Abstract: A seismic spread is constructed having an arrangement of towed components to be neutrally buoyant in water when towed in a seismic survey. The towed components at least include streamers and paravanes. Immersed weight and drag of the towed components is determined, and drag forces versus buoyancy required to neutrally buoy the towed components at at least one tow speed in the water is calculated based on the determined weight and drag of the towed components. Floatation is configured for the seismic spread based on the calculated drag forces versus buoyancy; and the arrangement of the towed components in the seismic spread is constructed with the configured floatation.

Abstract: A towed vessel suitable for containing and transporting various liquids is disclosed. The vessel further comprises various features useful in the transportation, navigation, and storage of the towable vessel, both when in use for transporting fluids and when transported in an emptied state. Such features include navigational and positioning devices and methods, power supply devices and methods, and means for filling, inflating, emptying, and deflating a non-rigid, towed vessel. Aspects of embodiments of the present invention further include features useful for purifying or preserving the purity of the fluid to be transported.

Abstract: A system and a method are provided for determining the position of an underwater vehicle while the vehicle is operating underwater. A buoyant float stays on or near the surface of the water and is attached to the vehicle by thin tether that can include insulated wires. The vehicle moves under the water and pulls the float behind it. The float can receive a localization signal, such as a signal indicating its GPS position, and so can determine its position precisely. The position can be transmitted to the underwater vehicle over the wires located in the tether. The underwater vehicle can use sensors and/or calculations to determine the positional offset of the vehicle from the float buoy and generates its true position based on the known position of the float and the positional offset. The float can be constructed with attributes that will allow the float it operate with a greater tether length, and in turn allow the underwater vehicle to operate at greater depths.

Abstract: Deflectors configured to be attached to cables towed behind a vessel for performing a marine survey and associated methods are provided. A deflector has a body including a wing portion and a knuckle portion. The wing portion has substantially flat wings extending away from a position where the body is attached to the cable. The knuckle portion is configured to attach the wing portion to the cable so that the wing portion remains able to rotate about three rectangular axes while being towed underwater.

Abstract: A tow body and associated method have an acoustic projector that can be rotated about a vertical plane while the tow body is being towed through the water. In some embodiments, the tow body and method allow the tow body to be coupled to a tow cable while the tow cable is being towed through the water and under tension.

Abstract: A method and a marine towing system for towing streamers or sources. The towing system includes a connecting line; a first paravane connected to the connecting line, wherein the connecting line is configured to connect the first paravane to a vessel; a spur line connected to the first paravane and configured to provide a tension to maintain streamers apart from each other; and a second paravane connected to the connecting line, between the first paravane and the vessel. The second paravane is configured to increase an angle (?4) between the connecting line and the spur line.

Abstract: Techniques are disclosed relating to using a remote operated vehicle (ROV) to facilitate cleaning of a submerged geophysical equipment (e.g., a streamer) being towed behind a tow vessel. The ROV may, in one embodiment, attach a streamer cleaning unit (SCU) to the streamer, where the SCU is configured to clean the streamer. In another embodiment, the ROV may facilitate cleaning by cleaning the streamer itself using a cleaning attachment coupled to the ROV.

Abstract: A lead-in cable used to tow a streamer behind a vessel includes a replaceable portion removably connected between a portion of the lead-in cable attached to the vessel and the streamer. Alternatively a lead-in additional cable is inserted between a lead-in cable and a towed streamer. The replaceable portion or the lead-in additional cable covers a portion most likely to be damaged between the streamer and the towing vessel.

Abstract: A technique for seismic surveying is presented in which a towed array, marine seismic spread, includes a plurality of streamers and a deflector system. The deflector system laterally spreads the seismic streamers, wherein at least one streamer in the spread is deflected using more than one deflector attached to the tow cable or streamer, and where the deflectors are not connected to a float on the sea surface. Other aspects of the technique include methods for towing such a spread and for controlling such a spread. Still other aspects include computing resources which may be used to perform the methods.

Abstract: Method and marine acoustic source array for generating an acoustic wave in a body of water. The marine acoustic source array includes first and second external source sub-arrays, each sub-array including one or more individual source elements; a first actuator device connected to the first external source sub-array; and a second actuator device connected to the second external source sub-array. The first actuator device has a corresponding cable configured to connect to a first lead-in, and the second actuator device has a corresponding cable configured to connect to a second lead-in such that a position of the source array as a whole is controllable along a line substantially perpendicular to a path of the source array.

