Stability and seakeeping performance of a deep-V high-speed vessel based on Maxsurf simulations

1. Core Research Hypothesis This study puts forward three interrelated hypotheses targeting the performance of a 4.5-tonne wave-piercing deep-V high-speed craft (HSC) for coastal patrol and rescue, filling the research gaps identified in existing literature (separate static stability and seakeeping analysis, oversimplified linear high-speed hydrodynamic models, lack of unified Maxsurf evaluation framework for small deep-V vessels): Stability Hypothesis: The wave-piercing deep-V hull geometry (25°–30° deadrise, slender waterline, wide midship waterplane) will deliver sufficient intact static and large-angle stability reserves across full-load departure, full-load arrival, light-load departure, light-load arrival four operating loading conditions. Initial metacentric height (GM) will far exceed international regulatory minimum thresholds, and the vessel will maintain positive righting arm (GZ) at large heel angles over 60°, with strong anti-capsizing capacity. Seakeeping Motion Hypothesis: Heave, pitch and roll Response Amplitude Operators (RAOs) of the planing deep-V hull will present single resonance peaks; rising sailing speed (10–60 kn) shifts peak encounter frequencies to higher values due to reduced wetted surface area and added mass during planing transition. Beam seas trigger maximum pitch motion, head seas induce the largest roll response, and the wavelength-to-ship-length ratio λ/L=2–6 forms a critical resonance band amplifying all motion amplitudes significantly. Wave Resistance Hypothesis: Wave added resistance increases exponentially with significant wave height (Hs=0.3–4.0 m) and reaches peak values within the λ/L=2–6 resonance band. Head seas generate the largest added resistance, following seas the minimum. Although planing reduces frictional drag at 30–60 kn, wave-induced added resistance dominates total drag and offsets friction reduction, creating obvious hydrodynamic coupling between speed and wave parameters. A secondary auxiliary hypothesis: A unified Maxsurf numerical workflow combining Stability and Motions modules, with medium-density meshes (2.875 million cells) and ITTC-standard validation against geometrically similar Taunton-C deep-V model test data, can produce converged, low-uncertainty hydrodynamic results suitable for preliminary engineering design of small composite deep-V patrol vessels. 2. Data Introduction & Acquisition Hydrostatic data: Displacement, waterplane geometric parameters, LCB, LCF, metacentric radii, form coefficients under drafts 0.05–0.55 m. Intact stability data: GM, trim, Bonjean curves, GZ and dynamic stability area at 0°–60° heel under full-load departure/arrival, light-load departure/arrival. Seakeeping RAO data: Motion response amplitude operators varying with speed (10–60 kn), wave heading (0°–180°), encounter frequency and λ/L (0.5–12). Added resistance data: Drag under JONSWAP irregular waves (Hs=0.3–4.0 m), correlated with speed, wave direction and wavelength ratio.