Abstract: An explosive device neutralization system includes a penetrating tip, a reaction stake, and a deployment mechanism. The reaction stake includes a reaction initiation material (R.I.M.) which is configured to burn, thereby dispersing burning R.I.M. beyond the reaction stake. The deployment mechanism and penetrating tip are configured to deliver a portion of the reaction stake adjacent to a bulk charge of the explosive device, such that the burning R.I.M. is dispersed to the bulk charge. The reaction stake includes a stake housing that encloses the R.I.M. proximate an egress hole in the stake housing. The reaction stake also includes an ignition system proximate the deployment mechanism. Upon activation of the deployment mechanism, the ignition system initiates burning of the R.I.M. The deployment mechanism can include a deployment charge that is connected to a detonator.

Abstract: An open loop magnetic field minesweeping system, with a small and light weight body to be towed through seawater by a helicopter or other vehicle, hydrodynamic control surfaces on the body, a single sweep cable extending a substantial distance from the body with a first electrode in cable, sleeve or sock form attached to the end of the sweep cable, and a second electrode provided on the body as part of its skin. A rectifier and transformer on the body convert AC power fed to the towed body from the towing vehicle, to DC power applied to the first electrode. The rectifier and transformer are encapsulated by a thin waterproof layer and directly exposed to the sea water for cooling through the layer. The body may have a winch to deploy and retrieve the first electrode. Acoustic transducers may be mounted on or within the body.

Abstract: A vehicle is towed underwater by an air traveling helicopter through a towing cable to induce powered rotation of impellers on the vehicle during its underwater travel at a preselected seawater depth. An electrical generator driven by such impeller supplies electrical energy conditioned to produce a sternwise extending signature simulating magnetic field which is effective to detonate a sea mine in the underwater vicinity toward which the underwater vehicle is being towed.

Abstract: A mine localizing and identifying system. Each mine is equipped with a signalling device adapted to transmit a specific signal in response to receiving a specific activating signal. The system includes a mine-clearing tool that is adapted to transmit the specific activating signal and to receive the specific signal from the signalling device, and includes a direction-finding device for localizing the mine with the aid of the signal transmitted from the mine.

Abstract: A system for aiding the clearing of mines includes an equipment assembly composed of a portable processing unit (10) having multimedia capabilities, a helmet (12) with projection by overprinting, at least one position sensor (13) integral with the helmet and a camera for taking shots (14), capable of recording the actions of the operator. The system further includes a software assembly composed of software for the management of a data base of the various existing mines, software for the creation of synthesis and animation images, software for retouching an image which allows the images to be improved, and vocal command software.

Abstract: A mine neutralisation vehicle comprises a first portion to which propulsion units are attached by which propulsion units the vehicle is positioned. Pivotally connected to the first section is a second section containing a shaped charge warhead. By means of the pivot connection the shaped charge can be directed at a mine, for example a buried mine, while the main body of the vehicle is maintained in a horizontal direction.

Abstract: A device for clearing obstructions from surf zones comprising an elongated enerally cylindrical housing having a first end and a second end, the housing encasing a fuse positioned inside of the first end and a compartment containing a gas generating compound positioned inside of the second end, the fuse detonationally attached to the compound and being capable of causing the compound to initiate burn, the compound having a burn time which is capable of producing sufficient amounts of gas capable of rupturing the housing with the burning of the compound. A method for clearing obstruction which provides the device, interring the device within the subsoil proximate to the obstructions, and, detonating the compound wherein a burning of the compound forms sufficient amounts of gas to rupture the housing and sunder subsoil support of the obstructions effective to clear the obstructions also is disclosed.

Abstract: A demining coil to be fastened to a demining vehicle, which coil comprises a magnetic core and wherein the ratio of length to the largest transversal dimension of the core of the coil is greater than or equal to 4. The core of the coil may be fluted in shape and/or magnetically laminated. A demining device utilizes a plurality of demining coils spaced in different directions to maximize the area of detection.

Abstract: An apparatus for and method of detonating unexploded mines is disclosed. A ground-engaging foot is caused to reciprocate by power means with sufficient force to activate an unexploded mine. Control means is used to control the manner of reciprocation of the foot by controlling the power applied to the foot. A shock absorption arrangement absorbs shock energy created upon detonation of an unexploding mine. Preferably the apparatus is vehicle mounted for example upon a remotely controlled tracked vehicle.