Abstract: A marine acoustic source system for generating an acoustic wave in a body of water. The marine acoustic source system includes a first marine acoustic source array having first and second external source sub-arrays, each sub-array including one or more individual source elements; a first actuator device connected to the first external source sub-array; and a first rope connecting the first actuator device to a first lead-in that is configured to connect to a head of a streamer. The first actuator device is configured to control a length of the first rope in order to control a position of the first source array relative to the streamer.

Abstract: A towing device, intended to be fitted to the deck of a ship, comprises a winch, a cable and a fairlead, the cable running through the fairlead under the action of the winch. The fairlead comprises at least a first and a second sector, the sectors allowing the cable to be guided in a groove made in each of the sectors, a first articulation with a degree of freedom to rotate about an axis, the articulation connecting the two sectors, the axis being substantially perpendicular to a direction in which the cable runs substantially through the fairlead at the articulation, and limiting means that limit the angular travel of the articulation. The sectors and the limiting means are dimensioned so as to prevent the cable from exceeding a lower limit of radius of curvature.

Abstract: A towable antenna system is deployable and retrievable from and tetherable to an underwater vehicle while the underwater vehicle is submerged under water. An underwater vehicle having a towable antenna system is capable of communicating with one or more remote communication systems, the towable antenna system acting as an intermediary for communications between a submerged underwater vehicle and the one or more remote communication systems.

Abstract: A trawl door, deflector, vane or paravane (40) constructed with adjustable panels (22, 23, 24) and driving units (25) for control the water flow through the spreading device during towing through the water with remote control where driving units (25) are used to adjust the position of the panels control the water flow through the spreading device and maneuver the spreading device in optimum position in the towing direction, horizontally or vertically, the panels are adjustable independently to give enhanced performance of the operating systems, fishing trawl or seismic survey system, without having to pull the system to the towing vessel to adjust manually.

Abstract: Deflectors configured to be attached to cables towed behind a vessel for performing a marine survey and associated methods are provided. A deflector has a body including a wing portion and a knuckle portion. The wing portion has substantially flat wings extending away from a position where the body is attached to the cable. The knuckle portion is configured to attach the wing portion to the cable so that the wing portion remains able to rotate about three rectangular axes while being towed underwater.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: A method, according to one or more aspects of the present disclosure, includes positioning an elevated handling beam in a slip of a marine vessel, the handling beam extending from an inboard position to a outboard positioned proximate to an open slipway; and moveably positioning a handling winch on the handling beam, the handling winch capable of selectively connecting with a gun assembly and moving the gun assembly vertically and laterally relative to the handling beam.

Abstract: A bridle line control winch for a deflector for marine towing, with fore and aft double or triple bridle lines to attachment points in upper, possible middle, and lower parts of the deflector, preferably in horizontal plate frames, wherein at least said fore or aft bridle lines are arranged to be adjusted inwardly and outwardly so as for adjusting an attack angle of said deflector relative to a course line. The bridle line control winch is provided with a pivotally arranged control winch frame arranged between said bridle lines' attachment points to the deflector, and the bridle lines themselves. The control winch frame is provided with a winch sheave with an asymmetrically arranged pulley arranged on said winch sheave for holding an eyelet or end of said bridle line. The winch sheave is arranged to be driven by an actuator in a desired direction of rotation.

Abstract: Techniques are disclosed relating to using a remote operated vehicle (ROV) to facilitate cleaning of a submerged geophysical equipment (e.g., a streamer) being towed behind a tow vessel. The ROV may, in one embodiment, attach a streamer cleaning unit (SCU) to the streamer, where the SCU is configured to clean the streamer. In another embodiment, the ROV may facilitate cleaning by cleaning the streamer itself using a cleaning attachment coupled to the ROV.

