CFD-Based Hydrodynamic and Operability Assessment of a CB90-Derived Multipurpose High-Speed Craft

This study evaluates the hydrodynamic and operability characteristics of a multipurpose high-speed craft derived from the CB90 through stern-region refinement. Calm-water performance was assessed using unsteady Reynolds-averaged Navier–Stokes simulations with volume-of-fluid free-surface capture in STAR-CCM+, while wave responses were analyzed with ANSYS AQWA for several speeds, wave headings, and sea states. The assessment covered resistance, effective power, running attitude, global motions, accelerations, deck wetness, and slamming-sensitive responses. The developed hull carries a displacement volume of 20.8 m3 against 18.0 m3 for the baseline CB90, on a waterline length 7.4% shorter. In calm water, its total resistance and effective power are 3.6–10.4% higher, its running trim is reduced by 4.1–19.3%, and its total resistance coefficient, referenced to the static wetted surface area, is 4.2–10.2% lower. The free-surface wave patterns of the two hulls remain closely similar. The developed hull reduced vertical acceleration by 6.1–15.6%, lateral acceleration by 4.9–6.7%, and deck wetness by 9.1–28.7%, but increased roll by 8.8–9.8% and pitch by 7.7–12.7% in every condition investigated. The results show that stern-region refinement of this type acts primarily on running attitude and arrangement flexibility, and they support an integrated assessment of small multipurpose high-speed craft under representative coastal conditions.