Abstract: Methods and apparatus are provided for determining the intent of a driver of a motor vehicle in moving a trailer towed by the motor vehicle along a desired path. The method comprises the step of positioning a first reference point at a first location spaced apart from the motor vehicle and sequentially positioning a second reference point at a plurality of way points along the desired point. A signal relative to the motor vehicle, the first reference point, and the plurality of way points is transmitted as the second reference point is positioned at each of the way points. The transmitted signals corresponding to each of the way points are received and are used to determine the position of the plurality of way points relative to the motor vehicle by a process of triangulation. The position of the plurality of way points indicate positions along the desired path.

Abstract: The invention relates to low-frequency underwater detection systems comprising a towed linear antenna (12, 13). It consists in producing the transducers of the transmission antenna (12) in the form of flextensional arrays of cylindrical type (20) and in forming directional transmission channels covering all of space. It makes it possible to lighten the assembly and to facilitate implementation at sea, which becomes able to be automated.

Abstract: The invention relates to low-frequency underwater detection systems comprising a towed linear antenna (12, 13).

Abstract: A system for sonically probing a seabed comprises at least one row (14) of transducers (22) that each can produce a sonic beam, and at least one sonic detector (24). Each transducer is independently energized to produce a narrow sonic beam (40), with resulting seabed or subsea echoes being detected to produce one pixel of a display (60, 80, 90, 150) formed by an X-Y array of pixels, before a next transducer is energized and its echoes are detected to produce another pixel of the display. When the system detects a large change in echo amplitude at adjacent seabed locations, then scanning at those locations is accentuated by analysis and by additional sonification at different frequencies. The transducers are closely spaced, at a center-to-center distance (G) of less than 25 cm, to provide good horizontal resolution and usually lie within 6 meters from the seabed. Each transducer is energized to produce a sonic pulse which, dependent on the application, has a carrier frequency (32) of at least 200 kHz.

Abstract: The sonar array system includes a receive array of hydrophones and a transmit array of acoustic projectors disposed on a common axis. The sonar array system can be coupled to a ship and deployed and recovered from a single winch and through a single ship hull penetrator. When towed through water by the ship, the sonar array system provides a substantially horizontal transmit/receive array.

Abstract: A termination assembly for disposal between a marine tow cable and an acoustic receiver array includes a cable sleeve having a grip portion adapted to grip a cable outer jacket, and a collar portion for disposition on a strength member portion of the cable. The termination assembly further includes a coupling comprising an inner sleeve for mounting on a coax portion of the cable, an electrical connector for abutting a distal end of the coax portion, a coupling body interconnecting the inner sleeve and the electrical connector, the coupling body having a cylindrically-shaped wall disposed around the electrical connector to define therebetween an annular recess for receiving a connector of the acoustic receiver array, a coupling nut mounted on the coupling body and engageable with the acoustic receiver array connector to lock the acoustic receiver array connector onto the electrical connector, and an outer sleeve fixed to the coupling body.

Abstract: An encapsulation assembly includes a housing having a nose end, a tail end, and a body portion between the nose end and the tail end. A plurality of acoustic transducers are positioned within the body portion of the housing, each of the plurality of acoustic transducers having a wiring connection attached thereto. A tow cable is connected to the nose end of the housing and is in communication with the wiring connection from each of the plurality of acoustic transducers. A characteristic of the assembly is that at least the body portion of the housing is entirely formed of a solid casting of plastic material thereby environmentally isolating the plurality of acoustic transducers within the body portion of the housing. This configuration prevents water intrusion into the transducer elements, and increases the cavitation threshold for the acoustic array, thereby allowing the array to be driven to higher acoustic intensities.

Abstract: A method of and an apparatus for mounting seismic vibration sensors to a cable designed for use offshore, such that the sensors are optimally coupled to the ocean floor through all cylindrical rotations when the cable has reached the bottom after being slipped over the transom of a deployment vessel. Said coupling is accomplished without the use of a sub-surface robotic vessel to force the sensors into a particular orientation. The housing for the sensors is adapted to endure and minimize the impact on the host cable of the mechanical extremes the system is subjected to in the process of the conventional deployment and retrieval methods.

