A system for cutting an underwater structure, the system comprising: a cutting head, said cutting head comprising: an abrasive water jetting nozzle; a cryogenic nozzle; said abrasive water jetting nozzle and cryogenic nozzle mounted in fixed spaced relation; said cutting head arranged to position tips of the nozzles proximate to a cutting surface, and arranged to form a cutting zone defined by the nozzle tips and cutting surface; wherein a water repelling shield is located about said cutting zone and arranged to hinder water entering said cutting zone.

A stiffening member for a protective housing assembly which defines a bore for receiving a utility line. The housing assembly includes a first body member, and a second body member arranged adjacent to one another to define immediately adjacent sections of the bore which surrounds the utility line. The stiffening member includes a first side for engagement with the first body member, and a second side for engagement with the second body member wherein pedestals extend from the first side of the stiffening member in a first direction away from the second side.

A sliding subsea foundation comprises a polymeric shoe layer on the underside of a mudmat or subsea structure. The shoe layer defines a soil-engaging face that comprises an array of parallel grooves. The grooves are shallower than the thickness of the shoe layer such that each groove has a closed top, defined by and integral with the shoe layer, that spans the groove. Where a subsea structure is supported on the foundation with a subsea pipeline attached to the structure, the grooves are substantially parallel to a longitudinal axis of the pipeline.

A system provides impressed current cathodic protection (ICCP) of a marine structure (50) and powers a load in a load arrangement (100) arranged on the marine structure (50) and in contact with the water (10). The power source provides a supply current to generate an electrical potential of the marine structure. The load arrangement (100) has an electrode arranged (130) to extend from the load arrangement into the water for transferring the supply current via the water. The load (20) is coupled between the electrode (130) and a power node (120). The power source is connected to the marine structure and to the power node. The load arrangement is arranged to use the supply current to provide power to the load. Thereto the supply voltage may have an AC component at a high frequency. The load may be an UV-C LED for emitting anti-fouling light.

A system and a method are for positioning a drilling rig arranged to drill in a ground. The system has a positioning jig including at least one coupling portion; a drilling rig including at least two coupling portions; and at least two anchoring elements including an upper coupling portion and a lower coupling portion. The lower coupling portion of the anchoring element is arranged to be releasably fixed to the ground. The upper coupling portion of the anchoring element is arranged to be connected to the coupling portion of the positioning jig and to the coupling portion of the drilling rig, so that the upper coupling portion of the anchoring element can optionally be connected to the positioning jig or the drilling rig.

Systems and methods for the ultrasonic disruption of biofilm and algae growth on underwater structures utilize an ultrasonic actuator that produces a natural frequency in the ultrasonic range. In some embodiments, the ultrasonic actuator includes one or more piezoelectric transducers.

The present invention provides an assembly platform of a large tidal current energy generating device. The assembly platform is internally provided with at least one horizontal axis hydro-generator. The assembly platform includes supports, at least four fixed piles, at least two sleeving members and at least two force-bearing supports. The fixed piles are connected through the supports to form an installation space. The hydro-generator is installed inside the installation space, one end of each fixed pile is driven to be fixed to a seabed and the other end extends to be above a water surface. Ends of the at least two force-bearing supports are respectively mounted on the left and right sides of the horizontal axis hydro-generator along the water flow direction and the other ends are respectively provided with corresponding sleeving members so as to resist an impact force of a water flow on the horizontal axis hydro-generator.

Method for stabilizing a jack-up platform unit, the unit including a hull, a plurality of legs which are extendible from and/or through the hull and which are arranged to support the platform unit during off-shore operations, and a jacking system arranged to move the legs between a transport position and an operational position, wherein the jacking system is also arranged to move the hull along the plurality of legs between a floating position and an operational position, the method comprising the steps of lowering the plurality of legs until the legs stand on or in the seabed, raising the hull substantially above the sea surface, temporarily applying a preloading on the plurality of legs, further raising the hull to an operational height above the sea surface.

Described is a device for providing a sizeable, slender object having a longitudinal direction into an underwater bottom from a deck of a vessel. The device includes a lifting means configured to take up the object at a lifting point thereof and position it on the underwater bottom; an upending tool connected to an edge of the vessel and configured to engage a first circumferential part of the object suspended from the lifting means and provide a pivot around which the object can be upended; and a gripping tool connected to an edge of the vessel and configured to engage a second circumferential part of the object suspended from the lifting means, whereby the first and second circumferential parts are optionally spaced apart in the longitudinal direction of the object. The gripping tool includes an actuator system configured to act on at least one of the upending tool and the gripping tool and control movements of at least one of the first and the second circumferential parts, relative to the vessel. A method using the device is also described.

Described is a device for providing a sizeable, slender object having a longitudinal direction into an underwater bottom from a deck of a vessel. The device includes a lifting means configured to take up the object at a lifting point thereof and position it on the underwater bottom; an upending tool connected to an edge of the vessel and configured to engage a first circumferential part of the object suspended from the lifting means and provide a pivot around which the object can be upended; and a gripping tool connected to an edge of the vessel and configured to engage a second circumferential part of the object suspended from the lifting means, whereby the first and second circumferential parts are optionally spaced apart in the longitudinal direction of the object. The gripping tool includes an actuator system configured to act on at least one of the upending tool and the gripping tool and control movements of at least one of the first and the second circumferential parts, relative to the vessel. A method using the device is also described.