Abstract: Release device for a cable used during seismic surveys at sea and towed through the water behind a vessel so that in the event of the occurrence of obstacles or other occasions when it is desirable to release the cable (1) from the towing vessel, a controlled release of the cable is possible so that it is not severed, but can be recovered for further use. At one or more locations in such cables release sections (2) are inserted which contain sensors which sense loading in the section and in the event of overloading or other occasions when release is desirable, an element (5) is activated which cause a release mechanism (6) to be activated and thereby causes a split in the cable (1) at a predetermined location.

Abstract: The invention provides a floatation apparatus for maintaining a longitudinal object at a constant depth below the water surface in a body of water. Several airtight chambers are connected in a serial connection to form a string of air tight chambers. A one-way check valve is installed in the chamber at one end of the string while the other end chamber is connected to a nose piece. Air is continuously supplied to the check valve connected to the end chamber. A separate one-way check valve is installed between each pair of adjacent chambers in the string in a manner that air can pass between only in the direction from the air source to the nose member. The floatation apparatus is pivotaly connected to the longitudinal object at more than one place by means of parallel links.

Abstract: A method for simultaneous collection of seismic data of shallow and deep targets, in which two seismic streamers are towed at different water depths (1 and 2 in FIG. 2), and only one acoustic source of seismic signals is used. The seismic data recorded by the different streamers are mixed in a subsequent processing step, seismic data being weighted before being mixed by a weight which is made dependent on the recorded two-way travel time for the respective streamers, so that data from one or several streamers located at the least water depth receive a weight which decreases with travel time, whereas data from a corresponding number of streamers of greater depths receive a weight which increases with travel time.

Abstract: A seismic receiver array device for shallow water and near-shore operations which is comprised of an elongated low-profile, flexible casing having a plurality of geophones and hydrophones spaced along its length, and the geophones and hydrophones are electrically connected to a transmitter for transmitting the seismic impulses into a master receiver. Spikes are extended downwardly at spaced intervals along the length of the casing and a setting tool is provided to releasably anchor the spikes into the earth below a body of water.

Abstract: A hydrophone is provided for use with a hydrophone array enclosed in a streamer cable that is deployed in a body of water. The active transducer elements of the hydrophone are electrically isolated from the sealed metal case in which they are mounted. The signal input and output terminals are protected from short-circuiting due to water invasion of a faulty streamer cable jacket.

Abstract: In a preferred embodiment, a cable for serially connecting segments in a multisegment array, at the terminus of which cable the position of a first conductor uniquely identifies that conductor as originating at the nearest segment, the position of a second conductor uniquely identifies that conductor as originating at the second nearest segment and so forth. In a further aspect of the invention, segments can be connected with any one of identical cable sections.

Abstract: A vertical hydrophone array and a system of multiple arrays are disclosed. The vertical hydrophone array includes multiple groups of hydrophones mounted along a cable. A floatation device is coupled to the cable at one end, and an anchor is coupled to the cable at another end via a remotely controllable release. Depth transducers and position transponders are preferably mounted along the cable to provide precise depth and position indication to the surface. The release allows for retrieval of the array while leaving the anchor behind, thus reducing the potential for array damage. In the system including multiple arrays, a central positioning anchor is disclosed, through which tensioning cables pass. Each tensioning cable is connected to the float end of a vertical array, so that tension of the tensioning cable allows for control of the angle of the sensor array from the vertical. A clamp is preferably provided so that the position of the array may be held without maintaining tension thereon from the surface.

Abstract: A towed streamer having a buoyant core, a data bearer layer surrounding the buoyant core, an inner jacket layer formed of a resilient material surrounding the data bearer layer, and an outer jacket layer surrounding the inner jacket layer, wherein a series of longitudinally positioned strength members are embedded in the inner jacket layer to extend along the streamer to transmit tension along the streamer while the streamer is held in the inner jacket layer.

Abstract: Longitudinal shocks and longitudinal emotional disturbances are reduced between members attached to opposite ends of a vibration isolation module. An elongate, essentially cylindrically shaped cord extends the length of the module and is fabricated from a compliant and dissipative material. At least one cord-like essentially nonextensible member is wound about the core in a helical fashion with at least one symmetrically located pitch reversal, and with attachment to the core at least at the ends and pitch reversal points. Longitudinal shocks and motional disturbances are translated by the essentially nonextensible cord-like member into torsional shear strains in the compliant core. The dissipative characteristics of the core material coupled with the nonlinear relationship between longitudinal and torsional strain produce a tensile shock absorber with both damping and a spring constant that increases with longitudinal strain.

