A buoyant structure contains a hull having a main deck, a lower inwardly-tapering frustoconical side section that extends from the main deck, a lower ellipsoidal section extending from the lower inwardly-tapering frustroconical side section, a keel having an n-polytope shape, a fin-shaped appendage secured to a lower and an outer portion of the exterior of the keel having the n-polytope shape, and a plurality of columns connected between the keel having the n-polytope shape and the main deck forming one or more tunnels between the plurality of columns.

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 floating wind power generation device comprises: a main buoyant body which has buoyancy and a space portion provided in the center; an auxiliary buoyant body which has buoyancy and is connected to the main buoyant body by being inserted into the space portion of the main buoyant body; a plurality of wind power generators which are vertically provided on top of the auxiliary buoyant body and generate power; a location control means which is connected to the main buoyant body and controls the location of the main buoyant body; an oscillation inhibiting means which is connected to the main buoyant body and enables the main buoyant body to maintain an equilibrium state by absorbing the sea waves; and a dock connection unit which is connected to the main buoyant body and enables a ship to lie at anchor on the sea.

A buoyant structure having a hull, a main deck, an upper cylindrical side section extending downwardly from the main deck, an upper frustoconical side section, a cylindrical neck, a lower ellipsoidal section that extends from the cylindrical neck, an ellipsoidal keel and a fin-shaped appendage secured to a lower and an outer portion of the exterior of the ellipsoid keel. The upper frustoconical side section located below the upper cylindrical side section and maintained to be above a water line for a transport depth and partially below the water line for an operational depth of the buoyant structure.

A system and method dampen sound. In one embodiment, the system is a damping system that has a first damper. The damping system also has a second damper. In addition, the damping system has a false ceiling bracket. Moreover, the damping system has an assembly bushing. The damping system also has a positioning ring.

A method for offshore floating petroleum production, storage and offloading comprising receiving hydrocarbons from at least one of an FPSO, production risers, or wellhead on the seabed by a floating hull; processing received hydrocarbons forming hydrocarbon product in the floating hull; storing the hydrocarbon product in the floating hull; and offloading the stored hydrocarbon product. The floating hull contains a hull plan view that is circular and wherein the floating hull has a bottom surface, a top deck surface, at least three connected sections, joined in series and symmetrically configured about a vertical axis with the connected sections extending downwardly from the top deck surface toward the bottom surface. The at least three connected sections contain an upper cylindrical portion, a lower conical section, a cylindrical neck section, and a set of fins secured to the hull configured to provide hydrodynamic performance through linear and quadratic damping.

A stabilizer (10) includes a base (20) fixed on a motion reduction target (1); a gimbal (40) supported by the base to be rotatable around a first axis (RA); a damper mechanism (30) disposed to damp a relative rotary motion of the gimbal (40) to the base (20); a flywheel (50) disposed to be rotatable around a second axis (RB) orthogonal to the first axis (RA). The damper mechanism (30) is a passive-type damper mechanism. A first value (D1) of a damping coefficient (D) of the damper mechanism (30) when an angular velocity of the gimbal (40) is a first angular velocity is larger than a second value (D2) of the damping coefficient (D) of the damper mechanism (30) when the angular velocity of the gimbal (40) is a second angular velocity smaller than the first angular velocity.

Techniques are disclosed herein for minimizing movement of an offshore wind turbine. Using the technologies described, a wind turbine may be mounted on a marine platform that is constructed and deployed to reduce environmental loads (e.g., wind, waves, . . . ) on the platform in both shallow and deep water. In some configurations, a fully restrained platform (FRP) is configured to support a wind turbine. According to some examples, moorings are attached to the FRP and/or the structure of the wind turbine structure to reduce movement in six degrees of freedom.

A buoyant structure with a hull, a main deck, a lower inwardly-tapering frustoconical side section; a lower generally rounded section extending from the lower inwardly-tapering frustoconical side section; a generally rounded keel; a fin-shaped appendage secured to a lower and an outer portion of the hull proximate the generally rounded keel. In embodiments, the keel has a first frame extending from the keel and a first keel extension connected to the first frame.

A buoyant structure has a hull having a main deck. The hull further contains a lower inwardly-tapering frustoconical side section that extends from the main deck, a lower generally rounded section extending from the lower inwardly-tapering frustoconical side section, a generally rounded keel, and a fin-shaped appendage secured to a lower and an outer portion of the exterior of the hull proximate the generally rounded keel, the fin shaped appendage having a shape selected from the group consisting of: a triangular shape, a hump shape and a pair of connected triangular projections shape.