Abstract: A device capable of adhering to a wall surface by suction by the pressure of an ambient fluid and treating the wall surface, which comprises a pressure receiver member and a partition defining a pressure reduction zone in cooperation with the pressure receiver member and the wall surface.In one aspect, the partition has a sealing function of preventing inflow of a large amount of an outside fluid into the pressure reduction zone, and a treating function of treating the wall surface by being moved in a required manner.In another aspect, the partition has the above sealing function, and a travelling function of moving the device, by being rotated about an axis of rotation slightly inclined to an axis which is substantially perpendicular to the wall surface.

Abstract: A mechanical device for cleaning the bottom of a boat moored in a body of water includes a line with a central scrubber section, ends affixed above the boat's water line and means for urging the scrubber section upward. Passing the boat over the line forces the scrubber section against the bottom, cleaning it.

Abstract: A trolley to convey brushes for cleaning a stationary hull is drawn along the bottom and sides of the hull. Brushes are supported by variable buoyancy chambers to make the biasing of the brushes against the hull also in turn variable. The trolley can be supported and stored in a dock or alternatively supported by a floating platform. There is an electrical motor drive for a chain which pulls the trolley. A diesel prime mover may be used in the floating platform to generate power for the electric motor chain drive and for the submersible motors.

Abstract: A scrubbing machine is disclosed which is particularly useful for cleaning the hull of a ship below the waterline. The scrubbing machine includes rotary brushes driven by a single pump motor that also functions to create suction in a closed brush control circuit. The scrubbing machine also includes adjustable spacers that help provide efficient cleaning action.

Abstract: A submersible ROV removes extraneous material from the surface of submerged metal with a cleaning tool and measures the thickness of the metal with an ultrasonic probe. A camera allows visual operation of the ROV. The cleaning tool and ultrasonic probe can reach areas of limited access making the ROV useful for inspecting the interior of holding tanks. A submersible, electrical power supply can be combined with the ROV to provide an intrinsically safe system which is particularly useful in environments where sparks pose a substantial hazard.

Abstract: A device capable of adhering to a wall surface by suction by the pressure of an ambient fluid and treating the wall surface, which comprises a pressure receiver member and a partition defining a pressure reduction zone in cooperation with the pressure receiver member and the wall surface. In one aspect, the partition has a sealing function of preventing inflow of a large amount of an outside fluid into the pressure reduction zone, and a treating function of treating the wall surface by being moved in a required manner. In another aspect, the partition has the above sealing function, and a travelling function of moving the device, by being rotated about an axis of rotation slightly inclined to an axis which is substantially perpendicular to the wall surface.

Abstract: An underwater pylon cleaning apparatus is disclosed in which a rigid suction conduit mounted on an oceangoing vessel includes an eductor therein for providing a suction or lower pressure at the conduit inlet when water under pressure is supplied by a pump to the inlet of the eductor. A flexible hose connects an intake nozzle having an opening adapted to conform to the lateral surface of a cylindrical pylon to the inlet of the suction conduit. A discharge hose is connected to the outlet of the suction conduit by a flexible hose so that a diver may position the intake nozzle against the marine growth attached to the pylon whereby the growth will be removed from the pylon, transported through the hose and suction conduit and expelled through the outlet hose.

Abstract: A self propelled vehicle for traversing a surface of magnetic material having two or more endless tracks incorporating a plurality of permanent magnets spaced along each track to create a magnetic field of a strength to attach the vehicle to the surface being traversed. Each permanent magnet comprising a bar of magnetised ceramic magnetic material extending in a direction transverse of the track clamped between a pair of magnetic metal plates. The metal plates each extending beyond one face of the ceramic bar at opposite edges of that face to provide respective magnetic poles of opposite polarity so in use only these poles contact the surface being traversed and the ceramic bar is spaced from the surface being traversed.

Abstract: Floating small boat cleaning facility formed from a floating dock assembly having a pair of laterally spaced longitudinally extending side walls, a front entrance end wall, a rear exit end wall, a bottom wall, and a top wall spaced downwardly from the top edge of the side walls, to form a buoyancy chamber. The outside surface of the side walls have brackets to receive anchor pilings that have their bottom ends secured to the sea bottom. The front end wall and the rear end wall have a cutout portion formed adjacent their top edge and a plurality of vertically oriented strips of flexible material have their bottom ends attached to this top edge to form an entrance curtain and an exit curtain through which boats may pass. The curtains have structure for maintaining them in a floating substantially vertical orientation.