Abstract: In a marine seismic data acquisition system, a plurality of seismic data transmission paths are utilized to conduct seismic data to a central recording unit from seismic data acquisition modules positioned along the length of cable. Signals from a plurality of data acquisition modules are applied to each of the transmission paths. Data acquisition modules which apply seismic signals to a given transmission path may be spaced and substantially uniform distances along the length of the cable and may be interspersed with data acquisition modules which apply seismic data to each of the other transmission paths. The operation of the data acquisition modules is synchronized by means of a signal transmitted continually from a central recording unit. Each section of the cable includes a plurality of remote units distributed along the cable section for detecting seismic signal.

Abstract: A towed array of hydrophone modules employs bladders that are mounted to bulkheads at the ends of the hose sections. The bladders are configured and pressurized so that pressure waves produced by the oscillatory motion of the bulkhead are suppressed by the bladders thereby significantly diminishing noise due to the breathing waves.

Abstract: A large eddy break-up device for towed acoustic arrays for reducing the f noise due to the (TBL) around the towed array is described. It includes two identical halves, each having a circumferential airfoil and two flat flanges which are used to secure it to a coupling on the towed acoustic array and also to integrate the two halves using fasteners. The circumferential foil interferes with the flow noise and large eddys are broken up into easily dissipating small eddys of higher frequency.

Abstract: A magnetic coupler and the use of such couplers to place a plurality of etroacoustic transducers around a lengthy single conductor trunk cable is described. The magnetic couplers are used to place the electroacoustic transducers in any randomly selected configuration. They allow the use of a single conductor trunk cable so as to facilitate the deployment of the system at a relatively low cost.

Abstract: The disclosure concerns a directional hydrophonic antenna, consisting of several pairs of dipoles formed by omnidirectional hydrophones superimposed in a streamer and keeping the same reference angle for all the pairs of dipoles. The goal sought is achieved by means of a chain of superimposed, directional modules each bearing a hydrophonic sensor on each lateral face and joined by ringed tubular elements through which there goes a central rod made of fiber glass and a strand of electrical connection cables.

Abstract: A marine seismic cable network including cables towed parallel to the surface of the sea at at least two depths for providing time analysis of reflected seismic data to dimensionally clarify characteristics of reflecting surfaces.

Abstract: Walkaway vertical seismic profiling is conducted in a body of water. A marine seismic cable is positioned substantially vertically in a body of water. The cable has a number of hydrophones spaced along its length. A seismic source is moved along a line of traverse past the seismic cable and is periodically activated to emit acoustic waves. The response of the hydrophones to reflection of the acoustic waves from subsurface formations is then recorded for processing and analysis.

Abstract: A low noise hydrophone which is towed by a cable and has a smoothly increasing front cross-section to a maximum diameter and a smoothly decreasing rear cross-section. The hydrophone sensor is located in the forward section of the hydrophone such that the varying flexural rigidity and shape of the hydrophone results in low turbulence as the hydrophone moves through water.

Abstract: A streamer-cable assembly is provided having a tubular outer jacket enclosing an open-cell and closed-cell foam core. The foam core provides an axial hole for retaining a plurality of pressure sensors and a plurality of off-axial holes providing passages for the transmission bundle. Longitudinal channels along the exterior of the foam inserts receive substantially rigid stress members which provide longitudinally strength to the streamer. Cable noise associated with the cable jerk and cable whip/vibration is radially reduced by the open-cell foam core and rigid stress members while the closed-cell foam core provides buoyancy to the streamer cable at the connectors between sections.

Abstract: A processing method is disclosed for marine seismic surveying which utilizes two vertically spaced marine streamers each having a plurality of seismic detectors contained therein. A seismic energy source positioned at or near the surface of a body of water is utilized to generate seismic waves which propagate into earth formations below the water and reflect back up to be detected at each streamer. Seismic waves also reflect from the water/air interface back down toward the streamers and must be separated from the upgoing seismic waves to enhance the accuracy of the resultant trace. The seismic waves detected at two selected vertically displaced seismic detectors are combined to form a sum signal which is then combined with a scaled time integral of a difference signal to form a resultant signal which preserves either the upgoing or downgoing seismic waves.

