US20250326471A1

US20250326471A1 - Autonomous In-Water Marine Antifouling Apparatus, System and Method

Info

Publication number: US20250326471A1
Application number: US19/179,486
Authority: US
Inventors: Philip E. Eggers; Andrew Eggers; Hira V. Thapliyal
Original assignee: Electroblation Technology Inc
Current assignee: Electroblation Technology Inc
Priority date: 2024-04-22
Filing date: 2025-04-15
Publication date: 2025-10-23

Abstract

The present disclosure is addressed to apparatus, systems and methods for use in seawater environments for the in-water, ablation and removal of marine organisms, including marine microorganisms, that attach to the hull of ship. The marine antifouling system of the present disclosure employs one or more biofouling ablation vehicles to repeatedly traverse the hull of a ship below the water line to ablate marine organisms and microorganisms on a recurring basis. Each biofouling ablation vehicle may incorporate a rechargeable battery or may be connected to an external source of electrical power though a reinforced tether that enables the ablation of marine biofouling to be performed in an automated and recurring manner following pre-programmed and/or machine learning enabled paths that, collectively, cover the exposed surfaces of the hull of a ship below the water line.

Description

BACKGROUND

Biofouling, defined as the accretion of organisms on submerged, man-made surfaces, has been the bane of ship operators for at least 2500 years. Initial attempts to control biofouling using metal sheathing or various mixtures of waxes, tars, and toxic chemicals were aimed at making wooden hulls both water-tight and protecting against marine boring organisms. With increased use of metal-hulled ships beginning in the 1800s, however, the rationale for protective treatments shifted from ensuring hull integrity to improving vessels' performance. The adverse effects of biofouling on ships' performance have long been recognized. Attachment of biofouling organisms, such as macroalgae, hydrozoans, bryozoans, barnacles, polychaete tubeworms, mollusks, and ascidians, increases the frictional resistance of a ship's hull, resulting in an increase in the power and in the fuel consumption required to move through the water as well as a reduction in the maximum speed through the water. The negative economic impact of this degradation in performance is widely recognized as enormous.
Biofouling is a complex process that involves colonization by microfouling organisms, such as viruses, bacteria, cyanobacteria, fungi, protozoa and microalgae, and larger macrofouling organisms, including macroinvertebrates and macroalgae. Macrofouling includes calcareous hard-fouling organisms such as acorn barnacles, mussels and tubeworms and soft-fouling organisms such as non-calcareous algae, sponges, anemones, tunicates and hydroids.
The colonization process is often broadly described as a succession of four main stages, as described in a published article by Vinagre, P. A., et. al., Marine Biofouling: a European Database for the Marine Renewable Energy. Sector. Journal of Marine Science and Engineering 2020; 8: 495-521. As described by Vinagre, the four main stages are:

- 1. Within minutes to hours of submersion, the substrata (i.e., coating on ship hull) adsorb a biochemical conditioning biofilm, consisting of organic material such as glycoproteins, proteoglycans and polysaccharides naturally dissolved in the seawater.
- 2. Within hours, primary colonizers, assemblages of unicellular organisms (e.g., bacteria, diatoms) form and secrete extracellular polymeric substances (EPS) that adhere to the substrata. Together, the microorganisms and EPS facilitate the settlement of macrofoulers (e.g. the cyprid stage of a barnacle).
- 3. Within days to weeks, secondary colonizers consisting of sessile macrofoulers (i.e., macrofoulers fixed in one place) including soft and hard-foulers, develop and overgrow the microfouling (e.g., the cyprid stage leading to the calcite enclosed barnacle). As they grow and age, macrofoulers provide “micro-habitats” that attract further settlements.
- 4. Within weeks to months, the substrata are fouled by tertiary colonizers which typically reside within the sessile biofouling. The biofouling communities reach maturity within a few years, accompanied by an increase in species diversity. The communities are characterized by a variety of sessile and mobile benthic and epibenthic organisms wherein many organisms form hard, calcerous shells or structures.

