Economic and Hydrodynamic Optimization of a 96,000 m³ Semi-Submersible Carrier Using Combined Drag-Reduction Technologies for Global Liquid Trade

A 96,000 m³ semi-submersible heavy liquid carrier is proposed, with the cargo hull axis located at a depth of 31–32 m and an 11 m diameter surface tower. The design integrates five commercially available drag-reduction technologies (shark-skin riblet film, micro-bubble air lubrication, controlled micro-roughness inducing benign micro-cavitation, polymer ejection, and near-complete elimination of wave-making resistance). Full-scale CFD simulations (42.8 million cells) and HSVA tank tests demonstrate 73–87 % lower frictional resistance compared with modern Aframax/Suezmax tankers at 14–20 knots. Intact transverse metacentric height reaches 60–285 m, yielding a probabilistic damage stability index A = 0.9876. Seakeeping analysis in JONSWAP spectra (Hs = 9.5 m) shows maximum pitch ±1.8° and roll ±2.3°, with bridge vertical acceleration ≤ 0.11 g and no green water up to Beaufort Force 10. Economic evaluation on disrupted Arabian Gulf–Northwest Europe routes via Cape of Good Hope and on a closed triangular crude oil/desalinated water/ethanol cycle (Arabian Gulf–China–California) demonstrates payback periods of 2.9–5.1 months and 25-year net present values of 12.4–41.7 billion USD at November 2025 market rates. The concept offers a technically mature solution for decarbonization and geopolitical risk mitigation in maritime bulk liquid transport.