Abstract: A tethered buoy housing and deployment system includes a housing for disposition in a vessel, a tether for interconnecting a portion of the housing and a buoy, a reel mounted in the housing and rotatable to unwind the tether, means for maintaining tension on the tether as the tether is unwound, and a platform and linkage assembly adapted to support the buoy and move the buoy between a vertical disposition for storage in the housing and an angled disposition for release of the buoy into an external fluid stream.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: To analyze content of a subterranean structure, electric field measurements at plural source-receiver azimuths in a predefined range are received. Total magnetic field measurements are also received at plural source-receiver azimuths in the predefined range. The electric field measurements and the total magnetic field measurements are provided to an analysis module to enable determination of electrical resistivity anisotropy of the subterranean structure.

Abstract: The problem of providing a submerged vehicle with above-the-surface communications to a nearby vessel, shore platform, or satellite while traveling at operating speed is solved by an efficiently deployable tethered tow body having a hydrodynamic and buoyant hull body and incorporating a lift-generating wing that provides hydrodynamic lift to efficiently lift the tow body containing antennas and other communications devices to the surface. The tow body allows for stable operation during underwater tow, surface tow, and transitions between underwater tow and surface tow. Disclosed embodiments include communications apparatuses encompassing the principles of the tethered tow body, as well as various underwater systems that incorporate a tethered tow body or communications apparatus for establishing communications with a nearby vessel, shore platform, or satellite.

Abstract: A method and a marine towing system for towing streamers or sources. The towing system includes a connecting line; a first paravane connected to the connecting line, wherein the connecting line is configured to connect the first paravane to a vessel; a spur line connected to the first paravane and configured to provide a tension to maintain streamers apart from each other; and a second paravane connected to the connecting line, between the first paravane and the vessel. The second paravane is configured to increase an angle (?4) between the connecting line and the spur line.

Abstract: A method of towing a craft having a fore rudder and rear rudder using a towing vehicle with the fore rudder and rear rudder initially oriented parallel to the length of the craft such that the craft follows directly behind the towing vehicle. The fore rudder is rotated to a position less than 90 degrees off parallel to the length of the craft. The rear rudder is rotated in an opposite direction to the fore rudder and to a position less than 90 degrees off parallel to the length of the craft, causing the craft to move off to the side of the track of the towing vehicle while the craft maintains movement substantially parallel to the towing vehicle, producing an of offset tow.

Abstract: Controlling lateral force developed by a paravane system. At least some of the illustrative embodiments are methods including: towing a paravane system through water, the towing by way of a bridle comprising a plurality of fixed-length forward lines coupled to a respective plurality of forward tow points, and a plurality of fixed-length aft lines coupled to a respective plurality of aft tow points; and while towing the paravane system through the water changing one or both of the lateral force supplied by the paravane or the direction of the force supplied by the paravane.

Abstract: A system and method are provided for launching and recovering an unmanned, water-born vehicle (UWBV) from a mother ship. The UWBV mimics the behavior of dolphins and is positioned ahead of the ship in preparation for bow riding. The UWBV uses a guidance system to position and keep in the bow wave. A high-frequency (HF) sonar transceiver array aboard the ship computes and sends course corrections to maintain the UWBV within the bow wave. The frequency range of the HF array can be 100 kHz or higher due to the short distance between the ship and the UWBV. Accordingly, the HF array can have a small aperture allowing for accurate bearing resolution. Course corrections can be sent on a near-continuous basis such that changes in thrust and rudder angle can be minimized to allow for accurate control of the UWBV.

Abstract: A method for towing a sensor streamer array in a body of water includes towing a plurality of sensor streamers behind a vessel in the water, measuring tension at a plurality of positions along the array and determining at least one of an optimum operating speed for the vessel, when the streamers and associated towing equipment have become affected by marine debris so as to require cleaning, and an optimum angle of attack of at least one paravane in the towing equipment.

Abstract: Controlling lateral force developed by a paravane system. At least some of the illustrative embodiments are methods including: towing a paravane system through water, the towing by way of a bridle comprising a plurality of fixed-length forward lines coupled to a respective plurality of forward tow points, and a plurality of fixed-length aft lines coupled to a respective plurality of aft tow points; and while towing the paravane system through the water changing one or both of the lateral force supplied by the paravane or the direction of the force supplied by the paravane.

Abstract: A towable buoy having a tow point for connection to a tow cable of a vessel, wherein the position of the tow point is translationally moveable with respect to the remainder of the buoy. Also, a method of operating the towable buoy.

