Abstract: A subsea trencher for arranging at least partly into the seabed a subsea pipeline, includes at least one cart that separately carries at least one trench tool and is configured to run along the subsea pipeline. trench tool is configured to work the seabed underneath the subsea pipeline. A subsea support frame carries heavy subsea equipment connected to the trench tool for operating the trench too. When the subsea support frame is fixed to the cart, the subsea trencher is configured to load the assembled weight of the cart and subsea support frame onto the subsea pipeline as the subsea trencher runs on the subsea pipeline. When the subsea support frame is separate from the cart, the subsea support frame is configured to be suspended above the seabed or arranged beside the subsea pipeline at a distance from the subsea pipeline as the cart runs along the subsea pipeline.

Abstract: A system and method for laying an underwater pipeline is provided. The present invention includes a plurality of pipe support rings connected together by tension cables. The tension cables are secured to a S or J laying ship by a winch. The plurality of pipe support rings form a pipe channel sized to guide the underwater pipeline. The present invention further includes a sea water pipe having a distal portion and a proximal end. The proximal end is fluidly connected with a pump on board the ship. The distal end includes a plurality of nozzles. The sea water pipe is disposed underneath the plurality of pipe support rings. The underwater pipeline is fed through the plurality of pipe support rings while the nozzles form a trench on a sea bed.

Abstract: A device includes a digging device to cut the seafloor and with a device for hooking onto a pipeline and for sliding over the same. The device includes at least one float device constrainable to the pipeline for supporting it in span, connected to the back of said digging device with respect to the direction of the movement. The method includes excavating the seafloor by a digging device, collecting a float device from a storage base and transporting it to said pipeline, constraining the first float device to the pipeline behind the digging device and connecting the first float device to the digging device, when at least one portion of pipeline is in a suspended configuration, and when the portion of suspended pipeline increases, collecting a subsequent float device and constraining it to the pipeline and connecting the same to the float device previously constrained.

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: Various apparatuses and methods to traverse an undersea topographic feature (12) with a subsea pipeline (18) are disclosed. The apparatuses and methods of the present invention accomplish this task through the use of a concentrated buoyancy scheme (10). The invention disclosed can allow more efficient and cost effective traversal of hostile terrain for subsea pipelines at great depths while minimizing the risk of rupturing the pipeline (18) or negatively impacting the surrounding undersea environment.

Abstract: An apparatus for forming a trench in a seabed for burying a line generally consisting of a main frame, at least one buoyancy tank mounted on the main frame, a pair of endless track assemblies, each engageable in gripping relation with a side of the line for propelling the frame along the line, a pair of jet legs mounted on the main frame and communicable with a source of fluid under pressure, for ejecting high velocity streams of fluid to dislodge portions of the seabed when the track assemblies grip the line and propel the main frame along the line to form a trench and allow the line to fall therein.

Abstract: An air-can riser tensioning device for use in the production of oil and gas at offshore locations includes at least one air-can used to place a vertical force on the riser. The air-can includes an open port that extends into the water toward the sea floor to a depth sufficient to prevent water from entering or air from leaving the air-can during its upward and downward vertical movements while in use. A manufacturing method includes fabricating the air-cans out of one material and fabricating the open port out of another material, and in particular making the open port from a material that is more corrosion resistant than the material the air-can is fabricated from. The manufacturing method further includes fabricating a passage in one soft tank for fluid communication with a second soft tank, and connecting the second soft tank with the passage.

Abstract: A drilling unit comprises a floating drilling rig, a subsea wellhead, and a riser connecting the subsea drilling rig with the subsea wellhead. A floatation collar encircles the riser so as to reduce deck load on the floating drilling rig. The floatation collar comprises a hollow fabric body filled with gas. The floatation collar has a longitudinal axia and is formed from a sidewall body having a longitudinally extending slit extending through the sidewall body. The slit enables the floatation collar to be transversely mounted onto the marine riser.

Abstract: A drilling unit comprises a floating drilling rig, a subsea wellhead, and a riser connecting the subsea drilling rig with the subsea wellhead. A floatation collar encircles the riser so as to reduce deck load on the floating drilling rig. The floatation collar comprises a hollow fabric body filled with gas. The floatation collar has a longitudinal axis and is formed from a sidewall body having a longitudinally extending slit extending through the sidewall body. The slit enables the floatation collar to be transversely mounted onto the marine riser.

