Floating construction comprising: a flotation base, comprising at least one essentially hollow body selectively fillable with ballast, where the maximum horizontal dimension of the flotation base is greater than the maximum vertical dimension of the floating base; a building supported by said flotation base preferably comprising a telescopic tower; downward impelling means; and at least three retaining cables the corresponding upper ends of which are attached to said flotation base, preferably in peripheral positions of the flotation base, and the corresponding lower ends of which are attached to said downward impelling means, such that said retaining cables are taut and apply a downward force on said flotation base that increases the stability thereof. And the installation method for this floating construction.

A method includes calculating a frequency and a phase of a vibration of a floating vessel, generating a control signal based on the vibration frequency and the vibration phase, operating a motion compensation system of the floating vessel during an i.sup.th control cycle using the control signal to mitigate the vibration of the floating vessel, calculating a first vibration amplitude based on the control signal, updating one or more parameters including a magnitude of the control signal, a decay rate of the vibration, the vibration phase, and the vibration frequency using the first vibration amplitude, updating the control signal based on the one or more updated parameters, and operating the motion compensation system based on the updated control signal during an (i+1).sup.th control cycle.

A semi-submersible floating structure for the drilling and production of offshore oil and gas is provided. The semi-submersible floating structure includes a pontoon having a plurality of pontoon sections, an outer edge, and an inner edge, the pontoon sections defining an interior space. The semi-submersible floating structure further includes a plurality of columns extending vertically upward from the pontoon. Each column has an upper section having an upper column width; and a lower section. The lower section has a bottom end coupled to the pontoon and aligned with the outer edge of the pontoon, the bottom end having a lower column width greater than the upper column width, at least part of the bottom end protruding into the interior space. The lower section further has a flared portion between the upper section and the bottom end; the flared portion having a width that varies from the upper column width at the upper section to the lower column width at the bottom end. A pontoon center-to-center distance between central axes of opposing sections of the pontoon is greater than a corresponding column center-to-center distance between central axes of opposing upper sections of the columns coupled to the opposing sections of the pontoon.

The present invention provides a floating offshore wind turbine capable of suppressing yawing of a nacelle caused by a gyro effect which is a cause of adverse influence of power generating efficiency of a wind turbine and endurance of devices thereof. The floating offshore wind turbine includes a rotor which is rotated by wind, a nacelle in which a rotation shaft of the rotor is accommodated, and a tower including a turning seated bearing which supports the nacelle such that the nacelle can turn with respect to a sea surface to exert a weathercock effect. The tower is provided with yawing suppressing means which suppresses yawing of the nacelle. According to this, it is possible to suppress the yawing of the nacelle generated by a gyro effect caused by yawing generated in the floating body by waves of the sea surface.

A floating, offshore vessel having surface-piercing columns (e.g., a semi-submersible or a tension leg platform) has means for storage of liquid hydrocarbon liquids inside one or more columns. Hydrocarbon liquids may be stored in only two of the four columns typically found on a semi-submersible, thereby providing a safe-zone where the living quarters are located. A column houses at least one hydrocarbon storage (cargo) tank and at least one variable ballast tank, where the weight capacity of the hydrocarbon cargo tank(s) is approximately equal to the weight capacity of the variable ballast tank(s). The hydrocarbon cargo tank(s) and the variable ballast tank(s) are positioned in such an orientation that the horizontal center of gravity of the cargo tank(s) is (nearly) identical to the horizontal center of gravity of the variable ballast tank(s). Both the hydrocarbon cargo tank and the variable ballast tank may be directly accessible from top-of-column.

A mobile, wave motion-isolated, waterborne device having a platform with a plurality of support members extending beneath the platform configured to receive an articulated joint. The device further includes a plurality of corresponding clusters of spar buoys, wherein each spar buoy has an articulated joint at a first end of the spar buoy and a ballast operably configured at the second end. The articulated joint of each spar buoy within the cluster corresponds to a swivel footing configured to receive an articulated joint. The swivel footing itself includes an articulating joint. Each articulated joint of the swivel footing corresponds to one of the support members of the platform. The cluster of spar buoys can optionally move between a vertical orientation and a horizontal orientation. An optional movable ballast may be used in place of a stationary ballast. The invention also includes optional thrust/propulsion, steering, and damping features.

A semi-submersible floating structure for the drilling and production of offshore oil and gas is provided. The semi-submersible floating structure includes a pontoon having a plurality of pontoon sections, an outer edge, and an inner edge, the pontoon sections defining an interior space. The semi-submersible floating structure further includes a plurality of columns extending vertically upward from the pontoon. Each column has an upper section having an upper column width; and a lower section. The lower section has a bottom end coupled to the pontoon and aligned with the outer edge of the pontoon, the bottom end having a lower column width greater than the upper column width, at least part of the bottom end protruding into the interior space. The lower section further has a flared portion between the upper section and the bottom end; the flared portion having a width that varies from the upper column width at the upper section to the lower column width at the bottom end. A pontoon center-to-center distance between central axes of opposing sections of the pontoon is greater than a corresponding column center-to-center distance between central axes of opposing upper sections of the columns coupled to the opposing sections of the pontoon.

A mobile, wave motion-isolated, waterborne device having a platform with a plurality of support members extending beneath the platform configured to receive an articulated joint. The device further includes a plurality of corresponding clusters of spar buoys, wherein each spar buoy has an articulated joint at a first end of the spar buoy and a ballast operably configured at the second end. The articulated joint of each spar buoy within the cluster corresponds to a swivel footing configured to receive an articulated joint. The swivel footing itself includes an articulating joint. Each articulated joint of the swivel footing corresponds to one of the support members of the platform. The cluster of spar buoys can optionally move between a vertical orientation and a horizontal orientation. An optional movable ballast may be used in place of a stationary ballast. The invention also includes optional thrust/propulsion, steering, and damping features.

An offshore electricity production assembly comprising a floating platform, a wind turbine fixed to the floating platform, and inclined mooring tendons, the floating platform comprising: a tubular central buoyant column extending along a longitudinal axis intended to be vertical, the column having an immersed portion defining a first average external diameter, and a plurality of tubular radial buoyant pontoons protruding from the column along radial axes spaced around the longitudinal axis, each of the pontoons defining a second average external diameter, the pontoons being immersed in a body of water.

The first average external diameter is larger than the second average external diameter.

A mobile, wave motion-isolated, waterborne device having a platform with a plurality of support members extending beneath the platform configured to receive an articulated joint. The device further includes a plurality of corresponding clusters of spar buoys, wherein each spar buoy has an articulated joint at a first end of the spar buoy and a ballast operably configured at the second end. The articulated joint of each spar buoy within the cluster corresponds to a swivel footing configured to receive an articulated joint. The swivel footing itself includes an articulating joint. Each articulated joint of the swivel footing corresponds to one of the support members of the platform. The cluster of spar buoys can optionally move between a vertical orientation and a horizontal orientation. An optional movable ballast may be used in place of a stationary ballast. The invention also includes optional thrust/propulsion, steering, and damping features.