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.

The present invention relates to a hydraulic down-the-hole hammer. The hammer comprises an elongate shaft and a piston having a central bore therethrough, the piston slidably mounted for reciprocal movement on the shaft and arranged to impact a percussion bit. Forward and rear drive chambers for the piston are disposed between the piston and the shaft and the forward chamber is separated from the rear chamber by an annular shoulder formed internally of the piston bore. The hammer also comprises a control valve to control reciprocation of the piston, wherein the control valve is arranged within the central bore of the piston. The hammer may be a disposable water hammer in which the piston is an outermost component of the hammer.

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.

A monopile comprising a body (1) having a hollow interior, a toe (9) at a distal end for insertion into a soil (19) during monopile installation, and a proximal end region (2) for supporting a structure (7), such as a wind turbine tower, once the monopile has been installed. The body (1) further comprises a door aperture (12) provided in the body (1) for accessing the interior of the body (1). The door aperture (12) is configured to receive a door assembly (6,18) once the monopile (1) has been installed.

The present disclosure provides an in-situ observation system for a bottom boundary layer (BBL) over a shallow-water cohesive seabed and an arrangement method thereof. It establishes a low-cost and easy-operation hydraulic pile foundation system (2), which can ensure the piling depth to achieve the anti-settling and stability. The stainless-steel sticks are assembled freely to construct the interference-free observation unit (1). As the porous discs are used between the feet of the observation unit (1) and the top of the bottom piles, the observation system can be accurately fixed to the pile foundation. It is thus not limited by the self-weight and can integrate various instruments upon requirement. The components in this system can be easily obtained and conveniently maintained. The present disclosure has the advantages of low-cost and stability, can be widely used for long-term in-situ observation of the BBL.

A system for levelling and gripping a jacket leg into a hollow foundation pile has a levelling assembly for adjusting the longitudinal axis of a jacket leg partially inserted in a hollow foundation pile with an actuation group arranged about the jacket leg and configured to exert a force parallel to the longitudinal axis between the upper edge of the hollow foundation pile and the jacket leg and selectively attachable to the jacket leg and recoverable for further use in another levelling assembly; and a gripping assembly for locking the jacket leg in a designated position with respect to the hollow foundation pile once leveled.

A multi-impeller passive-rotating-stirring-type rotary drilling rig for open caissons includes a hollow main drill pipe, a drill bit, four cutting edges, four impeller shafts, four passive impellers and a rotation bracket. Through being uniformly distributed at a peripheral of the drilling rig, four passive impellers contact with a hole wall of a borehole during the drilling process for passively generating relative rotation opposite to the rotation direction of the drill bit, so as to accelerate sufficient mixing of silt and water for forming mud during the drilling process, thus enhancing the stirring effect of the drill bit on the mud. The present invention is able to improve the mud discharge efficiency without adding additional power, thus avoiding the blockage of the mud suction pipe and blockage or even breakage of the drill bit due to poor mud discharge during the drilling process.

A method of connecting a lower pipe portion to a subsea foundation is provided. The method comprises: providing the subsea foundation, wherein the subsea foundation comprises an upper pipe portion connected to the subsea foundation, deploying the subsea foundation subsea; and connecting the lower pipe portion to the upper pipe portion. A subsea foundation system is also provided. The subsea foundation system comprises: a subsea foundation; an upper pipe portion connected to the subsea foundation, and a lower pipe portion, wherein the subsea foundation system is arranged such that subsea the lower pipe portion can be connected to the upper pipe portion. The lower pipe portion may be connected to the subsea foundation in a stowed position before deployment subsea. The lower pipe portion may be connected to a pull-in arrangement before deployment subsea. The subsea foundation may comprise a pipe overlap section that is arranged to overlap a portion of the upper pipe portion and/or the lower pipe portion when the lower pipe portion is connected to the upper pipe portion.

The invention concerns a method for installing a tubular metal pile (28) in a rocky ground, successively comprising drilling the rocky ground (6) in order to form a cavity (14) of predetermined diameter and depth, filling the cavity with a granular material (18), arranging the granular material present in the cavity by vibration, and installing the pile in the cavity.

Disclosed is a system for the temporary holding, during pile driving operations, of a foundation pile intended to receive the mast of an offshore wind turbine. The temporary holding system includes a sleeve intended to receive a section of the foundation pile and a support frame intended to be secured to a floating device. The support frame includes a slide and an actuator, arranged to generate displacements of the sleeve according to the two translational degrees of freedom. The slide includes at least one rolling element including a cylindrical roller.