Abstract: A low friction surface is provided to hose-shaped acoustic envelopes for towed sonar arrays. The low friction surface permits multiple envelopes that are in intimate, parallel contact or that are crossed-over one another, to slide easily relative to one another, enhancing their deployment. The low friction surface is accomplished by blending particles of a low friction material with a base material. The mixture is heat extruded into pellets and the pellets are heat extruded into a hose of desired size. The exterior surface of the resulting hose is then subject to axially aligned abrasion to both expose the particles close to the exterior surface of the hose, and to create axially aligned micro-grooves in this surface. The micro-grooves allow water to enter and lubricate the boundary that is present, which is typically either another hose surface or the metal or other surface of an array deployment vehicle.

Abstract: A system for sonically probing a seabed comprises at least one row of transducers that each can produce a sonic beam, and a corresponding row of sonic detectors. Each transducer is independently energized to produce a narrow sonic beam, with resulting seabed or subsea echoes being detected to produce one pixel of a display formed by an X-Y array of pixels, before a next transducer is energized and its echoes are detected to produce another pixel of the display. When the system detects a large change in echo amplitude at adjacent seabed locations, then scanning at those locations is accentuated by analysis and by additional sonificiation at different frequencies. The transducers are closely spaced, at a center-to-center distance of typically about 3.5 cm, to provide good horizontal resolution. Each transducer is energized to produce a sonic pulse which, dependent on the application, has a carrier frequency of 0.25 MHz.

Abstract: A towed body yaw angle sensor arrangement used to sense the angle between the axis of a tow fish and the flow of water. The water flow vector is used as the reference for correcting towed body yaw so that a magnetic compass in the towed body is aligned with the towed arrays streaming in the water flow. A yaw angle in the towed body with respect to the flow will cause errors for target bearing and skew the arrays relative to each other which will also cause errors. The flow sensor must be in the free flow off the towed body and ideally the sensing part is aligned with water current flow. Also provided is a method for sensing and correcting a yaw angle.

Abstract: A soft-bodied, towable, active acoustic module includes a specially formed uspension fixture and a flexible faired body enclosing an active acoustic array. The suspension fixture is a Y-shaped tube having a single forward end and two trailing ends, one for attachment of a trailing tow cable and the other for attachment of the flexible, faired body. The flexible, faired body is an elongated hydrofoil having sections which allow lateral bending. The combination of the suspension feature and lateral bending feature allows the module to be deployed and recovered through shipboard undersurface deployment tubes. A weight attached to the faired body near the lower rear end balances the body to maintain a substantially vertical position during towing. Flow steps on the lower portion of the faired body reduce lateral oscillations.

Abstract: The invention relates to underwater mines countermeasures methods and devices that can be employed from a helicopter.It consists in using the body (101) of a known passive heli-winched sonar, fitting to it emitting antennas (105, 106) arranged in this body parallel to its axis and a receiving antenna perpendicular to this axis and formed of two articulated arms (107, 108) that can be retracted inside the body. Two other arms (114, 113) that can be retracted into the body have propulsion means (111, 112) at their free ends, to allow the body to be stabilized about its axis.The invention makes it possible to employ lightweight helicopters for underwater mines countermeasures, allowing the mines to be relocated and, if appropriate, destroyed without having to backtrack.

Abstract: A seismic ocean bottom positioning device include a series of seismic stations spaced apart at a predetermined interval along a cable. Each station includes a hydrophone, a motion sensing device such as a geophone and an acoustic positioning circuit. A preamplifier is coupled to a seismic channel. The hydrophone is also coupled to the seismic channel. An acoustic channel is also coupled to the preamplifier and coupled to the hydrophone.

Abstract: A system for surveying an underwater topography includes an ultrasonic sensor array disposable in physical contact with a body of water for generating electrical signals encoding ultrasonic echo responses of underwater objects in the body of water. The sensor array includes a plurality of electromechanical transducers in turn including at least one electroacoustic transducer and one acoustoelectric transducer. The transducers are disposed in a configuration extending in at least two dimensions. An a-c current generator is operatively connected to the electroacoustic transducer for energizing the electroacoustic transducer with an electrical signal of a pre-established ultrasonic frequency. Means are provided which operatively connected to the sensor array for determining locations of the electromechanical transducers relative to one another.

