Author(s): E. Karulin; M. Karulina
Keywords: No Keywords
Abstract: Turret ship is one of the moored floater types which can be used in arctic regions both as mobile platforms (for drilling or for exploration) and as stationary ones (floating plants or oil and gas storage). At designing of these floaters and their mooring system, it is necessary to assess a level of potential external action on the ship as well as her response on it. The purpose of performed work was an analytical investigation of turret ship behaviour under joint action of external forces–wind, current and broken ice. The study considers a turret ship hull whose dimensions approximately match one of the FPSO design options for Shtokman field. The paper looks at three scenarios of environmental effects on the turret ship on this field: 1) ship turning about the turret using her thrusters in a field of immovable managed ice; 2) ship weathervaning under wind, current and managed ice effects acting from different directions; and 3) ship behaviour under the effect of Sverdrup’s tidal wave. All the parameters of external factors–current, wind and their change were in accordance with corresponding data of Shtokman field. The broken ice cover was assumed to consist of floes of sizes ranging from 20 m to 40 m, with thickness of 1 m. The initial concentration was 72%. Two locations of the turret along the ship length were studied. The broken ice action was determined using 2D discrete element approach. The results give time variation of kinematic parameters of the turret ship motion–course angle, the ship COG and turret center trajectories, as well as of turret mooring system restoring force.