Abstract: An electroacoustic transducer, particularly for underwater use, having a ceramic body (10) and a pair of electrodes, whose flat electrodes (11, 12) are arranged on mutually averted end faces (101, 102) of the ceramic body (10). At least one electrode (11) is structured in order to effectively suppress the side-lobes in the directional characteristic for all spatial directions such that the density of the ceramic body (10) decreases from the body center to the body edge.

Abstract: A removable protective device for a submersible liquid level transmitter and method for using the same. The protective device includes a sensor cage assembly having a sensor component and a cage component. The cage component can include a bottom plate and a top plate coupled to the bottom plate through a plurality of spacers. The device includes a seat, located on a top surface of the top plate, and a securing mechanism capable of removably securing the sensor in the seat, and thus to the protective cage.

Abstract: A method for marine geophysical surveying according to one aspect of the invention includes towing at least one geophysical sensor streamer in a body of water. The streamer includes a plurality of spaced apart electromagnetic field receivers disposed at spaced apart locations along the streamer. The streamer also includes a plurality of seismic sensors disposed at spaced apart locations. The seismic sensors each include at least one pressure responsive receiver and at least one particle motion responsive receiver. At selected times, a seismic energy source is actuated in the water. Particle motion and pressure seismic signals, and electromagnetic field signals are detected at the respective receivers.

Abstract: Container systems used in storage, deployment or retrieval of a seismic cable array comprise a container, at least two coiling elements attached to a bottom side of the container, and storage means for allocating or accommodating, in an ordered arrangement, a number of seismic stations and/or a number of couplers/splices and/or other discontinuities which are being interconnected by sections of the seismic cable. Said storage means is arranged between said coiling elements and are attached to the bottom side of the container. The seismic cable is spooled or wound around said coiling elements. Corresponding methods of storing a seismic cable and deploying/retrieving the seismic cable are based on the use of at least two coiling elements and storage means for allocating or accommodating a number of seismic stations and/or a number of couplers/splices and/or a number of other discontinuities and arranged between said coiling elements.

Abstract: An acoustic mirror of alternately arranged layers of high and low acoustic impedances is manufactured in that a basic material having a first layer of the layer sequence is initially provided, on which a second layer of the layer sequence is created on the first layer such that the second layer of the layer sequence partially covers the first layer. Subsequently, a planarization layer is applied onto the layer sequence, and the planarization layer is removed in an area which in the common layer plane projects laterally beyond the second layer so as to result in a residual planarization layer. Finally, a termination layer is applied onto the layer sequence and the residual planarization layer.

Abstract: A volumetric displacement transducer is provided for generating acoustic signals. The transducer housing incorporates at least one pair of opposed plates mounted for radial vibration. A driving mechanism is coupled to the opposed plates for driving the plates simultaneously in opposition to each other at a desired frequency, whereby an acoustic signal is radiated into a medium, such as water, surrounding the housing.

Abstract: The subject of the present invention is a dynamic sensor of physical quantities with optical waveguide with optically-pumped amplifier medium, which requires no interferometer or reference sensor and which makes it possible to obtain at least the same level of performance, in terms of sensitivity, as known sensors of this type, and this waveguide is linked at one end to a selective mirror, and comprises at its other end an interrogation laser, the reflection of which on the selective mirror produces a wave which, by interference with the incident wave, provokes the periodic saturation of the gain of the waveguide.

Abstract: A diver unit computes the direction and distance to a specified target. When the target is obstructed, the diver unit receives navigation assistance data from another diver unit. The navigation assistance data includes direction information that is referenced to a common reference line extending between the two diver units.

