Abstract: A trencher includes a trencher body; a cable detection mechanism disposed at a front portion of the trencher body; a chain mechanism and a jet mechanism disposed in the center of a bottom portion of the trencher body; a first track mechanism and a second track mechanism, the first track mechanism being disposed on a first side of the bottom portion of the trencher body, and the second track mechanism being disposed on a second side of the bottom portion of the trencher body; and a soil discharging component disposed at a rear portion of the trencher body.

Abstract: The present invention provides an improved pipeline burying apparatus that uses specially configured jetting nozzles that intake sea water surrounding the nozzle. The apparatus provides a frame supporting spaced apart left and right inclined pipe sections that are configured to be placed on opposing sides of the pipeline to be buried. Each inclined pipe section is fitted with a plurality of jetting nozzles that are positioned on one of the inclined pipe sections, in vertically spaced apart positions and in horizontally spaced apart positions. At least some of said jetting nozzles include a nozzle body having an outer surface and a main, central longitudinal fluid flow channel with a central channel axis. A fluid inlet end portion of the nozzle body has an externally threaded portion that enables connection to an internally threaded portion of a selected one of the inclined pipe sections. A discharge end portion of the nozzle body extends outwardly from an inclined pipe and the threaded portion.

Abstract: A method of laying a pipeline in the bed of a body of water advancing a digging assembly along a pipeline laid along a path on the bed of the body of water, and digging a trench along the path in the bed of the body of water by means of the digging assembly, so a portion of pipeline settles onto the bottom of the trench. The method also includes acquiring, by means of the digging assembly, data related to the bathymetric profile of the portion of pipeline laid on the bottom of the trench, and comparing the acquired data with a set of permissible values. Further, the method includes emitting an error signal when the acquired data does not fall within the set of permissible values.

Abstract: Pipe burial apparatus are disclosed that include sets of rotary nozzle cutters configured to straddle a pipe that is to be buried and a nozzle array connected to a nozzle supply pipe in a manner that places the nozzle supply pipe in a cutting path of a rotary nozzle cutter. The nozzle supply pipe may be actuated to alternatingly move the nozzle array between a position straddling the pipe being buried and a cutting position that is below the pipe being buried.

Abstract: A jetting system for an undersea trencher has jetting conduits extending aftward of its trench-cutting jetting swords. Jetting conduit nozzles direct liquid radially from their jetting conduits into the trench after the trench is excavated by the jetting sword cutting nozzles. The jetting conduits direct sufficient liquid into the trench to maintain the mix of trenched soil and water in the trench along the length of the conduits at not more than a super-critical density, extending the distance in which the product being laid in the trench is able to descend in the trench and increasing the likelihood that the product will be buried at the intended trench depth.

Abstract: A method of controlling subsea laying of an elongate article includes guiding the article using a submersible vehicle such as an ROV that carries a guide tool. The guide tool has a sleeve through which the article moves axially during laying, while the vehicle applies cross-axial guide forces to the article via the sleeve. Also disclosed is a guide tool including a sleeve through which the article can move axially during laying, and a grab handle whereby a submersible vehicle may hold the tool using a grabber. Alternatively, the guide tool can be attached to or integrated with the vehicle.

Abstract: A seafloor auxiliary mining tool for use in a seafloor mining system. The seafloor auxiliary mining tool has a seafloor locomotion system enabling traversal of the seafloor. Umbilical connections receive power and control signals from a surface source. A boom mounted auxiliary cutting tool is configured to cut extremities of a seafloor deposit. Cuttings produced by the auxiliary cutting tool are sized by sizing means, to ensure such cuttings are no greater than a desired size.

Abstract: There is provided an underwater apparatus that includes a housing including a certain device, a pair of cable couplings including gimbals through which tail cables extends from the device to the outside of the housing pass, and the pair of cable couplings that connect the tail cables passing through the gimbals to a submarine cable, and a connecting holder configured to include gimbal rings fitted to the gimbals and to connect the pair of cable couplings to the housing via the gimbal rings so that the pair of cable coupling is rotatable relative to the housing, the connecting holder including an opening from which the gimbals are introduced toward the gimbal rings, wherein the connecting holder includes notches provided in an edge of the opening and the notches are formed so that the pair of cable coupling is rotatable relative to the housing.

Abstract: The present invention relates to a system for subsea installation of elongate flexible element, comprising a container for allocating/storing/accommodating an elongate flexible element intended to be installed, said container being positioned on a trenching vehicle arranged to trench said elongate flexible element into the seabed, which container comprises a guide system arranged to control the release of the flexible element, and which trenching vehicle is further linked to a surface vessel via an umbilical cable whereby said vehicle is remotely operable subsea from said surface vessel wherein said guide system comprises a coiling arrangement for keeping the elongate flexible element in a defined coiled configuration inside said container.

Abstract: An autonomous underwater plow can include a frame, a plow assembly and a propulsion assembly. The plow assembly is fixed to the one end of the frame, while the propulsion assembly is pivotably attached to the other end. The propulsion assembly includes thrusters that are rigidly coupled to a float, and that provide a propulsion force perpendicular to the float buoyancy force. The plow sinks when placed in the water, but the float provides sufficient buoyancy so that the float end floats while the plow end is in contact with the ocean floor. This establishes a rake angle of between the frame and ocean floor. The plow requires less propulsion force for motion because part of the plow is floating, and requires less force to overcome obstacles on the ocean floor because the thrusters provides a constant horizontal propulsion force while the frame tilts to overcome the obstacle.