Abstract: A drag antenna for a sonar system for detecting and/or locating sources of sound in water includes at least two acoustically sensitive lines positioned side-by-side and laterally spaced apart during a trailing operation. The lines are secured to each other at the leading ends and at the trailing ends by respective connecting element in order to lower the production costs for the drag antenna and to achieve a sufficiently constant lateral spacing between the acoustically sensitive lines.

Abstract: The invention relates to towed acoustic transmitters forming an underwater vehicle which is itself intended for towing a linear acoustic receiving array (105). It consists in placing the vertical faired acoustic array (303) of such a transmitter at the very rear of the underwater vehicle, and in balancing the weight of this array by a faired ballast (313) situated at the very front thereof. These two parts are joined by a girder (310) of small cross-section, and the center of gravity of the whole is situated at the front of this girder and beneath it. The vehicle is towed by a cable (101) fastened to the vehicle by a hook (314) fixed to a swivel joint (315) above the center of gravity. It makes it possible to facilitate the operations of submersion and fishing-out of the whole while also achieving a greater depth of submersion.

Abstract: A process of acoustic emission for sonar with a separate emission array from the receiving array. The emission array has the shape of a linear acoustic array and can either be towed simultaneously with linear acoustic receiving array or be suspended from a helicopter to form a "dipping" type sonar. Detection using this type of sonar is facilitated by increasing the sound level via the directivity index, while reducing the level of reverberation originating from the bed and from the surface of the sea.

Abstract: A system for transmitting signals between a plurality of towed sensor streamers and a seismic vessel, the system comprising: a plurality of seismic streamers, wherein each streamer of the plurality of seismic streamers comprises: a leading end, a trailing end, a plurality of sensors located therein and a transmitter of seismic signals received by the plurality of sensors to a terminal located in the leading end of the streamer; at least one spreader located between the leading ends of two streamers of the plurality of seismic streamers, the spreader comprising: connectors for connection to the terminals of the streamers, a spreader terminal, and a spreader transmitter of signals between the connectors and the spreader terminal; a lead-in having a lead-in connector for connecting to the spreader terminal and a transmitter of signals between the lead-in connector and the seismic vessel.

Abstract: A method and system are provided for frequency filtering compressional wave nergy. An elastic cylinder is filled with a fluid that is selected based on a fluid density .rho..sub.i and a dilatational wave phase velocity c.sub.i thereof. When the elastic cylinder so-filled is subjected to a compressional wave propagating in a fluid environment, a first radial resonance frequency of the elastic cylinder is controlled by the fluid density .rho..sub.i and the dilatational wave phase velocity c.sub.i. Further tuning of the first radial resonance frequency can be achieved by adjusting the radial wall thickness of the elastic cylinder.

Abstract: The present invention comprises a wide-band omni telemetry system adapted r increasing the signal transmission bandwidth of an existing tactical array having a single shared transmission line. In accordance with one embodiment of the invention electronic elements are provided for conditioning and converting a wide-band analog data signal, received from an underwater acoustic sensing device, to an appropriate wide-band digital signal. Timing elements provide a carrier wave signal interface with telemetry elements for modulating the carrier wave signal with the wide-band digital signal wherein the carrier wave is quadrature phase shift key modulated. In this way two separate carrier waves are created that are shifted in phase by about 90.degree. relative to one another.

Abstract: A side look sonar apparatus having a linear array of receiving elements mounted to an underwater platform vehicle which has an aperture with a cross track dimension greater than the along track dimension. The cross track beams are processed to form synthetic aperture beams in the along track dimension. One embodiment generates a synthetic aperture beam for each cross track beam. A second embodiment generates a single synthetic aperture beam.

Abstract: Method and apparatus are disclosed for reducing breathing-wave induced no in a liquid-filled elongate hose housing a hydrophone array. The arrangement involves sensing radial strain induced in the hose wall by the breathing waves (created as the hose is drawn longitudinally through water) and subtracting a multiple of the sensed value thereof from the array hydrophone output. Arrangements for measuring the breathing-wave-induced wall strains include (1) relative phase shifts in light passing through the sensing arm of an optical fiber interferometer, and (2) signal currents generated from piezolectric polymer both of which are disposed inside the hose wall surrounding a hydrophone.

