Abstract: A trench cutting apparatus and method, the apparatus comprising a central support element comprising at least one jetting outlet and a cutting element configured to be driven around the central support element. The trench cutting apparatus is configured to be operable in a mechanical cutting mode in which the cutting element is driven around the central support element to cut material forward of the trench cutting apparatus, and a jet cutting mode in which a pump is activated to eject fluid from the at least one jetting outlet to fluidize or cut material forward of the trench cutting apparatus.

Abstract: The present invention is a hydraulic excavation and delivery device capable of hydraulically removing soil overburden from a buried structure, like a pipeline, and delivering an article, such as an electro-mechanical connector for attachment to the buried structure. Hydraulic excavation is achieved by directing a stream of fluid at soil adjacent to and inside an open bottom region of the device to simultaneously dislodge adjacent soil, suspend dislodged soil in the accumulating fluid and form a pit that the device may fit within. Delivery of article is achieved by: (1) loading an article into the tool; (2) advancing the device toward the buried structure by deepening the pit without significant failure (slumping or sagging) of the pit walls until a portion of the buried structure is exposed and within the device; (3) landing the device on the exposed portion of the structure; (4) fixing the article to the exposed portion of the structure; and (5) releasing the article from the device.

Abstract: A self-burying microbial fuel cell can include a housing with conductive elements. An anode and cathode can be integrated into the housing at respective proximal and distal ends. A self-burying means for partially burying the microbial fuel cell in a submerged environment is included, so that the anode is buried but the cathode is exposed to the submerged environment can be included. The self-burying means can include omni-directional vibrating device located within the housing, a plurality of intake ports formed in the housing for a pump within the housing. The pump outputs into a longitudinal fluid conduit that extends through the housing and exits at the distal end of the housing. When the vibrating device activates at the same time as the pump, temporary slurry can be formed at the extreme distal end of the device, and the vibrating action causes the microbial fuel cell to become partially buried.

Abstract: A self-propelled underwater vehicle for underground laying a continuous elongated member in a bed of a body of water having a work assembly, which is configured to be set, at least partly, into the bed, and is provided with two facing supporting walls for delimiting a space there-between and supporting two opposite scarp slopes; and drive assemblies, which are arranged on opposite sides of the work assembly and are configured to rest on the bed and advancing the work assembly in a travelling direction.

Abstract: An apparatus including: a tubular suction pile; an indenter housing that surrounds the tubular suction pile, wherein the indenter housing is configured to: (a) be sunk into a seabed in response to a negative pressure created from water being removed from the tubular suction pile, and the indenter housing is configured to create a trench in the seabed; and comprise a water jetting device, within the indenter housing, that includes a first valve, a nozzle, and a channel that connects the first valve to the nozzle; and/or (b) impart a longitudinal vibration to the indenter housing and the indenter housing is configured to be sunk into a seabed in response to longitudinal vibration, and the indenter housing is configured to create a trench in the seabed.

Abstract: Systems and methods for unearthing, retrieving, and processing subsea tubulars can include engaging a cable to an end of a subsea tubular and a vessel, moving the vessel in a direction parallel to the axis of the tubular, and unearthing the tubular using the thrust of the vessel. Unearthed tubulars can be dragged to a remote location, retrieved to the surface for transport or processing. On-site processing can be performed using a tensioning device to continuously move a tubular into association with a cutting device, which severs a first portion of the tubular while a second portion remains engaged with the tensioning device.

Abstract: A method of temporarily supporting a soil mass susceptible to slide at a scarp slope bounding the soil mass includes advancing a supporting wall in an advancing direction along the scarp slope; and, in addition to the movement in the advancing direction, also moving a surface portion, in direct contact with the soil mass, of the supporting wall, so as to minimize friction between the soil mass and the supporting wall.

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: A method of underground laying a continuous elongated member in a bed of a body of water, wherein the continuous elongated member lies on the bed of the body of water along a given path; the method including the steps of: fragmenting a soil mass in the bed along the given path and under the continuous elongated member, so as to form in the bed two scarp slopes bounding the fragmented soil mass by two soil masses susceptible to slide; advancing two supporting walls along the given path in an advancing direction, along the respective two scarp slopes, and transferring the fragmented soil mass between the two supporting walls, so as to promote sinking of the continuous elongated member between the two supporting walls.

