Abstract: A submarine pipeline towing equipment including: a floater of prismatic shape with a horizontal or vertical axis, with a variable or partially variable buoyancy, whose lower base is at least partially open by an opening or hole to operate as an air chamber. The floater includes: at least one inlet including a valve through which air is supplied; at least one outlet including a valve through which air is discharged; an actuator to control the valve to supply air; an actuator to control the valve to discharge air; a mechanism connecting the equipment to the pipeline; a mechanism transferring air to the floater; a mechanism actuating the actuator to control the valve to supply air in function of a predefined level in the floater; and a mechanism actuating the actuator to control the valve to discharge air in function of the distance of the floater itself from the seabed.

Abstract: A pipe-laying apparatus for laying or raising a pipeline from a vessel. The apparatus includes a first pipe gripping assembly disposed on a pipe laying path along which pipeline passes during laying, a second pipe gripping assembly disposed on the pipe-laying path, and a drive unit for causing relative movement in a direction along the pipe-laying path between the first pipe gripping assembly and the second pipe gripping assembly. The first pipe gripping assembly includes both a pipe gripping arrangement for gripping a pipe during pipe-laying and a cable gripping arrangement for gripping a cable during an operation when a cable is connected to a length of pipeline.

Abstract: A laying ramp for laying a pipeline on the bed of a body of water can include an elongated frame having a first and second end; connecting members connecting the first end of the elongated frame to a vessel; at least one guide device fitted to the elongated frame to guide the pipeline along the elongated frame; and a support assembly, which has at least one undercarriage to roll along the bed of the body of water and support the second end of the elongated frame.

Abstract: A submarine pipeline towing equipment including: a floater of prismatic shape with a horizontal or vertical axis, with a variable or partially variable buoyancy, whose lower base is at least partially open by an opening or hole to operate as an air chamber. The floater includes: at least one inlet including a valve through which air is supplied; at least one outlet including a valve through which air is discharged; an actuator to control the valve to supply air; an actuator to control the valve to discharge air; a mechanism connecting the equipment to the pipeline; a mechanism transferring air to the floater; a mechanism actuating the actuator to control the valve to supply air in function of a predefined level in the floater; and a mechanism actuating the actuator to control the valve to discharge air in function of the distance of the floater itself from the seabed.

Abstract: A pipe-laying apparatus and method for laying or raising a pipeline from a vessel. The apparatus includes a first pipe gripping assembly disposed on a pipe laying path along which pipeline passes during laying, a second pipe gripping assembly disposed on the pipe-laying path, and a drive unit for causing relative movement in a direction along the pipe-laying path between the first pipe gripping assembly and the second pipe gripping assembly. The first pipe gripping assembly includes both a pipe gripping arrangement for gripping a pipe during pipe-laying and a cable gripping arrangement for gripping a cable during an operation when a cable is connected to a length of pipeline.

Abstract: A pipe-laying apparatus and method for laying or raising a pipeline from a vessel. The apparatus includes a first pipe gripping assembly disposed on a pipe laying path along which pipeline passes during laying, a second pipe gripping assembly disposed on the 10 pipe-laying path, and a drive unit for causing relative movement in a direction along the pipe-laying path between the first pipe gripping assembly and the second pipe gripping assembly. The first pipe gripping assembly includes both a pipe gripping arrangement for gripping a pipe during pipe-laying and a cable gripping arrangement for gripping a cable during an operation when a cable is connected to a length of pipeline.

Abstract: Process for the towing of underwater pipelines by means of head tugs for the pulling and tail tugs for the counter-pulling characterized in that it is effected by the use of a set of equipment, connected to the pipeline itself, including floats, of which at least a part has a variable buoyancy or partially variable buoyancy, which, when placed in a pre-established position and at pre-established intervals, provide a graded buoyancy to the pipeline in relation to the distance from the bed so as to obtain a “festoon” configuration of the pipeline, i.e. with suspended sections of pipeline, in correspondence with the floats, alternating with resting sections.

Abstract: Process for the towering of underwater pipelines by means of head tugs (R) for the pulling and tail tugs for the counterpulling characterized in that it is effected by the use of a set of equipment (A), connected to the pipeline (C) itself, substantially containing floats (G), of which at least a part has a variable buoyancy or partially variable buoyancy, which, when placed in a pre-established position and at pre-established intervals, provide a graded buoyancy to the pipeline in relation to the distance (f) from the seabed (F) so as to obtain a “festoon” configuration of the pipeline, i.e. with suspended sections of pipeline, in correspondence with the floats, alternating with resting sections.