Abstract: The emergency underwater notification device disclosed, one of which would be carried by each diver on a team of divers at a dive site, comprises (a) an activator; (b) one or more primary signal emitters, each of which emits a primary notification signal upon activation of the activator, the primary signal emitter comprising one or more of the following: a light source, a hydrophone, a siren, a speaker, or an acoustic transducer; (c) one or more secondary signal emitters, each of the secondary signal emitters emitting a secondary communication signal upon activation of the activator; (d) a receiver capable of receiving communication signals; (e) one or more tertiary signal emitters, each of the tertiary signal emitters to emit a tertiary communication signal upon receipt by the receiver of either a secondary communication signal or a tertiary communication signal from another notification device; and (f) one or more quaternary signal emitters, each of the quaternary signal emitters to emit a quaternary notifi

Abstract: An open-ocean fish-growing platform has a submersible cage structure for growing fish, an antenna for receiving positioning signals transmitted from an external source, a position-correction apparatus for calculating a position error signal from a target geostatic position, and an ocean thermal energy conversion (OTEC) system for generating electric power for thruster units to maintain the cage structure in the target geostatic position. The OTEC system inducts colder ocean water from a deeper ocean depth for driving its heat exchange cycle, and is also of hybrid type using a fuel-fired unit as a heat source. The cold water effluent from the OTEC system is directed into the cage for flushing wastes generated by the growing fish. The self-positioning, self-powered open-ocean platform enables unmanned, extended marine deployment in deeper ocean waters without the need for tethering or anchoring to the ocean floor.

Abstract: An electronic device and transducer structures are described.

Abstract: A system and method is provided for using acoustical pulses generated from an airborne laser source to locate objects under water. An array of acoustic sensors, such as passive sonobuoys at the ocean surface, is deployed in known or determinable locations by aircraft. Each area surrounded by acoustic sensors comprises a search cell, within which sonar scattering data can be used to locate objects. Following sonobuoy deployment, the aircraft uses the laser to rapidly generate many laser-acoustic pulse sources within each search cell, which in turn generate spherical acoustic pulses traveling through the water. The acoustic sensors receive the acoustic pulses, either on a direct path or on a scattered path after the pulse strikes an underwater object. The sensors record the acoustic signatures of the received pulses and transmit data of the recorded acoustic pulses to a processor such as processor on a nearby ship.

Abstract: Various exemplary embodiments of an increased aperture homing cavitator are disclosed. In one exemplary embodiment, a supercavitating body may include, e.g., but may not be limited to, a cavitator assembly having a front end and a back end, and having a shape operative to generate a concave cavity; an acoustical homing array coupled to the cavitator assembly; an afterbody coupled to the back end; a thruster coupled to the afterbody; and a ventilation system disposed within the afterbody, operative to supply gas to, and to maintain pressure within the cavity. In an exemplary embodiment, the size of the cavitator may be increased without a significant attendant increase in drag, thereby enabling a homing array of increased size and aperture.

Abstract: An underwater acoustic sensor is designed for attachment to a rigid or semi-rigid mounting structure. The sensor includes an outer casing and a secondary casing spaced therefrom. A compliance layer is disposed between the inner surface of the outer casing and the outer surface of the secondary casing. An inner sensor support is designed to attach to the mounting structure and is spaced from the inner surface of the secondary casing. A plurality of sensor elements are disposed between and interconnect the inner surface of the secondary casing and the sensor support.

Abstract: Methods and devices are provided for rescuing and recovering underwater vehicles. In one embodiment, a system is provided that includes a modular rescue device configured to attach to an underwater vehicle, such as with a tow line. The rescue device can include one or more emergency mechanisms that can be automatically and/or manually activated to aid in detecting the location of the underwater vehicle in the event of an emergency. One exemplary emergency mechanism includes a buoyancy mechanism, e.g., an expandable lift bag, configured to be inflated with a fluid to add buoyancy force to the system to pull the underwater vehicle toward a water surface. Another exemplary emergency mechanism includes a signaling mechanism configured to signal the underwater vehicle's location.

