General Design Study Of50,000DMT Semi-submersible Heavy Lift Vessel

This thesis presents a research on the key technologies involved in the general design of50,000-DWT semi-submersible heavy lift vessels, and proposes solutions for new propulsion systemlayout and an optimized hull form. It provides a scientific basis for further improving the general designtechnology and expanding the scope of semi-submersible vessels development.This thesis principally encompasses the following researches and conclusions:(1) Through a study of propulsion system solution, a comparison of the various applications ofpropulsion system in semi-submersible vessels is conducted in terms of functional requirement,working capacity, equipment, system configuration and economic aspect. Consequently, an optimalpropulsion system solution for50,000-DWT semi-submersible heavy lift vessel is determined.According to research findings: a compact Azipod propulsion solution has higher overallcost-effectiveness than conventional propeller solution. Moreover, Azipod propulsion systemequipment is becoming sophisticated and therefore represents numerous advantages such as highefficiency, energy-saving and environment-friendliness in terms of operation and management ofsemi-submersible vessels.(2) Due to the particularity of the scale ratio of hull form, the Bulbous bow form of conventionalcargo vessels has no remarkable effect in reducing resistance. Through hull form optimization, aninnovative solution combining tall upright bow and inclined longitudinal lines of stern is developed,which effectively reduces energy loss created by the wave-making of hull, making it particularlysuitable for semi-submersible vessels which have considerable load change and greater draft.(3) Semi-submersible vessels needs to be designed in such manner to sufficiently guarantee thesafety of cargos being transported and the reliability of dynamic positioning accuracy. Based on anumerical analysis method, the hydraulic performance characteristics of semi-submersible vesselsare determined and then verified using a model test method. As a result, the dynamic response ofvessels under regular wave conditions are obtained, thus providing a basis and reference for analysisof the actual working condition of50,000DWT semi-submersible heavy lift vessels, and providing arealistic value for guiding engineering practices.