Principal Dimensions of Two Lowerhull Type Semisubmersible Drilling Rig and Their Dynamic Responses in Waves

Abstract

Semisubmersible (S.S.) drilling rigs are being constructed for oil exploration in rough seas. Because of S.S. rigs' superiority to ships' dynamic characteristics in waves, the operational safety is improved. Recently, S.S. rigs have been required to work in a wide range of sea states (ice conditions excepted). So, for an optimum design of a S.S. rig, an estimate of the rigs' dynamic characteristics in the various environmental conditions it is supposed to operate in, is necessary. There are various sizes of S.S. rigs, but the relationship of the dimensions to the dynamic characteristics is unknown. Hence, in this paper, the relationship between sizes and characteristics of constructed S.S. rigs was studied and the effect of change in the dimensions on the dynamic characteristics was investigated conducting a series calculation.