Abstract: An underwater cable burial mechanism including a nozzle disposed in front of a plow blade wherein the nozzle is configured to spray a jet of water onto the sea floor in an intended path of the plow blade to bury a cable in the sea floor. In an embodiment, the underwater cable burial mechanism may include two or more straight flow nozzles disposed in front of the plow blade at various angles and heights. In an embodiment, the underwater cable burial mechanism may be a component of an array burial vehicle, the array burial vehicle further including a pump to provide water to the nozzle(s), cable pack to hold a cable array, at least one ski configured to ride along the sea floor, and at least one thruster configured to propel the array burial vehicle along the sea floor.

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 BAS plow creates a V-trench along the linear route of a pipeline path and an instrumented bottle moving with the BAS plow collects BAS data indicative of the pitch, roll, heading, yaw, three dimensional positioning, speed and depth of the chassis, the shearing force applied to the seabed material and the applied tow force. The bottle can be swapped to collect the acquired data or an umbilical can be used to provide a real time stream of data. The Bas plow can simultaneously backfill the created trench, leaving an undisrupted seabed, or the pipeline can be laid in the BAS trench, which can also be made deeper and wider by additional trench cutting passes, significantly reducing the total time required for combined BAS and pipeline laying processes. The BAS plow can be released and retrieved over-the-stem of a towing vessel.

Abstract: The invention facilitates provision of a point-to-point cable connection between first and second points separated by an extended span of water including a first region of shallow water and a second region of relatively deep water. A plurality of ducts are provided from the first point through the first region of the extended span to an offshore termination point between the first and second points. Preferably, the ducts are buried in the seabed to prevent damage. At least one first cable is placed in one of the plurality of ducts to provide a connection between the first point and the offshore termination point. A second cable from the second point is received at the offshore termination point. The first cable is connected to the second cable at the offshore termination point to create the point-to-point cable connection. In one embodiment, the offshore termination point is located on the continental shelf near the transition to deep water.

Abstract: A system for burying fabric cloth in marine sediment includes a sled having first and second ends and a partially open bottom surface proximate to the second end. A fabric deployer is coupled to and extended from the sled adjacent to the second end. A sediment disruption device resides opposite the fabric deployer and faces the first end. The fabric deployer is a tubular structure having a slot therein extending lengthwise along the tubular structure facing away from the first end. A fabric cloth is disposed on an axle within the tubular structure so a distal end of the cloth protrudes from the slot. An electronics package is releaseably secured adjacent to the second end by a release mechanism and to the end of the cloth by a tether. A cathode may be connected to the electronics package, forming, with a buried fabric cloth anode, a microbial fuel cell.

Abstract: An underwater cable burial mechanism including a nozzle disposed in front of a plow blade wherein the nozzle is configured to spray a jet of water onto the sea floor in an intended path of the plow blade to bury a cable in the sea floor. In an embodiment, the underwater cable burial mechanism may include two or more straight flow nozzles disposed in front of the plow blade at various angles and heights. In an embodiment, the underwater cable burial mechanism may be a component of an array burial vehicle, the array burial vehicle further including a pump to provide water to the nozzle(s), cable pack to hold a cable array, at least one ski configured to ride along the sea floor, and at least one thruster configured to propel the array burial vehicle along the sea floor.

Abstract: An underwater plow can include a depressor cam and a chute cam that are pivotably attached to a blade portion. The blade portion can be formed with a trough and the depressor cam can be biased in the trough. The chute cam can be formed with a groove having a minimum thickness at its attached end and an increasing taper to a maximum thickness at its distal end. A sensor passing through the plow contacts the edge of the depressor cam, causing depressor cam rotation away from the trough. The sensor passes the depressor cam and pushes against the chute cam, which causes the chute cam to contra-rotate relative to the depressor cam until the sensor passes through the chute arm at is maximum thickness. Once the sensor passes through, the cams contra-rotate back to their respective biased positions.

Abstract: A device including a plurality of disconnected ballast elements (24) for a pipe (16). Each ballast element (24) has a lower surface (34) to be laid at the bottom (12) of a body of water (14) and an upper surface (32) delimiting at least one concave trough (38) for supporting the pipe (16A, 16B). A top cover (26) for protecting the pipe and connecting at least two disconnected ballast elements (24) so as to cover the pipe (16A, 16B) between the ballast elements (24). The cover (26) extends opposite the trough (38) and delimits, together with the upper surfaces (32) of each ballast element (24), a passage for receiving the pipe (16A, 16B).