Abstract: A plurality of sensor arrays are mounted in a streamer cable. The sensors within each array are distributed over an elongated two-dimensional vertical plane. The seismic streamer cable is so constructed that its vertical dimension is substantially greater than its width and the top portion is relatively more buoyant in the water than the bottom portion. Because of that configuration the streamer cable resists vertical strumming and, when the sensor arrays are used in the differential mode, there is no orientation uncertainty.

Abstract: A sonar array connected to a data unit includes a substantial number of hydrophone units distributed along a small diameter cable having a substantial number of connecting wires, a center strength member and a tough polyurethane jacket. The hydrophone units each include a strong metal bracket bifurcated at each end and fastened to the strength member. A generally cylindrical hydrophone member is fastened to the bracket as is a circuit board including a preamplifier and the entire unit is sealed with paraxylene resin and then molded into a smooth generally cylindrical unit which is tapered at the ends and sealed to adjacent parts of the cable jacket. To minimize the cross-sectional area and the effects of cross currents, the cable is composed of a plurality of interconnected sections, each of which is of smaller cross-section and carries fewer conductors than the section next closer to the data unit.

Abstract: A latching mechanism used to couple external devices to marine seismic streamer cables is disclosed. The latching device universally couples to collars predominantly used in the seismic industry. A mounting bracket or shank is provided which is coupled to the external device. The shank has a lug or finger fixed therein which extends from a mounting surface. Adjacent the lug is a latching device which is comprised of a cylinder having a cam defined at the upper end. The cylinder is recessed within the shank so that the cam and the lug are engaged with an aperture defined in the collars attached to the streamer cable. A lever extends from the cylinder through the exterior of the shank so that an operator may rotate the cylinder, turning the cam in the aperture to a locking position. A spring applies a tensile force to the cylinder, drawing the cam down against the aperature, and pulling the shank tight against the collar.

Abstract: An endfire seismic array comprises one or more marine seismic cables having a plurality of acoustic-to-electrical hydrophone receivers spaced therealong, each being operatively connected in combination so that as a unit an endfire receiving beam pattern with respect to any frequency across the seismic band is formed by causing the signals from the individual hydrophone receivers to be additive for that frequency. A plurality of cables results in a more narrow beam than a single cable. A geologic or lithologic formation that is a dip change from the norm may be detected either as an extra strong increase or decrease in signal, depending on the mode of use.

Abstract: Method for determining the geometry of a seismic wave emission device comprising a plurality of seismic sources (S11, S12, S21, etc.) towed by a ship (1) with different transverse and longitudinal offsets. It comprises the isolated triggering of each of the sources (S11, S12, S21, etc.), the detection of acoustic waves coming therefrom by means of proximity sensors (C) arranged at known distances from other sources and optionally from the ship or from a seismic flute, and the recording of detecting signals by means of an acquisition system on board the ship (1). After various corrections of the distances and various processings performed on the signals, parameters (propagation time, phase shiftings) representative of intersource distances are determined and, consequently, the relative coordinates of the sources with respect to each other and their positions with respect to other points. The previous measurements are completed by other measurements related to the immersion depth of different sources.

Abstract: A marine seismic data acquisition system and method includes a plurality of hydrophone arrays. A marine cable is towed in the water by a boat. The marine cable includes a plurality of active modules. Each active module is connected to a corresponding hydrophone array and collects seismic data from the geophones. The marine cable also includes a plurality of passive modules interspersed with a plurality of active modules, with each passive module generating, receiving and transmitting signals. The passive modules and the active modules are connected by electrical wires with each other and to the electronic equipment on the boat. The electronic equipment on the boat includes a subsystem for activating the active modules; another subsystem for interrogating the active modules and the passive modules and circuitry connected to the activating subsystem and to the interrogation subsystem which determines the source of transmission errors in signals received over the marine cable.

Abstract: A float for use in seismic surveys of the sea bed supports a plurality of seismic pulse transmitters (6) which are suspended on lines (7) beneath the float (1). At a distance from the front end of the float (1), on one sidewall thereof, a fastening device for a towing cable and a lead-in for control lines and lines for supplying operating medium to the pulse transmitters are provided. These lines and cables are gathered in a common line (3) which extends behind the tow ship. The line (3), at a distance away from the float (1), is connected to a line (4) which leads to a length-regulating device (12) inside the front section of the float. The float is also provided with at least one motor (10) with a drive shaft (9)leading to hoisting drums (8) for the lines (7) to the respective seismic pulse transmitters (6). Both the motors (10, 12) and the seismic pulse transmitters (6) are connected to the pneumatic supply line.

