Ajax-Class Heavy Frigate

Ajax-Class Light Frigate

Traditionally, the UNSC Navy has shunned the use of Heavy Frigates in favour of full-fledged Destroyers. Though similar in armament and defense, there are major differences in terms of functionality and combat role. Frigates are designed for long-term long-range deployment, operating in tandem with small groups of corvettes or other frigates. Destroyers, on the other hand, are designed as escorts for fleets providing a screen of firepower behind which larger ships can operate with relative safety. At the beginning of the Human-Covenant War, Destroyers outnumbered Heavy Frigates nearly 15:1.

As the war raged through the Outer and Inner Colonies, however, the Admiralty began to realise that the Heavy Frigate was desperately needed. Reconnaissance and patrol battlegroups were woefully underpowered against Covenant invading forces, and while UNSC fleets had found tactics that worked and made use of their few strengths, Destroyers simply couldn't respond fast enough for the Navy's liking. In 2549, the Reyes-McLees Shipyards were commissioned constructing XFFG-217, the prototype for the design - another nine were constructed and entered service, with the hulls for another seventeen laid down. The fall of Reach saw these uncompleted frigates destroyed, but the models that had already entered service acquitted themselves at the Battle of Earth, and though certainly battered, were part of the remnant of the UNSC Navy left after the end of the war. They would continue to serve in the UNSC Navy until 2567, when they were retired.

Quotes

 * "The middle section looks kinda brittle, don't it? I heard one cracked in two over Earth, the G-forces from combat snapping it like a twig. That turned out to be a load of bunk, but it's easy to believe."
 * "In terms of firepower, it can compete with any Destroyer in the fleet. In terms of defence, all it has in it's favour is a layer of Ancile metamaterial and anti-laser ablative coating. But at least it can carry fighters - you wouldn't believe how much I missed having fighter protection aboard the Cole"
 * "The engines are HUGE! Seriously, look at them! There's almost as much mass there as the rest of the ship!"
 * "It may have two MAC's, but their light ones. Higher rate of fire, but less kinetic penetration. I still say a Destroyer is more useful in a head-to-head fight - It's just that we don't get many of those, these days, do we?"