Abstract: Discharge of fluid into or suction of fluid from the boundary region around such structures as offshore marine elements and moored marine vessels to reduce fluid current induced stress to marine elements and low frequency oscillations of moored vessels due to waves and wind striking the vessel is disclosed.

Abstract: Components of a flexible fairing shroud are attached adjacent their leading edges to bushings through which the fairing shroud is angularly displaced about a protectively surrounded structure exposed to a fluid medium. Inflow of the fluid medium is thereby accommodated in a direction resulting in inflation of the fairing shroud to a desired streamline shape established and maintained between leading and trailing edges during flow of the fluid medium to substantially reduce vibrations otherwise induced by such flow.

Abstract: A strake receptor (24) for a pipe deployed from an off-shore lay vessel comprises a formation (27) for engagement with the strake (29) and for deployment on the pipe when the pipe is received in pipe handling equipment located on the vessel. A removable dust cover protects the channel (25) until the strake (29) is received in the channel (25).

Abstract: A drilling unit comprises a floating drilling rig, a subsea wellhead, and a riser connecting the subsea drilling rig with the subsea wellhead. A floatation collar encircles the riser so as to reduce deck load on the floating drilling rig. The floatation collar comprises a hollow fabric body filled with gas. The floatation collar has a longitudinal axia and is formed from a sidewall body having a longitudinally extending slit extending through the sidewall body. The slit enables the floatation collar to be transversely mounted onto the marine riser.

Abstract: An apparatus and method for improving the efficiency of marine cable tow operations. Indentations such as dimples in the exterior surface of cable fairings reduce cable strumming and reduce frictional drag forces as the cables and fairings are towed through the water. The size, configuration and orientation of the indentations can be selected to control the desired water flow parameters, and overall tow efficiency is increased.

Abstract: The present invention is directed to a fairing system for the reduction of vortex-induced vibration and minimization of drag about a substantially cylindrical element immersed in a fluid medium. The fairing system includes a plurality of cylindrical shells rotatably mounted about a cylindrical element immersed in a fluid medium. Each cylindrical shell has opposing edges defining a longitudinal gap configured to allow the shells to snap around the cylindrical element. The longitudinal gap has a circumference of about 120° relative to the circumference of each shell. Alternatively the longitudinal gap can have a circumference of about 60° relative to the circumference of each shell. The shells also include a fin positioned along the each opposing edge of the longitudinal gap, in which each fin extends outwardly from each shell. The fins are positioned on each shell so as to reduce vortex-induced vibration and minimize drag on the cylindrical element.

Abstract: An apparatus and method for improving the efficiency of marine cable tow operations. Indentations such as dimples in the exterior surface of cable fairings reduce cable strumming and reduce frictional drag forces as the cables and fairings are towed through the water. The size, configuration and orientation of the indentations can be selected to control the desired water flow parameters, and overall tow efficiency is increased.

Abstract: A drilling unit comprises a floating drilling rig, a subsea wellhead, and a riser connecting the subsea drilling rig with the subsea wellhead. A floatation collar encircles the riser so as to reduce deck load on the floating drilling rig. The floatation collar comprises a hollow fabric body filled with gas. The floatation collar has a longitudinal axis and is formed from a sidewall body having a longitudinally extending slit extending through the sidewall body. The slit enables the floatation collar to be transversely mounted onto the marine riser.

Abstract: A fairing for reducing the drag produced by a lead-in cable which is being used to tow one or more seismic streamers forming part of a wide streamer array comprises a plurality of fairing sections, each having a central bore to receive the lead-in and a streamlined profile. The sections are coupled together end-to-end by swivel couplings which permit rotation of the sections relative to each other, so that each section can adopt the optimum orientation for drag reduction. Drag reduction is further enhanced by providing the upper and lower surfaces of the leading edge of each fairing section with respective sets of longitudinally extending ridges/grooves.