Abstract: A seismic streamer retrieval system utilizes an inflatable bag to lift the streamer to the water surface where it can easily be recovered. An acoustical signal or a pressure switch is used to activate said device so as to cause the inflatable bag to be ejected from said device and inflated to lift the streamer to the water surface. A small electric motor and drill bit are used to puncture a gas cylinder to release gas into the inflatable bag.

Abstract: In a seismic streamer cable, stress sensors are co-located with the hydrophones in the cable. The stress sensors are responsive to mechanical stresses applied to the cable but it are substantially unresponsive to acoustic waves propagating in fluid media. The signal outputs from the stress sensors are combined with the signal outputs from the corresponding co-located hydrophones to cancel spurious signals due to bulge waves.

Abstract: For a simplified towed array configuration an integrated hydrophone, preamplifier and telemetry hybrid unit suitable for connecting with a single coaxial cable was developed. The preamplifier and FM hydrophone telemetry assembly comprises an air backed ceramic assembly connected to a preamplifier/voltage control oscillator chip. In addition the chip includes a regulator and power separation network.

Abstract: A streamer-cable assembly is provided having a tubular outer jacket enclosing an open-cell foam case providing an axial hole for retaining a plurality of pressure sensors. A plurality of off-axial holes provide passages for the transmission bundle. Longitudinal channels along the exterior receive stress members which provide longitudinal rigidity to the streamer. Cable noise associated with cable jerk, and cable-whip or vibration is radically reduced by the foam core and rigid stress members.

Abstract: The invention is a method of reducing phase distortion in a detected seismic signal resulting from Doppler shifting of the transmitted signal. An operator is convolved with the seismic data to correct the dispersion. The operator is determined for the particular transmitted signal and boat speed. The operator is normally determined in the frequency-wave number domain. The seismic data may be transformed to the frequency-wave number domain for performing the convolution. The transformed data may then be transformed back to the time-space domain. Alternatively, the determined operator may be transformed to the time-space domain and the convolution performed in that domain.

Abstract: A sensor for resolving the left-right ambiguity encountered in horizontal line hydrophone arrays consists of an orthogonal pair of dipole hydrophones, a monopole hydrophone, and a tilt sensor, the tilt sensor connecting the dipole hydrophones so as to provide a single dipole hydrophone which is always oriented horizontally. The tilt sensor consists of two variable capacitors made from hollow cylinders of high permittivity dielectric material, partially filled with a quantity of liquid mercury which forms the variable inner electrodes of the capacitors. The outer electrodes of the capacitors, on the outside of the cylinders, having a sinusoidally-shaped perimeter and being oriented at right angles to each other, are connected to the crossed dipoles in order to provide the required horizontal dipole hydrophone.

Abstract: An arrangement for deployment and towing of a plurality of seismic cables (2) in parallel and at a mutual distance behind a vessel whereby seismic cables (2) are wound on winch barrels (4), and are provided with an inner cable member (3) which forms a connection with the vessel (1) during a towing operations, and is, additionally, provided with a paravane/control (14, 15) to guide and maintain the cable (2) laterally in relation to the towing vessel (1). Reliable and simple depolyment and towing of the seismic cables (2) at a large distance laterally in relation to the center line of the vessel is achieved by running the inner cable member (3) through at least one guide pulley (5) suspended from a line (7) that is adjustable in length from the vessel, and is, preferably extended over a derrick device (9) projecting from the vessel. Guide pulley (5) can be hauled in and paid out from the vessel, at the same time as inner cable member (3) can be let out to a greater length from the vessel.

Abstract: A seismic exploration method and system employing a streamer that houses at least one pair of orthogonally mounted hydrophones. The streamer may be operated downhole in a well, or may be towed in a body of water by a marine vessel. In the downhole embodiment, the invention permits detection of seismic signals of interest with suppression of noise due to tube waves and (dipole and monopole) modal waves propagating in and along the well, and without the need for locking the seismic detectors to the wall of the well. In the marine embodiment, the invention permits selective detection of waves incident from any incidence direction of interest (including the horizontal and vertical directions). In all embodiments, the incidence angle of the detected seismic wave is determined. The amplitude of the detected wave may also be determined from the incidence angle and the amplitude components detected at each hydrophone.