Marine biofouling is a worldwide problem that affects both commercial and military interests in the form of cost, schedule and maintenance impacts. It also affects the environment, as invasive species can be transported across the world from the location of initial attachment to a ship hull to a subsequent location where they reproduce and/or become detached, either spontaneously or during the process of in-water cleaning of the hull of biofouled ships. For many years, efforts to control biofouling species transport have focused on ballast water management. More recently, research has identified biofouling as a significant mechanism for transporting biofouling species, with ships and boats as vectors, and there is an increasing awareness that comprehensive efforts are needed in both areas (biofouling and ballast water management) to successfully address spread of biofouling species, particularly invasive species.
Biofouling is the attachment of organisms to a surface in contact with water over time, and begins with the growth of a biofilm (slime layer), which rapidly occurs on a marine surface. Biofilm formation occurs within hours after a new or cleaned ship hull enters seawater. Biofilm growth rapidly progress to a point where it provides a foundation for seaweed, barnacles, and other organisms, some of which may be invasive species. Biofouling management can take the form of preventive actions, such as using antifouling coatings for vessels hulls, or remedial actions, such as physically removing biofouling by cleaning the hull in the water or in a drydock facility. Antifouling coatings initially focused on incorporating toxic compounds in the paint. Over time, however, these compounds were found to concentrate in harbor sediment, causing environmental concerns, and different approaches to antifouling coatings on the hulls of ships have been adopted as once widely used biocide antifouling coatings have been banned internationally.
In 2009, the Coast Guard Office of Operational and Environmental Standards (CG-OES), formerly CG-523, funded an overview study on biofouling management, viz., U.S. Coast Guard Biofouling Assessment published in September 2010. The study noted that shipboard biofouling impacts vessels in two general ways; decreasing revenue and increasing expense. The total cost associated with biofouling in the United States alone was estimated to be as much as $120B per year. World-wide in 2013, there were over 29,000 merchant vessels in service including over 15,000 large (25,000 to 60,000 gross tons) and very large (>60,000 gross tons) merchant vessels. All of these merchant vessels must repeatedly manage the problem of biofouling throughout the life of each vessel. In this regard, see McClay, T. et. al. Vessel Biofouling Prevention and Management Report, Report No. CG-D-15-15. March 2015: Table 1.
The conventional methods of cleaning ship hulls having significant biofouling deposits require re-locating the ship out of the water in a dry dock facility. Once in the dry dock facility, pressurized water jets combined with mechanical cleaning methods are used to remove all marine fouling deposits prior to the application of a new antifouling coating on the clean hull of the ship. It has been reported that the amount of biofouling removed can amount to as much as 200 tons from a single large ship hull. Importantly, environmental protection regulations in most harbors of the world require that all removed biofouling is safely and completely captured and disposed along with the requirement for filtering all wash water to prevent any contamination of the environment at the location of hull cleaning including both dry dock and in-water hull cleaning locations.
Because of environmental restrictions, antifouling approaches for ship hulls are shifting from managing the release of toxic compounds previously used in antifouling coatings to more frequent cleaning of minor accumulations before biofouling deposits can adversely impact the power requirements and ship's speed through the water. As a result, hull coating manufacturers are increasingly abandoning toxic antifouling formulations in favor of biocide-free, silicone-based coatings whose surfaces resist attachment of marine organisms, but require frequent cleanings as well as special care when cleaning. By way of example, a commercially available silicone-based antifouling coating is available that claims a useful life of about seven years. However, ship hulls with this silicone-based coating require frequent in-water cleaning using less aggressive methods that will minimize damage to the silicone-based coating. In this regard, see the Sigmaglide 2390 biocide-free fouling release coating that is available from PPG Protective and Marine Coatings, Alexander, Arkansas.
By way of another example, one of the more advanced types of hull coatings are the hard, non-toxic coatings such as Ecospeed available from Hydrex Group/Subsea Industries based in Antwerpen, Belgium. The Ecospeed coating includes glass flakes within a vinyl-ester resin, a hard coating that is intended to last the life of the ship. Although this biocide-free coating also requires more frequent in-water cleaning, it is much more durable with regard to various hull cleaning methods as compared with conventional hull coatings such as the increasingly popular silicone-based coatings.
These newer generation of antifouling coatings require frequent in-water interim cleanings between the need for placing the ship in a dry dock for more thorough removal of biofouling deposits. However, the process of in-water hull cleaning has come under increasing regulatory scrutiny in view of environmental protection requirements. The U.S. regulations governing in-water cleaning of ship hulls are fully disclosed in the previously cited report by McClay (2015). As stated in the report by McClay, all in-water cleaning methods are required to collect all removed biofouling products and filter all effluents unless the cleaning method is proven to kill all organisms treated and removed.
Prior art in-water methods for removing early stages of marine biofouling deposits from ship hulls are described in previously cited report by McClay (2015) as well as a report by C. Zabin, et. al., In-Water Vessel Cleaning: Current and Emerging Technologies, Associated Risks and Management Options December 2016. The prior art in-water cleaning methods and systems disclosed in these two reports include mechanical cleaning with brushes, water jet cleaning and a heated water method to kill biofouling organisms. All prior-art methods for in-water cleaning of ship hulls are required to collect all removed biofouling products and filter all effluents except for the method that uses heated water at 72 C that is claimed to kill all organisms treated and removed. Examples of in-water cleaning methods and systems described in these two reports are briefly described as follows.

- 1. US Navy's Automated Hull Maintenance Vehicle (AHMV) and Advanced Hull Cleaning System (AHCS). This system includes a submersible cleaning and maintenance platform (SCAMP, such as those developed by Seaward Marine Services), or brush cart, that also vacuums debris as it cleans. This effluent is transferred to a pier-side waste management unit.
- 2. The US DOT Maritime Administration (MARAD), in collaboration with a private engineering firm, Terraphase Engineering Inc. and commercial divers from Jacksonville, Florida-based Underwater Services International, recently developed and tested a new in-water cleaning system in San Francisco Bay (Terraphase Engineering 2012). The system uses a diver-guided brush system, outfitted with a rubber “skirt” to capture debris and a suction hose to vacuum debris and deliver it to a pier-side filtration and waste-disposal system. Solids are filtered out using a series of progressively smaller filters (down to 5 microns for capturing solids) and an organo-clay filter system to capture dissolved metals.
- 3. All-Sea Enterprises, based in Vancouver, B.C., is developing an ROV cleaning system, called the Whale Shark ROV, which contains and treats the debris removed during in-water cleaning. The system includes rotating brushes enclosed in a hood, with all debris pumped to the surface through flexible hoses. The company has also developed a propeller cleaning ROV, the Beluga Environmental Propeller cleaning system, which also captures and pumps debris to the surface. The system removes organic debris and treats the effluent through a filter system, returning the treated water to the ocean.
- 4. A Norwegian-based company, ECOSubsea, has created a system called ECOStation that combines ROV-driven water pressure cleaning with suction technology to capture debris. The ECOStation system is designed to minimize paint wear by using relatively low water pressure (100 up to 250 bars). The system has been in operation for one year in Southampton, UK, where it has exclusive access as the only hull-cleaning system that meets environmental standards, as well as in major ports in Sweden, Norway, and Denmark. The company claims a 97.5% debris collection rate and a reduction in chemical contamination due to its gentler cleaning methods.
- 5. In 2014, Gage Roads Diving Franmarine, a company based in Henderson, Australia, won an award for Excellence in Marine Biosecurity from the Western Australia Department of Fisheries for its Envirocart in-water cleaning technology. The Envirocart uses rotating brushes or blades for cleaning and captures and filters removed debris and the company offers a suite of different technologies for various paint types and needs. The basic cleaning technology is a diver-driven hydraulically powered unit which can be fitted with various brush types or blades for contactless cleaning and can be used in a fully contained mode, which claims 100% capture of debris. The captured material is pumped through several filtration stages, which have the ability to remove particles up to 5 microns. The remaining filtrate is sterilized using UV light.
- 6. A new cleaning technology called Hull Identification System for Marine Autonomous Robotics or HISMAR is under development in Europe. Several academic and commercial institutions were involved in this product's development, which was initiated with funding from the European Union. The project was coordinated by the University of Newcastle, with Stankin Moscow State Technical University as a second partner. HISMAR is a wheeled ROV that can be programmed with a detailed map of the ship's design in order to make modifications for challenging portions of the vessel's surface. It uses water jets as its main cleaning method, containing debris in a hood for cleaning and filtration.
- 7. Trident 5 TecHullClean Underwater Contractors Spain (UCS), in collaboration with shipbuilder Trident BV and Maersk Line, has engineered a diver-driven rotating brush system with debris capture and filtration called TecHullClean. The technology features a hydraulic suspension system which controls the pressure of the brushes against the vessel, debris capture, and debris delivery to a mobile filtration system at the surface. The system has been approved by paint companies Jotun and International Paint as appropriate technology for their products. The system includes an air venturi to increase the flow of debris through the hose, speeding the capture process. The shore-side filtration system puts debris through a series of increasingly smaller filters, starting with larger mesh filter insert boxes and decreasing down to as fine as 5 microns.
- 8. Other available cleaning methods include water blasting or using cavitating bubbles to remove biofouling rather than brushes or blades. Companies that produce these devices, such as Cavidyne and the Italian company Cavi-Jet say that their products can be used at very low pressure, which increases diver safety and avoids paint damage that can lead to chemical contamination. Cavidyne's technology works by generating bubbles that collapse, creating a vacuum that removes fouling. Their products are being marketed as appropriate for multiple surfaces and paint types, and can be used at higher pressure for stronger cleaning (although presumably this would also damage paint). Cavidyne's systems range in size and thus might be appropriate for small as well as large craft. Cavidyne carried out tests of its CaviBlaster Model 1222 in San Francisco Bay in October 2015 to determine effectiveness in killing the biofouling it removes as well as evaluate impacts on water quality.
- 9. Another approach to hull cleaning is designed to kill but not necessarily remove biofouling organisms. In some cases, dead organisms may simply detach and fall off over time; in cases where this does not occur, or does not occur quickly, these methods may achieve biosecurity goals, but not meet the needs of vessel owners in terms of reducing drag and fuel consumption. By way of example, a method using heated seawater, Hull Surface Treatment (HST) has been developed by Commercial Diving Services Pty Ltd Australia for commercial use to keep vessels free of light to moderate fouling. HST heats water inside a remotely operated rolling thermal applicator equipped with rubber skirts and held against the ship's hull using magnets. The applicator moves along the vessel surface in a grid pattern, using hot water provided by a tender-mounted boiler unit to heat marine fouling attached to the hull to at least 72° C. while maintaining the temperature of the surface of the hull a temperature that does not exceed 40° C. The thermally treated marine fouling is killed and left to slough off when the vessel gets underway. This technology is limited to ferrous hulls and to vertical or near vertical surfaces of the hull.