Abstract: A mine disposal device comprises an automatically guided tractor with a stabilizer provided in front of the tractor. The stabilizer has a plurality of soil pulverizing rotor disks, and a solid semi-cylindrical shield covering the upper half of the rotor disks. Front and rear movable skirts are rotatably attached the shield. A sled, touching the surface of the land, is attached to the shield and keeps constant the depth of soil pulverized by the rotor disks. The front and rear movable skirts are opened, forward and backward, by the blasts of the antipersonnel mines. The blast force works against the resilient forces of front and rear shock absorbers. Each of the front and rear movable skirts is bent such that a top portion faces outside of the shield.

Abstract: An unmanned armored minesweeping vehicle includes a vehicle body having a heavily armored vehicle part; a power plant accommodated in the vehicle part for propelling the vehicle; a vehicle steering control accommodated in the vehicle part; and a simulating arrangement for disguising the vehicle as a target for triggering the mines to be cleared.

Abstract: A method for ocean surface delivery of ordnance and clearing of explosive mines and obstacles from a navigable sea channel includes the step of providing quantities of ordnance adapted to survive impact and prolonged immersion in sea water and to arm in response to release from a mobile ocean surface vehicle and to pressure actuation upon submersion to a desired depth in sea water and then to detonate in response to receiving a preselected signal transmitted to the ordnance from a standoff location. The method also includes the step of delivering the quantities of ordnance from a mobile ocean surface vehicle toward multiple sites in a navigable sea channel containing obstacles and explosive mines therein so as to cause arming of the ordnance followed by impact thereof with the navigable sea channel and submersion and emplacement thereof at the multiple sites in the navigable sea channel.

Abstract: An armed-state detector for the testing of "live" antitank mines is discld. The invention allows a user to determine, from a safe distance, if a mine is in an "active" state. A pole mounted sensor array is placed over the mine to sample the weak repetitive magnetic field that emanates from "active" mines. A hand-held, battery powered, detector box provides an audible or visual indication of whether or not the mine is "active". In addition to indicating that the mine is "active", the armed-state detector allows the user to determine the angular orientation of the magnetometer common to all antitank mines. The detector also provides a means whereby limited diagnostics can be performed on an unexploded mine. With the armed-state detector the user can determine if the fuze of an unexploded mine has been "killed" outright, or has merely failed to respond to the test stimulus.

Abstract: A method for air delivery of ordnance and clearing of explosive mines and stacles from a navigable sea channel includes the step of providing quantities of ordnance adapted to survive impact with land and sea and prolonged immersion in sea water and to arm in response to air flow pressure and then detonate in response to receiving a preselected signal transmitted to the ordnance from a standoff location. The method also includes the step of delivering the quantities of ordnance through the air toward multiple sites in a navigable sea channel having obstacles and explosive mines therein so as to cause arming of the quantities of ordnance followed by impact thereof with the navigable sea channel and submersion and emplacement thereof at the multiple sites in the navigable sea channel.

Abstract: A mine sweeping system including deployable horizontal antennas to establ a detection and navigation grid extending underwater from a beach to a distance offshore. A computer-controlled transmitter unit having a waveform generator and amplifier, transmits signals to each antenna, at unique frequencies and phases for different spatial locations within the grid. An autonomous underwater vehicle having multi-integrated sensors detects anomalies in the electromagnetic field caused by both magnetic and non-magnetic objects therein during underwater travel utilizing the electromagnetic field as a navigational grid. The autonomous underwater vehicle also deposits mine-clearing explosives at each magnetic anomaly for detonation under command signal using the horizontal antennas which provide a means for establishing a navigation grid to permit landing craft and other vessels to navigate in the region cleared of mines.

Abstract: The static magnetic field signature of a sea-going vessel is reduced by sly of degaussing current to pairs of loop coils adjacent to the port and starboard sides of the vessel hull. The coils of each pair are positioned at equal angles to a vertical plane extending longitudinally along the keel of the hull. The degaussing currents in the respective coils of each pair are simultaneously varied with respect to amplitude and polarity in accordance with geometrical heading of the vessel and changes in its roll and pitch orientations.