Abstract: A method for compensating for lateral distortion in a moving linear array using a frequency domain beamformer, comprising the steps of measuring the instantaneous lateral distortion of the linear array at discrete points along the array, corresponding to array element locations, calculating a shading weight for each of the discrete points along the array, corresponding to array element locations based on the instantaneous lateral distortion at each said point and calculating the compensated beam magnitude by multiplying said shading weight into the frequency domain beamformer equation.

Abstract: A system for compensating for noise induced in a sensor data stream from a sensor array towed by a towing device includes a towing device motion data input receives a towed motion data stream representative of towing motion of the towing device. A sensor array input for receiving the sensor data stream. An adaptive filter connected to the towing device motion data input and the sensor array input for receiving the towed motion data stream from the towing device motion data input and the sensor data stream from the sensor array input and for generating a corrected sensor data stream representing sensor array data with ship motion noise attenuated therefrom.

Abstract: A stern torpedo defense system uses a pair of passive sonar towed tactical etectors in tandem alignment to detect the presence and trajectory of a stern torpedo attack. The detectors are towed below the wake of a surface ship and include arcuate arrays of transducer elements mounted in low self-noise, roll pitch and yaw stabilized platforms. The region aft of the stern of the ship is examined by an overlapping plurality of preformed passive sonar beams of preselected beamwidth. Signal processing means monitor the power level of the beams and detect the presence and trajectory of an attacking torpedo so that suitable ordinance may timely and effectively be deployed to destroy the torpedo and thereby thwart the attack.

Abstract: A magnetic heading sensor alignment and roll reducing device is provided. A enerally cylindrical assembly has a first end and a second end. Each end has a plurality of grooves located equiangularly on a circle with the center thereof located at the cylindrical assembly's center longitudinal axis. Bearings, positioned at and supported by the first and second ends, support a magnetic heading sensor at either end thereof. The bearings provide the sensor with rotational freedom about the center longitudinal axis. A counterweight is affixed to the sensor such that its center of gravity and the sensor's center of gravity are located at a common axial loci. A plurality of longitudinal spring strips are provided to fit into corresponding ones of the grooves on the first and second ends of the cylindrical assembly. The spring strips cooperate with the inner surface of a tubular housing when the device is inserted therein. All materials used to construct the device are non-magnetic.

Abstract: A system for storing and deploying a number of elements sequentially in connected but spaced-apart relationship is described. Adjacent elements are joined together temporarily by connectors which overlay adjacent elements. The connectors are bound to the elements by a plurality of cables, one of which is wound around each element and the overlying connectors. One end of each cable is connected to the element around which it is wound and the other end is connected to the next preceding element. When tension is applied between the cable of the first element and the last element, for example, by connecting an underwater tug to the cable and connecting a drogue to the last element, the cables unwind one by one releasing the connectors and extending the elements in a straight line, spaced apart by the length of the connecting cables.

Abstract: The objects of the present invention are achieved by a method and means for temporarily suspending sonar beam transducer means on a dihedral wing body at a first underwater location within sonar beam range of said scoured area; scanning a first portion of said scoured area with said sonar beam in a first substantially vertical plane that points in a first azimuth direction, so as to generate signals indicative of the range and bearing of said scanned first portion from said transducer means; and scanning at least a second different portion of said scoured area with said sonar beam in a second different substantially vertical plane that points in a second different azimuth direction, so as to generate signals indicative of the range and bearing of said scanned second portion from said transducer means. In actual practice, scanning by the sonar beam occurs in many different vertical planes and also can be done from different underwater locations.

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: The system comprises measuring means and carrying or supporting means (6), to which the measuring means are fixed. The carrying means are dragged underwater by a helicopter (2) via a cable (4). The carrier means, equipped with measuring means, have a hydrodynamic shape such that they remain at a substantially constant depth when dragged underwater by means of the cable.Application to marine soundings.

Abstract: A system for measuring the speed in water of an underwater towed array has towbody connected in close proximity to the array by means of a rope drogue. The towbody has a freely turning propeller that turns a shaft that has a rotor magnet. Magnetic pulses from the rotor magnet are converted first to an electrical and then to an acoustical signal. The acoustical signal from the towbody is received by the towed array and converted back to an electrical signal that is transmitted along a line to a ship that is towing the array. The ship then displays the detected speed and/or utilizes the information received for control purposes.

