Abstract: De-trenching apparatus (100) for extracting a buried line, such as a cable or pipeline, is disclosed. The de-trenching apparatus comprises a channel (112) configured to receive a buried line to be extracted, the channel comprising a first flared opening (114) at a front end of the de-trenching apparatus and a second flared opening (115) at the rear end of the de-trenching apparatus, the first and second flared openings each having a curved surface (111) configured to support the line during extraction, and material removal means for removing material from around the buried line ahead of the de-trenching apparatus.

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: An underwater trenching machine is particularly adapted to clear anodes secured on a pipeline while maintaining engagement of the propulsion assembly with the pipeline. A plurality of rollers of the propulsion assembly grippingly engages opposing sides of the pipeline. The rollers are secured on powered articulated connector arms in pairs. As the rollers come into contact with the anodes, the connector arms cause forward rollers to temporarily move out of contact with the pipeline, while remainder of the rollers maintain the contact with the pipeline. As the first pair of rollers clears the anode it returns to its normal gripping position relative to the pipeline, while the next pair of rollers moves out of engagement with the pipeline. The trenching machine also has a ballast tank and air jet assemblies mounted on the ballast tank for maintaining vertical alignment as the trenching machine moves along the pipeline.

Abstract: A light weight self propelled jetting sled operable by a diver used to bury pipelines below the ocean floor with vertical jetting heads, horizontal jetting heads, bumpers, air lifts, buoyancy chambers, adjustable power rollers, upper rollers, water hand jet, and a control panel.

Abstract: A vehicle (1) for installing a cable (2) in a ground formation, in particular in a seabed, comprising a frame (3), propulsion means (4, 6), a cutter assembly (8) for forming a trench and a guide (15) for placing the cable (2) in the trench. The guide (2) is releasably connected to the vehicle (1). The vehicle and guide according to the present invention facilitate installing a cable in a ground formation, in particular in a seabed, as well as interrupting installation.

Abstract: A method of performing a seismic survey of a hydrocarbon reservoir in the earth formations beneath a body of water includes deploying a seismic cable from a drum carried by a remotely operated vehicle on the seabed. The cable is deployed into a lined trench, which is formed either concurrently with cable deployment or during a previous survey, to ensure good repeatability of successive surveys of the reservoir, in order to enable changes in characteristics of the reservoir, eg due to depletion, to be monitored.

Abstract: A marine plough includes twin, complementary steering mechanisms, one or more soil-engaging fins, which are able to be steered, and a tow rope attachment mechanism that enables adjustment of the position of the tow rope retention point relative to the plough. This alters the position at which the line of a tow rope crosses the longitudinal axis of the plough, so that the plough can operate at offset tow positions. The tow rope attachment mechanism includes a bridle having two bridle limbs terminating at respective bridle limb retention points. The adjustment of the position of the tow rope retention point relative to the plough is done by moving the bridle rope retention points or adjusting the relative length of the bridle limbs. The bridle limb retention points can be moved, using cylinders, from towing positions to lifting positions at which the tow bridle can be used to lift plough in a substantially level attitude.

Abstract: Fiber-optic cable is dispensed underwater into a trench from a vehicle moving along the bed of the body of water. The cable is wound on a stationary spool and dispensed over the end of the spool by a rotary arm driven by a motor controlled to maintain a desired tension in the cable. The cable has a fiber optic core, metal wires wound around the core, and a tensioned laminate of copper tape adhered to plastic tape wound around the wires.

Abstract: An underwater cable deployment system includes a series of cables, pre-wound on a set of reels, disposed upon a pallet and connected to a distribution hub on the pallet. The pallet is lowered to the ocean floor and a remotely operated vehicle (ROV) is also lowered to the ocean floor to deploy cables to form a predetermined array on the ocean floor. Preferably, the pallet is delivered to the ocean floor in advance by crane with the reel-mounted sensor array cables being deployed later by ROV. Optionally, the ROV may include a jetting package configured to bury the sensor cable as it is being deployed from the reel on the ROV.