Abstract: A self-guided system for trenching water bottoms for the installation of a pipeline. The preferred embodiment of the present invention teaches a system which is configured to be mounted about the pipeline to be buried, and which further contemplates a uniquely configured, forward mounted trenching/drive mechanism incorporating a cutter wheel generally about the width of the desired trench, the mechanism configured to propel the system as well as trench the desired area. An alternative embodiment of the contemplates a frontal high pressure jet array in lieu of the cutter head. The trenching/drive mechanism of the preferred embodiment of the present invention further includes a high pressure spray array mounted about the frontal cutter wheel area, and a suction/mud pump assembly to the rear of the cutter wheel. The high pressure spray array provides the dual purpose function of loosening the area to be trenched, as well as cleaning and removing the trenched matter from the cutter wheel.

Abstract: A self-guided system for trenching water bottoms for the installation of a pipeline. The preferred embodiment of the present invention teaches a system which is configured to be mounted about the pipeline to be buried, and which further contemplates a uniquely configured, forward mounted trenching/drive mechanism incorporating a cutter wheel generally about the width of the desired trench, the mechanism configured to propel the system as well as trench the desired area. The trenching/drive mechanism of the present invention further includes a high pressure spray array mounted about the frontal cutter wheel area, and a suction/mud pump assembly to the rear of the cutter wheel.

Abstract: A self-guided system for trenching water bottoms for the installation of a pipeline. The preferred embodiment of the present invention teaches a system which is configured to be mounted about the pipeline to be buried, and which further contemplates a uniquely configured, forward mounted trenching/drive mechanism incorporating a cutter wheel generally about the width of the desired trench, the mechanism configured to propel the system as well as trench the desired area. The trenching/drive mechanism of the present invention further includes a high pressure spray array mounted about the frontal cutter wheel area, and a suction/mud pump assembly to the rear of the cutter wheel. The high pressure spray array provides the dual purpose function of loosening the area to be trenched, as well as cleaning and removing the trenched matter from the cutter wheel.

Abstract: Pressure-triggering buoys are constructed of prebuckled pipe segments and attached to an offshore structure or pipeline under construction. The attached buoys move with the structure or newly added pipe segment toward the sea bottom, easing the descent. As the structure or segment of pipeline reaches a predetermined depth, the buoy attached thereto collapses, causing the structure or segment of pipeline to be heavier. In the instance of a pipeline, this collapse, in turn, causes the adjacent upper segment of pipeline to move lower, causing the next buoy to collapse, and so on.

Abstract: Disclosed is an apparatus for simultaneously trenching and laying a submarine pipeline within the bed of a body of water covered with a relatively thick ice mass. The apparatus comprises a pipeline construction spread which precedes a trenching and pipe installation spread, both of which traverse the ice mass. The pipe installation vehicle advances toward the constructed pipeline, elevates the pipeline, forms a slot-like opening in the ice and directs the pipeline into the water through the slot. A submersible dredging assembly extends from a installation vehicle which forms part of the installation spread. As the vehicle advances, the dredging assembly forms a trench in the sea bed. At the same time the dredging assembly guides the pipeline into the trench and provides support to a submerged component of the pipeline which is threaded through a slot in the dredging assembly.

Abstract: An underwater trenching apparatus for burying pipeline and the like including a frame for positioning about the pipeline to be buried, a drive roller system operatively connected to the frame for driving the frame along the pipeline and including at least one pair of opposed rollers, each of the rollers having a curved pipe contact surface having a radius less than the radius of the pipeline to be buried and configured to grasp about 40 percent of the circumference of the pipe, the arms to which the rollers are mounted pivot about a shaft which is removably mounted to the frame, and a cutting system attached to the frame for cutting a trench, the cutting system includes at least one pair of rotating discs rotating about a horizontal axis, and having water nozzles extending out from them, the water forced out of the nozzles scoops the seabed and disperses it up, away from the bottom of the trench. The pair of discs are mounted so that they can be moved up and down as well as rotated in and out.

Abstract: A trenching machine for digging a trench beneath a pipeline lying on the floor of a body of water, with a pair of laterally spaced vertical cutting members, shown to be a series of water jets, positioned at each end of the machine. The cutting members are laterally adjustable to move apart and tilt with respect to the vertical centerline of the machine. The cutting members are also arranged to oscillate about a vertical axis. Fore and aft side rollers are longitudinally spaced under the framework of the machine and are arranged to contact the pipeline to drive the machine along the pipeline and to stabilize the machine in its upright operating position over the pipeline. The rollers have selectively adjustable hydraulic biasing cylinders associated with each set of rollers to maintain a constant gripping force between the rollers and pipeline. The rollers are selectively reversibly driven to provide back and forth operation of the trenching machine.

