The pipe includes at least one tubular sheath delimiting a passage for circulation of the abrasive material, at least one tensile armor layer externally positioned with respect to the tubular sheath, the armor layer including a plurality of filiform armor elements. It further includes a protective internal layer positioned inside the tubular sheath in the circulation passage, the protective internal layer including an elastomeric matrix and a longitudinal reinforcement assembly embedded in the matrix.

Described are a vessel and vessel/barge systems for dredging underwater surfaces. The vessel includes a hull with a bottom, bow portion, stern portion, port side, and starboard side. The vessel also includes a deck supported by the hull and a pump system mounted within the hull. A drag arm pivotably couples to the pump system. The vessel additionally includes a void defined by contiguous watertight walls or bulkheads joined to and extending upward from the bottom of the hull. The contiguous watertight walls or bulkheads are (i) vertically extensive of a perimeters of an aperture in the bottom of the hull, (ii) outboard, astern, and forward the aperture, or (iii) some combination thereof. The barge is releasably coupled to the vessel. Moreover, the barge is in fluidic communication with the drag arm.

A method for deep sea mining includes generating an upward flow of valuable matter in a riser line from the bottom of a body of water to a matter processing platform; processing the matter at the processing platform; generating a return flow in a return pipe of a mixture of seawater and a non-valuable part of the matter from the processing platform towards the bottom of the body of water; and controlling the pressure in the return pipe for avoiding collapse of the return pipe and/or cavitation of the return pipe, in particular for avoiding collapse of or cavitation in an upper part of the return pipe.

A method for deep sea mining includes generating an upward flow of valuable matter in a riser line from the bottom of a body of water to a matter processing platform; processing the matter at the processing platform; generating a return flow in a return pipe of a mixture of seawater and a non-valuable part of the matter from the processing platform towards the bottom of the body of water; and controlling the pressure in the return pipe for avoiding collapse of the return pipe and/or cavitation of the return pipe, in particular for avoiding collapse of or cavitation in an upper part of the return pipe.

A watercraft propulsion system for moving a watercraft along a waterway having a bottom and a surface, wherein the watercraft presents a port side and a starboard side. The watercraft propulsion system comprises a boom assembly having a proximal end and a distal end, with the proximal end being rotatably coupled with the watercraft. The watercraft additionally comprises a wheel mounted to the distal end of the boom. The wheel includes at least one generally radially-extending blade assembly, with the blade assembly comprising a primary blade and a secondary blade. The secondary blade extends at an angle with respect to the primary blade so as to present a fluid channel between the primary blade and the secondary blade.

A seafloor nodule concentrating system is provided. The seafloor nodule concentrating system has a surface vessel and an undersea steering vehicle secured to the surface vessel. The undersea steering vehicle is adapted to be towed by the surface vessel. The seafloor nodule concentrating system also has a nodule collecting apparatus connected to the undersea steering vehicle. The nodule collecting apparatus is located on the seafloor. The seafloor nodule concentrating system also has a position determination device adapted to determine the position of the nodule collecting apparatus and communicate position information of the nodule collecting apparatus to the undersea steering vehicle and surface vessel.

A seafloor nodule concentrating system is provided. The seafloor nodule concentrating system has a surface vessel and an undersea steering vehicle secured to the surface vessel. The undersea steering vehicle is adapted to be towed by the surface vessel. The seafloor nodule concentrating system also has a nodule collecting apparatus connected to the undersea steering vehicle. The nodule collecting apparatus is located on the seafloor. The seafloor nodule concentrating system also has a position determination device adapted to determine the position of the nodule collecting apparatus and communicate position information of the nodule collecting apparatus to the undersea steering vehicle and surface vessel.

A system and method for stockpiling material on the seafloor, the system and method using seafloor collection machines, such auxiliary or bulk cutters or collection machines, to capture seafloor material to be stockpiled. The captured seafloor material is carried in slurry form over a flexible transfer pipe to an outlet at a desired seafloor site. In a preferred form the outlet is mounted in a seafloor stockpiling hood that sits on the seafloor at the desired seafloor site and captures and contains slurry from the outlet while allowing egress of water. The captured seafloor material can then be extracted to a surface vessel.

A system and method for stockpiling material on the seafloor, the system and method using seafloor collection machines, such auxiliary or bulk cutters or collection machines, to capture seafloor material to be stockpiled. The captured seafloor material is carried in slurry form over a flexible transfer pipe to an outlet at a desired seafloor site. In a preferred form the outlet is mounted in a seafloor stockpiling hood that sits on the seafloor at the desired seafloor site and captures and contains slurry from the outlet while allowing egress of water. The captured seafloor material can then be extracted to a surface vessel.

A system for seafloor mining comprising a vertical riser anchored to the seafloor; a mining machine to deliver seafloor ore to the vertical riser; a lifting system to pass the ore through the vertical riser; and a transport vessel removably connected to the vertical riser to receive ore from the vertical riser.