Abstract: A method of laying a pipeline in the bed of a body of water advancing a digging assembly along a pipeline laid along a path on the bed of the body of water, and digging a trench along the path in the bed of the body of water by means of the digging assembly, so a portion of pipeline settles onto the bottom of the trench: The method also includes acquiring, by means of the digging assembly, data related to the bathymetric profile of the portion of pipeline laid on the bottom of the trench, and comparing the acquired data with a set of permissible values. Further, the method includes emitting an error signal when the acquired data does not fall within the set of permissible values.

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 method of performing a seismic survey of earth formations beneath a body of water is disclosed. The method includes: (a) deploying a seismic cable having a plurality of seismic sensors distributed therealong in close proxmity to elongate locating means provided at the bottom of the body of water; (b) operating an acoustic source in the body of water to produce seismic signals which enter the formations; (c) detecting seismic signals which return from the formations with said sensors; and (d) removing the seismic cable from the bottom of the body of water.

Abstract: An apparatus for burying cables and pipes in soil includes a support structure adapted for movement across a surface of the soil. A water jetting machine is provided for producing a source of pressurized water. At least two jetting arms are in fluid communication with the source of pressurized water. The jetting arms have vertical adjustment structure for varying at least the vertical position of each jetting arm relative to the support structure so as to adjust for varying soil conditions. A method for burying cables and pipes in soil is also disclosed.

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: A submarine apparatus is laid undersea by a submarine-cable laying device. The submarine apparatus comprises a cylindrical body performing a signal processing, a conical boot arranged at each of both ends of the body so as to fix an end of a submarine cable, and a gimbal joint provided on each of both ends of the body so as to support an end of an arm portion extending from the boot. The diameter of an end of the boot is smaller than a diameter of each of both ends of the body. A spacer mechanism is provided between the body and the boot so as to occupy a part of a space therebetween.

Abstract: A device (6) for attachment to a pipe (7) to be installed in the ground has load cells (17) for detecting a pulling force applied to the pipe (7), as the latter is pulled through the ground, an inclinometer (18), for detecting the inclination of the device (6), and a pressure transducer (20) for detecting the pressure surrounding the device. Data representative of the pulling force, inclination and pressure is stored in the device (6) and protected against unauthorised access by a security code or procedure, so that a verifiable record of the pipe installation process is available.

Abstract: A submarine apparatus is laid undersea by a submarine-cable laying device. The submarine apparatus comprises a cylindrical body performing a signal processing, a conical boot arranged at each of both ends of the body so as to fix an end of a submarine cable, and a gimbal joint provided on each of both ends of the body so as to support an end of an arm portion extending from the boot. The diameter of an end of the boot is smaller than a diameter of each of both ends of the body. A spacer mechanism is provided between the body and the boot so as to occupy a part of a space therebetween.

Abstract: A plough by means of which a cable may be buried below the sea-bed is characterized by means to vary the length of the path of a cable extending through the plough, which means is responsive to changes in tension in the cable. In one preferred form of the plough, the cable extends over two surfaces and these surfaces are mounted so as to be relatively movable in response to changes in the cable tension.

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: 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: A device for burying a submarine cable under the water by easily and accurately detecting the cable position and a method for guiding the same by utilizing the characteristics unique to submarine cables, by supplying an AC only to the portion of the cable between two arbitrary repeaters through a so-called transformer-coupling system to generate an AC magnetic field, and by detecting the magnetic field with a magnetic field detector.

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: 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: The present invention aims at providing a method and a device for guiding the cable burying device along the cable effectively as well as accurately even if the cable should be reburied after repairment. The present invention is mainly characterized in that an ultrasonic command signal transmitted from an ultrasonic transmitter/receiver mounted upon the cable burying device is received by an ultrasonic, transponder which has been mounted on the cable. An ultrasonic signal is transmitted in turn from said ultrasonic transponder to be received by said ultrasonic transmitter/receiver so that the position of said ultrasonic transponder on the cable is detected by processing such signals.

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 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 cable detecting system with a cable ship, a cable detector towed by said cable ship via a towing wire and said cable detector dredging the water bottom to find a buried cable, has been improved. When the cable detector detects a buried cable, and the cable is engaged with the cable detector, the towing wire between the cable ship and the cable detector is released either by drawing out a wire from the cable ship or by extending an auxiliary wire from the cable detector, thus, the cable detector stops just when a cable is detected, even when the cable ship continues to move by inertia, and no damage is caused to the cable. The presence of a cable is sensed either through a mechanical means which detects the cable by contact between the cable and the detector, or through electromagnetic means. The detection of a cable triggers the above release of the towing wire.

Abstract: An underwater trenching machine comprising a carriage and a pair each of fore and aft pivotal frames, each of which carries a drive roller means for intimately contacting the pipeline, said front and rear frames being adapted to mutually exclusively pivot outwardly upon command so that the frame carrying the roller means resting at that time on the pipeline takes over the drive function performed by the roller means on both pair of frame means theretofore, and further including improved jet legs each divided into multiple sections for enabling differential water velocity while minimizing water pressure loss through the length thereof, all while the machine is maintained at a predetermined buoyance and attitude.

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 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.