Abstract: An intercepting vehicle, which is being towed by a towing vehicle, may home in on and attach to a retrievable vehicle that catches up to the intercepting vehicle from behind. Then, the intercepting vehicle, with the retrievable vehicle docked thereto, may be brought to the towing vehicle by reeling in the intercepting vehicle with the retrievable vehicle docked thereto.

Abstract: A device for selectively opening and closing a fuselage coupled to a towed submarine object. The device comprises first and second shells articulatable with respect each other by a hinge assembly. A releasable locking system locks the shells on each other. Hinge members of the hinge assembly are slidable with respect to each other along the articulation axis of the shells in order to actuate the locking or unlocking of these shells.

Abstract: The present invention provides a steerable hydrofoil. The apparatus includes at least one steerable hydrofoil panel, at least one body part coupled to the at least one steerable hydrofoil panel to allow the at least one steerable hydrofoil panel to rotate about an axis, and at least one actuator for rotating the at least one steerable hydrofoil panel by a selected angle about the axis.

Abstract: A system for interconnecting a mother ship with a submersible vehicle using a cable towed by the mother ship. The cable has a first cable end connected to the mother ship and a second cable end to be connected to the submersible vehicle. The second cable end is provided with a first connector. A capturing mast is arranged at the submersible vehicle for capturing the cable towed by the mother ship. A connector holder is arranged at the submersible vehicle for holding the first connector when it is to be connected to a second connector. The second connector is connected to the submersible vehicle. A first guide is arranged at the submersible vehicle for guiding the first connector towards the connector holder of the submersible vehicle. A second guide turns the connector to a well defined position into the connector holder.

Abstract: A system includes a subterranean survey data acquisition network and a processor. The network has first nodes that are distributed along a length of the network between a first end of the network and a second end of the network. Each of the first nodes is capable of being either in a state in which the first node is transparent to the network or in a state in which the first node is visible to the network. The processor is adapted to communicate with the closest visible first node relative to the first end, and the processor is adapted to, based on the communication, determine whether the closest visible first node is the closest first node of all of the first nodes relative to the first end.

Abstract: A method for towing marine geophysical sensor streamers in a body of water includes moving a towing vessel at a selected speed along the surface of the body of water. At least one geophysical sensor streamer is towed by the vessel at a selected depth in the water. A velocity of the streamer in the water is measured at at least one position along the streamer. The selected speed of the towing vessel is adjusted if the measured velocity exceeds a selected threshold.

Abstract: A method for towing a sensor streamer array in a body of water includes towing a plurality of sensor streamers behind a vessel in the water, measuring tension at a plurality of positions along the array and determining at least one of an optimum operating speed for the vessel, when the streamers and associated towing equipment have become affected by marine debris so as to require cleaning, and an optimum angle of attack of at least one paravane in the towing equipment.

Abstract: A system comprises towed marine seismic equipment marine seismic equipment, adapted for towing through a body of water; and a coating of copper particles covering the marine seismic equipment to protect from marine growth. A method comprises towing marine seismic equipment having a coating of copper particles thereon to protect from marine growth.

Abstract: The present invention refers to a floating auxiliary structure, similar to a floating rigid portal, of simple construction and low cost, designed to facilitate moving of equipment of large sizes and mass in sea operations. With the aid of the auxiliary floating structure of the present invention, equipment of large size and mass, for exporting oil production, for example, may be transported until site and lowered into sea with the use of two conventional tug boats. The invention also includes the procedure for removal of equipment from main tug boat and its descent until the sea.

Abstract: A paravane for a seismic acquisition system includes a float, a frame suspended from the float, deflectors affixed to the frame, and means for coupling a tow rope to a lead-in functionally extending between a forward end and an aft end of the frame. The paravane includes means for selectively changing an effective position along the lead-in of the means for coupling the tow cable.

Abstract: A seismic survey system includes a winch having a winch cable coupleable to a source array towable between two deflected lead-ins, a positioning system for determining a current position of the source array and a controller for adjusting the winch to modify the current position of the source array to a desired crossline position. The winches may be attached to the deflected lead-ins or mounted on a tow vessel. The winches exert lateral forces on the source array, derived from the deflected lead-ins, to control the inline position of the source array. A method includes positioning a seismic source array in tow behind a vessel comprises determining a current position of the source array and adjusting a lateral force applied to the source array to move the source array to a desired crossline position. Optionally, by adjusting the gun cable winch, the inline position may be controlled.

