampton, although such a vessel was never specifically named in the sources mentioning this class. In the Starship Tactical Combat Simulator, this class was misspelled "Northhampton".