Abstract: A dive accessory has an outer shell that encompasses a light maker and a noise maker. The light maker is waterproofed and has a light source electrically connected to an electrical power source for powering the light source. A light switch selectively opens and closes the electrical connection to switch the light source on and off. The noise maker has a hollow chamber containing a solid object that is movable within the hollow chamber to produce a noise when the solid object strikes a wall of the hollow chamber. The solid object may be restrained from moving to prevent the solid object from making noise. Combining a light maker and a noise maker provides a more effective dive accessory.

Abstract: A relative positioning system enabling a user to return to a starting position or some other point on the user's path. The system may include an array of accelerometers. The output from the accelerometers may be integrated to quantify movement of the array. The various movements of the array may be reconstructed to determine a net two or three dimensional translation. The current location of the array may be compared to a reference point to derive at trajectory directing the user to the reference point The trajectory may be continuously or periodically updated. Another application may include an accelerometer array secured at various positions on a ski to monitor distortion of the ski and the skier's movements. Reconstructing the skier's movements may be accomplished by integrating the accelerometer output and transforming the integrated output into a two or three dimensional path or location.

Abstract: A submersible loudspeaker assembly is provided. The loudspeaker assembly includes: a housing; a loudspeaker enclosed within the housing; an external diaphragm disposed adjacent to the loudspeaker. The external diaphragm is acoustically transparent when subject to ambient air pressure, but configured to flex towards the loudspeaker when submerged in water.

Abstract: The invention includes a geographical sensor apparatus for use under water in the sea, including a plurality of seismic sensors (1) for sensing seismic waves associated with underground formations, and a plurality of EM-sensors constituted preferably by electrodes (4) for sensing electromagnetic waves associated with the underground formations. In a preferred receiver cable configuration embodiment of the invention, the geophysical sensor apparatus includes a seismic receiver cable with a linear array of a plurality of seismic sensors (1) and EM-sensors arranged inside a flexible outer skin (25), with the EM-sensors having electrodes on the outside of the outer skin. The cable is operated on the seafloor by a surface vessel, the vessel towing an electromagnetic transmitter antenna in addition to the seismic source.

Abstract: A system for locating a diver is provided. The system includes a diver module for association with a diver that is capable of producing both an audible frequency signal to assist in locating the diver while submerged, and a radio frequency signal to assist in locating the diver when surfaced. In addition, the diver module includes a switch to enable the initiation of an active mode of the diver module. The diver module may also include a receiver visual display to indicate the direction to another diver module or to a boat module. The location signal boat module provides a boat operator with an indication of the direction from which a location signal is being received.

Abstract: A seismic acquisition system comprising a remote-controlled buoy for conducting seismic acquisition operations. The buoy comprises an operating system for operating a seismic wave production device on the buoy, a placement system, a communications system, and dynamic position locating system. The seismic acquisition system also comprises a remote control system for controlling the buoy systems. The seismic acquisition system also comprises receivers for receiving the seismic wave and generating a data signal indicative of the received seismic wave. The seismic acquisition system operates by controlling the placement system with the remote control system to position the buoy and then controlling the operating system with the remote control system to produce a seismic wave from the seismic wave production device. The receivers then receive the seismic wave and generate a data signal indicative of the seismic wave.

Abstract: A sensor arrangement is provided for use in the seismic investigation of geological formations below the seabed. A plurality of sensor nodes (20) are provided and are positioned gfor deployment on the seabed to collect pressure waves and shear waves from the geological formations and to transfer seismic data to a surface receiver. Each sensor node (20) may include a cylindrical structure (22), which is intended to penetrate downwardly into the seabed. At least one, preferably three, geophones (30-32) are positioned in connection with this structure (22). An advantageous method for operating a seismic mapping system with sensor arrangements orderly deployed on the seabed records data concerning system behavior and seismic data. This data may be further processed separately.

