| 摘要 |
An offshore drilling and production apparatus (20) in which an upper buoyant hull (24) of prismatic shape has a passage (38) longitudinally extending through the hull in which risers (42) extend to the sea floor, the hull bottom (24) located at a depth dependent upon the wind, wave, and current environment at the site, which reduces the wave forces acting on the hull bottom (24), a frame structure (26) connected to the hull bottom and extending downwardly and comprising a plurality of vertical bays (50) defined by horizontal water entrapment plates (52) and providing windows (56) around the periphery of the frame structure, the windows providing transparency in a horizontal direction to reduce drag, the vertical space between the plates (52) corresponding to the width of the bay window (56), the frame structure (26) being below significant wave action whereby wave action thereat inhibits heave motion, the frame structure (26) modifies the natural period and stability of the apparatus (20) to minimize heave, pitch, and roll motions.
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