Abstract: An apparatus for removing surface material such as contaminated textures including asbestos and the like from walls and ceiling structures, and for preventing the removed material from escaping into the ambient environment. The apparatus provides a portable shroud enclosing a material removal member which could be a shredding head or an emitter of sonic, ultrasonic or ultraphonic signals. A liquid or coagulant spray mainfold will operate in close proximity to the material remover and is utilized to capture and retain air borne microscopic particles. The material remover and spray manifold are mounted on a power carrier which is adapted to reciprocally move these elements within the shroud and above a material receiving hopper. A vacuum recovery system acts in cooperation with the hopper to retrieve and retain for disposal the removed surface material.

Abstract: A device for scrubbing marine growth from the submerged portion of a boat hull. The device being particularly concerned with manual operation by one person from deck or dock side and comprising handle attached to a flexible buoyant base to which is fastened on one of its surfaces, a scrubbing material which when moved about on the submerged portions of a boat's hull scrubs therefrom unwanted marine growth.

Abstract: A water-driven scrubber device is used particularly in scrubbing wall and floor surfaces of a swimming pool or the like. The scrubber device comprises a compact housing adapted for connection to a supply of water under pressure and encasing a water-driven turbine wheel in combination with reduction gear elements for rotatively driving removable scrubber members, such as brushes. In one operational mode, a mounting yoke is carried by the housing for connection to a standard pool service utility pole to manipulate the scrubber device over pool surfaces, wherein the mounting yoke can be installed on the housing in either of two positions to permit or prevent pivoting motion relative to the housing, as desired. A retractable stabilizer wheel is also provided on the housing to facilitate accurate and smooth movement of the scrubber device over pool surfaces. In another operational mode, a portion of the housing defines a handle for easy grasping and direct manual movement of the scrubber device over pool surfaces.

Abstract: An erosive fluid jet tool for underwater operation, comprising an erosive fluid jet nozzle connected to a fluid receiver receiving fluid under elevated pressure for providing hydraulic power to the tool, the nozzle providing the working output jet of the tool; and a counterthruster for providing a counterthrusting force for balancing the thrust on the tool produced by the erosive fluid jet, the counterthruster including (a) a counterthrusting fluid jet nozzle connected to the fluid receiver and facing oppositely to the erosive nozzle for providing a counterthrusting jet, and (b) an open ended shroud coaxially surrounding the counterthrusting nozzle, whereby water surrounding the submerged tool is entrained through the shroud for providing additional counterthrusting force during operation of the counterthrusting nozzle, the erosive fluid jet nozzle and the counterthruster being constructed so that in excess of 50% of the hydraulic power provided to the tool is provided to the erosive fluid jet nozzle.

Abstract: A vehicle and its control system is disclosed for inspecting or servicing a remote limited access location. The vehicle has a drive frame comprised of first and second opposing legs, and third and fourth opposing legs pivotable connected to the first and second legs to form a parallelogram. A drive mechanism is interconnected between the first and second legs of the parallelogram drive frame for opening and closing the drive frame. First and second attachment devices, illustratively in the form of magnets, are also attached to the first and second legs. The vehicle control system taking the form of a programmable computer in an illustrative embodiment of this invention responds to the opening and closing of the drive frame for alternatively actuating and deactuating the first and second attachment devices, whereby the vehicle is controllably driven.

Abstract: Vessels and the like require cleaning either periodically or whenever a need arises to remove various living things such as seaweeds and shells or contaminants such as oil for the sake of appearance and proper performance. Divers were conventionally employed to manually remove them one by one using a scraper as one means to remove such substances. Such manual operation is, however, extremely inefficient, involving great amounts of time and labor especially for large ships. According to the present invention, the main body of a cleaning apparatus is pressed against an underwater object to be cleaned by means of impellers which are provided substantially at the center of the main body and driven to rotate, whereby cleaning brushes which are provided at the bottom of the cleaning apparatus concentrically with the impellers are rotated to remove substances adherent to the object while the cleaning apparatus is manipulated to run on the object's surface.