Abstract: A fluid filled marine seismic streamer employs a plurality of hydrophones spaced apart along its length to detect seismic reflection signals from subsurface formations below a water layer. A plurality of fluid blocking members are also spaced apart along the length of the streamer. A plurality of flow through spacers having varying flow through apertures are positioned between each hydrophone adjacent to a fluid blocking member that generates pressure pulses in the fill fluid of significant magnitude to be detected by such hydrophone. The size of the flow through apertures of such spacers progressively increases in a direction leading from the fluid blocking member toward the hydrophone.

Abstract: A marine seismic streamer employs a plurality of sections connected together sequentially with fluid blocking connectors. Each section contains a plurality of groupings of hydrophones with the hydrophones within each grouping connected together to provide a single seismic signal output for such groupings. The two terminal groupings of each section have variable hydrophone densities along their lengths so as to discriminate against noise generated in the streamer by the action of the fluid blocking connectors in producing pressure waves in the fluid fill within the streamer.

Abstract: System for interconnecting elements of a receiving device of great length, for example a seismic streamer, comprising a plurality of data aquisition apparatuses, each of which is adapted to collect 12 separate signals generated by receiver groups distributed in the different elements.The 12 groups of separate receivers (R.sub.1, R.sub.2 . . . R.sub.12) are regularly distributed in each element (T.sub.1, T.sub.2 . . . ), forming 6 pairs of groups. A first group of each pair (R.sub.1, R.sub.3, R.sub.5) is connected to an input of an acquisition apparatus (B.sub.2). The second group of each pair is connected either to an input of another acquistion apparatus, or to inactive electric connection means (B.sub.1, B.sub.3) adapted to connect in parallel the second and the first groups of each pair.This system can be used in seismic prospecting.

Abstract: A spacer for a marine seismic streamer employs a compliant material that mechanically isolates the spacer from the hosewall and strain members of the streamer and also allows the flow of fill fluid therethrough so as to prevent pressure pulse build-up in such fluid during towing of the streamer along a line of exploration.

Abstract: A flexible line array transducer assembly for detecting underwater acoustical signals. The assembly includes an array of spaced-apart piezoelectric elements arranged generally in a line and selected to have low cross-coupling characteristics, low sensitivity to incoherent mechanical perturbations in the directions longitudinal and lateral to the axis of the array, and high sensitivity to coherent mechanical perturbations such as acoustical signals. The elements are polarized in a direction generally transverse to the array and each include opposing surface areas which are generally parallel with the linear axis of the array. Electrodes are disposed on the opposing surface areas of the elements and are coupled to conductors which carry signals produced by the piezoelectric elements when the elements are stressed by acoustical signals. A porous, open-cell material is disposed about the piezoelectric elements as an encasement to maintain the elements in place and mechanically isolate the elements.

Abstract: A high ambient liquid pressure-resistant electrical connector is shown with an airgun having a solenoid actuated valve mounted on the airgun. A multi-conductor electrical cable is connected by this pressure-resistant connector to a plurality of terminals of the solenoid valve for protecting from ambient liquid the terminals and the adjacent portions of the conductors. This pressure-resistant electrical connector includes a connector housing having an upper end and a lower end, with the lower end of the housing being mounted to the airgun. The connector housing has a fluid sealant chamber for enclosing the electrical terminals and adjacent portions of the conductors connected to the terminals and includes at least one barrier for engaging the cable to protect against ambient liquid seeping past the barrier to the electrical terminals. The connector housing defines a cylindrical space carrying a spring-loaded piston.

Abstract: A float for use in seismic surveys of the sea bed supports a plurality of seismic pulse transmitters (6) which are suspended on lines (7) beneath the float (1). At a distance from the front end of the float (1), on one sidewall thereof, a fastening device for a towing cable and a lead-in for control lines and lines for supplying operating medium to the pulse transmitters are provided. These lines and cables are gathered in a common line (3) which extends behind the tow ship. The line (3), at a distance away from the float (1), is connected to a line (4) which leads to a length-regulating device (12) inside the front section of the float. The float is also provided with at least one motor (10) with a drive shaft (9) leading to hoisting drums (8) for the lines (7) to the respective seismic pulse transmitters (6). Both the motors (10, 12) and the seismic pulse transmitters (6) are connected to the pneumatic supply line.

Abstract: A tapered wiring harness is disclosed for an array of hydrophones with spaced take-out points on the harness at which a signal wire and a ground wire are connected with a hydrophone. The harness comprises a bundle of signal wires, which diminish in number from one end to the other, and it also comprises a ground wire and a strain cord, which extend throughout the length of the harness. The bundle of wires and the strain cord are held in a bundle of substantially circular cross-section by a lacing of thread formed as a sewing machine stitch of the zig zag type. Hairing members of uniform length are secured to the bundle under the lacing at predetermined intervals with the hairing more closely spaced on the larger diameter of the bundle. In another embodiment, the hairing members are spaced uniformly but are of variable length with longer members on the larger diameter of the bundle.