Abstract: A method of underground laying a continuous elongated member in a bed of a body of water, wherein the continuous elongated member lies on the bed of the body of water along a given path; the method including the steps of: fragmenting a soil mass in the bed along the given path and under the continuous elongated member, so as to form in the bed two scarp slopes bounding the fragmented soil mass by two soil masses susceptible to slide; advancing two supporting walls along the given path in an advancing direction, along the respective two scarp slopes, and transferring the fragmented soil mass between the two supporting walls, so as to promote sinking of the continuous elongated member between the two supporting walls.

Abstract: An underwater trenching system is mountable on a side of a barge to be propelled by the barge along a waterway, the bed of which contains a trench with a laid pipeline. To remove the excess sediment from the trench the trenching unit delivers pressurized water and air to the trench. A sparge assembly with jet nozzles directs jets of water, breaking up the formation that has built up around the pipeline. The airlift assembly creates a turbulent flow to lift the disturbed sediment and remove it from the created trench.

Abstract: Apparatus and method for connecting a lateral pipe to a main pipe are provided by a tool having a first end within the main pipe and a second end outside the lateral pipe so as to apply pressure to the below-ground connection of the main and lateral pipes from an above-ground location. The entire operation may be done without a person having to enter into an access opening in the ground to connect the lateral pipe to the main pipe. A laser is used to determine the depth of the access hole relative to the surface of the ground and the main sewer pipe.

Abstract: An underwater trenching system is mountable on a side of a barge to be propelled by the barge along a waterway, the bed of which contains a trench with a laid pipeline. To remove the excess sediment from the trench the trenching unit delivers pressurized water and air to the trench. A sparge assembly with jet nozzles directs jets of water, breaking up the formation that has built up around the pipeline. The airlift assembly creates a turbulent flow to lift the disturbed sediment and remove it from the created trench.

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: An installation for conveying superheated fluid discharged from a vent located at or near the base of a body of water. The installation comprises a hood for locating the installation over the vent, and an insulated conduit that is in fluid communication with the hood and extends upwardly through the body of water.

Abstract: A method and apparatus for stabilizing and burying a conduit in a waterbed is disclosed. A plurality of spoilers are placed on the conduit at longitudinally and radially different positions to promote self-burial, reduce vortex-induced vibration, prevent upheaval buckling, minimize future corrective work by continuous reburial of the under water conduit or pipeline.

Abstract: An apparatus for retrieving a cable or pipe buried under water in bed material comprises a shank (2) having a first surface and a fluke member (5) having a second surface. When the apparatus is towed in a towing direction, the fluke member (5) and shank (2) become buried in the bed material to a predetermined depth suitable for retrieving the cable or pipe. The first and second surfaces are arranged such that under normal working conditions the interaction between the material and at least the first and second surfaces generate opposing forces in these surfaces causing the apparatus to be maintained at substantially the predetermined depth. The apparatus may also be adapted for burial of a cable or pipe by ploughing a furrow in the bed material into which the cable or pipe is supplied using guiding means.

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: A method and system for laying and burying pipe a seabed using a pipe trenching plow that is advanced along the seabed to form a continuous trench. The pipe trenching plow cuts a pilot hole in the seabed using a cutting apparatus and widens and forms a trench from the pilot hole using expandable spreading side sections. A pipe guiding sled also is used to support and guide the pipe into the trench and a trench box section retains the trench geometry as the pipe trenching plow is continuously advanced in a forward direction. The pipe trenching plow cutting the trench and burying the pipe with minimal turbidity and seabed disturbance.

Abstract: A system for supporting pipe within soil or fill material which minimizes positional disturbances of the pipe despite seasonal fluctuations in atmospheric temperature is provided. The system provides a length of double walled pipe, a support member placed in the soil or fill material and a wicking device which transfers energy between the inner pipe of the double walled pipe which is typically full of a cryogenic fluid and the support. The energy transfer stabilizes the soil or fill material, typically by freezing.