Abstract: Apparatus for protectively enclosing and/or treating the submerged portion of a body floating on a surface of water, such as a boat hull, to prevent or reduce the growth of marine organisms on the submerged portion. The apparatus is formed of a generally rectangular frame having a depending water impervious envelope attached thereto sufficiently large to enclose the submerged portion of the floating body. The frame is formed of hollow tubular front, side and rear members with the front member being filled with floatation material which maintains the front member floating at all times on the surface of the water. Pump means are associated with the frame, preferably mounted the rear tubular member, with the pump adapted to pump water into the side and rear tubular means to cause the rear member to be submerged and moved pivotally downwardly about the floating front member so that the floating body, such as a boat, can be moved across the submerged rear member into the area defined by the rectangular frame.

Abstract: An aquatic scrubbing device for attachment to an underwater ferro-magnetic surface incorporates a carriage, at least two independently energizable electromagnets supported by the carriage for rotation about mutually parallel axes, and at least one drive motor for rotating the electromagnets relative to the carriage, whereby alternative energization of the electromagnets and the drive motors will cause a walking motion of the carriage when attached to the ferro-magnetic surface, the device incorporating rotatable scrubbers for removing aquatic growths from that surface.

Abstract: A device capable of adhering to a wall surface by suction by the pressure of an ambient fluid and treating the wall surface, which comprises a pressure receiver member and a partition defining a pressure reduction zone in cooperation with the pressure receiver member and the wall surface.In one aspect, the partition has a sealing function of preventing inflow of a large amount of an outside fluid into the pressure reduction zone, and a treating function of treating the wall surface by being moved in a required manner.In another aspect, the partition has the above sealing function, and a travelling function of moving the device, by being rotated about an axis of rotation slightly inclined to an axis which is substantially perpendicular to the wall surface.

Abstract: Underwater scouring apparatus comprises a flexible sheet (1), a plurality of rotatably drivable scouring tools (4, 5) secured to the sheet. The sheet may flex or twist in use allowing one of the tools to pass independent of the other tool over an irregularity in the surface being scoured. This enables the tool to clean efficiently around welds and rivets.

Abstract: Self-contained apparatus able to move along a non-horizontal surface and comprising a first train and a second train (48) connected to the first train by devices allowing to obtain a relative displacement by translation and rotation in a plane parallel to the surface, and first and second holding devices (2) carried respectively by the first and the second trains and able to fix removably the apparatus on the surface, wherein the holding devices carried by at least one of the trains are connected to the train through devices capable of displacing said train with respect to the holding devices in a direction perpendicular to the surface. Preferably, the holding devices (2) of the first train are comprised of a plurality of adherence devices forming a polygon and arranged outside the center of the holding devices of the second train, and the apparatus further comprises a processing or inspection tool (60) mounted so as to pivot with respect to the first train.

Abstract: An autonomous and semi-submerged station for cleaning the hulls of pleasure craft, comprising a floating ballasted pontoon or a wharf and principally a mobile cabin, ballasted, in unbreakable transparent material, with an open roof, having on its forward wall (40) two openings provided with sealed rotary bearings (1) by which enter and exit, while sweeping, tubes (2) for water under pressure fed with fresh or salt water through an autonomous pump. The work is performed under visual surveillance. Secured to the cabin, a mechanism of pulley and externally grooved wheels, controlled from the interior of the cabin permits the longitudinal displacement on the tubes secured to the floating pontoon or to the wharf. The externally grooved wheels enclose the tubes that mate the cabin to the floating pontoon or to the wharf.

Abstract: An improved scraping tool is provided for removing barnacles from the propeller shafts of boats with inboard marine engines while the boat is in the water. The scraper is comprised of a curved metal blade with cutting edges on each end which engage substantially one-half of the periphery of the workpiece to remove the debris when moving the tool longitudinally in both directions to effect the desired scraping action. A handle is fastened longitudinally on the axis of the blade and centered on the body of the tool, to easily grasp and position the tool positively on the workpiece from a perpendicular position, and yet provide the leverage necessary to forcefully attack the barnacles.

Abstract: A device for scrubbing marine growth from the submerged portion of a boat hull; said device being particularly concerned with manual operation by one person from deck or dockside and comprising an operator's guidance handle attatched to a flexible arm to which is fastened on its underside, surface-seeking-flotation and to its upper surface, scrubbing material which when moved about on the submerged portions of a boat's hull scrubs therefrom unwanted marine growth.