Abstract: A self-propelling device for burying and digging up subsea conduits laid on beds of an incoherent material. The device has:disintegrating members using high pressure water jets to create a slurry of material,digging members having suction members which draw the suspension prepared by the disintegrating members, thus leaving a trench behind, anddisplacement members for moving the device on the seabed astride the conduit.

Abstract: The apparatus will include a support sled portion having a pair of spaced apart elongated pontoon sections. The pontoons are interconnected by a plurality of I-beam spacer members. A cutter apparatus, including an endless cutter chain projecting into the soil is mounted to the underside of the I-beam spacer members.

Abstract: A marine continuous pipe laying system comprising a variable departure angle reel operably connected to a retractable trenching plow and backfilling apparatus. The reel comprises a pipe straightening mechanism connected to the rotational axis of the reel by a yoke for automatically maintaining proper bending moment regardless of the departure angle of the pipe. The plow comprises a shaped chisel share which is pivotally retractable within a sled frame for avoiding existing pipelines and varying the depth of cut and is provided with instrumented guide rollers to permit an operator to adjust the tow length of the plow to properly position the plow with respect to the catenary curve of the pipe being laid. The distance between the plow and the backfilling apparatus is adjustable to insure that the pipe is in the bottom of the trench before backfilling occurs.

Abstract: This invention relates to the self-propelled underwater trenching apparatus and method for burying pipelines, cables and the like with minimum underwater diver supervision. The apparatus includes a frame having frame members positioned about the pipeline and buoyancy tanks with variable positions. Drive rollers are connected to the frame members for drive engagement with the pipeline. The frame members are movable by power rams about vertical and horizontal pivots selectively to engage or disengage the drive rollers with the pipeline. Oscillating water jet nozzles are secured to the apparatus for preselected sweeping movement to cut away the bottom formation to enable the pipeline to be buried in the trench so formed.

Abstract: A system for excavating a trench in the sea bottom and removing the excavated spoil from the trench in order to enable an elongated structure, such as a pipeline, to settle into the trench is disclosed along with a corresponding method of operating such system. The system includes a sea sled which can be towed along the bottom of the sea and a towing vessel for towing the sled along the sea bottom. The sea sled includes a frame to be disposed over the area in which the trench is to be formed, a fluid jet excavator mounted on the frame and located adjacent to the rear end of the sea sled and a spoil removal mechanism mounted on the frame and located aft of the fluid jet excavator. Both the center of buoyancy and the center of gravity of the sled are located in front of the fluid jet excavator.

Abstract: A method, as well as applied apparatus facilitating the free-floating, controlled suspension deployment of all semi-flexible and non-buoyant high voltage submarine electrical power transmission conduit/cable; including shore to shore interconnection installations employing the said method and apparatus in at least some portion thereof. The said method provides for deployment at specific depths of submersion between the surface and the bottom of a body of water, via tangentially applied flotation support and tethering stabilization apparatus, so employed to provide relative free-flotation of the said conduit/cable at approximately specific gravity at the specified depth of deployment, while facilitating maximum heat dissipation requirements attendant their thermally active functional character.

Abstract: This invention relates to the self-propelled underwater trenching apparatus and method for burying pipelines, cables and the like with minimum underwater diver supervision. The apparatus includes a frame having frame members positioned about the pipeline. Drive rollers are connected to the frame members for drive engagement with the pipeline. The frame members are movable about a pivot to selectively engage into or disengage rollers out of drive engagement with the pipeline. The apparatus also may include extensible means to move the pivot axis laterally or transversely of the pipeline. The formation is cut away by water jets secured to the apparatus to enable the pipeline to be buried in the trench formed. Upon meeting an obstruction on the surface of the pipeline, power rams in the fore portion of the frame member separate the frame member that may bend the frame member to bring the forward drive rollers out of driving engagement with the pipeline.

Abstract: An apparatus for imparting suitable buoyancy to submerged articles, such as pipelines, to reduce their weight in water and enable efficient movement thereof. The apparatus comprises at least one float comprising air tight material, pipe for supplying pressurized air thereinto, and a differential pressure regulating valve arranged close to the float and connectable to the pipe for regulating the amount of pressurized air supplied to the float dependent upon the difference in pressure between that in the float and a predetermined value. Advantageously, the apparatus is easily transportable, stored and attached to the items to which it imparts the desired amount of buoyancy; the apparatus also keeps constant the buoyancy regardless of the depth of water, thus, enabling easy and safe moving of submerged articles.

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.