Abstract: An apparatus for activating a magnetic influenced mine from a distance includes a circuit arrangement for conserving power use and simulating the magnetic signature of a vehicle. The circuit arrangement includes a magnetic field generating coil connected to an electric feed circuit. The electric feed circuit is comprised of a voltage source, a circuit breaking element, and at least one capacitor connected to the terminals of the magnetic field generating coil. The circuit breaking element operates to alternately connect and disconnect the set of capacitors from the voltage source. By oscillating the current to the magnetic generating coil, the magnetic signature of a vehicle is simulated, and a mine is fooled into activation.

Abstract: A muzzle launched grapnel hook projectile having a body with an internal cavity which is sized to fit over the muzzle end of a rifle or spigot. A bullet trap within the internal cavity permits launching of the projectile one time with a live bullet cartridge as the propulsion force. The projectile can then be launched multiple times with a blank propellant cartridge. The front of the projectile mounts several torsion springs which serve as tines to grab trip wires and detonate trip wire mines as the projectile is being dragged back to the launch point. The torsion spring design and mounting scheme permits the tine to bend and release from non-trip wire obstacles along the retrieval path. Attached to the base of the projectile at a flange is a bridle consisting of multiple leader lines. Pulling on the bridle causes the leader lines to come together to form a cone-like surface which allows the base of the projectile to slide easily over obstacles.

Abstract: An apparatus for destroying a target underwater object includes a targeting system and a gun system. The targeting system has a laser which produces a laser beam, a laser ranging sensor sensitive to reflections of the laser beam from an underwater object, and electronic circuitry that determines the position of a target underwater object using an output signal of the laser ranging sensor. The gun system includes a gimballed gun that fires a projectile and is pointed at the underwater target by the targeting system. The targeting system may be operated to track the projectile in the water as well as the target to be destroyed and to correct the aim of the gun according to the relative position of the target and the projectile.

Abstract: The invention relates to a method and a device for sweeping marine mines having a magnetic sensor by at least three electrodes (10, 11, 13) spaced apart and tractored by a vessel (12) and behind each other, the electrodes being provided with electric current from the vessel (12) for generating a magnetic field in the water surrounding the electrodes (10, 11, 13), each of the electrodes (10, 11, 13) separately being provided with electric current of individually adjustable strength. The invention is characterized by varying in time the current strength of the current fed to the electrodes between positive and negative limits with intermediate zero passages to separate the time for zero passage of the current to at least one of the electrodes (10, 11, 13) from the time for zero passage of the current to the rest of the electrodes (10, 11, 13).

Abstract: A service platform for transport within an area wherein an explosive device is present. A remotely controlled tractor provides the primary motive force for moving the service platform through the explosion-prone area. Because of the danger personnel might experience in entering such an area, the tractor is remotely controlled by a transmitter manned by a person at a remote location. In situations where the explosive device comprises one or more mines hidden in the earth, the mobile support of the tractor will distribute the weight of the tractor over a sufficiently large ground surface area such that mines embedded in the ground will not have their firing circuitry triggered by passage of the tractor above the mine. However, the service platform is equipped with rugged, massive, ground contacting elements which are sufficiently light so as to not trigger the firing mechanism of anti-tank mines, but sufficiently massive to cause the firing of anti-personnel mines.

Abstract: An underwater mine warfare countermeasure system is disclosed in which an air cushion vehicle carries an acoustic transmitter for sending out an acoustic wave pattern capable of exploding mines having acoustic responsive detonators. The vehicle includes a transmitter retraction apparatus for raising and lowering the transmitter between a storage position located just beneath the vehicle and an operative position spaced remotely from the vehicle, and also from raising the transmitter through an opening in the vehicle for placing it in an access position on the vehicle. The vehicle also includes an air seal or pressure boundary assembly which normally forms an air-tight cover for the aforementioned opening while still permitting the transmitter to be deployed to the operative position and retracted to the storage position while the vehicle is on cushion, but which opens to permit removal of the transmitter to the access position when the vehicle is off-cushion.

Abstract: A unique system of disposition-controlled, water-filled, fabric bags is sended from and towed beneath a ship to effect the modification of the inherent water pressure signature thereof and thus prevent detonation of a marine mine programmed to be exploded thereby.

Abstract: The invention relates to an underwater mine or decoy which should lie on the ocean bottom or which has buoyancy characteristics. The mine or decoy is made up of at least an expandable material and a foldable, preferably webbed shell which determines the external form of the mine. The disadvantages associated with the storage, transportation and stowage of heavy mines of fixed shape in submarines, small ships and aircraft are thereby avoided. It is possible to manufacture decoys or mines rapidly and economically, and they may have variable magnetic and/or sonar reflecting properties. The release of the decoys or mines from submerged submarines via forceful ejection is possible.