Abstract: A fairing for a towed cable is described that comprises a pliable material folded over the cable and stitched together, to give a substantially drop shaped cross section, wherein the flexible material is segmented into individual sections in the longitudinal direction of the cable, wherein each section being fastened to a free-rotating, but along the cable non-sliding, fastening device and wherein each section independent of each other may rotate around the cable together with its is fastening device. A faired tow cable is also described that has a fairing comprising a pliable material folded over the cable and stitched together to give a substantially drop shaped cross section, wherein the fairing is segmented into individual sections where each section at its upstream end is fastened to a free-rotating, but non-sliding, fastening device attached to the cable and wherein each section independent of each other may rotate around the cable together with its fastening device.

Abstract: An ultrashort fairing is disclosed for suppressing vortex-induced vibration in substantially cylindrical marine elements. The ultrashort falling has a leading edge substantially defined by the circular profile of the marine element for a distance following at least about 270 degrees thereabout and a pair of shaped sides departing from the circular profile of the marine riser and converging at a trailing edge. The ultrashort fairing has dimensions of thickness and chord length such that the chord to thickness ratio is between about 1.20 and 1.10.

Abstract: A fairing system is disclosed for protecting a cylindrical marine element from drag and vortex induced vibration. A noncorrosive fairing shroud is rotatably mounted about the cylindrical marine element and defines an annular region between the exterior of the cylindrical marine element and the inside of the fairing shroud and at least one copper element is mounted at the annular region to discourage marine growth at the fairing shroud-cylindrical marine element interface. This enables the fairing to remain free to weathervane to orient most effectively with the current Another aspect of the present invention is a method for protecting a substantially cylindrical marine element from vortex-induced vibration in which a rotatable fairing is installed about the marine element and a marine growth inhibitor is mounted in active communication with the annular interface of the rotatable fairing and the cylindrical marine element.

Abstract: The present invention is a method for deploying a drilling riser VIV suppression system in which a first retaining ring is installed on a syntactic foam buoyancy module encircling the drilling riser with a spring loaded connection. The spring loaded connection is capable of adjusting the diameter of the retaining ring automatically to compensate for compression of the syntactic foam under the influence of water pressure. VIV suppression provisions is then installed about the drilling riser using the first retaining ring as a load shoulder.

Abstract: A fairing system is disclosed for installation about a drilling riser deployed in a deepwater application. In another aspect of the invention, a method for deploying a drilling riser fairing system is disclosed in which a first retaining ring is installed on a buoyancy can encircling the drilling riser and a drilling riser fairings is installed above the first retaining ring. Drilling riser fairing installation folds a pair of fairing sides of a fairing shroud about an axially disposed hinge to surround the buoyancy can above the first retaining ring. A tail connection system secures the tail ends of the fairing sides together and a pair of struts are installed to further secure the fairing sides together. A plurality of interior bearing pads are provided on the internal circumference of the fairing shroud and axial bearing pads are provided on flanges at the upper and lower edges of the fairing shroud.

Abstract: A fairing system is disclosed for protecting multiple, parallel, bundled but separate cylindrical elements deployed in offshore applications. The fairing system deploys a plurality of elongated fairing surface elements foldable about an axis with a connection system joining the elongated edges of the fairing surface elements in a folded manner about the axis. A plurality of thrust bearings are orthogonally connected across the fairing surface elements at each axial end and an axially extending circular rotational surface is defined by the interior of each of the folded fairing surface elements and a transverse edge of the thrust bearings connected thereto. This rotational surface has a diameter which circumscribes the multiple bundled cylindrical elements. A plurality of clamps interconnect the bundled, cylindrical elements and a bearing collar on the axial ends of the clamps is provided to receive the thrust bearings of the axial ends of the fairing elements.

Abstract: The present invention relates to an improved apparatus and method for minimizing vortex induced vibrations and hydrodynamic drag of a drilling riser. Vortex induced vibrations and hydrodynamic drag are minimized by installing on a drilling riser streamlined faring sections. The fairing sections are installed on and removed from a riser through the use of one or more door panels on a rounded front portion that have a latch mechanism which can be easily opened and closed. The fairing sections are configured so they can nest one inside the other for easy storage. A tapered back or tail section of each fairing section has an attachment receptacle for engagement by a handling mechanism with a telescoping arm for grasping the fairing section. The handling mechanism is designed to move the fairing sections between a rack, where they are stored, and a position adjacent to the riser.

