| 摘要 |
<p>The present invention relates to a semi-rig having a plurality of pontoons (10) and columns (20), wherein an outer wall (35) is concentrically arranged around each column (20) to reduce rig area on water surface (WS). According to the present invention, a regular heave movement from an ocean wave in a semisubmersible structure like a drilling rig ship is alleviated, thereby protecting a worker and maintaining the capacity of equipment.</p> |