Abstract: Apparatus for locally disturbing an underwater bed to enable the burial of an elongate member (39) comprises a mounting (30,31), resilient means (88-93) such as brush filaments coupled to the mounting, and means (9) for moving the resilient means with respect to the mounting. The resilient means is constructed such that on moving the mounting along the line of the elongate member while moving the resilient means with respect to the mounting, the underwater bed is disturbed by the resilient means to enable the elongate member to be buried.

Abstract: An ocean plow device and accompanying method which incorporate a passive plow blade and a jetter tool working in conjunction with one another to lower drawbar and increase cable deployment speeds. In order to avoid cavitation due to sand dilation, in one embodiment of the plow device, the jetter tool includes nozzles oriented in a downward and backward direction relative to the plow device which creates a flow pattern to turbulently remove surface soil in front of the jetter tool in a rapid manner. The jetter tool is pivotally suspended from a point in front of the passive plow blade, such that the jetter will be free to find its own equilibrium position. That is, the pivotal mounting enables the jetter tool to rotate upward in harder soils and become fully extended in softer soils in order to reach the equilibrium position. The passive plow blade behind the jetter tool provides a constant burial depth for the cable and also provides protection from side loads encountered during deployment.

Abstract: A steerable plow configured for towing in a direction along a seabed comprises a body and a soil cutting member slidingly connected to the body. The soil cutting member defines a cutting vane for cutting a trench in the seabed. The body includes two skids and a cross member spanning the two skids. The skids are spaced apart from each other and from the soil cutting member to stabilize the plow. A motive element is included to move the soil cutting member relative to the body, and a steering control receives commands from a remote location to control the motive element. At least one towing member is included to attach the plow to a tow cable.

Abstract: A steerable plow configured for underwater towing along a sea bed. The plow includes a plow body and a soil cutting member attached to the body. The soil cutting member is configured for forming a trench in the sea bed in a forward direction of travel of the plow. A tow member is attached to the body for attaching the plow to a tow cable. The tow member defines an effective tow point which is forward of the cutting member. A steering device is provided for creating a steering moment capable of varying the direction of travel. The steering device is positioned rearwardly relative to said tow member.

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 ditch backfilling device and apparatus therefor are disclosed. In particular, the ditch backfilling device includes a mainframe for supporting a compartment for storing the backfill material and a screening system for sorting and directing the backfill material into a ditch. The backfilling device includes a support for holding a roll of warning tape and an application roller for placing the unrolled portion of the warning tape above a uniform structure, such as a pipeline, within a layer of backfill material in the ditch. The warning tape is thereafter buried in subsequent layers of backfill material poured by the backfilling device. The backfilling device also includes a guide structure which is configured to follow the surface of the uniform structure. The guide structure positions a conduit adjacent the uniform structure for burial in the backfill material. The conduit may contain cables for the transmission of communication information or operating instructions.

Abstract: A method consisting in forming a preliminary excavation along the pipe and in then digging, starting from the bottom of the preliminary excavation, two lateral trenches that are adjacent to the sides of the pipe, converge downwardly, and go deeper than the level set for the final excavation bed that lies below the pipe, so as to form respective lateral collection channels; and in removing, by cutting, the wall that separates the trenches in the region below the pipe, dumping the corresponding residual material into the lateral collection channels. The invention also relates to an apparatus, of the integral type or composed of dedicated units, for digging the lateral trenches and/or for cutting away the wall that lies below the pipe.

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: In a trench is disposed a closed flexible envelope filled with a fluid having a density or pressure greater than that of the surrounding fluid, movable by itself under the effect of the pressure exerted at its end by said pipe, which envelope is in the form of a cylinder each end of which has been turned in concentrically to its longitudinal axis, in the direction of the opposite end, the two central portions of this turning in being welded together so as to form a central envelope web turned in along its axis.