Abstract: A marine riser system having a fairing rotatably mounted thereon. The fairing is comprised of two substantially identical components which when assembled around the riser form a wing-like structure which weathervanes about the riser. Each fairing component is configured so that it will nest within the others thereby saving valuable storage space. Each fairing is mounted on the riser by a pair of bearing collars which are spaced at a distance substantially equal to the width of the fairing. Each bearing collar is made in two parts for easy assembly and each has two spaced bearing surfaces thereon. One end of one fairing is mounted onto one of the collar's bearing surfaces while one end of an adjacent fairing is mounted on the other bearing surface.

Abstract: A device for acoustically shading selected portions of the projected acouc signal from an omnidirectional transducer array being towed through a fluid. The device consists of an acoustically transparent, cylindrical outer covering attached to the transducer array by means of bearing assemblies. The bearing assemblies allow the device to freely rotate about the array. Sound absorbing material is placed on the interior side of the covering along a top portion and a bottom portion of the circumference. The bottom portion is weighted so as to maintain the orientation of the device with respect to the surrounding fluid as the array twists or rotates. The sound absorbing material prevents or shades the acoustic signals projected from the array from striking and being reflected from the fluid surface and the bottom layer of the environment. The cylindrical shape of the device fits easily over existing circular shaped towed arrays and also minimizes hydrodynamic drag as the array is towed through the fluid.

Abstract: A towing cable is fitted with segmented fairings, each segment being furt provided with a negative lift vane that is adjustable in orientation relative to the axis of the cable. Each vane has a channel shaped wing with the legs of the channel defining winglets one of which is attached at the inboard end of the wing to a strap that is pivotally mounted to the fairing at a point immediately behind or after the cable. The other end of the strap is releasably secured to the trailing edge of the fairing for locating the vane at a desired angle relative to the axis of the cable on which the fairing is mounted.

Abstract: A unique fluid drag reducing structure arranged such that the center of mass of the apparatus, when assembled, is positioned forward of the center of rotation of the apparatus when installed. Such an arrangement assures that the apparatus will be flutter free, while still allowing the apparatus to feather into the wind. The structure of and method for assembly provides for easy installation and removal of the apparatus on existing cylindrical structures without the need to disassemble the existing structure.

Abstract: A non-rotatable fairing for suppression of vortex-induced vibration of a marine tubular is provided, the tubular having a circular cross section and a centerline that is normal to the circular cross section, the fairing comprising:shaped sides that extend essentially tangentially from the outer surface of the tubular toward a point that is about a distance equal to the outside diameter of the tubular or less from the centerline of the tubular; anda means to fix the fairing to the tubular so that the fairing cannot rotate around the tubular, wherein the maximum length of the cross section of the combined fairing and tubular is between about 1.25 and about 1.5 times the outside diameter of the tubular.

Abstract: A stabilizing jacket for a towed cable or antenna structure is operative preventing rotation of the antenna/cable structure as it is towed through the water. The stabilizing jacket consists of an elongated body having a longitudinal bore extending therethrough for receiving the antenna/cable structure therein. The body may extend along the entire length of the antenna/cable structure and is symmetrical about a vertical median. The body further includes first and second symmetrical deflection vanes which extend outwardly from opposite sides of the body, and first and second symmetrical keel fins which diverge outwardly and downwardly from the body immediately adjacent the median. The deflection vanes and keel fins may extend along an entire length of the body. The symmetrical keel fins effectively increase the metacentric height of the antenna/cable structure and thereby tend to prevent rotation of the antenna/cable structure due to hydrodynamic forces as the antenna/cable is towed through the water.

