Abstract:The deep-draft semi-submersible platform, which is applied to 1 500 m operation water depth, is taken as the research object. Through the hydrodynamic model test, the hydrodynamic performance is deeply studied, and compared with that of a typical shallow-draft semi-submersible platform. The results show that the natural period of rocking and heave motion of the deep-draft semi-submersible platform is significantly shorter than that of the shallow-draft platform, the motion response of the former is greatly reduced in the wave frequency range, the maximum rocking motion is 1.54°and the maximum horizontal motion is 13.12 m under the operating sea condition, which means the deep-draft semi-submersible platform is of excellent motion performance and can meet the engineering needs of deep-sea combustible ice exploitation.