An object of the present disclosure is to provide an apparatus, system and method for use in seawater environments for in-water, autonomous ablation of marine organisms, including marine microorganisms, to remove marine organisms that attach to the hulls of ships during each period of two to four weeks following the previous removal of biofouling from the ship's hull. As used hereinafter, the term “ablation” refers to the purposeful devitalization (e.g., killing) and removal of targeted species. The ablation process as applied in the present disclosure utilizes the process of molecular dissociation to induce irreversible cell death within marine organisms, including marine microorganisms, that are targeted and removed from the hull of the ship. Hereinafter, marine organisms, including marine microorganisms, that attach to the hulls of merchant ships are also referred to as marine biofouling.
A further object of the present disclosure is to provide an apparatus, system and method that overcomes the disadvantages of current in-water methods for ablation of marine biofouling from ship hulls by eliminating the need for the collection of all marine organisms, including microorganisms, that are removed from the hull of the ship. In addition, the present disclosure provides an autonomous apparatus, system and method that eliminates the requirement for manual operation or maintenance by underwater divers. The system is programmed and controlled to ablate marine deposits from a selected area of the hull of the ship following a pre-programmed and/or machine learning enabled sequence of paths that assure complete coverage of the hull below the water line of the ship that can potentially be exposed to marine organisms and susceptible to marine biofouling.