Abstract: A cable fairing preferably for an underwater cable is formed from regenerated cellulose sponge material. The fairing is attached to the cable while the material is in an expanded and dehydrated state. Once hydrated, the fairing may be compressed from a flexible state to a compacted state for storage of the cable. The fairing assumes its original streamline shape when again deployed in water.

Abstract: A tow cable includes a high density, high damping core of a material such as lead, surrounded by a layer of helically wrapped or braided strength fibers of a material such as steel, or alternatively, of aramid fibers. Over this is provided a layer of a resilient, deformable thermoplastic material such as polyurethane, to provide for movement of the subsequent data-bearer layer under strain, so that no strain is applied to the data-bearer themselves. Around this layer is provided a layer of helically wrapped (or braided) power and data bearers, the bearers including coaxial cables, twisted pairs, and fiber optic bearers. To ensure water-blocking, this layer may be enclosed in an extrusion of thermoplastic material, such as polyurethane. Around this is wrapped or braided a layer of protective fiber, of material such as steel or aramid fiber, and over this, in a roughly trochoidal cross-section, is extruded an outer layer of thermoplastic material, such as polyurethane.

Abstract: Protective fairings which can be easily added to existing unfaired underwr sensor line arrays or incorporated into new faired underwater sensor line arrays to provide shock and impact protection to array sensors and cables without degradation of sensor output and allow the line array to be repeatedly raised and lowered under tension from a ship and stored on the ship without disassembly.

Abstract: A fairing for use with a tow cable and operable to suppress strumming vibions induced in the cable as it is towed generally longitudinally of its length through water includes a plurality of tab members extending in continuous, end to end fashion over the longitudinal length of the cables' outer jacket. Each of the tab members extends radially outwardly from the outer jacket in angularly spaced relation to adjacent tab members so that the plurality of tab members extend in an indexed helical pattern along the longitudinal length of the outer jacket.

Abstract: An underwater cable has a flexible, elongated core surrounded by a flexible, elongated jacket. A distributed jacket includes a helically displaced phase shifter to decouple the cable from strumming produced by shedding of von Karman vortex streets from the cable.

Abstract: A water fillable chute, to be employed as a submerged tractor device is cected to a plurality of wire severing grapnels by means of a metallic chain for sweeping command type river mines.

Abstract: The invention provides an aerodynamically profiled structural pipe (1) comprising a supporting pipe (2) and a rear tapered part (3) of soft material. The tapered part (3) has on both sides beads (15) forced into and captively held by rearwardly open chambers (12) of the supporting pipe (2).

Abstract: A fairing 13 for an element is made up of body sections 17. Each body section 17 comprises a moulded plastics body which has an open recess or hollow 18 along its leading edge 19. The body section 17 becomes slightly wider to the rear of the leading edge 19 and then increasingly rapidly decreases inside along a smooth curve until reaching a trailing portion 20 which thins, at a much slower rate, to edge 21. The mouth of the hollow 18 is defined by lips 23 which are dimensioned to straddle a trailing portion of the cable 12.In use, the body section 17 automatically aligns along the line of movement of the cable 12 and the body is held against the cable. The arrangement is such that the body sections will compensate for sidewards forces or drags.

Abstract: A series of streamlining elements surrounding a cable, pole, pipe or a similar long round member in a relatively moving fluid such as water or a high wind as an arrangement to reduce drag. Contiguous, independently rotatable elements are added easily to the cable to reduce drag forces by a factor of four or more and to provide some lift.

Abstract: Cable fairing is formed by weaving a filamentary yarn about one or more insulated conductors with the yarn serving to anchor the conductors in the cable and extending outwardly therefrom to form fairing hairs.

Abstract: A stacking ring of elastomeric material for supporting a plurality of fairings is formed by molding the elastomeric material around a cable which has been prepared with a bonding agent to provide a compliant ring capable of supporting substantial loading along the cable axis. Low-friction bearing surfaces may be incorporated in the ends of the ring which also increase the axial force retention capability of the ring.

