Abstract: A trenching assembly lays a continuous pipeline in a trench dug in a bed with uneven bathymetry, the trenching assembly including a trench digging device having a main body; at least four ground contact units, each unit having a height adjustment device, to position each ground contact unit with respect to the main body independently. A trench cutting tool digs in the bed includes a cutting depth adjustment device, for positioning the cutting tool with respect to the main body. A detection device detects bed bathymetry. A control device simultaneously allows cooperation between the detection device, the height adjustment device of each ground contact unit, and the cutting depth adjustment device. A command device cooperates with the control device to adjustment each ground contact unit and the cutting depth adjustment device, to obtain a trench having a height difference lower than a predefined tolerance and a predetermined burial depth.

Abstract: A joining device configured to join two facing and aligned pipeline sections presents two coupling members selectively couplable to respective pipeline sections at two respective facing flanges located at the ends of respective pipeline sections; a pulling mechanism suitable to move the coupling members towards each other in abutment against the flanges and to temporarily tighten the flanges by moving the coupling members towards each other; and a tightening mechanism suitable to definitively tighten the coupling members while the pulling mechanism keeps the flanges tight.

Abstract: A vessel for laying a pipeline includes a plurality of workstations disposed along a pipelaying path that includes an upstream portion away from a first end of the vessel and a plurality of ramps, includes a first ramp and a downstream second ramp disposed along the pipelaying path, in the region of the first end of the vessel. Each of the plurality of ramps has a first upstream end, a second downstream end, and an adjustable inclination. The downstream end of the first ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel and the upstream end of the second ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel. An external ramp assembly includes ramps that can be pivoted relative to one another and locked in a selected position.

Abstract: 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.

Abstract: A connection assembly for engaging a tubular member underwater to restrain the tubular member from radial movement relative to the connection assembly includes a plurality of pads for engaging the tubular member at circumferentially spaced positions; and a plurality of biasing arrangements, each for biasing a respective pad radially inwardly into engagement with the tubular member; wherein each biasing arrangement includes a pre-loadable, mechanical, compressed spring arrangement for resiliently pressing its respective pad against the tubular member. The assembly need not employ any hydraulic components.

Abstract: A system for laying an underwater pipeline on a bed of a body of water has a construction site to form a string of an underwater pipeline, the string being defined by a curved portion shaped substantially like a portion of the bed of the body of water characterized by an abrupt change in slope; at least two vessels to transfer, in the body of water, the string from the construction site to a laying site in the body of water and substantially on the vertical of a path along which to lay the string; and a plurality of floating devices configured to be coupled to the string and so as to selectively support and sink the string in the body of water, and progressively lay the string along the path on the bed of the body of water.

Abstract: A vessel for laying a pipeline includes a plurality of workstations disposed along a pipelaying path that includes an upstream portion away from a first end of the vessel and a plurality of ramps, includes a first ramp and a downstream second ramp disposed along the pipelaying path, in the region of the first end of the vessel. Each of the plurality of ramps has a first upstream end, a second downstream end, and an adjustable inclination. The downstream end of the first ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel and the upstream end of the second ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel. An external ramp assembly includes ramps that can be pivoted relative to one another and locked in a selected position.

Abstract: A self-propelled underwater vehicle for underground laying a continuous elongated member in a bed of a body of water having a work assembly, which is configured to be set, at least partly, into the bed, and is provided with two facing supporting walls for delimiting a space there-between and supporting two opposite scarp slopes; and drive assemblies, which are arranged on opposite sides of the work assembly and are configured to rest on the bed and advancing the work assembly in a travelling direction.

Abstract: An electronic control system configured to control a variable-configuration lay ramp of a pipeline laying vessel, to lay a pipeline on the bed of a body of water, is configured to: acquire data including data related to the configuration of the lay ramp, data related to the laying vessel, and data related to the forces transmitted by the lay ramp and the laying vessel to the pipeline; generate a plurality of step sequences to change the configuration of the lay ramp from a first to a second work configuration; and select a best step sequence as a function of the plurality of step sequences and the acquired data, so as to minimize the stress induced in the pipeline at each intermediate configuration between the first and second work configuration.

Abstract: A stinger extends away from an end of a vessel, and a pipeline passes over the stinger as the pipeline is laid from the vessel. The inclination of the pipeline increases as the pipeline passes along the stinger and after leaving the stinger until the pipeline reaches an inflection point beyond the end of the stinger at which inclination is at a maximum. Inclination of the pipeline thereafter reduces until the pipeline touches down on the seabed. A method of S-laying the pipeline includes providing guides on the stinger that limit lateral movement of the pipeline relative to the stinger and moving the vessel and the stinger during S-laying to an orientation in which the longitudinal axis of the stinger is inclined to the path of the pipeline just laid. The vessel and the stinger are rotated about a vertical axis passing through or adjacent to the inflection point.

