Systems, apparatuses, and methods for removing fixed offshore platforms using a semi-submersible marine vessel are described. The semi-submersible marine vessel may comprise a main body, a mooring system, a lifting system, and a gate disposed at the second end. The main body may have an extended shape sized to house a fixed offshore platform oriented in a prone position. The main body may have a first end opposing a second end and a first side opposing a second side, the first end and the second end having dimensions that exceed dimensions of a footprint of the fixed offshore platform, the first side and the second side having dimensions that exceed dimensions of the fixed offshore platform oriented in a prone position. The lifting system may have a plurality of strand jacks and plurality of strand jack cables.

According to one or more embodiments disclosed herein is a method of transporting equipment between sea-surface and seafloor by providing a structure with a subsea equipment package mounted thereon. The structure is used for installation and recovery in a subsea environment by changing the buoyancy of the structure or ballasting the structure to effect a controlled sinking motion.

A floating structure includes: a floating body including one or more buoyant bodies disposed around a structure; and a plurality of first support wires disposed between the structure and the floating body and configured to transmit the self-weight of the structure to the floating body. Each of the first support wires having: one end connected to the floating body; and another end connected to the structure below the one end.

A system and method for mating equipment offshore to a spar buoy secured to a foundation without the use of a crane barge. The system comprises a floating vessel having a pair of forks defining a slot. A gimbal table, defining an opening, is positioned within the slot and connected to the vessel and a locking collar is mounted to the gimbal table. A mating member is attached to the spar buoy. The vessel is maneuvered to bring the spar buoy within the gimbal table opening. With the spar buoy positioned within the gimbal table opening, the locking collar is arranged and designed to releasably attach to the mating member of the spar buoy and restrict relative vertical motion between the spar buoy and the vessel while the gimbal table allows the floating vessel to roll and pitch without driving these motions into the spar buoy.

A ground anchor with an upper helical member attached to or near the upper end of an elongated rod and at least lower helical member attached to the elongated rod below the upper helical member. The upper helical member includes a fixed, spiral-shaped, curved flange. Near or on the outer edge of the curved flange is a continuous or intermittent vertical wall. The lower helical member includes a curved flange similar to the curved flange used on upper helical member. The upper neck of the elongated rod engages a torque generating tool that rotates the anchor into the subsea floor until the helical members are embedded in the subsea floor. A swivel arm attaches to the neck that connects to a line that extends downward to a floating buoy or dock. A piling may be longitudinally aligned over the neck and threaded connectors securely attach the piling to the anchor.

A method of constructing and assembling a floating wind turbine platform includes constructing pre-stressed concrete sections of a floating wind turbine platform base, assembling the floating wind turbine platform base sections to form the base at a first location in a floating wind turbine platform assembly area, and moving the base to a second location in the floating wind turbine platform assembly area. Pre-stressed concrete sections of floating wind turbine platform columns are constructed, and the column sections are assembled to form a center column and a plurality of outer columns on the base to define a hull at the second location in the floating wind turbine platform assembly area. The hull is then moved to a third location in the floating wind turbine platform assembly area. Secondary structures are mounted on and within the hull, and the hull is moved to a fourth location in the floating wind turbine platform assembly area. A wind turbine tower is constructed on the center column, and a wind turbine is mounted on the wind turbine tower, thus defining the floating wind turbine platform. The floating wind turbine platform is then moved to a launch platform in a fifth location and launched into a body of water.

An observation platform device, including a platform deck, an observation mechanism disposed on the platform deck, a primary swing reduction and self-righting mechanism, and a secondary swing reduction mechanism. The primary swing reduction and self-righting mechanism includes a hollow upper support rod, a solid lower support rod, a buoyant cabin, and a counter weight cabin. The lower support rod includes a lower end fixedly connected to the counter weight cabin, and an upper end fixedly connected to the buoyant cabin. The secondary swing reduction mechanism includes a water pond, a plurality of wing-type supports, and a plurality of spaced fan-shaped floating cabins. The plurality of wing-type supports each includes an upper end fixedly connected to a lower plane of the platform deck, and a lower end fixedly connected to an upper plane of the fan-shaped floating cabins.

A ground anchor with an upper helical member attached to or near the upper end of an elongated rod near one end and at least lower helical member attached to the elongated rod below and spaced apart from the upper helical member. The upper helical member includes a fixed, lateral spiral-shaped, curved flange. Near or on the outer edge of the curved flange is a continuous or intermittent vertical wall. The lower helical member includes a curved flange similar to the curved flange used on upper helical member. The upper end of the elongated rod engages a torque generating tool that rotates the anchor into the subsea floor until the helical members are embedded in the subsea floor and the upper neck is exposed. A swivel arm may be attached to the neck that attaches to a line that extends downward to a floating buoy or a floating dock. A piling may be longitudinally aligned over the neck and threaded connectors are used to securely attach the piling to the anchor.

The invention relates to floating offshore facilities, columnar in form, often referred to as spars comprising a body having an upper column, a main compartment and a lower leg joined together to define the spar, wherein the spar further comprises an articulation for connecting an end of the lower leg to the seabed, wherein the lower leg geometry has been configured as having a particular geometry that in combination with a particular residual buoyancy of the spar, and for any particular geometry of the upper column and main compartment and in any specific water depth, the spar provides a particular dynamic response to wind, wave and forces applied by sea currents. The invention also relates to methods for varying the dynamic response to wind, wave and forces applied by sea currents of the spar and to methods for transferring materials and personnel between a production facility such as the spar and at least one transportation apparatus such as a dynamically positioned vessel.

The present belongs to offshore wind power engineering field, and particularly relates to a convenient-to-disassemble underwater penetration system for offshore wind power and an operation method thereof. The system includes a penetration device, a suction pump, a sonar ranging module and a control module. The penetration device is configured to be detachably butted with a suction bucket. The suction pump is configured to suck the suction bucket by the penetration device to settle the suction bucket. The sonar ranging module is configured to acquire settlement depth data of the suction bucket. The control module is configured to receive the data and to control the suction pump to work according to it, thereby achieving synchronous settlement of different suction buckets. The present invention is capable of achieving automatic multi-bucket synchronous penetration, thereby improving the installation efficiency of the suction bucket for offshore wind power, shortening construction time and reducing construction cost.