An apparatus for use in marine platform jacking is disclosed herein. In one aspect, a jetting valve includes a valve body with a piston assembly disposed therein. The piston assembly is selectively operated to open and close the valve. A biasing member is coupled to the piston assembly. The piston assembly includes a first piston and a second piston. The dual pistons, in cooperation with the biasing member, allow the valve to self-seal thereby preventing entry of a fluid which is external to the valve.

A jack-up platform is described having a horizontal working deck that may be jacked up out of the water by moving its legs to a position wherein they take support on an underwater bottom. The jack-up platform further comprises a mooring system for mooring a floating vessel at a mooring side of the jack-up platform. The mooring system comprises an elongated support means for supporting a hull part of the floating vessel, and guiding means connected to the hull of the jack-up platform at the mooring side. The guiding means are able to rigidly hold the elongated support means in a support position, in which the elongated support means is within reach of the hull part of the floating vessel to be supported when the hull is jacked out of the water and the jack-up platform rests on its legs. A method for mooring a floating vessel using the jack-up platform is also described.

A method for monitoring movement of a cantilever structure of an offshore platform, such as a jack-up platform or a self-elevating vessel, comprising providing a boundary model containing boundary limiting information of positions of the cantilever structure, wherein the boundary limiting information comprises at least position information of boundary limiting elements, such as obstacles; providing, during movement of the cantilever, position information of the cantilever representing an actual position of the cantilever; determining, during movement of the cantilever, a difference between the cantilever position information and the boundary limiting information of the boundary model; providing an output signal when the determined difference exceeds a predefined threshold value.

A supporting system for a floating unit in shallow water exerts controlled stresses on the floating unit hull and includes supporting structure for the hull. An extendable supporting device operatively connects to the supporting structure and is suitable to support a predetermined weight of the floating unit and load when entirely supported by the extendable supporting device and when the extendable supporting device rests on a bed of a water body. An actuator device connects to the supporting structure and operatively connects to the extendable supporting device for extension or contraction. A control device operatively connects to the actuator device to control the extraction or contraction movement of the extendable supporting device. The system includes at least one hull stress monitoring device operatively connected to the control device. A device to monitor the stress, or load, on the extendable supporting device operatively connects to the control device.

Disclosed is a jack-up rig that includes a cantilever platform mounted on a buoyant hull. At least two drilling assemblies are provided on the cantilever platform, each of the drilling assemblies being movable relative to the cantilever platform and being moveable independently from the other drilling assembly or assemblies. Each of the drilling assemblies is also movable within a plane that is parallel to the cantilever platform in both X-direction as well as Y-direction which is orthogonal to the X-direction.

The offshore jack-up has a hull and a plurality of moveable legs engageable with the seafloor. The offshore jack-up is arranged to move the legs with respect to the hull to position the hull out of the water. The method comprises moving at least a portion of a vessel underneath the hull of the offshore jack-up or within a cut-out of the hull when the hull is positioned out of the water and the legs engage the seafloor. A stabilizing mechanism mounted on the jack-up is engaged against the vessel. The stabilizing mechanism is pushed down on the vessel to increase the buoyant force acting on the vessel.

The offshore jack-up has a hull and a plurality of moveable legs engageable with the seafloor. The offshore jack-up is arranged to move the legs with respect to the hull to position the hull out of the water. The method comprises securing the vessel with respect to the hull of the offshore jack-up when the hull is positioned out of the water and the legs engage the seafloor. A lifting mechanism mounted on the offshore jack-up engages with a cargo carrying platform positioned on the vessel. The platform is lifted with the lifting mechanism between a first position on the vessel and a second position clear of the vessel.

The offshore jack-up has a hull and a plurality of moveable legs engageable with the seafloor. The offshore jack-up is arranged to move the legs with respect to the hull to position the hull out of the water. The method comprises securing the vessel with respect to the hull of the offshore jack-up when the hull is positioned out of the water and the legs engage the seafloor. A lifting mechanism mounted on the offshore jack-up engages with a cargo carrying platform positioned on the vessel. The platform is lifted with the lifting mechanism between a first position on the vessel and a second position clear of the vessel.

Scale habitable units are disclosed for use in marine environments, such as the open sea, which are inexpensive to assemble and maintain, while providing habitable space.

A self-propelled offshore installation vessel (1) operates at an offshore position and has at least one water pump (27) being operable to pump water from a water inlet opening (22) to a water outlet opening (25) via water conduit pipes (24). The water system can eject water out through the water outlet opening(s), whereby the ejected water interacts with the waves to dampen waves in an affected area (35) of the sea at the self-propelled offshore installation vessel (1).