Abstract: A pipe-laying apparatus and method for laying or raising a pipeline from a vessel. The apparatus includes a first pipe gripping assembly disposed on a pipe laying path along which pipeline passes during laying, a second pipe gripping assembly disposed on the 10 pipe-laying path, and a drive unit for causing relative movement in a direction along the pipe-laying path between the first pipe gripping assembly and the second pipe gripping assembly. The first pipe gripping assembly includes both a pipe gripping arrangement for gripping a pipe during pipe-laying and a cable gripping arrangement for gripping a cable during an operation when a cable is connected to a length of pipeline.

Abstract: An insulated pipe structure suitable for use in an undersea pipeline comprises, intermediate its ends, an inner pipe (11) for serving as a conduit for fluid flowing through the pipe structure, thermally insulating material (3) extending around the inner pipe and an outer shell (2) extending around the insulating material (3). At each of the ends of the pipe structure the inner pipe is connected to the outer shell by a thermally insulating connecting element (4) which is secured to the inner pipe (11) at least partly by virtue of adhesive forces between the inner pipe (11) and the connecting element (4). The thermally insulating connecting element (4) and the outer shell (2) together protect the insulating material (3) from water ingress and from ambient pressure.

Abstract: A method of abandoning a pipeline (2) being laid by a vessel having an A/R system, wherein a sealine (2, 11, 13) is initially held by a pipe laying and tensioning arrangement. The method includes a step of reducing tension at sea level of the sealine (2, 11, 13), by connecting one or more buoyant members (13) to the end of the pipeline (2). The members (13) are then lowered into the sea, using a line (16). At least one member (13) is connected to the pipeline (2) through a connection (12) which allows pivoting of the member (13) so that the end of the member (13) at the end of the pipeline (2) projects upwardly from the seabed (3).

Abstract: A pipe-laying vessel includes a vessel that is propelled during pipe-laying; a tower on the vessel; a device for raising a length of pipe from a deck of the vessel to a position aligned with the tower; a device for joining such a length of pipe to a pipeline being laid; and tensioners arranged to grip such a pipeline and to lower it into the water while maintaining a desired tension in the pipeline as the pipeline passes through the tensioners; and one or more clamps arranged to grip the pipeline below the tensioners.

Abstract: A method of abandoning a pipeline (2) being laid by a vessel having an A/R system, wherein a sealine (2, 11, 13) is initially held by a pipe laying and tensioning arrangement. The method includes a step of reducing tension at sea level of the sealine (2, 11, 13), by connecting one or more buoyant members (13) to the end of the pipeline (2). The members (13) are then lowered into the sea, using a line (16). At least one member (13) is connected to the pipeline (2) through a connection (12) which allows pivoting of the member (13) so that the end of the member (13) at the end of the pipeline (2) projects upwardly from the seabed (3).

Abstract: A pipe-laying vessel comprises: means (2) for propelling the vessel during pipe-laying; means for assembling sections of pipe generally horizontally on the vessel to form longer lengths; a tower (14) at the bow of the vessel, with respect to an intended direction of movement, pivotally mounted so that it can be angled forwards towards the top; means (29) for raising a length of pipe from the deck to a position aligned with the tower; means (21, 23) for joining such a length of pipe to a pipeline being laid; tensioners (20) arranged to grip such a pipeline and to lower it into the water while maintaining a desired tension in the pipeline; one or more clamps (18) arranged to grip the pipeline below the tensioners; and a lower ramp (17) provided with rollers and arranged to guide the pipeline as it leaves the vessel.

Abstract: An apparatus for digging a trench beneath a pipeline laid on the bottom of sea or a water body, in which a clamp arrangement is split into a wider sector portion and a narrower sector portion which, as they are united under the control of a driving mechanism, embrace the pipeline and allow a set of digging discs to excavate the ground beneath the pipeline. Provisions are made to remove the debris on completion of digging. The apparatus is driven along the pipeline and means are provided to maintain both the correct vertical trim of the entire apparatus and the correct position of the pipeline track.