A method is presented for simulating marine assets (MA) in an offshore operation. The marine assets comprise at least an anchor, a line coupling the anchor with a winch, and a support platform located offshore for supporting the winch. The method involves a computation stage for estimating a state of the marine assets using a computational model and received sensor data (Ds) pertaining to a state of the marine assets and/or of an environment (ME) wherein the marine assets are used. The computational model of the marine assets (MA) includes at least a specification of an anchor, a specification of a winch and a specification of a line coupling the anchor with the winch. The at least a line is modeled as a first portion extending between the winch and a touch-down point where the line touches the seabed and a second portion extending between the touch-down point and the anchor. Additionally a simulation system is presented for simulating the marine asset, and an arrangement including the marine asset and the simulation system.

An offshore structure comprises a hull having a longitudinal axis, a first end, and a second end opposite the first end. In addition, the structure comprises an anchor coupled to the lower end of the hull and configured to secure the hull to the sea floor. The anchor has an aspect ratio less than 3:1. The hull 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. Further, the structure comprises a ballast control conduit in fluid communication with the variable ballast chamber and configured to supply a gas to the variable ballast chamber. The structure also comprises a topside mounted to the first end of the hull.

Systems and methods for tensioning mooring lines are provided. The systems include an in-line tensioner that may include a removable chainwheel, a tail chain disconnecting table configured for disconnection of a tail chain and docking of an ROV, a chain guide having low-friction pads that reduce frictional engagement between the in-line tensioner and mooring chains, and a target link stopper that is configured to stop movement of the mooring line at a predetermined location, such that the mooring line has a predetermined length and such that a predetermined link of the mooring line is positioned within a gripping zone of latches of the in-line tensioner.

A buoy (10) comprising a central column (12), an outer frame (14) attached to the central column with buoyancy which may be provided by the outer frame and/or by attached buoyancy units (16). The central column is negatively buoyant and is normally open at one end to allow water to flow in, and create an oscillating water column caused by waves. This water column dampens the effect of wave or other forces on the buoy, thus providing a more stable foundation for a wind powered generator. A further generator may be provided to extract energy from the oscillating water column. The buoy is normally attached to an anchor by one or more tension leg tethers which maintains the buoyancy below the surface of the water which has also be found to increase stability. The anchor may be a modular gravity base anchor.

A mooring assembly for attaching a vessel to a subsea well including a well conductor, the mooring assembly comprising: (a) a housing for the well conductor; (b) a base defining an interface for a subsea ground surface; and (c) a rotatably mounted vessel attachment point; wherein, in use, a vessel moored to the subsea well is capable of rotational movement around the subsea well.

A method of assembling a floating wind turbine platform includes forming a base assembly of the floating wind turbine platform in either a cofferdam or a graving dock built in water having a first depth. The base assembly includes a keystone and a plurality of buoyant bottom beams extending radially outward of the keystone, wherein longitudinal axes of each of the plurality of bottom beams are coplanar. The cofferdam or the graving dock is flooded and the assembled base assembly is floated to an assembly area in water having a second depth. A center column and a plurality of outer columns are assembled or formed on the base assembly, a tower is assembled or formed on the center column, and a wind turbine is assembled on the tower, thereby defining the floating wind turbine platform.

A system is disclosed including but not limited to a processor; a hybrid power source for servicing a system load, the hybrid power source comprising a natural gas engine, a diesel engine and a battery; a linear computer program comprising, instructions determining a current system load serviced by power provided from the hybrid power source; instructions to determine a current operating state for the natural gas engine, the diesel engine and the battery; instructions to use linear programming to determine a new operating state for the natural gas engine, the diesel engine and the battery to reduce power consumption servicing the current system load the natural gas engine, the diesel engine and the battery; and instructions to replace the current operating state for the natural gas engine, the diesel engine and the battery to the new operating state for the natural gas engine, the diesel engine and the battery.

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.

An anchor rope system for an offshore device for fixing an offshore device to a subsea floor. The anchor rope system includes at least one anchor rope surrounded by at least one sheathing. The anchor rope system includes at least one condition sensor formed by at least one fiber optic cable.

Disclosed is a chain tensioner for employment on a bottom of a water body, wherein the chain tensioner is configured for adjustment of the length of a tensioning chain that extends between the chain tensioner and a floating offshore facility, wherein the chain tensioner includes a chain lock for engaging and confining a link of the tensioning chain in the chain passage from aside the tensioning chain, and a chain switch device having a chain guide for engaging the tensioning chain in the chain passage from aside the tensioning chain, wherein the chain guide is moveable between a first position in which the chain lock engages a link of the tensioning chain, and a second position in which the tensioning chain passes the chain lock.