초록 ▼

The vessel comprises a pair of laterally spaced elongated hulls having a plurality of upstanding columns spaced therealong supporting a working platform in spaced relation above the hulls a distance slightly greater than the maximum anticipated wave height. The hulls buoyantly support the vessel in

The vessel comprises a pair of laterally spaced elongated hulls having a plurality of upstanding columns spaced therealong supporting a working platform in spaced relation above the hulls a distance slightly greater than the maximum anticipated wave height. The hulls buoyantly support the vessel in a low draft floating condition with the hulls having free-board. The hulls have ballast compartments to submerge the hulls and portions of the stabilizing columns to a distance of approximately half the effective height of the stabilizing columns which is slightly greater than maximum anticipated wave height, to maintain the vessel in a high draft floating condition with the platform elevated above the waterline. The columns stabilize the vessel in the high draft condition about roll and pitch axes. The working platform mounts either a drilling rig or a heavy duty crane or like operational equipment along the centerline of the vessel.

대표청구항 ▼

A method of constructing a column stabilized semisubmersible variable draft vessel comprising the steps of: fabricating a pair of elongated hulls with each of said hulls having an oblong transverse cross section with a breadth greater than its height and having top and bottom substantially planar pa

A method of constructing a column stabilized semisubmersible variable draft vessel comprising the steps of: fabricating a pair of elongated hulls with each of said hulls having an oblong transverse cross section with a breadth greater than its height and having top and bottom substantially planar parallel surfaces extending substantially the entire length of each hull between bow and stern thereof; and disposing said hulls in substantially parallel spaced side-by-side relation with each of said hulls spaced from and lying on an opposite side of the longitudinal centerline of said vessel; fabricating a working platform and also means for supporting said platform in fixed spaced relation above said hulls a predetermined height and normally lying in a generally horizontal plane, said means including at least three pairs of upstanding columns connecting with said hulls and said platform, each of said columns being made with a substantially constant cross sectional area over the effective height of the column between the platform and associated hull; fabricating and disposing a plurality of longitudinally spaced structural truss means interconnecting and reinforcing the structural relationship of the hulls, platform and columns, with such truss means including substantially transversely extending members structurally interconnecting uppermost portions of the hulls; forming said vessel with said hulls, columns and related components so that the vessel is generally rectangular in plan with the length of said vessel along its longitudinal centerline and roll axis being at least plural times as great as the width of said vessel along its transverse centerline and pitch axis; locating at least three of said columns on each of said two hulls on opposite sides of the vessel\s roll axis with pairs of such columns being located near opposite ends of each of said hulls on opposite sides of the vessel\s pitch axis and at least another pair of said columns being located at an intermediate position on each of said hulls; and providing such columns with configurations and cross-sectional areas throughout effective height thereof and locating said columns at distances from the vessel\s longitudinal roll axis and transverse pitch axis such that said columns will maintain the vessel\s metacenter above the vessel\s center of gravity for the high draft semisubmerged operating positions of the vessel and also such that said columns will provde righting moment about the longitudinal roll axis which is less than righting moment provided about said transverse pitch axis when the vessel is in semisubmerged column stabilized operating position; providing said hulls with ballast compartments, and proViding means for ballasting said vessel when required to alter its draft between a low draft hull-supported floating condition in which the hulls have freeboard with said transversely extending members structurally interconnecting uppermost portions of the hulls being disposed above the mean waterline and a high draft semisubmerged column stabilized floating and operating condition in which the mean waterline is located along intermediate portion of said columns above said hulls and below the underside of said platform.