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.