Abstract: A system for harvesting natural gas from a clathrate deposit includes a storage system and a processing system. The storage system is located at a surface of a body of water and is configurable to couple to a conduit for receiving a slurry including clathrate hydrate pieces and natural gas from an underwater apparatus. The processing system is coupled to the conduit and is configured to separate the natural gas from the slurry.

Abstract: A cutter head for dredging ground under water is disclosed. The cutter head is suitable for attachment to the ladder of a cutter suction dredger and for being moved through the ground therewith in a lateral sweeping movement. The cutter head includes a rotation-symmetrical revolving body which is rotatable around its rotation axis by means of drive means and which is provided along its peripheral surface with a number of cutting tools for penetrating into the ground, wherein the rotation axis of the cutter head runs substantially perpendicularly of the longitudinal direction of the ladder and substantially tangentially to the direction of the sweeping movement. Likewise, a method for breaking ground underwater, making use of the cutter head is shown.

Abstract: A cutter head for dredging ground under water is disclosed. The cutter head is suitable for attachment to the ladder of a cutter suction dredger and for being moved through the ground therewith in a lateral sweeping movement. The cutter head includes a rotation-symmetrical revolving body which is rotatable around its rotation axis by means of drive means and which is provided along its peripheral surface with a number of cutting tools for penetrating into the ground, wherein the rotation axis of the cutter head runs substantially perpendicularly of the longitudinal direction of the ladder and substantially tangentially to the direction of the sweeping movement. Likewise, a method for breaking ground underwater, making use of the cutter head is shown.

Abstract: A cutter head for a cutter suction dredger to be mounted rotatably about a cutter head center axis with respect to a suction device for sucking up material cut loose by the cutter head from the bottom of a body of water, which cutter head includes a base ring, a boss spaced from the base ring in the direction of the center axis, and a plurality of arms which extend from the base ring to the boss and are distributed at regular intervals in the peripheral direction, each arm has a series of teeth located on the radially outermost parts of the arm and directed outwards at an angle with respect to the peripheral direction, the direction of rotation of the cutter head being set such that the teeth perform a cutting movement, with non-return mechanisms, preventing movement of cut material from the center axis to the exterior.

Abstract: An assembly for mounting an excavating tooth particularly suited for a dredge cutterhead includes a base, an adapter, and a lock. The base includes a convex, curved bearing surface that abuts a concave, curved bearing surface on the adapter. The curved bearing surfaces are able to maintain substantially full contact with each other under transverse loading. The undersurface of the base is formed with a groove to improve the strength and durability of the weld.

Abstract: A wireless CDMA communication system receiver receives a stream of chips generated by spreading data symbols formed by grouping bits of information at a wireless CDMA communication transmitter which are broadcast at a certain chip-rate. The received chips are de-spread and symbols pertaining to respective users are reconstructed. The stream of chips are formatted into blocks of chips, and an iterative block decision feedback equalization is performed in a frequency domain at the chip-rate of the broadcast stream of chips to remove inter-symbol interference by defining a transfer function. The chips generated are interleaved by spreading each data symbol being transmitted before broadcasting the stream of interleaved chips in distinct blocks of chips.

Abstract: A portable dredging apparatus comprising a cutter housing in communication with a hydraulic power supply and a discharge pump through lengths of tubing whereby said cutter housing is submersible. The cutter housing is comprised of a platform having walls depending therefrom with the cutter blade positioned therewithin and height adjustable wheels exteriorly located on opposing sides. Also extending between the walls proximate to the cutter blade is an angularly positioned wiper element designed to dislodge debris caught between the teeth of the cutter blade. Angularly depending screen situated between the wiper blade and discharge port located in the rear wall prevent objects larger than the screen mesh from discharge port passage. Releasably fastened to the exterior side of the discharge port is an appropriate length of flexible conduit terminating at a remote discharge pump with additional conduit extending from the discharge pump to a desired debris discharge location.

Abstract: A sludge harvester for removing a concentrated nutrient sludge from a sludge pond includes a frame, one or more wheels or skids attached to the frame, means for gently breaking up at least a portion of the sludge layer adjacent to a dilute layer, and means for capturing at least a portion of the broken up sludge layer. The organic sludge product recovered by the harvester has a higher nutrient concentration as compared to alternative methods because of minimized mixing of the sludge and dilute layers during collection of the organic sludge product. The organic sludge product captured by the harvester can be applied directly to agricultural land or used in the production of a certifiable organic or other fertilizer.

Abstract: The apparatuses for improving the permeability of a fluid containment basin having a plurality of ridges and furrows in the bottom of the basin are configured to disturb sediment that has settled on the ridges so as to place the sediment back into suspension. In one configuration, the apparatus comprises a tool support frame adapted to support one or more ridge cleaning tools on top of the ridges. The tools include dragging, discing and grinding tools. The discing tool is configured with a flexible axle to allow the tool to move in response to changes in the contour of the ridge. In another configuration, a boat or other device is moved across the basin above the ridges to cause wave energy from the boat's propellor to disturb the sediment on the ridges. The tool support frame with one or more ridge cleaning tools can be pulled behind the boat.

