A self-propelled integrated ship for transporting and installing immersed tubes of an underwater tunnel comprises a first ship body and a second ship body which are parallel with each other, a connection structure is arranged between the first ship body and the second ship body; the first ship body, the second ship body and the connection structure are provided with hauling and hoisting devices, a loading space is formed between the first ship body and the second ship body and below the connection structure; a to-be-installed member is arranged in the loading space and is connected with the ship; and the first ship body and the second ship body are provided with propelling power devices and positioning devices. The loading space is provided in a lower part of the integrated ship, and a member to be transported is placed in the loading space and floated in the water, so that most of the weight of the member is shared by buoyancy. The member is transported to a designated site and installed precisely. Thus, the independent transportation and installation of immersed tubes of the underwater tunnel or similar large members with various sizes can be successfully realized by one self-propelled ship without assistance of other additional ships. Moreover, there is no need to close navigation lanes to other ships, thus not affecting the navigations of the other ships.

Delivery of a high volume of floating systems for wind turbines can make floating wind economic. The delivery can involve the standard design of sections, such as tubes or cans, comprising a rolled plate and ring stiffeners. The delivery can then involve the transportation of the sections in block to an assembly site that is closer to the planned installation point. The sections are used to manufacture floating vessels, such as semi-submersibles, buoyant towers, and/or spars, at the assembly site, which can include a barge with cranes. For semi-submersibles, the delivery can then involve the installation of the Tower, the nacelle, and blades using the barge cranes. Alternatively, for spars or buoyant towers, the nacelle and blades can be installed at an off-shore location using a platform, such as a standard jack-up vessel or a crane jacket.

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.

The invention relates to a pile holding system configured to support the pile in an upright position at a pile installation location next to the vessel. The pile holding system comprises a pile holder and a pile holder support system. The pile holder support system is configured to be mounted on the deck of the vessel, to moveably support the pile holder, and to move the pile holder in a first direction between an inboard position and an outboard position. The pile holder, when in the outboard position, is located outside the contour of the vessel, for holding the pile in the upright position at the installation location. The pile holder, when in the inboard position with the first and second jaw in the open position, is located within the contour of the vessel.

A wind turbine offshore installation method of installing a wind turbine using a semi-submersible type floating substructure includes: a step of towing the semi-submersible type floating substructure on which the wind turbine is erected to an installation target site on a sea; and a step of coupling the wind turbine and a spar type floating substructure for supporting the wind turbine on the sea at the installation target site to install the wind turbine on the sea.

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.

A process for installing or removing a subsea structure in a non-vertical manner at a well includes securing a plurality of barges together in a linear formation in which one of the plurality of barges has a downline extending therefrom, connecting an end of the barges to a primary vessel, moving the primary vessel such that one of the barges is positioned over a target at or adjacent to the well, connecting a plurality of secondary vessels by plurality of mooring lines to an opposite end of the barges, tensioning the mooring line so as to fix the opposite end of the barges, positioning a deployment vessel away from the barges, deploying an ROV, manipulating the ROV so as to connect the subsea structure to the downline, and moving the downline and the subsea structure toward or away from the well.

The invention relates to an auxiliary floating system for the installation, transport or maintenance of an offshore structure, said structure comprising at least one essentially vertical shaft, wherein said auxiliary floating system comprises: at least one floating element that remains semi-submerged during the process of installing the offshore structure; at least one coupling structure connected to said floating element; and guide elements secured to the coupling structure and in sliding contact with the shaft. Advantageously, the sliding contact between the auxiliary floating system and the shaft is such that it allows essentially horizontal relative movement between the auxiliary floating system and said shaft, such that during the process of installing the offshore structure, said structure sinks while the auxiliary floating system remains at essentially the same level on the surface.

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).