Abstract: The invention provides a method of assembling and installing pipes comprising disposing at least one cable between a first station and a second station; attaching and clamping a first pipe to the cable at or adjacent one of said stations; moving the pipe away from said one station with the cable; connecting a second pipe to the first pipe and attaching and clamping the second pipe to the cable at or adjacent said one station; repeating the connecting, attaching and clamping operation to provide an elongate connected sequence of pipes attached to and clamped to the cable; and drawing the cable away from said one station towards the second station to move the sequence of pipes into its desired position between the first and second stations.

Abstract: For burying conduits in the bottom of a waterbed the invention proposes to provide protruding parts such as fins on or in the proximity of the conduit, which cause disturbances in the flow of water near the conduit to erode the bottom of the waterbed in such a way that the conduit will be buried.

Abstract: An encasing method and apparatus in which an external casing, has an insulating, tubular liner therewithin, and one or more pipes or electrical cable are located within the liner. The liner and pipe or cable are floated into the casing after the casing has been flooded with water or other flotation liquid, following the laying of the casing on a support surface, such as the ground or a seabed. After installation of the liner and pipe or cable, water continuously flows through the casing and through the liner, whereby dissipation of waste heat can be controlled by controlling the velocity of flow of the water through the casing. The pipe or cable can be floated out of the liner for repair or replacement without removing or modifying the casing or the liner. Moreover, leaks in the pipe or cable can be monitored on a continuous basis, such as by using a gas chromatograph.

Abstract: A hollow curved auger is provided for simultaneously laying and trenching a pipeline, as from the surface of an ice-covered body of water. The pipeline passes through the auger which comprises rotary teeth encircling the pipeline and turning in opposed directions. The depth and direction of pipeline trenching and burial are controlled by varying the longitudinal force in the pipe and rotational orientation of the auger.

Abstract: One construction method for burying offshore pipelines utilizes a segmented excavation shield for forming a trench in the seafloor. The present invention provides a propulsion method for advancing the shield which eliminates the need to pull the shield. This is done by advancing skin plates which are attached to the shield, then advancing the shield by transmitting soil reaction through the skin plates, which remain stationary, to the shield.

Abstract: The plough has a front and a rear lifting assembly (60, 62) each including an arm (64, 80) which is extensible and angularly adjustable by hydraulic rams (65, 68; 81, 84). The arms carry rollers (74, 76, 78; 94, 96, 98) upon which the pipeline (110) is lifted by the arms. The plough can be positioned beneath the pipeline as the arms retract while supporting the pipeline as the plough approaches the pipeline from one side. Having been positioned, the plough advances to cut a trench, the pipeline being supported in yielding manner by the two arms, having their lifting rams (68, 84) connected to hydraulic accumulators. Pressurized gas in the accumulators maintains the rollers (74, 76; 94, 96) in contact with the pipeline as the plough moves up and down and pitches relatively to the pipeline, during ploughing. The plough requires no structure over the pipeline. The plough body (12) is not required to comprise parts which separate to allow positioning of the plough in relation to the pipeline.

Abstract: A process and apparatus are provided for the simultaneous trenching and installation of submarine pipelines. The apparatus is based on a single unit which includes an excavating portion, an attached ditch sidewall retention shield, and a pipeline installation guide. The excavator creates a trench of a slightly larger cross section than required, the shield prevents the trench from closing due to the collapse of the sidewalls, and the pipe guide causes the pipeline to be deflected into that portion of the trench protected by the shield. The pipeline is fabricated on the surface of the sea or on floating ice, and is supported and guided to enter the forward portion of the shield by a stinger or other means, when required.

Abstract: A trench is dug under the pipe. A collapsible means formed by a supple and deformable envelope is conveyed into the trench as it is dug in a state folded or coiled upon itself. The envelope is filled with water by a pump assembly and unfolded in a diverging cone, and progressively substituted for materials extracted as the trench is dug. The pipe is then lowered into and positioned in the trench by the escape of water out of the envelope through orifices or valves.

Abstract: An apparatus for digging a trench under a pipeline or cable which has been placed on the sea bottom. A carriage moves along the pipeline. Two forward digging chains are mounted on the carriage so as to be disposed on each side of the pipeline, and so that their ends define two points on a line extending beneath the pipeline or cable. The digging chains are arranged one behind the other in the direction of movement of the carriage. Each digging chain is movable from a first position of incline with respect to the direction of movement of the carriage to a second position substantially at right angles thereto. The digging chains are shaped and positioned so as to dig the trench with an undercut slope at both sides.

Abstract: Method and installation for depositing materials on an ocean bed in accordance with a given line in which the autonomous vehicle is displaced on the ocean bed by accurately following said line, whereby the vehicle is provided with a hopper, a ship is moved on the surface of the ocean roughly in accordance with said line, the materials are discharged from this ship towards the hopper and are guided by means of a pipe suspended beneath the ship and whose lower end is not integral with the hopper, wherein the propulsion means of the pipe disposed at the lower end thereof are operated so that the lower end of the pipe is forced to remain above the hopper.