Abstract: A system and process for neutralizing unexploded ordinances and clearing explosive infested areas such that maneuvers can be both readily and confidently continued without significant delay is disclosed. The system clears such unexploded ordnances infested areas by initially spraying the explosive infested area with a cryogenic liquid to neutralize the unexploded ordinances and reduce an output voltage of a detonator of the unexploded ordinances thereby rendering the unexploded ordinances inert, gathering the now unexploded ordinances and submerging the inert unexploded ordinances in a tank containing the same or similar cryogenic liquid so that the unexploded ordinances are maintained in a neutralized and inert state to allow for disposal.

Abstract: A vehicle mountable seismo-magnetic mine detonation system having apparatus, associable with a vehicle, for providing a seismic signal which, when sensed by a seismomagnetic mine, causes at least arming thereof when the vehicle is at at least a predetermined distance from the mine; and apparatus, associable with the vehicle, for modifying the magnetic field sensed by apparatus forming part of the seismomagnetic mine so as to at least cause arming thereof when the vehicle is at at least a predetermined distance from the mine, the apparatus for providing and apparatus for modifying cooperating so as to cause detonation of the mine at at least a predetermined distance from the mine without causing unacceptable damage to the vehicle or to its occupants.

Abstract: The invention relates to a method and a system for sweeping marine mines having a magnetic sensor. According to the method spaced electrodes (10, 11, 13) are towed by a vessel (12) and the electrodes (10, 11, 13) are supplied with electric current from the vessel (12) so as to set up a magnetic field in the water surrounding the electrodes. At least three electrodes are utilized in the sweeping, and each electrode is supplied with electric current individually, the strength of which can be controlled. The system comprises a power source arranged on the vessel so as to generate current for the electrodes. The power source allows individually supply and control of the current to each of the electrodes.

Abstract: An apparatus for destroying a mooring mine, which can be deployed with known underwater drones as well as with area sweeping devices to grip a mine mooring connecting a mine body to a mine seat, is composed of a mine sweeping unit and a ballast unit. Both units, which are releasably connected to each other, include active charges with which, if actuated simultaneously from a remote location, it is possible to disintegrate a mine seat as well as sever a mine body from the mooring joining the two units and destroy the mine body. Preferably, the overall specific weight of the apparatus is equal to that of water, with the ballast unit having a heavier specific weight and the mine sweeping unit having a lighter specific weight, so that the ballast unit and mine sweeping unit automatically move respectfully down and up toward the mine body and mine seat after engaging the mooring and being released from each other.

Abstract: A device for detecting and/or sweeping electrically controlled mines, which evice will provide an indication of the presence of a control cable connected to the mine, and will serve as a countermeasure for such mines, by selectively detonating same after cutting of its control line after the sweeping vessel is beyond the mine's effective range. The circuitry of the device includes a high D.C. voltage source connected with a capacitor so as to charge the capacitor through a protective current limiting resistor, whereby the voltage is caused to discharge through the control cable so as to indicate the presence of the mine. An insulated blade type grapple knife system, to prevent inadvertent shorting of the detonating circuit, is used in conjunction with a sensitivity adjustable magnetometer and a switch to provide the desired safety range to permit the cutter to sever the mine's control cable without endangering the tow vessel or its personnel.

Abstract: This invention discloses a magnetic field generator employing a direct cunt electromagnetic coil which is swept through a predetermined area by a drive motor and transmission means. Circuit means are disclosed to periodically reverse the polarity of the generated magnetic field either in synchronism with the sweeping of the electromagnetic coil or at a time related frequency.

Abstract: Apparatus is disclosed for detecting partially submerged wires and determng the location of the above water portion thereof by injecting into the submerged portion a radio frequency electrical signal, and utilizing radio direction finders to obtain a fix on the resulting radiating above water portion. An insulation cutting probe is used, and a radio frequency injection signal generator is described that minimizes power loss to the water medium.

Abstract: An unmanned, self-propelled minesweeping apparatus, capable of sweeping at ubstantial depths, is described, comprising a torpedo-like submarine vehicle that deploys and tows a string of explosive mooring cable cutters terminating in a sea anchor. The sea anchor serves as a carrier for the cutters and the towline and, after ejection as a package from the vehicle, is actuated to an expanded condition and displaces the cutters and coils of towline therefrom.

