A method for the offshore installation of a construction laid by gravity on the seabed, comprising: the provision of a concrete base (1) delimited by a lower slab (8), a roof (2) and a perimeter wall (5), the interior whereof comprises vertical walls (6, 6′) forming cells (7, 12, 22); connecting at the periphery of the roof (2) a plurality of hollow metal floats (3) formed by a column with a circular or polygonal base; towing the assembly to the offshore location where the construction is to operate; allowing seawater to enter the cells (12) located below the roof (2), maintaining the cells (22) located below the metal floats (3) empty, in such a way that when the cells (12) located below the roof (2) are totally full, both the base and the metal floats (3) are submerged; once the cells located below the roof (2), but not those located below the metal floats (3) are full of water, allowing water to enter the cells (22) located below the metal floats (3) in such a way that the immersion of the assembly is completed, the base thereof resting on the seabed; and removing the metal floats. A gravity-based structure comprising a concrete base (1) and a plurality of hollow metal floats (3) connectable thereto.

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.

Methods and apparatuses for onshore or offshore erecting an upstanding construction comprising longitudinal construction parts, comprising the steps of providing the longitudinal construction parts, transporting the longitudinal construction parts on a vehicle to an erection site, providing a crane for hoisting the longitudinal construction parts, using the crane for placing the respective longitudinal construction parts on top of each other on a construction base at the erection site, providing the construction base and/or the longitudinal construction parts with a support and guide facility for the crane, arranging that the crane is mountable on the support and guide facility, and mounting the crane on the support and guide facility of at least one of the construction base and the longitudinal construction parts that is placed on the construction base, so as to arrange that the crane is movable up and down along the support and guide facility of the construction.

An apparatus and methods for installation of an offshore platform for supporting equipment installations is provided. The apparatus includes a vertical compression assembly and a counteracting tensioning tendon system. The vertical compression assembly may comprise multiple compression members, a column truss, or other configurations. The methods of fabrication, load out, and installation provide for cost-effective port and installation vessel requirements.

Methods for onshore or offshore erecting an upstanding construction comprising longitudinal construction parts, comprising the steps of providing the longitudinal construction parts, transporting the longitudinal construction parts on a vehicle to an erection site, providing a crane for hoisting the longitudinal construction parts, using the crane for placing the respective longitudinal construction parts on top of each other on a construction base at the erection site, providing the construction base and/or the longitudinal construction parts with a support and guide facility for the crane, arranging that the crane is mountable on the support and guide facility, and mounting the crane on the support and guide facility of at least one of the construction base and the longitudinal construction parts that is placed on the construction base, so as to arrange that the crane is movable up and down along the support and guide facility of the construction.

A method includes providing a lower platform block (300) including a first frame (315), a plurality of docking tubes (305) connected to the first frame, and a plurality of first conductor tubes (310) connected to the first frame. At least a first jacket connector block (400) including a second frame (415) and a plurality of second conductor tubes (405) connected to the second frame is releasably coupled to the lower platform block to align the second conductor tubes with the first conductor tubes. A platform deck block (500) including a third frame (515) defining a deck and a plurality of third conductor tubes (505) connected to the third frame is releasably coupled to the first jacket connector to align the third conductor tubes with the first conductor tubes.

An offshore structure for drilling and/or producing a subsea well includes a hull having a longitudinal axis, a first end, and a second end opposite the first end. The hull includes a plurality of parallel elongate columns coupled together. Each column includes a variable ballast chamber positioned axially between the first end and the second end of the hull and a first buoyant chamber positioned between the variable ballast chamber and the first end of the hull. The first buoyant chamber is filled with a gas and sealed from the surrounding environment. The offshore structure also includes an anchor fixably coupled to the second end of the hull and configured to secure the hull to the sea floor. The anchor has an arrow-shaped geometry and a central axis coaxially aligned with the longitudinal axis of the hull. The anchor includes angularly-spaced penetration members extending radially from the central axis of the anchor. In addition, the offshore structure includes a topside mounted to the first end of the hull.

The present disclosure relates to an offshore substructure supported by a template-integrated suction foundation and an installation method thereof, more particularly to an offshore substructure installed by pre-piling construction including: a suction foundation having a plurality of suction piles pre-inserted into the seabed by suction, joint sockets connected to each head part of the suction piles, and connecting members connecting spaces between the joint sockets; and a substructure connected onto an upper part of a suction foundation pre-piled, wherein an insertion socket connected to a lower part of the substructure is inserted into the joint socket, and the suction foundation and the substructure are connected by grouting a space between the insertion socket and the joint socket.

An apparatus for applying grout in a region between a tubular sub-sea foundation pile and a leg of an offshore structure inserted into the foundation pile is provided. The apparatus includes a rigid tube adapted to be inserted into the region. The rigid tube includes an inlet for receiving grout, and an outlet. A method for grout application is also provided.

A system for controlling a motion compensated pile guide for a floating vessel comprises a pile guide for guiding a monopile in its longitudinal direction during driving the monopile into a seabed, an actuator for moving the pile guide in horizontal direction with respect to a vessel to which the pile guide is mounted, a control unit for controlling the actuator, which control unit is configured for compensating motion of the vessel to which the pile guide is mounted so as to maintain the horizontal position of the pile guide during driving a monopile into a seabed, a first sensor for determining an inclination angle of a monopile with respect to the vertical during driving the monopile into a seabed, and a second sensor for determining magnitude and direction of an actual force of a monopile onto the pile guide during driving the monopile into a seabed. The control unit is configured to determine a desired force of the pile guide onto the monopile for minimizing the inclination angle when determined by the first sensor, and to control the actuator for moving the pile guide opposite to the direction of the actual force when the desired force is larger than the actual force and in the same direction as the actual force when the actual force is larger than the desired force.