A plough for inserting a cable into a trench in the seabed is disclosed. The plough comprises a plough share for forming a trench in the seabed and a drawbar for enabling attachment of tensile members to the plough. The drawbar is moveable relative to the plough share between a first position, in which the plough is adapted to be towed by a towing cable to move the plough share relative to the seabed to form a trench, and a second position, in which the plough is adapted to be supported by the towing cable to enable the plough apparatus to be deployed to the seabed. A cable path receives the cable and an attachment part of the drawbar is moveable relative to the plough share between the second position and a third position, to enable the cable to be received in the cable path from above the plough.

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 (α) 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.

An apparatus for locating an elongate object in the seabed is disclosed. The apparatus comprises a body and a pair of jetting swords arranged on lateral sides of the elongate object to form a trench in the seabed. Chain cutters arranged on lateral sides of the elongate object cut respective parts of a trench in the seabed and are moveable relative to the body between a stowed position and a deployed position, independently of the jetting swords.

A system and method is provided for enhancing the working end of a hydrovac boom hose having a longitudinal axis and a perimeter disposed transversely to the axis, the working end configured to vacuum earthy material from a digsite along the axis. A plurality of high pressure nozzles are disposable in spaced relation along the perimeter of the working end, and configured to emit high pressure fluid towards the digsite to dislodge the earthy material. The nozzles are angularly actuatable to selectively emit the high pressure fluid along a range of angles relative to the longitudinal axis, and are rotationally actuatable to selectively emit the high pressure fluid from a range of locations along the perimeter of the working end. The angular and rotatable actuation is independent of movement of the working end and/or of movement of the hydrovac boom hose.

“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 passedpast or across the rotor (10) is at a first angle (α) from the axis of rotation (A). The excavation apparatus (5) comprises the rotor (5) 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.”

Systems and methods include a wing tool configured to be operable from work vessel(s), the wing tool including thrusters capable of fluidizing sediments from a first seabed location and moving it to a second seabed location, the second seabed location including a trench or differently shaped collection sump previously made by the wing tool and/or an extraction pump. The extraction pump operates from a second work vessel having sufficient capacity to pump fluidized sediments from the trench. Certain systems include a separation unit that separates sand from silts and clays and water from collected sediment. Systems and methods for reclamation of reservoirs, moving sand waves, for pre-trenching and/or recovering marine pipelines and cables, for removing cover from marine archaeological sites and for disposing of contaminated bottom materials in an environmentally acceptable manner.

A system and method for laying an underwater pipeline is provided. The present invention includes a plurality of pipe support rings connected together by tension cables. The tension cables are secured to a S or J laying ship by a winch. The plurality of pipe support rings form a pipe channel sized to guide the underwater pipeline. The present invention further includes a sea water pipe having a distal portion and a proximal end. The proximal end is fluidly connected with a pump on board the ship. The distal end includes a plurality of nozzles. The sea water pipe is disposed underneath the plurality of pipe support rings. The underwater pipeline is fed through the plurality of pipe support rings while the nozzles form a trench on a sea bed.

A liquid level control system, which may be used with a clarifier in a sewage treatment plant, manages liquid level of an upstream basin by controlling liquid flow in or out of a system that may use a midstream device to equally distribute flow in or out of the basin. This headloss inducing device creates a non-linear relationship between upstream liquid level to be controlled and the lesser downstream liquid level behind the gate or valve. Without the use of electrical controls, the systems of the invention include a gate or valve with counterforces that manage the outflow stream of liquid while accounting for the non-linear head loss created by the midstream device, thus reaching a desired liquid level range for all system flowrates.

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.

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.