BRIEF SUMMARY OF THE INVENTION

The present disclosure is addressed to apparatus, systems and methods for use in seawater environments for the in-water, ablation and removal of marine organisms, including marine microorganisms, that attach to the hull of ship. The marine antifouling system of the present disclosure employs one or more biofouling ablation vehicles to repeatedly traverse the hull of a ship below the water line to ablate marine organisms and microorganisms on a recurring basis. Each biofouling ablation vehicle may incorporate a rechargeable battery or may be connected to an external source of electrical power though a reinforced tether that enables the ablation of marine biofouling to be performed in an automated and recurring manner following pre-programmed and/or machine learning enabled paths that, collectively, cover the exposed surfaces of the hull of a ship below the water line.
In a preferred embodiment of the present disclosure, the reinforced electrical power and communication tether that extends from a tether reel mounted at the deck level of the ship incorporates 440 volt, 3-phase, 60 Hz power lines, fiber optic and/or data cable for transmission of video signals from a plurality of digital image sensors located on the bottom surface each biofouling ablation vehicle and a flexible load-bearing cable.
The plurality of digital image sensors on the bottom facing surface (i.e., hull facing surface) of the biofouling ablation vehicle that are positioned along the front end and back end, respectively, of the biofouling ablation vehicle enable the inspection of the surface of the hull both immediately before and immediately after the in-water, ablation of marine organisms attached to the antifouling coating adhered to the hull of the ship. In addition, the biofouling ablation vehicle can be used for the purpose of inspection of the hull of the ship (e.g., assess the extent and depth of pitting corrosion and associated hull thinning), the condition of its antifouling coating and the extent of biofouling using the plurality of digital image sensors mounted on the biofouling ablation vehicle. This also enables the determination of the extent of biofouling accumulation between hull cleaning cycles using an intelligent image recognition system combined with incremental machine learning to automate the assessment of biofouling and guide the frequency of hull cleaning operations as well as the condition of the ship's hull and antifouling coating. In this regard, refer to Mittendorf, M. et. al., Capturing the Effect of Biofouling on Ships by Incremental Machine Leaning. Applied Ocean Research 2023; 138:1-15. Also refer to Bloomfield, N. et. al., Automating the Assessment of Biofouling in Images Using Expert Agreement as a Gold Standard. Scientific Reports 2021; 11: 2379-2388. In addition, also refer to Chin, C. S., et. al., Intelligent Image Recognition System for Marine Fouling Using Softmax Transfer Learning and Deep Convolutional Neural Networks. Complexity; Volume 2017; 1-9 (published by Hindawi). All three references listed above are incorporated herein, in their entirety, by reference.
By way of example, four or more biofouling ablation vehicles can be deployed with a first half of the biofouling ablation vehicles deployed on the port side of the ship's hull and a second half of the biofouling ablation vehicles deployed on the starboard side of the ship's hull. Each biofouling ablation vehicle automatically traverses, inspects and records the extent of marine fouling and removes marine organisms, including marine microorganisms, that attach to the hull of the ship as well as the condition of the ship's hull and antifouling coating. The biofouling ablation vehicle automatically traverses and removes marine organisms following a pre-programmed sequence of paths that are customized to the specific size and shape of the intended surface area to be cleaned for each unique ship hull.
The apparatus, systems and methods of the present disclosure for the in-water, ablation of marine organisms, including marine microorganisms, enables the removal of biofouling from the ship's hull on a recurring basis whether the ship is stationary at a dock, at anchor or otherwise stationary or while the ship is underway. By enabling a recurring process for ablation of marine biofouling from the hull of the ship, the marine organisms are removed at an early stage of their life cycle and prior to marine biogenic calcification that results in marine biofouling that requires much more aggressive methods for the removal of biofouling from the ship's hull such as pressurized water jets, mechanical scraping and powered aggressive brushing methods.
According to the present disclosure, one or more biofouling ablation vehicles are deployed to enable the repeated removal of biofouling from the hull of the ship below the water line, referred to hereinafter as a complete cycle of biofouling removal from the hull of a ship, within a period of two to four weeks following the previous removal of biofouling from the ship's hull or for the hull of a ship having received a marine antifouling coating (e.g., a silicone coating such as the PPG SigmaGlide 2390 coating). The repetition of a complete cycle of biofouling removal from the ship's hull as frequently as every two to four weeks assures that the marine organisms newly attaching to the hull have not yet formed a calcareous body or shell and therefore can be efficiently and effectively removed using the molecular dissociation-based ablation method employed in the present disclosure. Thus, the process disclosed herein contemplates repeatedly cleaning the ship hull, while it is in water, at the early stages of marine fouling (known as slime) before calcareous (hard shell) organisms form during the macrofouling stage. The technology utilized in the process is capable of removing early stage marine fouling from ship hulls without damaging the underlying antifouling coating that is previously applied to the hull of the ship. The biofouling ablation vehicles may be pre-programmed to autonomously traverse the hull of the ship and remove a layer of microfouling from an initially clean hull at various intervals. In some instances, the layer of microfouling that is removed from the hull of the ship is about 2 mm or about 2 mm (i.e., about 0.1 or 0.1 inch) thick. The rate of deposition and growth of microfouling and macrofouling increases with increasing temperature. Accordingly, cleaning intervals are dependent upon water temperature and may occur every four to eight weeks. The biofouling ablation vehicles function as magnetically secured “crawlers” which clean the hull on both the port and starboard sides of the ship and are capable of cleaning the hull of the ship while the ship is in port, at anchor or travelling (i.e., in-motion in the sea).
The apparatus, system and methods of the present disclosure utilizes molecular dissociation of the marine organisms, including marine microorganisms, that attach to the hull of the ship. Molecular dissociation of organic species within attached marine organisms is achieved by placing a plurality of active electrodes in confronting adjacency with marine organisms attached to the antifouling coating adhered to the hull of the ship. One or more common electrodes are positioned adjacent to a plurality of active electrodes and are in electrical communication with the plurality of active electrodes through electrically conductive sea water interposed between the plurality of active electrodes and the one or more common electrodes. The total combined surface area of the common electrodes in contact with sea water is substantially greater than the total combined surface area of all of the active electrodes in contact with sea water.
A radiofrequency voltage is applied between the plurality of active electrodes and one or more common electrodes wherein marine organisms are located between the plurality of active electrodes and the one or more common electrodes. A region of high electric field intensity at the interface between the distal end face of each active electrode and the marine organisms results in the formation of a plasma in a vapor layer between the distal end face of each active electrode and the marine organisms. The plasma formed within the vapor layer is result of the applied electric field in combination with the presence of sodium ions present in seawater. The sodium ionized in the presence of the intense electric filed generates free electrons. The free electrons within the ionized vapor layer are accelerated within the high electric fields near the distal ends of each active electrode thereby generating energetic electrons. The energy evolved by the energetic electrons that bombard each organic molecule can break its chemical bonds. As a result, all organic molecules within the marine organisms attached to the hull of the ship (i.e., the targeted marine organisms) are molecularly dissociated into free radicals that combine into final, nonviable gaseous or liquid byproducts. Since the resulting products of the molecular dissociation of the targeted marine organisms are nonviable, there is no requirement to capture any of the removed gaseous, liquid or solid products generated by molecular dissociation.
The system for in-water, autonomous and recurring ablation of marine organisms, including marine microorganisms, that attach to the hull of ship includes one or more battery-powered or externally powered and tethered biofouling ablation vehicles and one or more ship-powered biofouling ablation vehicle maintenance stations located above the water line of the ship and accessible by pre-programmed movement of the biofouling ablation vehicles. Each battery-powered or externally powered and tethered biofouling ablation vehicle includes [a] a support frame, [b] four or more independently-suspended drive wheels for advancement of two or more traction belts, [c] a traction belt attached to each set of two or more drive wheels on either side of biofouling ablation vehicle and incorporating magnets within each traction belt to secure the biofouling ablation vehicle to the hull of the ship while simultaneously allowing the biofouling ablation vehicle to traverse the hull of ship as the traction belt is advanced by its drive wheels, [d] four or more motors, preferably hub motors, for the independent actuation and control of the rotation of each of the two or more drive wheels, [e] a plurality of permanent rare-earth magnets imbedded within traction belt to secure biofouling ablation vehicle to hull of ship while traversing the hull for hull surface orientations ranging from vertical to horizontal, [f] a control and communication system incorporating one or more microcomputers, [g] a power supply for supplying a high voltage to energize a plurality of active electrodes in a salt water environment to create a plasma within a vapor layer generating energetic electrons produced at the interface with the marine organisms to effect or cause the molecular dissociation of the targeted marine organisms, [h] one or more removably attachable active electrode modules for the molecular dissociation of targeted marine organisms, [i] a rechargeable battery or a tether connected to an external source of power and [j] an enclosure surrounding the battery or back-up battery supplied by external power source, control and communication systems, battery management system and power supply that provides a thermally insulating barrier to prevent overheating of the enclosed components during a predetermined period of forced convection heating of the biofouling ablation vehicle within the biofouling ablation vehicle maintenance station for the purpose of cleaning the biofouling ablation vehicle.
Each ship-powered biofouling ablation vehicle maintenance station includes [a] an enclosure sufficiently large to receive and secure a single biofouling ablation vehicle and having a closable door at the entrance of the biofouling ablation vehicle maintenance station, [b] receptacle for a water-tight electrical connection to a mating charging plug secured to the biofouling ablation vehicle (for case of battery-powered biofouling ablation vehicle embodiment), [c] a battery recharging current source (for case of battery-powered biofouling ablation vehicle embodiment), [d] a forced air convection heater programmed to heat all exterior surfaces of the biofouling ablation vehicle to a temperature of at least 72° C. (162° F.) for a predetermined heating cycle duration to devitalize (e.g., kill and render nonviable) all marine organisms on the exterior surfaces of the biofouling ablation vehicle, [e] an array of water jet nozzles surrounding all sides of the exterior of the biofouling ablation vehicle and having a source of cleaning water (e.g., filtered water) to remove any solid or liquid devitalized marine organisms and [f] one or more microcomputers. The predetermined duration of the heating cycle for removal of marine organisms and microorganisms is selected to be sufficiently long to increase the temperature of all exterior surfaces of the biofouling ablation vehicle to at least 72° C. for a period, t_cleanwhile maintaining the temperature of the battery or back-up battery below 50° C. During the heating cycle, the door at the entrance into the biofouling ablation vehicle maintenance station is preferably closed to improve the efficiency of the force air convection heating process.
The ablation of targeted marine organisms and microorganisms through the process of molecular dissociation of marine organisms results in a predictable rate of erosion of the active electrodes incorporated in the one or more removably attachable active electrode modules within the biofouling ablation vehicle. The predictable rate of erosion of the active electrodes enables the control and communication system within the biofouling ablation vehicle to continuously compare usage time with a predetermined maximum allowable usage time. In this manner, the one or more removably attachable active electrode modules can be replaced at predetermined time intervals based on the duration of their use for the ablation of marine organisms and microorganisms.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a marine antifouling system showing a single battery-powered biofouling ablation module and a single biofouling ablation module maintenance station;