Abstract: A marine mine control wire tagging system is disclosed as including a traitter and a receiver, a mobile underwater vehicle having a launcher mounted thereon, a radio frequency signal tag loaded in said launcher, a sensor and a fire control system for launching said tag upon the detection of said marine mine control wire by the aforesaid sensor. If so desired, said transmitter and receiver may be mounted on a boat which also tows said underwater vehicle to a position in proximity with said control wire.

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

Abstract: A sweep device for river mines of the command type is described. The device mploys two spaced, parallel blades which support the sweep device on the bottom of the river as it is towed therealong. The blades constitute laminated cutting elements which provide a signal of the presence of a command wire as it is severed on contact, as well as serve as electrodes for supplying an electric signal to sweep the mine. An electrical circuit is also described to process the signals from the blades, so as to distinguish between small metallic debris and metallic bodies bridging the two blades.

Abstract: A mine sweeping method and related apparatus for achieving at least tempoy passivation of underwater acoustic influence mines, by the generation of particular underwater sounds of progressively increasing intensity. The water is by repetitively injecting into the water individual metered slugs of heated water, which water is heated to its saturation pressure but below the critical point. The metered slugs of heated water may be of the same or of progressively increasing size, i.e. weight, and can be released from a heated pressure chamber into the water from either a stationary array or from an array towed from a moving ship, and at a depth such tht the expanding bubbles, produced by the change of state of the heated water, do not break the water surface. The rapid expansion of the metered slugs produce the desired sound output for temporarily rendering the acoustic influence mines passive by actuating their anticountermine circuits.

Abstract: Disclosed is a system for locating a wire that is partially submerged wit water and partially extends out thereof which includes a transmitter for broadcasting radio frequency electromagnetic signals, a phase gradiometer for receiving said radio frequency electromagnetic signals after they have been received by that portion of said wire that extends out of said water and re-radiated by that portion of said wire that is submerged therein and for timely producing a pair of output signals in response thereto, a pair of constant output amplifiers for processing said pair of gradiometer output signals to identical useful levels, a phase comparator for determining the phase relationship between said pair of processed output signals, and a readout for indicating said phase relationship. The aforesaid phase gradiometer may be housed in a probe-type of mobile underwater vehicle which is towed by a tractor vehicle in such manner as to cause said phase gradiometer to traverse an underwater course in search of said wire.

Abstract: An underwater transient sound generator for broadcasting optimum acoustical onic energy in sea water with an appropriate intensity and frequency spectrum to achieve passivation of acoustical mines. A high pressure bubble is released from a chamber while a resilient diaphragm is simultaneously vibrated, the diaphragm having at least one of its surfaces in contact with the sea water. The system provides an improved pneumatic-mechanical impact sound source that produces a controllable distribution of high power, broad band spectrum acoustical energy, to temporarily inactivate acoustical mines, while masking the noise of the ship as it passes the mine.

Abstract: A self-contained, freely floating, freely operating minesweeper is disclo which facilitates the neutralization of marine mines in rivers, streams, and other water courses. Said minesweeper includes a barrel with a permanent magnet array mounted on the bottom thereof. An internal combustion engine, having a drive shaft and an exhaust output, in mounted within said barrel in such manner that the drive shaft extends through the side wall thereof. A partially fender shrouded paddle wheel is mounted on the end of said drive shaft for rotation therewith, and an exhaust pipe is connected to the exhaust output of said internal combustion engine, with the effluent end thereof located outside said barrel and radially therefrom in such manner as to cause the exhaust gases emanating therefrom to effect rotation thereof. A float collar is partially mounted around the outer periphery of the aforesaid barrel, so as to facilitate the attitude stabilization thereof.

Abstract: A system for sweeping acoustic and magnetic mines or a combination of both s disclosed as comprising a pair of spatially disposed magnetic pipes that are held in their respective spatial dispositions by front and rear straps, and an acoustical energy generating pipe suspended between said front and rear straps by hinges in such manner that it is also disposed between said pair of spatially disposed magnetic pipes. A tractor vehicle moves all of the aforesaid pipes and their associated elements as a unit along a course intended to be cleared of acoustic and/or magnetic mines.