Abstract: The present invention is concerned with an underwater communication device, that is simple in design, in operation, powered solely from the hand against the resistance of a spring or elastic band, is low maintenance, is resistant to accidental sound generation, offers a wide margin of safety, reliability, and enables audible communication. The present invention is concerned with a device containing a housing (3) an acoustic signature generating means (1) to produce an audible sound when struck. A strike element (2) powered by a kinetic energy generating means (4) causing it to impact the acoustic element (1). A gripping attachment (5) attached to strike (2) pulled away from the acoustic signature generating means (1) increasing tension in the kinetic energy generating means (4). Upon gripping attachment (5) release, increased tension of kinetic energy generating means (4) powers strike element (2) to impact acoustic signature generating element (1), creating distinguishable sound.

Abstract: A reflector (14) reflects energy emitting from an energy source (16) and focuses and directs it to a target. An aperture stop or suppressor disk (18) is positioned between the energy source (16) and target. The outer periphery of the aperture stop or suppressor disk (18) is an irregular curve (FIGS. 12 and 13). This shape of the periphery prevents diffraction enhancement to the direct wave. In another emobidment, the suppressor disk (18) is replaced by a suppressor member (18?) that is directly mounted on a frame portion of the energy source (16). This energy source (16) includes a spark-gap, or the like, and an open frame (36) that surrounds the spark-gap (52) or the like. This frame (32) includes a pair of laterally spaced apart frame members (42, 44) on the side of the frame (36) that faces the target (F2). The suppressor member (18?) is connected to these frame members (32, 44). It may have longitudinal grooves (48, 50) in its side edges into which the frame members (42, 44) snap-fit.

Abstract: A transducer for use in an acoustic energy cleaner is provided. The transducer includes a resonator and a plurality of crystals bonded to a surface of the resonator. The plurality of crystals is configured to be bonded to the surface of the resonator in a staggered arrangement with respect to each other. In one embodiment, the plurality of crystals is bonded to the surface of the resonator in a horizontally staggered arrangement. In another embodiment, the plurality of crystals is bonded to the surface of the resonator in a vertically staggered arrangement.

Abstract: An array of pressure sensors and motions sensors is contained in a layered material system that includes an acoustically compliant layer and an acoustically transparent layer. The compliant layer (which vibrates in accordance with acoustical influence thereupon) is the foundation for both sensor types and is the vibratory medium for motion sensing. The transparent layer is the matrix for both sensor types and is the window permitting sound waves to reach the pressure sensors (which sense pressure of the sound waves) and the compliant layer (the vibration of which is sensed by the motion sensors). The compliant layer's exposed surface can be attached to a structure's exterior for passive sonar detection purposes. Since the pressure sensors are effective primarily for low frequency sound waves, and the motion sensors are effective primarily for high frequency sound waves, the invention is aggregately effective for a broad band spanning low and high frequencies.

Abstract: The present invention relates to a semiconductor electret condenser microphone capable of being reduced in size and including an acoustic sensor 100 and a case 200 for accommodating the acoustic sensor 100, the acoustic sensor 100 has a semiconductor chip 110 forming necessary electronic circuits 111A to 111C, and opening a through hole 112 away from the electronic circuits 111A to 111C, an electrode layer 120 formed on the surface of the semiconductor chip 110 away from the through hole 112, an electret member 130 laminated away from part of the electrode layer 120 and through hole 112, and a diaphragm 140 provided with a spacing 160 to the electret member 130, in which the electrode layer 120 exposed from the electret member 130 is connected to the electrode 111a of the electronic circuit 111A through the case 200 (FIG. 6).

Abstract: The invention relates to surface acoustic antennas for submarines. It consists, in a known antenna, in replacing certain pressure sensors with velocity sensors in order to obtain cardioid directivity with a zero oriented toward the hull of the submarine. It allows the use of baffles serving to attenuate the noise generated inside the submarine.

Abstract: This invention serves as a method and apparatus for delivering power to a series of remote sensors in an on hull sensor grid for the purpose of biasing the active circuitry on the sensors. It requires no physical connection between the source of power and the sensor. It works by delivering electrical energy across the insulating gap that separates the sensor from the hull by means of a displacement current. In particular, the method and device include a conducting layer interposed between inner and outer decouplers and a ground plane interposed between a bonding layer and the inner decoupler. An application of alternating current to the ground plane will activate the conducting layer and provide power to the sensors at a location of the outer decoupler. The inner decoupler acts as a capacitor and the ground plane further provides an electrical path back to the hull.