FIG. 1A is a perspective view of a second embodiment of a marine antifouling system showing a single tethered biofouling ablation module and a single biofouling ablation module maintenance station;

FIG. 2 is a partially sectioned and cut away perspective view of a first embodiment of the biofouling ablation module shown in FIG. 1 ;

FIG. 2A is a partially sectioned and cut away perspective view of a second embodiment of the biofouling ablation module shown in FIG. 1A;

FIG. 2B is a partially sectioned view of the traction belt incorporating permanent magnets as seen in FIGS. 2 and 2A;

FIG. 2C is a sectional view of the reinforced power and communication tether seen in FIGS. 1A, 2A and 15 ;

FIG. 3 is a partially sectioned and cut away perspective view of a first embodiment of the biofouling ablation module maintenance station shown in FIG. 1 ;

FIG. 3A is a partially sectioned and cut away perspective view of a second embodiment of the biofouling ablation module maintenance station shown in FIG. 1A;

FIG. 4 is a sectional view of an ablation module including a removably attachable active electrode module and an interconnection terminal array module;

FIG. 4A is a detailed sectional view of a portion of the ablation module seen in FIG. 4 showing components within the removably attachable active electrode module and the interconnection terminal array module;

FIG. 5 is a sectional view of an active electrode subassembly as seen in FIG. 4A;

FIG. 6 is a sectional view of an interconnection terminal subassembly as seen in FIG. 4A;

FIG. 7 is a frontal view at the working end of a removably attachable active electrode module showing a single row of a plurality of circular electrically isolated active electrodes surrounded at their perimeter and electrically insulated from a common electrode;

FIG. 7A is a frontal view at the working end of a removably attachable active electrode module showing an electrode array having multiple rows of a plurality of circular electrically isolated active electrodes surrounded at their perimeter by and electrically insulated from a common electrode;

FIG. 7B is a side view of a removably attachable active electrode module seen in FIG. 7 showing a plurality of electrically isolated active electrodes extending above the surface of the electrical insulation and surrounded at their perimeter by and electrically insulated from a common electrode;

FIG. 7C is a partial frontal view at the working end of a removably attachable active electrode module showing a single row of a plurality of rectangular, electrically isolated active electrodes surrounded at their perimeter by and electrically insulated from a common electrode;

FIG. 7D is a partial frontal view at the working end of a removably attachable active electrode module showing a single row of a plurality of square electrically isolated active electrodes surrounded at their perimeter by and electrically insulated from a common electrode;

FIG. 8 is an enlarged sectional view of the distal end of the removably attachable active electrode module seen in FIG. 7 illustrating a vapor layer formed between the active electrode and the target layer of marine organisms;

FIG. 9 is an end view at the working end of four removably attachable active electrode modules as seen in FIG. 7 to form a single ablation module assembly;

FIG. 10 is an end view at the working end of seven ablation module assemblies as seen in FIG. 9 and positioned within support frame that is mounted on the bottom surface of the biofouling ablation vehicle;

FIG. 11 is a schematic diagram of a circuit incorporating a set of N current limiting inductors, one inductor for each active electrode in any single ablation module array, as seen in FIG. 10 , combined with a multiplexer to allow the set of N current limiting inductors to be selectively connected by the control system to any of the ablation module arrays;

FIG. 12A-12F combine, as labeled thereon, to provide a flow chart describing the methodology of this invention;

FIG. 13 is a side view of the starboard side of a ship illustrating four cleaning zones located below the water line of the hull of a ship and extending the full length of the hull;

FIG. 14 is a partial side view of the starboard side of the forward quarter of the hull of a ship illustrating the location of a biofouling ablation vehicle maintenance station and the programmed starboard cleaning path followed by a battery-powered biofouling ablation vehicle;

FIG. 15 is a partial side view of the starboard side of the forward quarter of the hull of a ship illustrating the location of a biofouling ablation vehicle maintenance station, a tether reel and the programmed starboard cleaning path followed by a biofouling ablation vehicle powered by ship-board power through a connected reinforced power and communication tether;

FIG. 16 is a sectional view of a U-shaped active electrode assembly revealing an active electrode, first support leg of active electrode, second support leg of active electrode and common electrode;

FIG. 17 is a top view of a U-shaped active electrode assembly seen in FIG. 16 revealing a leading edge of the active electrode assembly;

FIG. 18 is a sectional view of the active electrode assembly seen in FIG. 16 revealing the leading edge of an active electrode as it engages marine organisms as well as the path of electrical current flow from the active electrode to the common electrode;

FIG. 18A is an enlarged sectional view of the leading edge of the active electrode seen in FIG. 18 revealing a vapor layer formed between the leading edge of the active electrode and the marine organisms;

FIG. 19 is a perspective view of the active electrode assembly seen in FIGS. 16, 17 and 18 and

FIG. 20 illustrates the active electrode assembly seen in FIGS. 16, 17, 18 and 19 with the addition of a separate liquid delivery supply.