Abstract: The plough consists of two portions separable by rams (72). Each portion comprises a beam (14, 16) joined to a plough body part (18, 20). The portions include two pairs of longitudinally-spaced arms (69) interconnected by pivots (70). At each end of the plough a support including bearers (61) is closed by a ram (59) to entrap the pipeline (26). Another ram lifts the support to raise the pipeline between the plough body parts (18, 20). The support ram is connected to a pressurized accumulator so that the support rollers (62) are kept against the pipeline (26) as the plough rises and falls and pitches. The elevated positions of the arms (69) and the relatively short separation between the two pairs of arms (69) allows the plough to descend and pitch relatively to the pipeline. In a modification the two beams are joined by rigid bridging structure and the plough body parts are pivotally connected to their respective beams. In other modifications the supports are dispensed with; or only one is used.

Abstract: A self-propelled underwater bed cable burying machine is disclosed, which comprises a bottom running gear body with a high pressure water generator mounted therein and an arm-shaped water jet trenching unit mounted the base end capable of revolution in a horizontal plane on a front portion of the running gear body and having a multiple joint degree of freedom. The arm-shaped water jet trenching unit includes an elbow arm having at least one portion capable of being bent in a vertical plane. The elbow arm having a U-shaped hand provided at the free end for capturing and holding an underwater cable. The U-shaped hand having finger portions each provided at least one cable sensor and a trenching water jet nozzle communicating with the high pressure water generator.

Abstract: Apparatus and a method for progressively forming a subsea trench and for laying a pipeline in that trench are provided. The apparatus includes a towable sled for supporting the pipeline as it is being laid in a subsea trench that is being created by fluid jetting, mechanical cutting or a combination of both, using jetting and cutting devices mounted on the sled. In the preferred embodiment, the jet device proceeds the mechanical cutter on the sled and is vertically adjustably mounted so it can be raised out of the way while the mechanical cutter is in use.

Abstract: For burying piping (1) in a sea-bed, at least one excavating machine (3) is provided for forming a first trench (4) parallel to the front portion (1.sub.1) of the piping and to a guide formwork (5) adapted both for moving parallel to the first trench (4) and for then forming automatically, during its horizontal advance, a second trench (8) parallel to this first trench, contiguous therewith and extending planewise in the extension of the front piping portion, said structure having for this purpose an oblique front moldboard (9) which pushes back laterally into the first trench the earth engaged thereby and for automatically burying the piping (1) in the second trench (8) thus formed.

Abstract: Inductive coupling of a high-frequency signal into a cable to be detected d tracked in a seawater medium for sensing the relative position of the cable with respect to capacitor plates. The capacitor plates are positioned so that in conjunction with the cable a differential capacitor is formed. Relative movement of the capacitor plates with respect to the position of the cable is used to unbalance a Wheatstone Bridge circuit. The output signal from the bridge circuit is proportional to their displacement and is used to provide a guidance signal to realign the capacitor plates and the cable.

Abstract: The present invention aims at providing a method and a device therefor which can effectively as well as accurately bury a cable under marine beds not only when a cable is newly laid and buried but also when a cable has to be reburied. The method and the device according to the present invention are characterized in that a burying device is guided to approach the cable by using a travelling member provided on said burying device, a travelling control mechanism thereof being controlled by a receiving output from a transmitter which is mounted on the cable in advance by a receiver provided on the burying device, that the cable is caught and held by a cable engaging member of said burying device while the burying device is detecting the buried cable track and travelling therealong, and that at the same time an excavation member of said burying device digs and forms a groove while the burying device guides and buries the cable within the excavated groove.

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 trenching device for previously laid cable or pipeline, particularly those laid under water, has a plough (1), means (8) for following the cable or pipeline, a carriage (9), which may be a tractor, connected to the plough through a towing member (6), and vertical pivots between the towing member and the plough and the towing member and the carriage.The double pivot system allows the plough to follow the cable or pipeline independently of the motion of the carriage.