Abstract: The emergency underwater notification device disclosed, one of which would be carried by each diver on a team of divers at a dive site, comprises (a) an activator; (b) one or more primary signal emitters, each of which emits a primary notification signal upon activation of the activator, the primary signal emitter comprising one or more of the following: a light source, a hydrophone, a siren, a speaker, or an acoustic transducer; (c) one or more secondary signal emitters, each of the secondary signal emitters emitting a secondary communication signal upon activation of the activator; (d) a receiver capable of receiving communication signals; (e) one or more tertiary signal emitters, each of the tertiary signal emitters to emit a tertiary communication signal upon receipt by the receiver of either a secondary communication signal or a tertiary communication signal from another notification device; and (f) one or more quaternary signal emitters, each of the quaternary signal emitters to emit a quaternary notifi

Abstract: The present invention relates to a semiconductor electret condenser microphone capable of being reduced in size and including an acoustic sensor 100 and a case 200 for accommodating the acoustic sensor 100, the acoustic sensor 100 has a semiconductor chip 110 forming necessary electronic circuits 111A to 111C, and opening a through hole 112 away from the electronic circuits 111A to 111C, an electrode layer 120 formed on the surface of the semiconductor chip 110 away from the through hole 112, an electret member 130 laminated away from part of the electrode layer 120 and through hole 112, and a diaphragm 140 provided with a spacing 160 to the electret member 130, in which the electrode layer 120 exposed from the electret member 130 is connected to the electrode 111a of the electronic circuit 111A through the case 200 (FIG. 6).

Abstract: A marine acoustic source system has relativley densely packed energy sources arrayed in a tandem-like fashion along a horizontal plane. Preferably, a longitudinal axis of each source lies orthogonal to a pre-determined towing direction. The system includes protective tubes that encloses supply lines and auxiliary equipment, and a harness. The harness provides the primary mechanical connection for towing the sources through the water. To minimize bending of the supply lines, connectors having angular portions connect the sources to the supply lines. Further, the sources can be arranged such that source connection interfaces for receiving power, hydraulic fluid, or data point alternately in opposing directions. During use, the sources, e.g., air guns, are supported at a predetermined depth beneath the water's surface by a floatation buoy. Upon activation, the sources of a cluster each release individual air bubbles into the water.

Abstract: A staggered vertical marine seismic source contains upper and lower arrays (10, 11) of emitters of seismic energy (S11, S12; S21, S22). The upper array (10) is horizontally displaced relative to the lower array (11). The source is used in a marine seismic surveying arrangement that has means for moving the source and at least one seismic receiver. In use, the source is moved through the water in a direction parallel to the direction in which the two arrays are displaced. The arrays (10, 11) are fired sequentially, and the time delay between the firing of the first-fired array and firing of the second-fired array is chosen such that each seismic emitter in one array is fired at the same x- and y-co-ordinates as the corresponding emitter in the other array. The seismic wavefields generated by firing the two arrays are thus generated at the same x- and y-co-ordinates, but at different depths.

Abstract: A surface acoustic wave device includes a piezoelectric substrate and at least one interdigital electrode disposed on the piezoelectric substrate. The interdigital electrode is made of ?-tantalum.

Abstract: An optical fiber splice protection apparatus that allows optical fiber to be spliced and placed in position on a mandrel in cases of assembling a module or repairing optical fiber that has been broken. The present invention comprises a splice protector affixed to a mandrel and a rotation sleeve for winding excess fiber onto the mandrel. The rotation sleeve is located between the splice protector and an adjacent mandrel. The rotation sleeve facilitates winding excess fiber onto the mandrel, and has a longitudinal axis aligned with the longitudinal axis of the hydrophone assembly with a groove to receive the fiber and maintain the fiber's minimum bend radius. The splice protector and the rotation sleeve are substantially semi-circular in cross-section. A method is also provided for protecting spliced optical fibers using a splice protector and rotation sleeve.