Abstract: In towing sources of seismic energy behind a vessel, especially in connection with seismic surveys in waters which are covered with ice, the buoyancy floats and also the sources of seismic energy are readily influenced by broken up ice collecting behind the icebreaking towing vessel. In order to stabilize the tow of sources of seismic energy a towing line (7) is secured between the buoyancy means (4) belonging to the tow of sources of energy (3) and the vessel (1) at a point (10) which is located in the area of the waterline, so that towing line (7) will extend in the area of the waterline. Another towing line (8) is connected directly with the array of sources of seismic energy (5) and is secured to a towing point (11) on the vessel (1) located below the waterline. An arrangement is also disclosed for securing the towing line (8) in a suitable location to avoid influence from ice and, furthermore, the design of floats (4) avoids influence from the ice.

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: 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 submarine drone has special hydrodynamic performance features for operag as a moving underwater platform for underwater transport of a barrel stave type sonar receiving transducer and a pole type sonar transmitting transducer with highly precise vertical alignment. The body of the submarine comprises a generally spherical pressure hull for containing propulsion plant and electronic components. The barrel stave transducer is affixed about the upper half of the pressure hull. An acoustically transparent false wall forms a spherical hydrodynamic wall over the pressure vessel and transducer. The false wall also forms a tail cone projecting from the rear side of the submarine. The tail cone contains an annular channel which takes in boundary layer water from the spherical portion of hydrodynamic wall and conducts it back to a pump jet at the extreme rear of the tail cone. A fixed tail boom emerges from the center of the pump jet structure and extends rearwardly.

Abstract: A marine acoustic array employs a plurality of sections connected together sequentially with the outer surfaces of said sections having a non-smooth configuration to create a water flow along the length of the array as it is towed through a water layer that causes sensors within the array to provide outputs having improved signal-to-noise ratios.

Abstract: A high information rate catacoustic system having a sonar transmitter dised at a remote location from and facing a sonar receiver in such manner that forward-scattered echoes of sonic energy originally broadcast by said transmitter are reflected by and received from the sea floor by said receiver and displayed by a recorder connected thereto as an inverse function of the range from the sea floor to said transmitter.

Abstract: In a sonar used to determine the characteristics of the underwater mines, the emission diagram in the vertical plane is modified to obtain two main lobes separated by a central zero value. At reception, the bearing/frequency display system shows a dark strip separated by two luminous strips. When the echo from a mine persists, in going through the dark zone, it is recognized that it pertains to a moored mine floating in the water, thus enabling moored mines to be identified and their submersion depth measured.

Abstract: A sonar system having a transmitting transducer adapted for being moved ag a predetermined path, a transmitter for energizing said transmitting transducer, an omni-directional receiving transducer spatially disposed behind said transmitting transducer, a sidewardly and downwardly looking receiving transducer contiguously disposed with said omni-directional receiving transducer, a receiver connected to the output of said sidewardly and downwardly looking transducer, a series connected detector, differentiator, delay, and time base generator coupled to the output of said omni-directional transducer, and a readout connected to the outputs of the aforesaid receiver and time base generator.

Abstract: A means for extending the useful aperture of a multi-hydrophone towed array by using the overlap of the successive positions of the array hydrophones as the array moves forward through the water. The overlap information is used by an overlap correlator to provide phase correction factors for a synthetic aperture signal processing scheme. The overlap correlator continues to refine the correction factors using later in time hydrophone measurement data.

Abstract: A marine seismic streamer having a plurality of seismic recovery units spaced along the length thereof. Each unit includes an inflation flotation device that will deploy when the streamer sinks to a trigger depth which is continuously adjusted in response to the actual operating conditions at the time.

Abstract: A sonar transducer assembly for a fishing boat provides electrical signals corresponding to an image of the area surrounding the boat on both sides thereof based on sound echoes received by the transducer assembly. The transducer assembly comprises a transducer housing mounted on the transom of the boat so that the bottom surface thereof is at substantially the level as the hull of the boat in the normal position of the transducer housing, and such that the transducer housing can move rearwardly and upwardly in response to hitting an object in the water. The housing is generally bullet-shaped and houses a plurality of individual transducers directed in different directions away from the hull of the boat so as to provide scanning of areas of the water beneath and on both sides of the boat.