Abstract: The present invention pertains to an underwater seismic cable which has at least one tensile cable placed upstream in faired cross sectional arrangement. Located downstream of the tensile cable are placed other electrical, pneumatic and hydraulic cables and hoses, with the electrical cables being adjacent the tension cable.

Abstract: The fairing disclosed has a streamlined, segmented, tail portion (63). The two-cable (40) passes through a hole (20) in the nose portion (18). The hole has a large clearance on the cable which allows frictionless rocking of the fairing side-to-side. This prevents any misalignment of the fairing from being locked in by friction. In addition, the segments (80, 90) are either provided with a physical mis-alignment control (84, 95), or the segments may be supported in tension, so that the individual segments do not rub against each other. Pliable links (101;112) are provided between segments that could otherwise rotate freely relatively, to give some torsional stiffness to control the fairing during winching.

Abstract: A faired towline comprises a load-bearing member, as the leading edge mem, that has a cross-sectional configuration of a rectangle with rounded corners and the longer dimension being the vertical one, an elastomeric fairing that is in continuous contact with the load-bearing member, and a smooth, tough covering for both members.

Abstract: A fairing and a fairing assembly for towed underwater cables is provided, having two different embodiments of fairings. In the first embodiment, each fairing has a flexible nose portion and a substantially rigid tail portion having separable halves, with the connection between the nose portion and the tail portion being by way of a flange at each side at the rear of the nose portion fitting into a channel at the front of each of the half pieces of the tail portion, and with the channel being interrupted by a shear block which is accommodated by a discontinuity in the nose portion flanges. A special arrangement is made having half-length nose portions, and using a flexible link between at least certain ones of adjacent fairings, where the half-length nose portion accommodates a ring secured to the periphery of the cable.

Abstract: An aerodynamic damper for reducing wind-induced motion, especially galloping, of electrical transmission and distribution lines comprises a structure that in cross-section has a vane that is secured to the conductor by two arms. Each of the arms is formed on the inside partly by an arc of a circle substantially equal in radius to the radius of the circle enclosing the conductor. This arc extends for about 45 degrees on each of the arms. The remaining part, for approximately 90 degrees, of each of the arms is formed by an arc of a circle of a radius smaller than that of the conductor and centered below and off the centerline of the conductor. Each of the arms is terminated by a lip which is thicker than the adjacent portion of the arm. In a preferred embodiment the damper is formed by extending the cross section linearly along the conductor for a distance of the order of four feet. In an alternate embodiment, the damper is formed by winding the cross-section in a helix about the conductor.

Abstract: A fairing segment for a cable is of composite construction which combines an elastomeric fairing body with a flexible spring-steel clip in the fairing nose. The elastomeric body allows the fairing nose to conform to the cable catenary in the flow stream, presents a smooth leading edge of the flow, and reduces drag. The clip is flexible in the direction of the plane of the fairing to conform to bending of the cable over sheaves or in the water. The spring steel clip allows the fairing to freely rotate about the cable and to align with the flow stream by maintaining low interfacial friction between the cable and the fairing. The clip also minimizes or prevents cold flow of the elastomeric nose portion of the fairing segment into the interstices of the cable armor. The tail portion of the elastomeric body is stiffened to prevent cupping or bending which would cause kiting of the cable.

Abstract: A fairing for riser pipe immersed in a fluid medium, usually fresh water or sea water. The fairing is constructed of syntatic foam and is compatible with existing systems. The fairing may be removably secured to riser buoyancy modules. The fairing has special fluid flow characteristics.

Abstract: A fairing for elongated elements is disclosed for reducing current-induced stresses on the elongated element. The fairing is made as a stream-lined shaped body that has a nose portion in which the elongated element is accommodated and a tail portion. The body has a bearing connected to it to provide bearing engagement with the elongated element. A biasing device interconnected with the the bearing accommodates variations in the outer surface of the elongated element to maintain the fairing's longitudinal axis substantially parallel to the longitudinal axis of the elongated element as the fairing rotates around the elongated element. The fairing is particularly adapted for mounting on a marine drilling riser having flotation modules.