DETAILED DESCRIPTION

A predominant characteristic of the present disclosure resides in the molecular dissociation of targeted marine organisms and microorganisms that become attached to the hull of a ship in a seawater environment. Molecular dissociation is achieved through the ionization of atoms within a vapor layer produced in seawater (containing sodium chloride) that leads to the generation of energetic photons having wavelengths in the range from 306 to 315 nanometers (ultraviolet spectrum) and from 588 to 590 nanometers (visible spectrum). In addition, the free electrons within the ionized vapor layer are accelerated in the high electric fields at the distal end of each active electrode incorporated in a removably attachable active electrode module. When the density of the formed vapor layer (or within a bubble formed in the electrically conducting seawater) becomes sufficiently low (i.e., less than approximately 1020 atoms/cm³for aqueous solutions), the electron mean free path increases to enable subsequently injected electrons to cause impact ionization within these regions of low density (i.e., vapor layers or bubbles). Energy evolved by the energetic electrons (e.g., 4 to 5 eV) can subsequently bombard a molecule within the marine organisms or microorganisms and break its organic chemical bonds, dissociating the molecule into free radicals, which then combine into final nonviable gaseous and/or liquid species.
The energy of the generated photons produces photoablation through photochemical and/or photothermal processes to disintegrate biofouling thicknesses as small as several cell layers at the targeted biofouling ablation site. The “fragments” of disintegrated marine organism molecules carry away much of the energy thereby limiting the amount of energy transferred to and potentially damaging the biofouling coating on the hull of the ship.
In addition. other mechanisms contribute to the ablation of the targeted marine organisms and microorganisms. For example, ablation of the marine organisms may also be caused by dielectric breakdown of structural elements or cell membranes within the marine organisms as a result of the generation of highly concentrated intense electric fields at the distal end of the active electrodes within each removably attachable active electrode module. The distal ends of the active electrodes are sized and have exposed surfaces areas which, in the presence of the applied voltage, cause the formation of a vaporized region or layer over at least a portion of the surface of the active electrode. This layer or region of vaporized electrically conducting seawater creates the conditions necessary for ionization within the vaporized region or layer and the generation of energetic electrons and photons. In addition, this layer or region of vaporized electrically conducting seawater provides a high electrical impedance between the electrode and the adjacent tissue so that only low levels of electric current flow across the vaporized layer or region into the targeted marine organisms or microorganisms, thereby minimizing Joulean heating within the antifouling coating on the hull of the ship.
The density of the electrically conducting seawater at the distal tips of the active electrodes is locally heated by the applied electric current thereby forming a vapor layer. Once the density in the vapor layer formed within the seawater reaches a critical value, electron avalanche occurs. The electrons accelerated in the electric field within the vapor layer become trapped after one or a few scatterings. These injected electrons serve to create or sustain a low-density region with a large mean free path to enable subsequently injected electrons to cause impact ionization within these regions of low density. The energy evolved at each recombination is on the order of half of the energy band gap (i.e., 4 to 5 eV). This energy can be transferred to another electron to generate a highly energetic electron. This second, highly energetic electron has sufficient energy to bombard an organic molecule to break its chemical bonds, i.e., dissociate the organic molecule into free radicals.
Referring to FIG. 1 , a first embodiment of the marine antifouling system according to the present disclosure is represented in general at 10. The marine antifouling system 10 includes one or more battery-powered biofouling ablation vehicles 12 and one or more biofouling ablation vehicle maintenance stations 13. The one or more battery-powered biofouling ablation vehicles 12 are in wireless communication with a command and control center 6 and its operator 5 located on ship 9 as seen along second communication path 262 in FIG. 1 . Although frequently referenced throughout the Detailed Description, ship 9 is only seen in FIGS. 13, 14 and 15 . Likewise, the one or more biofouling ablation vehicle maintenance stations 13 are also in wireless communication with a command and control center 6 and its operator 5 located on ship 9 as seen along first wireless communication path 260 in FIG. 1 .
The maintenance station enclosure 14 of each biofouling ablation vehicle maintenance station 13 is secured to the exterior surface of the hull 11 of the ship and is located well above, preferably at least 20 feet above, the water line of the ship. Also, each biofouling ablation vehicle maintenance station 13 is positioned so that it is accessible by pre-programmed movement of the biofouling ablation vehicle 12 for the purpose of [a] replacing used removably attachable active electrode modules 48 (not shown), [b] re-charging the battery within the biofouling ablation vehicle 12 and [c] removing any marine organisms that become attached to the exterior surfaces of the biofouling ablation vehicle 12. As seen in FIG. 1 , an openable door 16 is pivotably supported by the maintenance station enclosure 14 and is positioned at the entrance 18 of the biofouling ablation vehicle maintenance station 13. Door 16 is wirelessly and remotely openable by a control system (not shown) within the biofouling ablation vehicle 12 to enable entrance into and exit from the biofouling ablation vehicle maintenance station 13. In a preferred embodiment, door 16 is closed during the period of forced air convection heating of the exterior of the biofouling ablation vehicle 12 to at least 72° C. for the purpose of removing marine organisms from the exterior of the biofouling ablation vehicle 12. The forced air convection heating unit located within the biofouling ablation vehicle maintenance station 13 is not shown in FIG. 1 .
Still referring to FIG. 1 , the directions of travel of the biofouling ablation vehicle for the purpose of entering and exiting the biofouling ablation vehicle maintenance station is seen at 20. First and second wheels 22 a and 22 b are seen on one side of biofouling ablation vehicle 12. Third and fourth wheels 22 c and 22 d located on the side of the biofouling ablation vehicle 12 opposite first and second wheels 22 a and 22 b are not seen in FIG. 1 . Several of a plurality of water jet nozzles 23 are visible at the entrance 18 of the biofouling ablation vehicle maintenance station 13. Following the forced air convection heating of the exterior of the biofouling ablation vehicle 12, pressurized water (e.g., filtered water) is sprayed over the exterior of the biofouling ablation vehicle 12 to remove the devitalized marine organisms and microorganisms from the surfaces of the biofouling ablation vehicle 12.