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: A submarine plough is disclosed comprising a plough share 216 having a cutting edge 207. A heel 220 is arranged rearwardly of the cutting edge 207, and a plough beam 205 has an attachment portion for enabling a towing means 209 to tow the plough to cut a trench in the sea floor. The plough share 216 is pivotable relative to the plough beam 205 to adjust the vertical separation between the cutting edge 207 and the attachment portion. Front skids 204 are arranged adjacent a forward end of the plough beam 205 and hydraulic rams 219 pivot the plough share 216 relative to the plough beam 205. A cable is passed in an arcuate path into the trench rearwardly of the cutting edge 207 and heel 220.

Abstract: A dredger for removing sand, silt and like material from a river or seabed has application to clearing wrecks and providing trenches in which, for example, pipeline may be laid. The dredger includes a body having first thrusters to direct, in use, a wash of water downwards an area of seabed. The dredger also includes an additional thruster to maintain the body of the apparatus above the seabed and to propel the body through the water.

Abstract: The present invention relates to a system for carrying electrical energy in connections made by means of underground cables. In particular, it relates to a method of laying cables and a trench filler having a low thermal resistivity, used for laying underground cables for carrying electrical energy. More particularly, it relates to the use of an inert filler to be disposed in an area around the cables or the parts of the system, such as joints, which are disposed underground.

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 cable-laying technique and apparatus are disclosed. A base is lowered to the seafloor which contains multiple cable reels, each of which is preconnected to a surface production facility. An articulated plow is lowered onto the base and manipulates a reel from its cradle. The plow is pulled by a surface vessel after obtaining the cable reel from the cradle. The cable is buried as it is payed out with the vessel pulling the plow. The plow is returned by the vessel to the base where it grabs another reel and the process is repeated. The cable does not need to be designed to support its own weight because it is payed out from the reel supported by the plow as opposed to being on the deck of the boat. Similarly, the boat structure required to perform the method is simplified due to the reduction in weight and bulk of the reels for the cables.

Abstract: The cable laying apparatus, which solves many of the problems heretofore associated with existing cable laying mechanisms for underwater burial machines, uses a pivotally liftable depressor wheel, located within a feed shoe which tracks the groove cut by the plow. There are a pair of arcuate cable guides, one on each side of the depressor wheel, which assist in the guidance of both cables and bodies, without permitting either to bind. When the assembly to which the depressor wheel is attached is raised upward and rearward the guides prevent the cable from escaping while allowing a body to pass through the opening which is formed.

Abstract: It is characterized in that it consists in using a self-propelled sea plough (1) remote-controlled via a control flexible (2), said sea plough carrying at least one reel (6) of flexible conduit (7), controlling said sea plough from a site (5) so as to lay and bury a length of the flexible conduit up to a first predetermined point (P.sub.1), controlling said sea plough beyond said first predetermined point from another site (10), continuing laying and burying of the flexible conduit as far as a second predetermined point (P.sub.2), one of said sites being the land (5) and the other comprising a waterborne vessel.Applications include simultaneous laying and burying of flexible conduits such as optical cables, coaxial cables for analogue transmission, electrical cables, single or multiple flexible tubular conduits.

Abstract: The underwater cable burial machine uses a single cable for both towing and lifting. The machine includes a retractable cable, which is connected between a retraction mechanism and the towing cable. There is a cable guide through which the retractable cable passes. The cable guide is located over the center of gravity of the machine. In order to use the towing cable to lift the machine, the retraction mechanism pulls the retractable cable and the towing cable until the point where the retractable cable and the towing cable meet is at the cable guide. At that point the towing cable will be over the center of gravity of the machine, and the machine can be lifted onto the surface vessel to which the towing cable is attached.

Abstract: A system for cathodically protecting a structure that is in contact with soil and for extracting vapor or liquid from the soil, comprising a porous conducting material in direct contact with the soil, a power source being connected to the structure, a tubing string including a central tubing passage, at least one anode electrically connected to the positive terminal of said power source and having a bore therethrough, said bore being aligned with said tubing passage, at least one screen section comprising a hollow member having perforations therethrough and end openings, said end openings being aligned with said tubing passage, said tubing string, said screen and said anode being surrounded and supported by said conducting material such that current provided by said power source flows through said lead to said anode, and from said anode through conducting material and soil into the structure, said tubing string, said screen and said anode being aligned and connected such that vapor or liquid present within th

Abstract: A cable burying device (3) comprises several heavy hollow tapered elements (7, 8) coupled to each other (7A, 7B, 8A, 8B) to provide limited flexibility, which is towed along the seabed and which digs a trench, the cable (1) passing through the length of the device to become buried in the trench. A guide tube (2) to guide the cable (1) from the ship to the burying device (3) has a flexible lattice construction (FIGS. 6, 7, 8) which can be folded flat for ease of storage on the ship.