Abstract: There is shown apparatus 1 for underwater painting of a substrate 9, comprising a tubular shield 2 having a closed end 3 and an open end 4, and a paint supply device 7 and a compressed air inlet 5. The air inlet 5 passes into a chamber formed between the end 3 and a perforated baffle plate 6 which serves to provide a uniform stream of air under pressure to the open end 4 for displacing water from the substrate 9, which can then be painted using a circular ring of paint issuing from a spray tip 11 of the device 7. The position of the shield can be adjusted using adjustable casters 14, or electronically (means not shown).

Abstract: An apparatus for cleaing underwater surfaces including at least one rotatable brush and pump for producing a stream of water from the front to the rear thereof. The brush and pump are axially reciprocable in a housing. The brush has bundles of bristles, each bundle having a head portion fitted into notches at the periphery of a main ring and held therein by a pinch ring, the main and pinch rings together constituting a brush base which is detachably secured to a rotatable base associated with the pump, by means of a pair of fixed members which are engagable upon relative rotation of the rotatable base and brush base.

Abstract: Apparatus for cleaning underwater surfaces and including at least one rotatable brush, and at least one pump the generating a stream of water passing from the front to the rear of the brush to hold the apparatus against an object to be cleaned. The apparatus can be readily manipulated and held in any desired attitude as a result of the brush being surrounded by an annular tube containing two immiscible materials of different specific gravity, such as a solid and a liquid, or two immiscible liquids.

Abstract: A marine antifouling material providing an antifouling surface for use in sea water comprises a layer of inert, water-insoluble, flexible and extensible elastomeric carrier material having embedded therein a single layer only of a plurality of copper or copper alloy particles of substantially uniform size and shape exposed at the outer surface of the material to provide a multiplicity of generally evenly sized discrete copper areas in the inert material continuum surface thereof. The particles are insulated from each other and from an opposed inner surface of the material.

Abstract: An underwater cleaning apparatus having a carrier, a plurality of wheels for shifting the position of the carrier along a submerged surface, a plurality of rotary brushes carried by the carrier and adapted to clean the submerged surface, and a source of power for rotating the rotary brushes. The apparatus further comprises flexible partition wall members for transmitting torque to the rotary brushes and forming reduced pressure chambers communicated with spaces formed by bristles of respective rotary brushes. As the rotary brushes rotate, the rotary brushes and the partition wall members in combination serve to provide vacuum to produce a force to press the carrier through the wheels onto the submerged surface to be cleaned. In addition, each of the rotary brushes are allowed to individually follow the configuration of the surface thanks to the flexibility of the partition wall members.

Abstract: An apparatus for abrasive cleaning comprising a truck adapted to run on the surface to be cleaned and at least one abrasive cleaner supported by a supporting mechanism on the truck and limitedly movable toward or away from the surface, the abrasive cleaner having an abrasive cleaning tool at its lower end, said or each abrasive cleaner being supported by the supporting mechanism so as to be limitedly tiltable in every direction with respect to an axis approximately perpendicular to the surface, the supporting mechanism being provided with a compression spring for biasing the abrasive cleaner away from the surface. Even when the surface to be cleaned has an undulation, the abrasive cleaner tilts with respect to the axis to hold the cleaning tool in uniform contact with the surface and assure a stable and uniform cleaning operation.

Abstract: A docking apparatus comprises a drive truck adapted to run along a side wall of a dock approximately horizontally, a surface treating truck connected to the drive truck at all times and having a hull surface treating device, and a docking truck connectable to and separable from the drive truck and having a retractable hull suction disk. The drive truck only is provided with drive units for running.

Abstract: A device for treating the surfaces of structures and ships, even under water, with a spray medium which cleans, preserves, or coats, and is sprayed onto the surface which is to be treated by way of a pressurized gas flow via an at least partially flexible conduit which leads to the work location and is provided with an outlet nozzle. The outlet nozzle, which is constructed as a Laval nozzle, is provided with a funnel-shaped nozzle adapter which has a longitudinally extending, parabolic inner chamber. A controllable shunt, capable of bypassing the spray medium source may be provided for the pressurized gas between the pressurized gas source and the line leading to the outlet nozzle so that the device can be used under water.