Abstract: Noise suppression is achieved in a closed Rankine cycle torpedo including a propulsor 36, a turbine 26 connected to the propulsor 36, the turbine 26 having an annular outlet 40. The regenerator 42 is disposed about the turbine outlet 40 and has a radially outwardly opening annular regenerator outlet 46. A hull condenser 10, 48, 52 has an axially opening inlet 54 and a conduit 56 connects the inlet 54 with the regenerator outlet 46 and has a wall 58 configured to cause fluid exiting in a radial direction from the regenerator outlet 46 to flow axially to the inlet 54. At least one curved vane 60, 62 is located within the conduit 56 for converting radial fluid flow to axial fluid flow and a sound suppressing elastomer 64, 74 is associated with each of the wall 58 and the vane 60, 62 for attenuating vibration imparted thereto by fluid impinging on the associated wall 58 or vane 60, 62.

Abstract: The present invention relates to a method and an apparatus for the reduction of the magnetic identity for such ship parts, primarily ship's guns, the aiming, fire control and possibly firing of which are controlled by a computer. The computer is used to control amplifiers which supply electromagnetic coils built in around the part with the current required for compensation of the magnetic identity of the gun in every specific position. The calculations performed by the computer are based on information on the latitude, course, speed and rolling and pitching position of the ship which it continually fetches from the log of the ship and a gyro reference system as well as on information on the angles of traverse and elevation of the gun which it continuously fetches from angle transducers disposed on the gun.

Abstract: A mine-removing apparatus to be drawn behind a mine-sweeping boat and comprising a pulling cable pulling a sound generator for igniting acoustic mines, and electrode-carrying floating cables or an electrically-conductive floating cable loop for igniting magnetic mines, wherein said pulling cable and said floating cables extend in the region close to the boat as a common strand permitting limited longitudinal displacement of said cables relative to each other, said pulling cable extends beyond the trailing end of said floating cables, and all cables can be wound on and off a single winch on the boat stern.

Abstract: The invention relates to magnetic assemblies and in particular, though not exclusively to magnets for use in mine-sweeping or ship degaussing systems.

Abstract: An apparatus for clearing land mines. The apparatus is provided with clearing elements which can freely move up and down independently of one another, and which are disposed in a movable carrier which is embodied as an attachment for a tracked or wheeled vehicle. Each clearing element is a small, rigid clearing plate having a supporting arm, which is suspended on a support associated with the movable frame, and is movable about a horizontal pivot axis which extends transverse to the direction of travel. The supporting arms of all of the clearing plates are the same length. All of the clearing plates, without contacting one another and at a slight distance from one another, are disposed in a compound arrangement which is parallel to the support and is arranged behind the latter in the direction of travel. The compound arrangement is either V-shaped, having its point facing in the direction of travel, or extends continuously at an angle to the direction of travel.

Abstract: A method of generating electrical and magnetic fields in salt water marine environments using an elongated dimensionally stable flexible electrode (30) having a current carrying inner portion (31) in an outer protective and electrically conductive sheath (33) formed of ruthenium dioxide or iridium oxide. A layer of titanium cladding (33) may be provided on the inner current carrying portion (31) for carrying the outer sheath (33). The anode electrode is utilized for generating electrical current, such as for use in developing magnetic fields in salt water marine environments, preferably as an element of a sweep cable device having a floatation means around which one or more electrodes are helically wound.

Abstract: An arrangement for sweeping mines having firing systems which are sensitive to magnetic fields is disclosed which utilizes a remote control mobile floating body with a built-in propulsion system. A magnetic field is generated within a group of permanent magnets located within the floating body in such a manner that these permanent magnets are either individually controlled or controlled as a group so that various types of magnetic field mines can be detected.

Abstract: A magnetic mine sweep has at least one block of permanent magnet material connected on each side in flux conducting relationship to respective distributor elements, typically of mild steel, which are secured to respective steel pipes which are closed to form cavities for providing buoyancy and for distributing the flux for mine sweeping purposes. Rigid plastic foam can be provided in the cavities for reserve buoyancy and stiffening purposes. A non-magnetic shroud extends around the block of permanent magnet material.

Abstract: 1. In a device for sweeping a pressure ground mine, the combination of an ongated tow cable adapted to be towed laterally at a substantially fixed distance above and parallel to the bottom of a seaway, a mop-like array of lines having their proximal ends secured to said tow cable and having the major portion of length, including their trailing ends, dragging on the adjacent to the bottom of the seaway, said lines being individually provided with bristly thrums.