Dockyards alone cannot preserve naval capability

Roman central fleet yards resembled royal dockyards and could build and maintain warships. Keeping a yard without a standing fleet preserved only part of the capability because a crisis fleet still took at least six months to construct and crew. Britain's difficulty restarting Astute-class submarine production after an industrial hiatus provides a modern comparison. Losing shipwrights, carpenters, sailmakers, trained crews, and their supporting institutions destroys more than a set of hulls. Restoring the complete system may take a generation, leaving an empire exposed while it relearns skills it once possessed.