Abstract: A calendar timer mechanism has an OFF mode for turning off all objects to be controlled, which include a heater, a display panel, and motors, an ON mode for turning on all the objects to be controlled, and at least two energy-saving modes for selectively turning off the objects to be controlled or turning on the objects to be controlled at a lower power consumption rate. Transitional times between at least three of the OFF mode, the ON mode, and the energy-saving modes can be set as desired.

Abstract: An electro-mechanical transducer is disclosed, which provides a wideband response by activating successive multiple resonant frequencies in a way which provides additive output between the resonant frequencies. A three mode wideband high output transducer is also disclosed along with an electro-mechanical feedback system which provides a smoothed response as well as array control under multiple element usage.

Abstract: An underwater sound source which comprises a housing having an inner and an outer surface and a monopole driver suspended within the center of the housing. The housing is adapted to receive fluid therein to form a fluid column inside the housing. The underwater sound source resonates at a frequency of 260 Hz when the monopole driver excites the fluid column.

Abstract: A encapsulation method of an acoustic sensor module and a resultant lightweight watertight acoustic sensor module for use in towed array retrieval systems. In the method, a composite is cast to encapsulate the support between end plates of the module, an exterior of a passage tube in which the array is retrieved, transducers positioned on the tube exterior and supporting telemetry lines for the transducers. The components, listed previously, are cast into a block of the cured composite such that the arrangement of the components is fixed. Residual composite emitting from an aperture of an end plate allows a conductor for the telemetry lines to be potted into the composite with an end of the conductor free from the composite thereby allowing connection to an external controller or generator.

Abstract: An underwater acoustic receiver sensor is disclosed that measure up to seven (7) quantities of acoustic field at a collocated point. The quantities measured by the acoustic receiver sensor are acoustic pressure, three orthogonal components of acoustic particle acceleration and three spatial gradients of the acceleration vector. These quantities are appropriately combined and provides for improved directivity of the acoustic receiver sensor.

Abstract: A trolling motor having an integral sonar transducer including: a submerged motor housing; an electric motor housed in the housing; a sonar transducer housed in the housing; a motor controller having a pulse width modulated output and a shielded electrical cable connecting the sonar transducer to a sonar device. Noise from all sources (i.e., electrical noise from ground loops, radio frequency interference, and magnetic interference) is suppressed in the output signal of the transducer through a number of techniques. The electrical cable includes an outer shield connected to the chassis ground of the trolling motor; an inner shield connected to the circuit ground of the sonar device; and a pair of signal carrying conductors comprising a twisted pair. In addition, the resonant frequency of the transducer is selected such that it is not a harmonic of the operating frequency of the pulse width modulated output of the motor controller.

Abstract: A flextensional transducer projector shell design is disclosed. The shell design has a shape formed so as to reduce the stress placed on the transduction driver as compared to other shell designs. The shell design includes first and second bulbous end portions, which can each be adapted to receive a respective end of a transduction driver. A middle portion of the shell design has both concave sections and convex sections, thereby defining a wave profile.

Abstract: A method of detecting a marine gas seep that includes: deploying a local probe on or near the seafloor; producing bubbles in water near or within the local probe; detecting the bubbles; producing data indicating the relative concentration of dissolved gas in the water; and associating elevated dissolved gas concentrations with the presence of a nearby marine gas seep. Another aspect of the invention involves an apparatus configured to carry out the inventive method. Preferred embodiments of the invention utilize an ultrasonic transducer to both produce bubbles and detect them.

