The Pompey Class was conceived as a light twin engine Destroyer variant of the successful Hermes Class Scout. The change to a twin engine layout improved the available power and manoeuvrability, however compromises in the Tactical system made the initial variant not wholly satisfactory, and an improved Mk 2 was soon introduced.
The Pompey never gained wide acceptance in service, and the later Saladin variant of the Hermes class displaced it from front line service. The Pompey continued to be used in longer duration missions in remote regions as the twin engine design was felt to be more robust than the single engined Saladin.
Mastercom Data Center (Corrected schematics supplied by Aridas Sofia)
The Kiaga (PA-820) Class was the first specialist Perimeter action class to commission in Starfleet. Building on the lessons learnt from the interim Gorgon class, the Kiaga was a smaller vessel, with a very flat side profile which was intended to increase the stealthiness of the design.
Unlike the larger Gorgon, the Kiaga was designed to optimise forward firepower, mounting four smaller accelerator cannons, all firing forward in specially designed twin launchers each side of the primary hull. The FL5 lasers were arranged with banks covering f/p, f/s and aft arcs of fire, it was realised that this left the aft vulnerable, so an additional FL4 was crammed in firing aft.
Weight was always an issue on the Kiaga, and the theoretical weapons load could have been almost double, but the engines would not permit the carriage of such a mass of weaponry. 35 Kiagas were produced, and all saw active combat, a number being lost in the Four Years war. The class was not modified until Photon Torpedoes and Phasers became available, and the Kiaga was the last PA class to begin refitting (well after the war had ended).
In Mk1 form the Kiaga had always been outperformed by its smaller sibling, the Agilis, but the Mk2 Kiaga could finally carry the maximum weapons fit that the M1 allowed, and as a result of this, and the upgraded FWB2 warp drive, the class finally outperformed the Agilis, even the new Mk2. For this reason additional construction was ordered to make up the vessels lost during the war. The Kiaga continued in service, but was always in the shadow of the later Agilis Class, despite this they were preferred by PA crews in peacetime as they were far roomier, but in wartime the Agilis was still the class of choice due to its far tougher construction.