| 摘要 |
A floating semisubmersible off-shore drilling platform or the like comprises an upper working level portion and a lower pontoon portion. When the platform is transported from one place to another, it floats on the pontoon portion, but when it is working as a stationary unit in open water, it is submerged deeper, so that the pontoon portion is at a considerable distance below the water surface and the working level portion is at a considerable distance above the water surface. The platform is adapted to withstand ice pressure from ice occurring in the ambient water by giving the pontoon portion of the platform a form particularly advantageous in ice conditions. When ice occurs, the platform is lifted to such a position, that its pontoon portion comes to float at the water surface level. |