Abstract: An abrasive cleaning apparatus comprising a truck adapted to run on the first surface to be cleaned, a first abrasive cleaner adapted to be pressed against the first surface and mounted on the truck by a first support assembly so as to be limitedly movable in the direction of a first axis substantially perpendicular to the first surface and and limitedly tiltable in every direction with respect to the first axis, and a second abrasive cleaner adapted to be pressed against the second surface to be cleaned and substantially perpendicular to the first surface and mounted on the truck by a second support assembly so as to be limitedly movable in the direction of a second axis substantially parallel to the first surface and to be limitedly tiltable in every direction with respect to the second axis.

Abstract: A self-balanced surface-processing apparatus includes a tool support movable along a strip of airplane body or other work surface, in spaced relation thereto a pivot arm mounted on the tool support and mounting a sander, or other surface-processing tool on one end and a balancing counterweight on the other end. A biasing means engages the pivot arm and biases the surface-processing tool against the work surface at a preselected pressure. The apparatus is operable to traverse various irregular surfaces while maintaining constant contact pressure of the surface-processing tool.

Abstract: The scour jet array system includes a pump, both fresh water and surface er intakes, an automatic water mixing valve, a chemical buffer injector, a water heater, a series of scour jets with control valves, and a central control system.The control system senses the beginning of ebb tide for starting an initial scour jet, and as each jet scours the freshly deposited mud from the area, temperature, salinity and pH of the surface suction intake water are measured to determine the amount of fresh water injection, chemical buffer injection, water heating and duty cycle time in order to minimize the energy required to scour the sediments from the area.

Abstract: A subsea platform inspection vehicle on a power tether cable adapted to be propelled through the water and lock onto an underwater member of a platform adjacent a welded joint and provided with a jet to clean a weld and a television camera to observe the condition of the weld.

Abstract: The present invention relates to a heavy-duty metal brush particularly, but not exclusively, for removing anti-corrosion materials from an immersed metal surface.The brush comprises a compact assembly of radial strands of, for example, steel wire, which are applied against each other and are clamped between two metal plates, the diameter of which is less than that of the assembly of strands by at most 20 mm.In use of such a brush for removing an anticorrosion covering, the brush may be rotated at a circumferential speed of the order of 17 meters per second and may be mounted on a carriage adapted to roll over the surface on rollers and which is displaced either automatically or manually.

Abstract: A cleaning device for removing foulant from the hull of a sea going vessel comprising a carriage, a plurality of cleaning nozzles secured to the carriage, a reactor nozzle aligned to produce a reactive force which opposed the force component of the cleaning nozzles which tends to urge the carriage away from the hull of a ship, and control members for displacing the carriage across the hull surface of the vessel. The control member can be flexible, in which case the reactor nozzle is also aligned to tension the control members. In any case, the control members provide remote control of the carriage throughout a regular pattern of predetermined paths.

Abstract: A dock device having a bottom for supporting a ship or the like and longitudinal walls standing up from the bottom, a carriage adapted to be moved along a longitudinal wall, an arm pivotably and deflectably connected with the carriage, swinging and deflecting mechanism for moving the arm with respect to the carriage, a head carrying a processing member and being rotatably and tiltably connected with the free end of said arm and tilting and rotating mechanism for moving said head with respect to the arm. Horizontal and vertical guide wheels on the head are alternately actuated by setting mechanism connected with the head.

Abstract: A device for removing encrusted marine growth from submerged structures and for Non-Destructive testing of welds and the like is disclosed. The device includes a flexible transparent sleeve or housing for encapsulating an area of the structure to be cleaned and a reservoir for admitting a corrosive chemical into the housing to dissolve the marine growth. The housing may also contain embedded conductors forming a magnetic yoke which, when coupled to a source of electric energy, will subject to area to desired AC and DC fields. Magnetic particle can then be admitted through the reservoir for magnetic particle testing.

Abstract: Apparatus for cleaning marine fouling material from a submerged surface, including a submersible unit movable along a submerged surface to be cleaned, and ultrasonic means carried by the unit and energizable to create a zone of cavitation at the surface, so that movement of the unit moves the zone along the surface to clean fouling material therefrom.

Abstract: An electrical paint stripping device for removing/detoxifying organotin afouling coatings includes a housing, a heating chamber containing a plurality of electrical heating elements, and a plenum chamber for cooling air which is separated from the heating chamber by a perforated ceramic separator element. A circumferential exhaust chamber encloses the heating chamber for collecting exhaust gasses from the heating chamber. The collected exhaust gasses are then fed to a treatment device for removing toxic substances therefrom prior to passing the gasses to the environment.