Abstract: A remotely actuable boom assembly for floating and positioning a sonar transducer in otherwise inaccessible positions for fishermen. A rigid, supportive frame assembly adapted to be coupled in a desired position upon the side of a conventional fishing boat pivotally mounts an articulated, elongated boom assembly comprised of a pair of control arms which extend generally horizontally outwardly from the side of the boat. The arms are normally spring biased into a preferred operational orientation. The outermost control arm terminates in a housing which is floated upon the water. The suspension system dynamically compensates for wave action or movement during use of the apparatus. The floating housing mounts and controls an internally disposed sonar transducer which may be remotely pivoted by a cable to sweep or scan various regions under the water. A pair of levers associated with the frame enable remote control of the boom and the captivated sonar sensor.

Abstract: A cable wiper assembly for airborne sonar includes a housing suspended from a hoist used to rapidly raise and lower a sonar transducer at the end of a cable. The wiper assembly is interposed ahead of the cable-directing sheaves forming part of the hoist to strip away the sea water which adheres to the cable as it is pulled from the ocean. The cable wiper housing includes a series of internal grooves each of which contains and secures one wiper stage. Each stage includes a washer-like wiper of elastomeric material whose internal diameter is just slightly smaller than the cable diameter carried in a shallow cup-shaped holder having an internal port significantly larger than the cable diameter and secured by means of an upper washer-member overlying the wiper whose internal diameter is slightly larger than the diameter of the cable.

Abstract: A variable depth towed sonar line handling system is arranged to provide a level wind of the sonar cable onto a cable winding drum without significant lateral deflection of the cable. The system includes a boom with sheaves at the inboard and outboard ends and an inboard winch with a cable winding drum. The winch is mounted for axial movement past the boom and is translated axially in synchronism with its rotation so that the fleet angle of the cable remains constant. In preferred embodiments, the winch is located beside the boom and translates fore and aft. This allows the cable to be taken off along the pivot axis of the boom, eliminating cable excursion through the sheaves in boom bobbing. Other features include a fairleading saddle and a combined passive and active shock absorbing system.

Abstract: A marine cable system including one or more elongated cable sections whose buoyancy may be independently controlled. Each section is associated with a pump and a variable volume, elongated bladder. In one embodiment, one reservoir containing buoyant fluid is included, and fluid from the reservoir is pumped between adjacent sections to inflate or deflate the associated bladders. In another embodiment, a rigid reservoir containing compressed gas is included in each section. The associated pump releases gas from the reservoir to inflate the bladder, or pumps gas from the bladder into the reservoir when desired. The pumps are operated in response to control signals from a remote control unit, such as one aboard a vessel towing the cable. One or more depth sensors may be attached in or near each section. Depth information from the sensors may be supplied to the control unit for use in generating the pump control signals. The buoyant fluid is entirely contained within the cable.

Abstract: An assembly is provided for mounting a sonar depth sounder transducer on an electric trolling motor such that the transducer is protected from entaglement with vegetation and from being knocked out of a predetermined orientation relative to the boat. The conventional bearing cap connected to the nose of a trolling motor is replaced by a bearing cap having a sonar tranducer integrally mounted therein such that the power cable, extending from the depth sounder in the boat to the transducer, is routed through the inside of the trolling motor housing and through the hollow tubular trolling motor support shaft. A power cable guide is mounted inside the trolling motor housing and is supported by a guide ring for positioning the power cable along a path preventing engagement with the armature, rotor and other moving parts in the trolling motor.

Abstract: The aft drogue module (18) of the towed sonar array has a body (20) as its main length. The body (20) contains strength member (26) which is covered by an extruded tube (28) of rubberlike material which is covered by braid (30) and which, in turn, is covered by extruded abrasion-resistant cover sleeve (32). At its forward end, the strength member is expanded into the conical interior of coupling (22). The tail (56) is attached to the body and contains fill material (60) which damps and is sufficiently stiff to inhibit whipping during towing.

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.