An off-shore wind turbine system is assembled using a platform or jack-up vessel, and a first base anchored to the seafloor at a bade assembly off-shore location. A buoyant tower is attached to the first base. A crane provided on the platform or jack-up vessel is used to lift blades and blades, which are then coupled to a turbine held in a nacelle provided at the top of the buoyant tower. The buoyant tower, the nacelle, and the blades are detached from the first base. The buoyant tower, the nacelle, and the blades are towed to a wind farm and connected to a second base provided in the wind farm. The buoyant tower, the nacelle, and the blades are further stabilized using mooring lines spanning between the buoyant towers and other bases provided in the wind farm. The first base and/or the second base include anti-rotation features.

To upend and lift an object, e.g. a foundation member of an offshore wind turbine, e.g. a monopole, use is made of an upending and lifting tool, wherein, with the tool suspended from one or more hoisting cables, e.g. from a crane hook of a crane, and with the frame of the tool initially in vertical orientation, a routine is performed which includes operating one or more shifting actuators, thereby moving a cable shifting member and engaging a cable engagement surface with the one or more hoisting cables at a height above a pivot axis. Further continuing this motion of the cable shifting member and thereby applying a cable shifting force on the one or more hoisting cables results, in reaction, in a pivoting of the frame into the horizontal orientation thereof.

The invention relates to an upending system for an elongated tubular element like an offshore foundation pile or a turbine mast, the system comprising; a pile frame for supporting a elongated tubular element, the pile frame comprising a pile support member for engaging a pile wall in order to avoid movement of the elongated tubular element with respect to the pile frame, and a coupling section, a support structure for supporting the pile frame, wherein the coupling section is rotatably supported by the support structure to allow rotation of the pile frame with respect to the support structure, wherein the support structure and the coupling section of the pile frame are configured such that the pile frame is detachably coupled to the support structure.

A ring-wing floating platform is disclosed. The ring-wing floating platform includes a floating hull, a top of the floating hull being above a sea surface and its geometry at a water plane is centrally symmetric, a ring-wing surrounding a perimeter of a bottom of the floating hull with a horizontal projection of concentric annular geometries, a positioning system located at the bottom of the floating hull, and a topsides located above the floating hull and connected to the floating hull by deck legs or installed directly on the top of the floating hull. The axes of the ring-wing and the floating hull are collinear, and their bottoms are in a same horizontal plane. The ring-wing and the floating hull are connected together as a unitary structure by multiple connecting components with an annular gap in-between.

An offshore structure includes an original structure and an extension structure. The original structure includes a main platform supported via a foundation on a seabed. The extension structure includes a platform extension positioned laterally of the main platform and a platform extension support, depending downwardly from the platform extension, into contact with the foundation, so as to support the extension structure directly on the foundation.

The invention relates to a method for coupling a jacket with a foundation pile, comprising; mounting a first flange with the jacket, contacting a second flange with the foundation pile such that the second flange is supported by the foundation pile, mutually positioning the first flange and the second flange such that the jacket may be supported by the pile through the first flange and the second flange, arranging an inflatable spacing member between the first flange and second flange such that the spacing member contacts both the first flange and second flange for supporting the jacket through the spacing member.

A method of installing a foundation (1) for a structure. The foundation body (2) has a toe (7) at its distal end which defines an aperture into an internal cavity (12) defined by an inner wall (8). Fluid is jetted from a plurality of nozzles (9) to direct fluid distally into the soil (5) ahead of the toe (7) during installation. A pump arrangement (13) controlled by a controller (16) is used to vary the quantity of fluid at a proximal end to thereby vary the fluid suspension pressure adjacent the toe (7) in a fluid communication channel (11) extending between the proximal end and the toe (7). The controller varies the fluid suspension pressure as the toe (7) inserts deeper into the soil (5) based on a target fluid suspension pressure as a function of toe depth.

A method includes mounting a lower platform block (300) to a plurality of piles (215) positioned on a surface. The lower platform block includes a first frame (315), a plurality of docking assemblies (305) connected to the first frame and engaging the piles, and a plurality of conductor tubes (310) connected to the first frame to a plurality of piles. The docking assemblies are released from the piles to separate the lower platform block from the piles.

A method and fixturing apparatus for manufacturing a suction caisson foundation includes providing an elevated center support and peripheral supports, elevating the foundation's prefabricated thumb section atop the center support, and temporarily securing radial frame members about the circumference of the prefabricated thumb section with the each frame member resting atop a respective peripheral support. The skirt panels are then affixed to the frame members, and the frame members to the prefabricated thumb section to thereby become self-supporting. The center support is removed from the interior of the resulting bucket, as by raising the peripheral supports to unload the center support, and lowering and dismantling the center support, whereupon additional panels are affixed to the frame members to define the foundation's lid, and further shaft sections added atop the prefabricated thumb section to complete the foundation. Temporary beams bridging preselected framing members advantageously allow use of transportation crawlers.

Process for installing an offshore tower, comprising: a) manufacturing a foundation comprising a block, manufacturing at least one superposition section of a shaft, and manufacturing a base section of a shaft; b) applying said base section to said foundation block (starting unit) to assume the relative position for the installed condition, applying said superposition sections to said starting unit in a multi-layered configuration, and applying lifting means to at least one of said foundation block and said base section; c) moving said starting unit up to the installation point; d) introducing ballast in said foundation block so that said starting unit sinks until resting on the bottom of the body of water; e) actuating said lifting means to expand said sections into the installed condition; f) between step a) and c), placing said foundation block or starting unit in the body of water of the installation point.