Short-term and extended reserve give a fleet mobilization depth

Unicorn's movement from ordinary reserve to extended reserve prompts a short lesson about fleet depth. Ships in short-term reserve could be activated quickly, while extended-reserve vessels were preserved for a slower and more demanding mobilization. The distinction allowed a navy to retain capacity beyond its fully commissioned force without pretending every stored hull had equal readiness. These layers recalled the older distinction between ships in ordinary and ships in commission. Unicorn's administrative status therefore shows how a navy preserved mobilization depth beyond its active fleet.