A method of dredging which comprises suspending dredging apparatus 200 from a vehicle 360. The sediment agitating apparatus comprising a chassis 210, and mounted on the chassis are an extractor, sediment agitating apparatus and respective pumps 220, 230. The dredging apparatus 200 is disposed above, but not in contact with a waterbed 340 to be dredged of sediment 350. The sediment 350 is agitated then extracted with the extractor. The dredging apparatus 200 is moved around the water and the extracted sediment 400 is deposited underwater and above the dredging apparatus 200, so that the sediment 400 is transported and deposited away from an area being dredged by the natural movement of the water. Apparatus and use of the apparatus are also described.

De-trenching apparatus (100) for extracting a buried line, such as a cable or pipeline, is disclosed. The de-trenching apparatus comprises a channel (112) configured to receive a buried line to be extracted, the channel comprising a first flared opening (114) at a front end of the de-trenching apparatus and a second flared opening (115) at the rear end of the de-trenching apparatus, the first and second flared openings each having a curved surface (111) configured to support the line during extraction, and material removal means for removing material from around the buried line ahead of the de-trenching apparatus.

A cutterhead for dredging a body of water. The cutterhead comprising a shroud including a top wall, a bottom wall, and two sidewalls each extending between the top and bottom walls. The cutterhead additionally comprises a rotatable cutterbar at least partially received within an interior space presented by the shroud, a first water-jet bar extending along a portion of the top wall of the shroud, and a second water-jet bar extending along at least a portion of one of the two sidewalls. The cutterbar and the water-jet bars are configured to generate a slurry of fluidized material from the water-bed.

The invention relates to a trench cutter and a method for producing a cut trench in the soil having a cutter frame, at least one pair of cutting wheels which are supported and driven in a rotatable manner on a lower end of the cutter frame, wherein each cutting wheel has a plurality of cutting teeth along its outer circumference, and a supply and/or discharge means for supplying or discharging a cutting liquid to or from the cut trench in the region of the cutting wheels. According to the invention provision is made in that spaced from the supply and/or discharge means a cleaning device is provided for cleaning the cutting wheels during the cutting operation with a cleaning fluid and in that the cleaning device has a plurality of cleaning nozzles which are directed onto the outer circumference of at least one cutting wheel and designed to inject the cleaning fluid to loosen adhering soil material.

A method of dredging which comprises suspending dredging apparatus 200 from a vehicle 360. The sediment agitating apparatus comprising a chassis 210, and mounted on the chassis are an extractor, sediment agitating apparatus and respective pumps 220, 230. The dredging apparatus 200 is disposed above, but not in contact with a waterbed 340 to be dredged of sediment 350. The sediment 350 is agitated then extracted with the extractor. The dredging apparatus 200 is moved around the water and the extracted sediment 400 is deposited underwater and above the dredging apparatus 200, so that the sediment 400 is transported and deposited away from an area being dredged by the natural movement of the water. Apparatus and use of the apparatus are also described.

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.

Device for removal of sediment from inside piles being at least partly immersed in water, comprising an outer guiding unit arranged to be temporarily positioned on the top of a pile. The outer guiding unit envelopes at least one inner dredging unit being arranged to be lowered from within the outer guiding unit, the inner dredging unit at its lower end exhibiting movable jet nozzles arranged to loosen sediment. The inner dredging unit furthermore comprises a central passage which is connected to a discharge hose arranged to transport loosened sediment therefrom.

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 invention relates to a trench cutter and a method for producing a cut trench in the soil having a cutter frame, at least one pair of cutting wheels which are supported and driven in a rotatable manner on a lower end of the cutter frame, wherein each cutting wheel has a plurality of cutting teeth along its outer circumference, and a supply and/or discharge means for supplying or discharging a cutting liquid to or from the cut trench in the region of the cutting wheels. According to the invention provision is made in that spaced from the supply and/or discharge means a cleaning device is provided for cleaning the cutting wheels during the cutting operation with a cleaning fluid and in that the cleaning device has a plurality of cleaning nozzles which are directed onto the outer circumference of at least one cutting wheel and designed to inject the cleaning fluid to loosen adhering soil material.

De-trenching apparatus (100) for extracting a buried line, such as a cable or pipeline, is disclosed. The de-trenching apparatus comprises a channel (112) configured to receive a buried line to be extracted, the channel comprising a first flared opening (114) at a front end of the de-trenching apparatus and a second flared opening (115) at the rear end of the de-trenching apparatus, the first and second flared openings each having a curved surface (111) configured to support the line during extraction, and material removal means for removing material from around the buried line ahead of the de-trenching apparatus.