Abstract: A vessel for laying a pipeline includes a plurality of workstations disposed along a pipelaying path that includes an upstream portion away from a first end of the vessel and a plurality of ramps in the region of the first end of the vessel. The plurality of ramps includes a first ramp which is disposed along the pipelaying path, whose inclination is adjustable and which has a first upstream end and a second downstream end, and a second ramp which is disposed along the pipelaying path downstream of the first ramp, whose inclination is adjustable and which has a first upstream end and a second downstream end. The downstream end of the first ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel and the upstream end of the second ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel.

Abstract: A method of securing a pipeline to the bed of a body of water includes moving an underwater vehicle selectively, on the bed of the body of water, along the pipeline; transporting a plurality of fastening devices on the underwater vehicle; and driving each fastening device partly into the bed of the body of water, close to the pipeline, by a handling device mounted on the underwater vehicle, to confine the pipeline between the bed of the body of water and the fastening device.

Abstract: A vessel for laying a pipeline includes a plurality of workstations disposed along a pipelaying path that includes an upstream portion away from a first end of the vessel and a plurality of ramps in the region of the first end of the vessel. The plurality of ramps includes a first ramp which is disposed along the pipelaying path, whose inclination is adjustable and which has a first upstream end and a second downstream end, and a second ramp which is disposed along the pipelaying path downstream of the first ramp, whose inclination is adjustable and which has a first upstream end and a second downstream end. The downstream end of the first ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel and the upstream end of the second ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel.

Abstract: A vessel for laying a pipeline includes a plurality of ramps in the region of the first end of the vessel. The plurality of ramps includes a first ramp which is disposed along the pipelaying path, whose inclination is adjustable and which has a first upstream end and a second downstream end, and a second ramp which is disposed along the pipelaying path downstream of the first ramp, whose inclination is adjustable and which has a first upstream end and a second downstream end. The downstream end of the first ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel and the upstream end of the second ramp is positioned inboard of the first end of the vessel and above the bottom of the vessel.

Abstract: A self-propelled underwater vehicle for underground laying a continuous elongated member in a bed of a body of water having a work assembly, which is configured to be set, at least partly, into the bed, and is provided with two facing supporting walls for delimiting a space there-between and supporting two opposite scarp slopes; and drive assemblies, which are arranged on opposite sides of the work assembly and are configured to rest on the bed and advancing the work assembly in a travelling direction.

Abstract: An electronic control system configured to control a variable-configuration lay ramp of a pipeline laying vessel, to lay a pipeline on the bed of a body of water, is configured to: acquire data including data related to the configuration of the lay ramp, data related to the laying vessel, and data related to the forces transmitted by the lay ramp and the laying vessel to the pipeline; generate a plurality of step sequences to change the configuration of the lay ramp from a first to a second work configuration; and select a best step sequence as a function of the plurality of step sequences and the acquired data, so as to minimize the stress induced in the pipeline at each intermediate configuration between the first and second work configuration.

Abstract: A method of temporarily supporting a soil mass susceptible to slide at a scarp slope bounding the soil mass includes advancing a supporting wall in an advancing direction along the scarp slope; and, in addition to the movement in the advancing direction, also moving a surface portion, in direct contact with the soil mass, of the supporting wall, so as to minimize friction between the soil mass and the supporting wall.

Abstract: A method of laying underwater pipelines in the bed of a body of water, the method including laying an underwater pipeline along a given path on the bed of the body of water; breaking up a ground mass along the path to a given depth in the bed; and fluidifying the broken ground mass beneath the underwater pipeline to sink the underwater pipeline into the fluidified ground mass.

Abstract: A method of underground laying a continuous elongated member in a bed of a body of water, wherein the continuous elongated member lies on the bed of the body of water along a given path; the method including the steps of: fragmenting a soil mass in the bed along the given path and under the continuous elongated member, so as to form in the bed two scarp slopes bounding the fragmented soil mass by two soil masses susceptible to slide; advancing two supporting walls along the given path in an advancing direction, along the respective two scarp slopes, and transferring the fragmented soil mass between the two supporting walls, so as to promote sinking of the continuous elongated member between the two supporting walls.

Abstract: A stinger extends away from an end of a vessel, and a pipeline passes over the stinger as the pipeline is laid from the vessel. The inclination of the pipeline increases as the pipeline passes along the stinger and after leaving the stinger until the pipeline reaches an inflection point beyond the end of the stinger at which inclination is at a maximum. Inclination of the pipeline thereafter reduces until the pipeline touches down on the seabed. A method of S-laying the pipeline includes providing guides on the stinger that limit lateral movement of the pipeline relative to the stinger and moving the vessel and the stinger during S-laying to an orientation in which the longitudinal axis of the stinger is inclined to the path of the pipeline just laid. The vessel and the stinger are rotated about a vertical axis passing through or adjacent to the inflection point.