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.

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. In one embodiment, the main central longitudinal channel has an inlet section with an inlet section diameter, a discharge section having an outlet section diameter and a connecting section that is in between the inlet section and the outlet section.

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.

A trenching assembly lays a continuous pipeline in a trench dug in a bed with uneven bathymetry, the trenching assembly including a trench digging device having a main body; at least four ground contact units, each unit having a height adjustment device, to position each ground contact unit with respect to the main body independently. A trench cutting tool digs in the bed includes a cutting depth adjustment device, for positioning the cutting tool with respect to the main body. A detection device detects bed bathymetry. A control device simultaneously allows cooperation between the detection device, the height adjustment device of each ground contact unit, and the cutting depth adjustment device. A command device cooperates with the control device to adjustment each ground contact unit and the cutting depth adjustment device, to obtain a trench having a height difference lower than a predefined tolerance and a predetermined burial depth.

The invention provides a trenching apparatus and a method of using a trenching apparatus. The trenching apparatus (100) may include a main body portion (10), trench cutting equipment (50) depending from the main body portion, at least two ground contacting units (16) arranged on opposed sides of the main body portion and on which the main body portion is supported, each of the ground contacting units being connected to the main body portion by a respective independently operable suspension assembly (20), the respective suspension assemblies being configured to compensate for unevenness of the ground thereby to maintain the trench cutting equipment in a desired angular orientation with respect to the vertical.

A jetting system for an undersea trencher has jetting conduits extending onward 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.

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.

A device for providing an elongated element in a seabed is disclosed. The device comprises a main body having trench forming means for forming a trench in a seabed, and a receiving section for receiving an elongated element. The main body is adapted to guide said elongated element, from said receiving section, into a trench formed by said trench forming means. The device further includes supporting means defining a contact surface for supporting said main body with respect to said seabed, wherein the receiving section is configured to receive the elongated element from a side substantially opposite to the contact surface along a loading path. The device further includes a drawbar connected to said main body. The drawbar is movable from a loading position to a towing position. In the towing position said device is towable in a trenching direction via a towing line connected to said drawbar. In the loading position the drawbar is spaced apart from the loading path to allow the elongated element to be loaded into the receiving section along the loading path.

A line and level determination system for a trenchless construction apparatus has a block assembly which is attached by welding to a lead casing to be installed with the trenchless construction apparatus. The block assembly has a water inlet, a water outlet, a tilt sensor and a light emitting device disposed within the water outlet. A water hose has a first end attached to the water inlet and a second end attached to a water source. The line and level determination system has a controller connected to the tilt sensor and the light emitting device. The controller selectively energizes the tilt sensor and the light emitting device. Data from the tilt sensor is displayed on a screen of the controller. A surveying instrument, such as a theodolite, may be utilized to determine line from the illumination of the light emitting device into the casing.