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.

An underwater trenching apparatus and pumping apparatus includes: first and second pumps and a trench-cutting jetting tool with first and second sections, the first pump having an inlet for fluid connection with a source of water and an outlet fluidly connected to the first section of the jetting tool, the second pump having an inlet for fluid connection with a source of water and an outlet fluidly connected to the second section of the jetting tool, wherein the outlet of the first pump is fluidly connected to the inlet of the second pump by valve means that is operable to divert at least a portion of an outlet flow of the first pump to the inlet of the second pump.

A subsea trencher for arranging at least partly into the seabed a subsea pipeline, includes at least one cart that separately carries at least one trench tool and is configured to run along the subsea pipeline. The trench tool is configured to work the seabed underneath the subsea pipeline. A subsea support frame carries heavy subsea equipment connected to the trench tool for operating the trench too. When the subsea support frame is fixed to the cart, the subsea trencher is configured to load the assembled weight of the cart and subsea support frame onto the subsea pipeline as the subsea trencher runs on the subsea pipeline. When the subsea support frame is separate from the cart, the subsea support frame is configured to be suspended above the seabed or arranged beside the subsea pipeline at a distance from the subsea pipeline as the cart runs along the subsea pipeline.

There is disclosed an excavation apparatus (5), such as an underwater excavation apparatus, having means for producing, in use, at least one vortex, spiral or turbulent flow in a laminar flow of fluid, e.g. water. The excavation apparatus (5) comprises a rotor (10) having a rotor rotation axis (A), wherein, in use, flow of fluid passed or across the rotor (10) is at a first angle (a) from the axis of rotation (A). The excavation apparatus (5) comprises the rotor (10) and means or an arrangement for dampening reactive torque on the apparatus (5) caused by rotation of the rotor (10), in use. The turbulent flow is provided within, such as within a (transverse) cross-section, of the laminar flow.

A hydraulic excavation apparatus may be used for providing access to a pipeline buried under shallow water or in wetland locations, for example, in order to install an electro-mechanical clamp on the pipeline. This clamp can then be used for connecting externals anodes to the pipeline, for monitoring the level of corrosion protection of the pipeline, or for any other purpose.

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.

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.

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. A plurality of lateral channels each intersect the main channel at an acute angle. 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.

The underwater trencher includes an underwater moving body, and a trench digger provided in the underwater moving body by a support plate and a cutter support provided on an upper surface of the underwater moving body; a cable guide member configured to guide the submarine cable to a trench excavated by the trench digger is coupled to the cutter support; and an upwardly opened guide portion of the cable guide member is provided with a depressor configured to press downwards the submarine cable drawn into and guided by the cable guide member or to release a pressing force so as to relax a tensioned state of the submarine cable when tension is generated in the submarine cable.

A hydraulic excavation apparatus may be used for providing access to a pipeline buried under shallow water or in wetland locations, for example, in order to install an electro-mechanical clamp on the pipeline. This clamp can then be used for connecting externals anodes to the pipeline, for monitoring the level of corrosion protection of the pipeline, or for any other purpose.