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: An apparatus for excavating a trench underneath a pipeline installed at the sea bottom, which apparatus is provided with rotating excavators, means for guiding the excavator relative to the pipeline, as well as means for advancing the excavator along the pipeline, whereby the excavators comprise at least two bucket wheels, 15, 16, 15', 16', disposed side-by-side on either side of the pipeline 9 parallel to the direction of advancement P, the main planes of said buckets enclosing an acute angle with each other and intersecting each other underneath the pipeline 9, which bucket wheels are disposed in said main planes, and being adjustable in height.

Abstract: An apparatus for burying a pipeline in a sea bed having a spoil collection scoop surrounding the air lift intake portions of the sled. The apparatus includes a jet sled having jetting legs for disposition on the opposite sides of a pipeline to be buried and directing a stream of high pressure water through nozzles into the sea bed to form a trench for the pipeline, and air lift conduits each providing spoil intake and spoil discharge portions for removing spoil cuttings from the trench cut by the jetting legs. A spoil collection scoop surrounds the intake portions of the air lift conduits, collecting and consolidating spoil cut by the jetting legs at the air lift conduit intake portion for discharge of the cut spoil material from the trench into which the pipe will be buried.

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

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

Abstract: Submarine pipe trenching apparatus for digging a trench below submarine pipelines, wherein jet supports having nozzles for digging into the ground are supported for oscillatory movement on a frame, and wherein a crawler assembly is mounted on the pipe for moving the jets supports along and below the pipe when the liquid is propelled through the nozzles for digging out the soil below the pipe. The nozzles may include orifice plate means defining their outlets and inclined so that liquid emanating therefrom strikes the earth formation at a small acute angle.

Abstract: The invention relates to a method and apparatus for burying a conduit at the bottom of a body of water.

Abstract: The sea sled includes a pair of pontoons mounting depending rollers for straddling a pipeline disposed on the sea bottom. Water jets fluidize the sea bottom to form a trench in which the pipeline settles. The slurry formed by the water jets is removed from the trench by the eductor system which includes a pair of conduits each having a suction inlet at its lower end for location within the trench, a discharge at its upper end, a pair of pump nozzles each having an inlet external to the associated conduit and an outlet within the conduit directed toward the corresponding discharge, and a pair of primary nozzles, the outlet ends of which respectively project into the inlet ends of the pump nozzles. A high pressure, low volume, fluid is pumped from the surface through the jet nozzles. Ambient fluid is entrained with the high pressure, low volume fluid emanating from the jet nozzles in the respective pump nozzles to deliver low pressure, high volume fluid to their corresponding discharges.