This document stipulates the overall structural requirements and specific dimensional requirements of each part of a composite multi-hull large yacht, including minimum plate thickness requirements, hull outer plates, outer plate frames, single-layer bottom structure and ancillary components, double-layer bottom structure, bulkheads Dimensional requirements and calculation methods for deep tanks, deck structures, superstructures, deckhouses, bulwarks and pillars. This document is applicable to the design, manufacturing and inspection of composite multi-hull large yachts with a length of 24m and above.