Abstract: A control device or “bird” for controlling the position of a marine seismic streamer is provided with an elongate, partly flexible body which is designed to be electrically and mechanically connected in series with a streamer. In its preferred form, the bird has two opposed wings which are independently controllable in order to control the streamer's lateral position as well as its depth.

Abstract: An apparatus for deployment and recovery of an underwater vehicle can be introduced into a recovery tube of an underwater recovery vehicle. The apparatus has a moveable tube provided with an insertion/extraction device at one of its ends. The device is in the form of a tube or of a ring in a retracted state and in the form of a funnel in an extended state. There is also disclosed a method for deployment and a method for recovery of an underwater vehicle by way of the above-mentioned apparatus that is introduced into a recovery tube of an underwater recovery vehicle. Additionally, there is disclosed a method for docking an underwater vehicle at a recovery tube of an underwater recovery vehicle provided with the above-mentioned apparatus.

Abstract: An at least partially self-propelled vehicle is configured for being towed by a towing vehicle, by way of a tow line. Operation of the vehicles may be coordinated so that, for a length of the tow line that connects the vehicles, the length of the tow line is curved in a manner that inhibits the tow line from transferring oscillatory motion between the vehicles while the entirety of the length of the tow line may be under tension.

Abstract: A buoyant device has a body and an elongate tail. The body carries a payload. The tail is moveable, e.g. by pivoting, between a closed and an open position. This movement changes the position of the center of mass of the device relative to the center of buoyancy. As a result the device can move through the water, with the tail in the closed position, with minimal drag. However, when the tail moves to the open position, the body pivots in the water so that the body, and hence the payload is supported in a stable manner.

Abstract: A deflector device (22) for use with a tow line between a seismic survey vessel and a tow, in particular a seismic streamer or streamer array, in the water behind the vessel comprises a vertically oriented wing-shaped body (28) shaped to produce in use a sideways force which urges the tow line laterally with respect to the direction of movement of the towing vessel. The wing-shaped body (28) includes one or more buoyancy elements, and a rearwardly extending boom (32). A pivotable control surface (54) extends sideways from the boom (32), and is shaped to produce in use a force having a substantial vertical component. The angle of the control surface is remotely controllable, in order to control the depth of the deflector device.

Abstract: A normal belt capstan assembly for arrays towed by vessels includes a drive wheel mounted on the vessel and adapted to deploy and discharge an array. The drive wheel has a continuous groove throughout an outer edge thereof with opposed rims on either side of the groove. The assembly further includes a normal belt mounted on a plurality of rollers and disposed along a portion of the periphery of the drive wheel, the belt having a continuous central groove formed in a surface facing the drive wheel. The combined drive wheel groove and central groove are adapted to receive the array and termination module, and a retaining groove on either side of the central groove are adapted for receiving the drive wheel rims. The normal belt provides a normal force to the array and termination module.

Abstract: An elongate article (100) such as a prefabricated pipeline of several kilometres length is towed through water. The article is provided along its length with buoyancy adjusting material (102) fitted closely to the article. The buoyancy adjusting material is sufficient to give the article overall a positive buoyancy so that it will not sink to the seabed, and is distributed unevenly along the length of the article so as to create regions of negative buoyancy. This causes the article to adopt a wave profile with peaks (+) and troughs (?) along its length. The article is connected at its extremities to lead and trail tugs (104, 106) for controlling movement of the article through the water. Intermediate peaks are optionally coupled to intermediate tugs (108) or buoys (702) via self-adjusting ballast chains (110). The wave profile allows the towed structure to extend without undue tension on the article itself.

Abstract: Systems for tethering an underwater vehicles using a low strength optical fiber tether. The tether system includes, a mechanical fuse that prevents a high load from acting on and severing the tether that is attached to the underwater vehicle, thus allowing use of far smaller cables than typically used. Upon separation of the fuse, a cable payout system pays out an optical fiber that keeps the underwater vehicle, typically a robotic craft, in communication with the surface vessel. The relatively light weight glass fiber may be reinforced and extended to lengths greater than 40 km allowing deep-sea exploration at depths up to 11,000 m.