Abstract: A one-piece fairing is provided which is a finite length monolithic one-piece, snap-on, foil-shaped, low drag fairing element of streamlined hydrodynamic shape, having an outer wall formed of high strength material, the fairing element being symmetrical about its central longitudinal axis, and adapted to be associated with a plurality of similar such fairing elements in end-to-end abutting relation on a cable.

Abstract: A streamlined fairing comprises an elongated leading edge tension member, elongated trailing edge member of flexible material integrally bonded to the leading edge member, and a flange member secured to the leading and trailing members for preventing relative displacements therebetween and for improving the shape stability of the fairing. The flange member has a cross-sectional width which is between about 10% and about 50% of the maximum width of the fairing and a cross-sectional length which is between about 5% and about 20% of the chord length of the fairing.

Abstract: A system using two or more lifting or depressing bodies positioned at intals along a cable used for towing a device displaced above, below, or to one side of the tow point and for providing radio frequency services for a submerged submarine. Each of the lifting bodies is symmetrical about the cable and provides hydrodynamic lift, depression, or side force, depending on whether the system is designed to lift, depress, or offset the towed device.

Abstract: This invention provides a substantially flat plate hingedly connected to a substantially cylindrical pipe intended to be moved through the water in a generally longitudinal alignment, the plate extending behind the pipe during movement through the water. The hinged plate can be formed in modular sections, one or more plate sections being hingedly connected to a pipe section. Individual pipe sections are intended to be joined together to form a single longitudinally extending pipe, for example, for use as a dredge pipe in deep ocean dredging. The hinged plate can be directly connected to the main dredge pipe or the hinged plate can be connected to a substantially smaller diameter pipe which is in turn connected to the main pipe. The plate is preferably not less than two inches away from the outer surface of the main pipe. The plate is especially effective for the movement of substantially vertical pipe through water at speeds of up to about two knots.

Abstract: A cable fairing to reduce the "strumming" of a tow cable comprising a pluity of tabs or stubs, having a height radially of the cable, less than the cable diameter, extruded onto the armor sheath of the cable. The stubs are integrally formed in a thermal-setting plastic sheath in a spiral pattern of small angle along the length of the cable. The spiral pattern is reversed at periodic intervals, or two sets of tabs are provided and arranged in opposite-hand spiral patterns criss-crossing within the same cable length.

Abstract: A fairing for pipes or other substantially rigid structures is disclosed, where the pipe may be immersed in a fluid medium, usually fresh water or sea water. The fairing is formed as a shell having a nose portion in which the pipe--or a pipe bundle--is accommodated and a tail portion; and at least the tail portion of the fairing has a plurality of upstanding ribs which extend at least from the forward portion of the tail to the rear portion thereof. The cross-sections taken through the upstanding ribs are different in absolute terms than the cross-sections taken through the alternating tail portions between the ribs; but the aspect ratios of length to breadth of each of the cross-sections are similar.

Abstract: A yarn or fiber is incorporated into the jacket of a long suspended small ameter cable for reducing low velocity current cable strumming in water. The yarn or fiber comprises at least one-quarter of the strands of a braided cable. A nap or mossy cable effect is produced when the jacket is brushed.

Abstract: A hydrodynamic cable fairing section comprising a nose portion for receiving a cable, a trailing body portion, and a plurality of vanes projecting outwardly from the body portion. The body portion includes two side surfaces that extend from the nose portion towards a trailing edge which forms part of the body portion. A plurality of vanes extend on both side surfaces and are substantially parallel to each other. Each of these vanes comprises flat surfaces which taper toward the trailing edge of the body portion.

Abstract: There is provided a reusable flexible fairing for securing to anchoring cables to reduce cable drag which consists of two wedge shaped interlocking body members interconnected by a flexible web providing a contoured inner surface which in combination with contoured end walls of the body members embrace the cable to be faired and provide a streamline cross-sectional profile for minimizing drag. There is also provided a system for adding and removing the fairing from a cable.