Abstract: A method and apparatus for entrenching under-water pipelines, in which auger assemblies are provided on a vehicle for inward tilting movement so that the auger assemblies both cut and convey bottom soil from the region beneath the pipeline. The respective augers are driven by hydraulic motors and can include deflectors for directing bottom soil toward the individual augers. In a variation, two sets of augers are provided on the vehicle in tandem.

Abstract: A trenching plow and technique for its use, especially for forming a trench under water for receipt of pipe. The plow includes a frame with a tandem set of wheels at the front, and a share with mould boards mounted at the back of the frame. During trenching the frame always makes a positive angle with respect to the horizontal, and a soil furrow splitter is formed on the bottom of the frame. A pair of coulters are mounted to the frame in front of the share, each of the coulters raking forward at an angle of about 60.degree.-70.degree. to the horizontal, and the coulters being staggered along the length of the frame. The coulters also have a positive clearance angle with the trench side wall, and they extend to a depth about two-thirds the depth of the share. A trench having a depth of about 1.1 meters with side walls at an angle of about 60.degree. to the horizontal may be formed at a towing speed of about two knots, the trench being formed having constant cross-section and constant depth.

Abstract: Underwater pipelines connected to at least one point on a coastline are constructed by means of a pipelaying vessel associated with an independent underwater vehicle mounted on caterpillar-tracks and capable of traveling along the sea bed. From within the vehicle, pipe sections can be assembled and rejected as the vehicle moves forward. The pipe sections pass through a wall of the vehicle and into the sea, through a port which is provided with a plurality of inflatable annular sealing rings that selectively sealingly bear against the exterior of the pipeline. One of these sealing rings is associated with an annular piston, and a jack acts between this piston and the vehicle to provide the propulsive force for ejecting the pipe sections from the vehicle. Potential applications include mining operations, off-shore installations and intercontinental tunnels.

Abstract: Submersible backfill machine for covering a submerged conduit disposed within a trench in a seabottom with material from the sea bottom, which includes a sled positionable over the conduit on the sea bottom. A pump is supported by the sled and is connected to an intake head that is adapted to pick up sea bottom material entrained in water drawn into the pump. A dispersion nozzle is connected to the discharge side of the pump to cause the entrained sea bottom material to settle into the trench and cover the conduit.

Abstract: A ditching machine for digging a ditch or a trench for submarine cables having at least several plurality pairs of blades disposed along the longitudinal direction of the center body of the machine. At least the blades in the forward position have a ditching portion which ditches soil, and a soil-pushing portion which pushes away the soil thus ditched substantially and horizontally in a direction lateral to the moving direction of the ditching machine. Said soil-pushing portion is at the top of said ditching portion and has a wider horizontal width as seen from front of the ditching machine than that of said ditching portion when the ditching machine is in a normal operating position.

Abstract: Disclosed are a method and apparatus for the covering and filling of a trench used for an oil and/or gas conduit on the sea bottom which utilize a surface vessel retained in position over the trench by means of positioning equipment while filling material is released downwardly towards the trench and sea bottom from the vessel. The method comprises supplying filling material, heavily mixed with water, to the surface vessel from a store or the like via a preferably floating hose, reducing the water content of the filling material in a separator aboard the vessel, and conveying the filling material thus treated downwardly to the trench and sea bottom via a tube or the like whose mouth is retained adjacent to the trench and the sea bottom.

Abstract: A method and apparatus for entrenching an elongated pipeline and the like uses a trenching apparatus having a trench cutting assembly which is detachably connected to a sled base. A floating vessel has means to control positioning of the trenching apparatus, including means to raise and lower, and to connect and disconnect, the trench cutting assembly and the sled base. Several methods and apparatus are disclosed for raising and lowering the trench cutting assembly while leaving the sled base positioned on the bottom of the body of water, straddling the elongated pipeline. In each embodiment, the cutting means may be lifted on board the vessel for maintenance and/or repair, leaving the sled base in position relative to the pipeline. Means are provided for abandoning the sled base at the entrenching site and returning later to lower the trench cutting assembly into its operational relationship with the sled base.

Abstract: A high pressure flow-through swivel joint is particularly adapted for connecting high pressure water lines to a jet sled in an underwater pipe burying apparatus. The joint includes mating spherical joint surfaces which allow pivotal adjustment during assembly, in order to compensate for construction tolerances. In addition, the mating spherical surfaces allow rotational freedom for the joint inlet passage when the pipe burying system is in operation.

Abstract: Method of assembling and laying at least one fluid conveying conduit between an on-shore point and an advanced off-shore point, including erecting, regularly on the bottom of the sea, partially emersed pillars, prefabricating conduit sections before or after erecting the pillars, mounting said sections between and at least partially supporting the same on the successive pillars and interconnecting these sections. Where there are at least three conduits, they may be provided in a bunch arrangement and suspended between the pillars. Where the conduits are partially immersed, they are provided with a rising branch at each end to be connected one to another above the level of the sea.