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: 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: The present invention has an object to provide an underwater cable burying device which can accurately be guided to align with the cables in the process of burying even if the cables have to be re-buried. The device according to the present invention is characterized in that a travelling device is provided on the body of the device which is further provided with a trenching device at the middle portion thereof, that a cable clamp member and a cable engaging member are provided at an arm projecting forward from the said device body and that said respective devices are controlled through a control cable on the mother ship.

Abstract: A cable or the like is embedded into an underwater ground by introducing the cable into a zone of reduced density which is produced progressively in the ground by a flushing process; upon meeting with ground formations which are only insufficiently loosened by the flushing process, mechanical loosening tools assist the loosening action of the flushing process. Preferably, the mechanical loosening tools are automatically put into and out of operation in dependence upon the depth of penetration of the flushing process.

Abstract: The invention relates to an apparatus for the entrenching of pipes in underwater beds, of the type in which a framework, provided with excavating means, is positioned across the pipe to be entrenched and dragged along the pipe so as to excavate two parallel trenches adjacent to both sides of the pipe, the pipe being entrenched due to the collapsing (either spontaneous or caused by disgregating means) of the bed zone thus remaining under the pipe already laid onto the bed. The excavated material is removed by means of a pump and discharged again, at a predetermined distance from and rearwardly of the framework, on the entrenched pipe. The framework is provided with side supporting skid members, by which furthermore the entrenching height is adjustable.

Abstract: A trenching implement (41) suitable for towing on the sea bed to make a trench for a submarine cable or pipeline (54) comprises a body (44) attached to which is a soil cutting member (46) which makes a soil surface in the direction of travel of the implement, a landside (45) engaging the soil surface and a towing means (56) connected so that, when the direction of travel is different from the line of the towing force (56), the line of the towing force (56), projected if necessary, passes through a point (50) in the region of the landside (45) with the result that the landside (45) resists the sideways component of the towing force (56). This reduces the risk of damage to the cable or pipeline (54).

Abstract: A trench digging apparatus comprising a cutter wheel with picks projecting from the outer periphery thereof. An electric drive motor is provided to rotate the cutter wheel about a substantially horizontal axis. The cutter wheel is supported by a support frame which is pivoted to a basic framework of the apparatus by spherical and eccentric hinge bearings. These hinge bearings allow a limited amount of movement about a vertical axis as well as pivotal movement about a horizontal axis. The movement about a vertical axis allows the cutter wheel to turn or be oscillated to free the apparatus, correct for crabbing or enhance cutting, and the movement about the horizontal axis enables the trench depth to be varied.

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: A method of and apparatus for laying a pipe or cable in a bed of material. There is provided an elongated generally straight tube having a plurality of cutter means mounted in generally parallel spaced relationship with one another along the outer surface of the tube. The cutter means is adapted to remove material by shaving to form a trench when the tube is moved along the bed of material. There is provided adjustable skid means mounted on the tube. The tube or cable to be laid is received by the tube, so that, during movement of the tube, the tube or cable is laid in the trench.

Abstract: A method and apparatus for laying pipeline in a bed substantially under water. Pipe is placed on the bed along the general line the pipeline will take. A trench is excavated in the bed generally parallel to the pipe by transporting spoil to the opposite side of the trench as the pipe and by excavating sufficient material adjacent the pipe so that the pipe will be supported by the bed after initial excavation but so that the bed ultimately will shear along a shear line under the weight of the pipe alone, so that the pipe will drop into the trench along with the material of the bed above the shear line. Material that has fallen into the trench after collapse of the pipe into the trench can be shifted out of the trench. The plow used for trenching includes a tandem set of wheels mounted to a forward portion of a frame, a center line of the plow extending between the wheels posterior thereof.