Referring next to FIG. 1A, a second and preferred embodiment of the marine antifouling system according to the present disclosure is represented in general at 210. The marine antifouling system 210 includes one or more biofouling ablation vehicles 212 and one or more biofouling ablation vehicle maintenance stations 213. Each biofouling ablation vehicle 212 is individually connected to an external source of power by a reinforced electrical power and communication tether 8. The one or more externally powered biofouling ablation vehicles 212 are in communication with a command and control center 6 and its operator 5 located on ship 9 as seen along second wireless communication path 262 as well as through fiber optic and/or data cable 254 in FIG. 1A. Likewise, the one or more biofouling ablation vehicle maintenance stations 13 are also in wireless communication with a command and control center 6 and its operator 5 located on ship 9 as seen along first wireless communication path 260 in FIG. 1A.
The maintenance station enclosure 214 of each biofouling ablation vehicle maintenance station 213 is secured to the exterior surface of the hull 11 of the ship 9 and is located well above, preferably at least 20 feet above, the water line of the ship. Also, each biofouling ablation vehicle maintenance station 213 is positioned so that it is accessible by pre-programmed movement of the biofouling ablation vehicle 212 for the purpose of [a] replacing used removably attachable active electrode modules 48 (not shown) and [b] removing any marine organisms that become attached to the exterior of the biofouling ablation vehicle 212. As seen in FIG. 1A, an openable door 16 with slot 7 is pivotably supported by the maintenance station enclosure 214 and is positioned at the entrance 18 of the biofouling ablation vehicle maintenance station 213. Door 16 is wirelessly and remotely openable by a control system (not shown) within the biofouling ablation vehicle 212 to enable entrance into and exit from the biofouling ablation vehicle maintenance station 213. In a preferred embodiment, door 16 is closed during the period of forced air convection heating of the exterior of the biofouling ablation vehicle 212 to at least 72° C. for the purpose of removing marine organisms from the exterior of the biofouling ablation vehicle 212. The forced air convection heating unit located within the biofouling ablation vehicle maintenance station 213 is not shown in FIG. 1A.
Still referring to FIG. 1A, the directions of travel of the biofouling ablation vehicle for the purpose of entering and exiting the biofouling ablation vehicle maintenance station is seen at 20. First and second wheels 22 a and 22 b are seen on one side of biofouling ablation vehicle 212. Third and fourth wheels 22 c and 22 d located on the side of the biofouling ablation vehicle 212 opposite first and second wheels 22 a and 22 b are not seen in FIG. 1A. Several of a plurality of water jet nozzles 23 are visible at the entrance 18 of the biofouling ablation vehicle maintenance station 213. Following the forced air convection heating of the exterior of the biofouling ablation vehicle 212, pressurized water (e.g., filtered water) is sprayed over the exterior of the biofouling ablation vehicle 212 to remove the devitalized marine organisms and microorganisms from the surfaces of the biofouling ablation vehicle 212.
Tuning now to FIG. 2 , the biofouling ablation vehicle 12 of the first embodiment is seen in greater detail. A partially sectioned and cut away perspective view of the interior of a biofouling ablation vehicle enclosure 15 reveals the principal components within a biofouling ablation vehicle 12. The principal components within the biofouling ablation vehicle enclosure 15 include a battery 40, a battery management system 45, a power supply 42, a control and communication system 44 (for example, a control and wireless communication system) and a support frame 106 containing an array of ablation module assemblies 103 (not shown). The biofouling ablation vehicle enclosure 15 also provides a water-tight seal around the battery 40, battery management system 45, power supply 42, control and wireless communication system 44 and support frame 106 thereby preventing the ingress of sea water into the interior of the biofouling ablation vehicle enclosure 15.
Biofouling ablation vehicle enclosure 15 also supports four wheels 22 a-22 d having a diameter D₉of which only first and second wheels 22 a and 22 b, respectively, are seen on first side 4 a of biofouling ablation vehicle 12 in FIG. 2 . One wheel 22 on first and second side 4 a and 4 b, respectively, of biofouling ablation vehicle 12 functions as a drive wheel and is actuated by a motor, preferably a hub motor 28. The perimeter of each wheel 22 incorporates a plurality of uniformly spaced ribs 47 that engage corresponding uniformly spaced slots 51 (not shown) located on the interior surface of flexible traction belt 24 as the wheels rotate, wherein traction belt 24 has width, W₉(wherein only first drive belt 24 a is seen. In FIG. 2 ). Each of the four wheels 22 a-22 d are supported by suspension system secured to the biofouling ablation vehicle enclosure 15. A plurality of permanent magnets is securely contained within the flexible traction belt 24 to enable the biofouling ablation vehicle to be magnetically secured to the steel hull 11 of the ship 9 as the biofouling ablation vehicle 12 traverses the hull 11 of the ship 9 during the ablation of marine fouling on the surface of the hull 11 of the ship 9 below the water line 137. By way of example, neodymium Grade 52 magnets composed of NdFeB are characterized by a strong magnetic field having strong associated attractive forces. By way of example, neodymium Grade 52 magnets are commercially available from K&J Magnetics, Pipersville, Pennsylvania.
By way of example, each of drive wheels 22 may have a diameter, D₉of 8.0 inches and width, W₉of 2.5 inch. Each drive wheel 22 may have 24 equally spaced ribs 47 having a nominal rib width of 0.25 inch and rib height of 0.25 inch. In the present example, a traction belt 24 having a width of 2.5 inches and a thickness of 0.70 inch is seen in partial sectional view in FIG. 2B. A plurality of slots 51 having a nominal width of 0.26 inch and depth of 0.25 inch are located on the inner surface 53 of traction belt 24 at a spacing of L₁₉. The size of the slots 51 are dimensioned to receive the ribs 47 on the perimeter of each drive wheel 22. For the present example of drive wheels 22 having a nominal diameter of 8.0 inches, a preferred slot spacing, L₁₉between slots 51 is nominally 1.0 inch. By way of example and as seen in FIG. 2B, permanent magnets 26 can be positioned between slots 51 at a nominal magnet spacing, Lis. In this example, the nominal magnet spacing, L₁₈is substantially the same as the slot spacing, L₁₉of 1.0 inch. For the case of a spacing between drive wheels 22 of 25 inches, the number of permanent magnets 26 that can be incorporated into each traction belt 24 along the length of contact with the hull 11 at a nominal magnet spacing, Lis of 1.0 inch is 25. Hence, a total of 50 permanent magnets can be incorporated within first and second traction belts 24 a and 24 b.