Abstract: A sound mitigation system and method reduce the transmission of acoustic output from explosions underwater. The system is submerged to bottom terrain of a body of water and has at a series of gas-generating devices providing volumes of gas that are fed to refractory heat resistant tubing assemblies and flexible general tubing assemblies. The heat resistant and general tubing assemblies extend between adjacent gas generating devices and are provided with at least one row of holes to vent bubbles of gas and form a virtually continuous curtain of bubbles rising to the surface of the water between detonating explosives and areas of interest. The curtain of bubbles mitigates the effects of the explosions on marine mammals and endangered, threatened, or protected species within an area adjacent to the explosions.

Abstract: An alarm arrangement for swimming pools includes an electronic transmitter unit (16) and an electronic receiver unit (18). The transmitter unit (16) has a housing (20) containing electronic circuitry. Water activated electrical contacts (24, 26) are provided outside the housing (20) for causing energization of the electronic circuitry when coming into contact with water for emitting an ultrasonic operative signal when a person wearing the transmitter unit (16) enters into water in a pool. The receiver unit (18) has a housing (36) containing electronic circuitry, water activated electrical contact (54, 56) outside its housing (36) for causing energization of the electronic circuitry when coming into contact with water, for detecting any preselected operative signal from the transmitter unit (16) when the transmitter unit (16) comes into contact with water in a pool so as to emit a suitable alarm signal.

Abstract: This invention is a steerable thermoacoustic array system for directing information between an object that is above the surface of the water and a sound detector that is beneath the surface of the water. The foregoing system comprises a laser or particle accelerator that is located above the water's surface. The laser or particle beam produces a light beam or particle beam which contains information that is moved along a small layer of water at the air/water interface at a speed equal to the speed of sound in water divided by the steering angle of the laser so that the light beam or particle beam is absorbed by the water causing the water to expand and produce a series of acousitic Braves that constructively interfere with each other and travel towards the sound detector.

Abstract: An acoustic vector sensor for monitoring acoustic energy underwater includes an acoustic sensing tri-axial accelerometer, a body of syntactic foam encasing the accelerometer, a body of viscoelastic rubber encasing the body of syntactic foam, and a rigid plastics coating encasing the body of viscoelastic rubber.

Abstract: A submarine bow dome acoustic sensor assembly comprises an outer hull bow portion, an inner pressure hull wall extending athwartships and in conjunction with the outer hull bow portion defining a free-flood compartment, and an acoustic bow panel disposed in the compartment and connected to the pressure hull wall by acoustically isolating supports. A laser scanner is disposed in the compartment and is oriented so as to project a laser beam onto a surface of the acoustic bow panel, and a sensor is disposed in the compartment and oriented so as to receive reflections of the laser beam off the acoustic panel and to transmit data from which a position of a sound generating source can be determined.

Abstract: A pressure-sensitive switch comprises a base member having a mounting surface formed of electrically-insulating material; two electrodes mounted on the base member and each having an electrically-conductive contact surface, and a flexible diaphragm having its periphery secured in a fluid-tight manner to the mounting surface with its electrically-conductive central portion overlying the contact surfaces of the electrodes. The diaphragm, which is formed with plural corrugations, is exposed to the external pressure. When the switch is exposed to atmospheric pressure, the central portion of the diaphragm does not touch the contact surfaces of said electrodes, but when the switch is exposed to a super-atmospheric pressure, this central portion is forced into contact with both contact surfaces, thus electrically connecting the two electrodes. This pressure-sensitive switch is especially useful for use with hydrophones, as in seismic streamer cables.

Abstract: The present invention relates to a flextensional transducer device comprising a multi-resonant shell and push-pull driving system for driving the shell so as to provide at least two tunable resonant modes, thereby increasing the operational bandwidth of the device. The push-pull driving system is formed by four rings of active drive material grouped to operate as two opposing push-pull pairs. The shell has a dog-bone configuration with two arcuately shaped interior web portions joined to the pairs of rings, end sections joined to the interior web portions, and a central concave section which functions as the primary radiating surface. Upon application of a desired current to the push-pull ring pairs, the interior web portions are caused to vibrate, which vibrations are transmitted to the end sections and the central concave section.