Abstract: A method and apparatus for mining of hydrocarbons from a hydrocarbon-containing clathrate such as is found on the ocean floor. The hydrocarbon containing clathrate is disaggregated from sediment by first disrupting clathrate-containing strata using continuous mining means such as a rotary tilling drum, a fluid injector, or a drill. The clathrate-rich portion of sediment thus disrupted from the sea floor strata are carried through the apparatus to regions of relative lower pressure and/or relative higher temperature where the clathrate further dissociates into component hydrocarbons and water. The hydrocarbon is recovered with the assistance of a gas that is injected and buoys the hydrocarbon containing clathrate helping it to rise to regions of lower pressure and temperature where hydrocarbon is released. The sediment separated from the hydrocarbon returns to the ocean floor.

Abstract: An excavating device has conical milling tools each having a longitudinal center axis. At least one motor is provided for rotatingly driving the milling tools about their longitudinal center axis. The milling tools each have a mantle surface. The mantle surfaces are positioned at one circumferential point adjacent to one another at a minimum spacing defining a working play between the milling tools such that the mantle surfaces form a continuous working plane. The longitudinal center axis of the milling tools are positioned angularly to one another and to a vertical axis extending between the milling tools. Each longitudinal center axis is positioned at an angle of between 50.degree. and 70.degree. to the vertical axis. Each one of the longitudinal center axes is positioned at an angle of less than 90.degree. relative to the advancing direction of the excavating device.

Abstract: A device for creating a localized water jet within a body of water allows for the displacement of material from the floor of the body of water. The device includes two powered screws within a jet pipe. The screws are arranged coaxially and their direction of rotation, pitch, and speed of rotation are arranged such that the torque produced by one of the screws tends to counteract the torque produced by the other, allowing for improved control of the device.

Abstract: An underwater mining machine includes a chassis mounted on a powered drive arrangement for driving the chassis on an underwater surface, the chassis having a front end and a rear end and being adapted to be manoeuvrable and driven in at least a forward direction, a rotatable cutting drum secured to a boom which is attached to a cradle mounted on the chassis, and material gathering arms adapted to gather material which has been excavated or broken up by the cutting drum.

Abstract: A system for recovering liquid hydrocarbons from hydrates on an ocean floor includes a vessel, a positioning subsystem coupled to the vessel for holding the vessel in a desired location over a hydrate formation, a hydrate recovery subsystem coupled to the vessel for delivering hydrates from an ocean floor to the vessel and separating gas from hydrates removed from an ocean floor, a gas conversion subsystem coupled to the hydrate recovery subsystem for converting gas to liquids, and a storage and removal subsystem. Excess energy from the gas conversion subsystem is used elsewhere in the system. A method of recovering hydrates from an ocean floor is also provided.

Abstract: A dredge apparatus with an improved cutter includes a hull, a boom extending from the hull, and a cutter element rotatably mounted at the free end of the boom. The cutter element is positioned adjacent a suction line that is supported by the boom. The improved cutter element includes a plurality of rings having large open central portions for transmitting material to the suction. At least a pair of rings are spaced apart, one of the rings being supported using a rotary hub and spokes to a drive shaft. The external periphery of each of the rings carries three circumferentially spaced helical vanes. The helical vanes extend circumferentially and from ring to ring beginning at a front ring and ending at a rear ring which is adjacent the boom. Each of the vanes is "V-shaped" in transverse cross section providing a concave and a convex vane surface. The concave surface of each vane faces the suction line. The convex surface of each vane faces the front of the cutter element.

Abstract: Floating aquatic vegetation is harvest from the surface of a body of water. The vegetation is chopped or shredded when floating in situ on the body of water. The vegetation is then removed from the water surface. The chopping, shredding, tearing or other action breaks down the structure of the plants or subdivides them into smaller parts. This reduces the structure of the plant and allows it to be compacted to a much higher density mass so that it can be handled more readily. The apparatus for harvesting the vegetation includes a self-propelled vessel. A shredding head is carried on the vessel for shredding the vegetation as the platform advances thereacross and removing the shredded vegetation from the surface of the body of water. The vegetation shredding means are two rotors arranged in a shallow V arrangement across the front end of the vessel, with the point of the V directed forwardly, in the direction of travel. Rotors arranged in this way assist with the positive tracking of the platform.

Abstract: An aquatic plant de-rooting apparatus includes a jib and a vertically adjustable hanger to be mounted on a vessel. The hanger carries two forwardly convergent rotors, each with a series of flat blades projecting radially from it. The rotors are independently driven by hydraulic motors. The rotors act to uproot the aquatic vegetation to remove the vegetation and inhibits its future growth.