Abstract: Scavenging apparatus for embedding cables or the like into the soil of waters, comprising an elongated scavenging sword being adapted to be attached at different heights to an embedding vessel movable on the soil of waters or to a surface water vessel, the sword having a guide channel extending through the sword from the top to the bottom in the rear area thereof for the guidance of the cable and its depositing on the bottom of the trench scavenged free, the sword further including a water channel extending through from the top to the bottom in the front region thereof and connected to a pressurized water supply at the upper end and to a set of scavenging nozzles located at the front side of the scavenging sword, and a vibrator for the scavenging sword, the vibrator being connected to an energy source located on the vessels by energy supply lines, with the vibrator being located with the scavenging sword near the sole of the sword and the energy supply lines for the vibrator extend inside the sword.

Abstract: A cable embedding device comprising a framework for supporting and hydraulically raising and lowering a rock saw and a cable carrying bellmouth relative to two spaced-apart sled-type runners. Each sled carries part of a jet spray system and an eductor system, which spray system creates a slurry and which eductor system carries and discharges the slurry to the back of the device. A hinge and a hinge-roller assembly connect the framework to the device for relative movement therebetween. The bellmouth is shaped to curve around the rock saw, and its pedestal foot supports the bellmouth in the cable embedding and/or trenching operation.

Abstract: A sled device for burying a pipe within the ground under water. The sled is arranged to be pulled over the ground and includes a blade adjustably mounted within a tower in the sled. The blade is arranged to cut a furrow in the ground as the sled is pulled thereacross and to pull a pipe, which is connected to the lower end of the blade, into the furrow. A mandrel assembly, including a cylindrical member located in front of the leading edge of the pipe is tethered to the blade to enlarge the diameter of the furrow as it is cut so that the pipe can be readily pulled therethrough. The mandrel also protects the pipe from impact by buried obstacles. The mandrel assembly is releasably secured to the lower end of the blade by a releasable means including a crank assembly.

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 method for progressively producing an underwater laying-out channel (3) for an object (53) to be laid out, like a cable or the like, in an underwater ground by flushing and by mechanically loosening ground formations (7) which are resistive against flushing, by means of a mechanical loosening device (31) having a given maximum working depth, characterized by lowering the mechanical loosening device (31) to the ground formation (7) which is resistive against flushing, and advancing, in an advancing direction, the mechanical loosening device through the ground formation which is resistive against flushing, with the working depth being effective from the surface of that ground formation.

Abstract: A ditching machine for digging a ditch or a trench for submarine cables having at least several 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 the soil thus ditched away in a direction lateral to the moving direction of the ditching machine. The soil-pushing portion is at the top of the ditching portion and has a wider horizontal width as seen from front of the ditching machine than that of the ditching portion when the ditching machine is in a normal operation position. Further, the tapering angle at the bottom of the center body being in the range between 10.degree. and 17.degree. and the towing tension of the towing wire between the ditching machine and the work ship is considerably reduced.

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: A method for progressively producing an underwater laying-out channel (3) for an object (53) to be laid out, like a cable or the like, in an underwater ground by flushing and by mechanically loosening ground formations (7) which are resistive against flushing, by means of a mechanical loosening device (31) having a given maximum working depth, characterized by lowering the mechanical loosening device (31) to the ground formation (7) which is resistive against flushing, and advancing, in an advancing direction, the mechanical loosening device through the ground information which is resistive against flushing, with the working depth being effective from the surface of that ground formation.

Abstract: A wear resistant and impact tolerant plow blade comprising a plurality of ternate layers of wear resistant and impact resistant materials. Each layer extends from the leading edges of the plow blade rearwardly and is fabricated of a homogeneous material. Each layer has substantially parallel sides and abuts an adjacent layer or layers to form a substantially seamless plow.