Abstract: A device for applying a coating to a submerged surface. This device comprises an applicator having a support plate and a tight deformable envelope provided on is outer face with bristles, springs being fixed to the inner face of the plate and exert a pressure on the inner face of the envelope. The applicator is connected to the rigid support by means of a group of articulated rods, thereof at least one is connected to the support by elastic means in order that the applicator is applied with an adequate pressure to the surface. Application to the painting of the hulls of ships.

Abstract: An apparatus for treating ships' hulls in a dry dock has a carriage movable horizontally on a longitudinal wall of the dry dock and having upper and lower portions, a control cabin located on the upper portion of the carriage, working platform or device connected with the carriage and pivotable about at least one vertical and horizontal axis, working aggregates for operating the apparatus, a container located in the region of the lower portion of the carriage under water in filled condition of the dry dock and being water-tight and accommodating the working aggregates, and a plurality of conduits including at least one fresh air supply conduit extending to the container and at least one exhaust gas and spent air discharge conduit extending from the container, wherein the conduits extend up to the upper portion of the carriage.

Abstract: A cleaning implement for cleaning the bottom of a boat while the boat remains in the water comprising an elongate handle provided at one end with a buoyant cleaning head presenting a cleaning structure for contacting the bottom of the boat, when the cleaning head is submerged beneath the boat, so that the boat bottom can be cleaned by movement of the cleaning head over the boat bottom as a result of manipulation of the handle. The cleaning head may comprise a hollow stock into which water may be introduced to adjust the buoyancy of the cleaning head. The hollow stock may be provided with detachable cleaning devices which may be stored in the hollow stock when the implement is not in use.

Abstract: A portable boat hull scrubber for detachably mounting onto a boat and adapted to scrub the adhering debris from the underwater portion of the hull, said scrubber functioning with the boat stationary in the water.

Abstract: A device for scrubbing algae and other marine growth from boat hulls comprising a one-piece belt of fibrous fluorocarbon abrasive material and a plurality of floats mounted along the belt undersurface. A number of the floats are of oval cross section and are mounted to pivot at right angles to the belt longitudinal dimension. As the belt is drawn in the direction of its length back and forth beneath a hull, the floats urge the belt into frictional scrubbing contact with the hull surface. The pivotal floats operate synergistically to combine buoyant forces and water drag forces to provide enhanced scrubbing contact with surface irregularities such as stabilization chimes.

Abstract: A submersible or semi-submersible structure, such as a boat, oil rig or pipeline, has an anti-fouling covering secured thereto. The covering comprises a mesh of copper or copper alloy embedded in a carrier, preferably of plastics material. The mesh has knuckles which on one surface are close to or protrude from the carrier so as to be accessible to sea water. The knuckles are spaced from the other surface so as to prevent contact between the structure and the mesh. A sea water permeable coating may be provided on the outer surface.

Abstract: A device and method for measuring the antifouling coating leach rates on ps' hulls uses a spherical segment shaped shell that circulates water over a coated area. A pump connected in closed circuit with the shell assures proper flow rate. A second pump creates a partial vacuum and holds the shell on the coated surface. A combination of nozzles and outlet fittings assures that the coating is exposed to a circulating flow of water. A portion of the circulated water is passed through a cupric ion electrode sensor which provides signals representative of the dissolved copper in water over time and, hence, the leach rate of the coating.

Abstract: An assembly for cleaning ships' hulls of such marine growth as seaweed, shell etc. is disclosed. The assembly has a frame with rotating brushes, the frame being reciprocally pivotal over the hull in an arcuate direction by being connected to one end of an arm or the like. The other end of the arm is pivotally connected to a joint which forms a stationary point for the assembly.

Abstract: The invention is a marine growth wiper and method of wiping for a waterborne object. The wiper includes at least one cord and a device for positioning the cord so that the cord is located below the waterline and within wiping distance of a submerged surface area of the waterborne object. With this arrangement, any water movement will cause the cord portion to wipe across the submerged surface area to remove primary marine growth therefrom. The wiping action is enhanced by utilizing a plurality of the cords either spaced from one another with respect to the surface of the object or attached to the object at a common location. The cords may be either positively or negatively buoyant depending upon the manner of their positioning. The method includes providing a plurality of such cords, positioning the cords so that the cords will wipe across the object, and suspending the cords free in the water so that water movement will activate the cords to wipe across the object.