Abstract: A device for receiving acoustic waves in water and adapted to be positioned vertically in the water in a stable position. The device comprises a tubular element formed of several connected sections, buoyancy means close to a first end, ballasting means close to the second end, several receivers spaced apart inside certain sections of the tubular element and stabilizer fins fixed to the second end thereof. A cable connects the tubular elements to a towing vehicle.

Abstract: A method of marine seismic investigation involves positioning or deploying at a predetermined point close to or within a multi-element seismic source array a calibration source which is an acoustic pressure wave point source which has a far-field seismic signature of broad bandwidth. The radiated pressure wave field of the calibration source (3) is weaker than that of the main source (2). The two sources are fired at separate instants within a predetermined time range, preferably with the calibration source (3) being fired about two seconds before the main source (2). The reflected response of the sub-surface strata is recorded and processed to generate seismic data. In one embodiment, the response is recorded with two hydrophone arrays - a short high-resolution array (4) and a conventional main array (5). The method can be used to determine the far-field signature of the main source array (2). It can also be used to obtain a high-resolution shallow seismic section simultaneously with a deep seismic section.

Abstract: A plurality of streamer-cable bulkheads mounted within a streamer cable in cascade for radially scattering tube-wave noise from a streamer-cable. Each bulkhead consists of an annular body with conical surfaces converging at a desired angle, extending outwards from both ends of the annular body. An axial hole and a plurality of off-axial holes extending through the bulkhead for receiving therethrough, electrical conductors and stress members respectively. Noise traveling within the tube in a waveguide mode, impinges upon the conical surfaces of the cascaded bulkheads, and is reflected out of the streamer-cable jacket.

Abstract: A gradiometer array of two or more sensors consists of a closed housing filled with a volume of fluid having a desired specific gravity. The sensors are freely suspended in the housing by flexible tethers. The sensors have different specific gravities such that one always sinks and the other floats. By that means, the sensors are self-aligning along an axis parallel to the gravitational vertical.

Abstract: A hydrophone section for a seismic streamer towed array in which the hydrophones 2 are arranged in groups of not more than 7, the spacing of the hydrophones within each group being such that each group has an overall length l=0.8-1.2 m. The hydrophone mounts 5 and mechanical spacers 3 are attached at their periphery to aramid fibre strainwires 4. The hydrophone mounts and mechanical spacers are acoustically open structures.

Abstract: The invention relates to novel laminate tubular articles comprising an outer layer having a modulus of at least about 10.sup.7 Pascals, an interior layer comprising a polymeric material having a loss tangent of at least about 0.5 at a temperature of from about 0.degree. C. to about 40.degree. C. at a frequency of from 10-4,000 Hz and whose modulus is less than the modulus of the outer layer and an innermost layer having a modulus greater than the modulus of said interior layer. The invention further relates to a device for sensing in a body of water, said device comprising at least one sensor surrounded by the novel laminate tubular articles of the invention. The mechanical and acoustic properties of the article make it particularly appropriate for use as the hose in a towed-array sonar system.

Abstract: A technique for a vibration isolation module (VIM) used for towed arrays is disclosed. The VIM has a stretchable cable on which is mounted one or more rigid spacers which make contact with an outer hose formed of a flexible material having a selected vibration attenuation characteristic. The spacer transmits energy between the parts of the VIM which contact the spacer for attenuation purposes. The spacer is "soft mounted" on the stretchable cable so that it may be moved by a limited amount along the cable in response to forces of a specified minimum magnitude. This ability to move allows adjustment of the internal parts of the VIM during use to avoid concentrating stress at any one particular contacting area. Disclosed is an embodiment where two sleeves are used to abut the spacer at opposing ends thereof.

Abstract: I provide a combination land/bay cable capable for simultaneous use on land and in water-covered areas. When the cable section is placed in a water-covered area suitable for hydrophone use, a polarized plug containing an impedance matching transformer is detachably connected to a polarized socket. The transformer connects the hydrophones to a transmission line. If the cable is to be used on land, the transformer is unplugged deactivating the hydrophones and at least one geophone having a substantially identical plug is inserted in the socket. The plug connects the geophone to the transmission line and leaves the hydrophones inactive.