A generally cylindrical element adapted for immersion in a fluid medium, the cylindrical element comprising an elongate body having a length and a generally circular cross-section, and a plurality of raised body portions disposed about and extending along the length of the elongate body, the raised body portions being arranged generally parallel to a longitudinal axis of the body and having a height between 2% and 10% of a diameter of the body. The plurality of raised body portions are adapted to reduce vortex-induced vibration and/or drag on the cylindrical element when the cylindrical element is immersed in the fluid medium and there is relative movement between the cylindrical element and the fluid medium.

A flow modification device connectable to a generally cylindrical element adapted for immersion in a fluid medium, the device comprising an elongate body having a length and a generally circular cross-section; a plurality of raised body portions disposed about and extending along the length of the elongate body, the raised body portions being arranged generally parallel to a longitudinal axis of the body and having a height between 2% and 10% of a diameter of the body; and an aperture extending through the length of the elongate body, the aperture being adapted to receive the generally cylindrical element such that the flow modification device is arranged about the cylindrical element. The plurality of raised body portions are adapted to reduce vortex-induced vibration and/or drag on the cylindrical element when the device is connected to the cylindrical element and the connected device and cylindrical element are immersed in the fluid medium and there is relative movement between the connected device and cylindrical element and the fluid medium.

An arrangement that brings all of the separate elements of equipment used to lay product offshore such as pipe, umbilicals, and power cables and assembles them into a single device that can be installed on a vessel of opportunity, and includes functional improvements of each. A base is used for mounting, integration, and installation of the separate elements onto a vessel. The base receives a movable lay chute, means for moving and stabilizing the lay chute, a movable hang off clamp and work table, a movable access platform, a product support arm and wheel, and a fixed chute.

Apparatus and methods related to pipeline freespan support are described. For example, some embodiments may contain an upper structure, which contains at least four legs connected to one another by a number of bracing members, and a number of attachment points through which the upper structure can be lifted, and a lower structure, which contains at least four posts that can be connected to, and disconnected from as needed, the four legs of the upper structure, two spaced mud mats on which the posts stand, and at least two horizontal arms that can be attached to the posts, rotate about the posts, connect to and be locked with the posts on the other mud mat, and be lifted to an appropriate height to provide suitable support at the pipeline freespan location.

A device configured to bury a conduit in the bed of a body of water has a digging module configured to dig a trench in the bed of the body of water; a manipulating module configured to feed conduit sections into the trench; and a push module configured to join the conduit sections inside the trench and move the device in a travelling direction.

A bending restrictor assembly has a pipeline section, a first overlying pipe section having a wall overlying a portion of the pipeline section at one end thereof, a second overlying pipe section having a wall overlying another portion of the pipeline section at an opposite end thereof, and a plurality of cylindrical members overlying the pipeline section between the first and second overlying pipe sections. The first and second overlying pipe sections extend outwardly beyond the respective ends of the pipeline section. The bending restrictor assembly achieves a permanent bend and restricts ovality of a subsea pipe.

A concrete mat apparatus, includes a plurality of elongated concrete members, each member being aligned with and next to another concrete member. Each of the concrete members has an upper generally flat surface, a lower generally flat surface, and a plurality of inclined surfaces that each extend away from an upper or lower surface. Reinforcement extends from a first end portion of each concrete member to a second end portion thereof, the reinforcement including a plurality of longitudinally extending reinforcement bars and a plurality of encircling tie bars at spaced apart intervals. Cabling connects each of the elongated concrete members to another of the elongated concrete members. The combination of elongated concrete members has a width and a length that is at least twice as long as the width. The upper inclined surfaces of one of the elongated concrete members forms a plane with the lower inclined surface of an adjacent elongated concrete member. A plurality of loops are provided along opposed edges of the mat, each loop formed by a portion of the cabling. The loops can be spaced between about one and three feet (30.5 and 91.4 cm) apart.

A detection system to check the position of a pipeline in a bed of a body of water and extending along a predetermined route; the system comprising a device, which is configured to be moved in a moving direction and along the predetermined route and comprises a support, which mainly extends transversely to the moving direction, a quantity of acoustic wave sources, which are mounted on the support and are configured to transmit acoustic waves through the body of water and the bed of the body of water, and a quantity of acoustic wave receivers, which are located along the support and are configured to receive reflected acoustic waves and emit reception signals related to the reflected acoustic waves; and a processing unit comprising an acquisition unit, which is configured to receive, from the outside, at least one datum selected within a group of known or expected data comprising: the known value of the cross-section of the pipeline, an expected value of the trenching height of the pipeline, the known shape of the pipeline, the expected bathymetric profile of the bed of the body of water, and an expected value of the position of the pipeline; the processing unit being configured to calculate a parameter related to the position of the pipeline in the bed of the body of water on the basis of the reception signals and of said at least one datum selected within the group of data.

Apparatus for use with fluid-processing plant configured to generate and store pressurized fluid. Fluid-processing plant is spaced apart from body of water. Apparatus includes variable-buoyancy assembly positioned in body of water in such way that buoyancy force urges variable-buoyancy assembly to move toward surface of body of water. Apparatus also includes non-collapsible fluid-line assembly positionally anchored, at least in part, underground in such way that non-collapsible fluid-line assembly extends, at least in part, into body of water. Non-collapsible fluid-line assembly fluidly connects fluid-processing plant and variable-buoyancy assembly together in such way that non-collapsible fluid-line assembly conveys pressurized fluid between fluid-processing plant and variable-buoyancy assembly. Non-collapsible fluid-line assembly transmits an anchoring force from ground to variable-buoyancy assembly; this is done in such way that anchoring force substantially counteracts, buoyancy force acting on non-collapsible fluid-line assembly. Anchoring force substantially urges variable-buoyancy assembly to remain below surface of body of water.

The present invention relates to a system and method for uncovering and removing pipeline from the seafloor using a subsea trenching system using pressurized water to uncover pipe, a subsea shear carried by a barge to cut lengths of the pipeline, and a grapple carried by a barge to lift cut lengths of pipeline for placement on a pipe haul and recovery barge.