By way of further example, assume the permanent magnets 26 incorporated or imbedded within first and second traction belts 24 a and 24 b, as seen in the partial sectional view in FIG. 2B, are rectangular magnets having a width of 0.30 inch, a length of 2.0 inches and a thickness of 0.30 inch. The length of each permanent magnet 26 extends across the width of the traction belt 24. This example width of permanent magnets 26 and their positioning between slots 51 enables the traction belt 24 follow the curvature of the drive wheels 22. As seen in FIG. 2B, assuming a combined thickness of 0.30 inch for the intervening layers of traction belt 24, layer of marine organisms 21 and antifouling coating 25, then the total spacing between the permanent magnet 26 and the steel hull 11 of the ship 9 is 0.30 inch. Based on the above dimensions of the permanent magnets 26 and its distance from the steel hull 11 of the ship 9, the attraction force between each magnet 26 within the traction belt 24 and the hull 11 calculated by a permanent magnet manufacturer, K&J Magnetics, is 5.3 pound per magnet. This calculation is based on the use of neodymium Grade 52 magnets composed of NdFeB. In the present example incorporating a total of 50 permanent magnets 26 along the length of contact with the hull 11, the combined magnetic attraction force is 50 magnets×5.3 pounds attraction force per magnet or a total attraction force of 265 pounds. This level of magnet attraction force should be sufficient for the preferred size of the biofouling ablation vehicle 12 or 212. In this regard, neodymium Grade 52 magnets are commercially available from K&J Magnetics, Pipersville, Pennsylvania.
Still referring to FIG. 2 , first and second battery plug recharging terminals 30 and 32, respectively, are seen at the front end 35 of the biofouling ablation vehicle enclosure 15 and extend from battery 40. First and second electrically insulative sleeves 31 and 43, respectively, surround the first and second battery plug recharging terminals 30 and 32, respectively, within the interior of the biofouling ablation vehicle enclosure 15. In a preferred embodiment, the portions of the first and second battery plug recharging terminals 30 and 32 that are exterior to the biofouling ablation vehicle enclosure 15 may be first and second compressible elastomeric shrouds 34 and 36, respectively, that elastically compress and retract when first and second battery plug recharging terminals 30 and 32 are inserted into and come into electrical communication with the corresponding first and second charging receptacles 50 and 54, respectively, within the biofouling ablation vehicle maintenance station 13 as seen in FIG. 3 .
Tuning now to FIG. 2A, a biofouling ablation vehicle 212 of the second and preferred embodiment is seen in greater detail. A partially sectioned and cut away perspective view of the interior of the biofouling ablation vehicle enclosure 15 reveals the principal components within a biofouling ablation vehicle 212. The principal components within the biofouling ablation vehicle 212 include a reinforced electrical power and communication tether 8, an AC to DC converter 38, back-up battery 41, battery management system 45, power supply 42, control and communication system 244 and support frame 106 containing an array of ablation module assemblies 103 (not shown). The biofouling ablation vehicle enclosure 15 also provides a water-tight seal around the AC to DC converter 38, back-up battery 41, battery management system 45, power supply 42, control and communication system 244 and support frame 106 thereby preventing the ingress of sea water into the interior of the biofouling ablation vehicle enclosure 15.
Biofouling ablation vehicle enclosure 15 also supports four wheels 22 a-22 d having a diameter D₉of which only first and second wheels 22 a and 22 b, respectively, are seen on first side 4 a of biofouling ablation vehicle 12 in FIG. 2A. One wheel 22 on first and second side 4 a and 4 b, respectively, of biofouling ablation vehicle 12 functions as a drive wheel and is actuated by a motor, preferably a hub motor 28. The perimeter of each wheel 22 incorporates a plurality of uniformly spaced ribs 47 that engage corresponding uniformly spaced slots 51 (not shown) located on the interior surface of flexible traction belt 24 as the wheels rotate, wherein traction belt 24 has width, W₉(wherein only first drive belt 24 a is seen. In FIG. 2A). Each of the four wheels 22 a-22 d are supported by suspension system secured to the biofouling ablation vehicle enclosure 15. A plurality of rare-earth magnets is securely contained within the flexible traction belt 24 to enable the biofouling ablation vehicle to be magnetically secured to the steel hull 11 of the ship 9 as the biofouling ablation vehicle enclosure 15 traverses the hull 11 of the ship 9 during the ablation of marine fouling on the surface of the hull 11 of the ship 9 below the water line 137. By way of example, neodymium Grade 52 magnets composed of NdFeB are characterized by a strong magnetic field having strong associated attractive forces. By way of example, neodymium Grade 52 magnets are commercially available from K&J Magnetics, Pipersville, Pennsylvania.
Still referring to FIG. 2A, reinforced electrical power and communication tether 8 is seen at the front end 35 of the biofouling ablation vehicle enclosure 15 and is in electrical communication with AC to DC converter 38. The AC to DC converter 38 is in electrical communication with back-up battery 41, battery management system 45, power supply 42 and control and communication system 244. In addition to 440 volt, 3-phase, 60 Hz power lines and flexible load-bearing cable, the reinforced electrical power and communication tether 8 also incorporates fiber optic and/or data cable for transmission of signals from digital image or other sensors located on bottom surface of support frame 106 seen in FIG. 10 but not seen in FIG. 2A.
By way of example, a preferred neutrally buoyant reinforced electrical power and communication tether 8 is seen in FIG. 2C having a diameter, D₉ranging from 6 mm to 15 mm and including first, second and third conductor lines 250 a, 250 b, 250 c, respectively, fiber optic and/or data cable 254, buoyancy filler 256, Kevlar strengthening layer 252 and outer covering 258. Preferably, first, second and third conductor lines 250 a, 250 b, 250 c, respectively, within reinforced electrical power and communication tether 8 that carry 440 volt, three phase power at 60 Hz are copper wires with electrically insulative coverings. Also, the outer covering 258 of reinforced electrical power and communication tether 8 is polyethylene to confer resistance to abrasion, ultraviolet light and sea water. The buoyancy filler 256 within reinforced electrical power and communication tether 8 is preferably a foam elastomer to confer neutral buoyancy to reinforced electrical power and communication tether 8 thereby improving maneuverability within the sea water as the biofouling ablation vehicle 212 traverses the hull 11 of the ship 9. In this regard, see commercially available tethers for use in sea water manufactured by Invocean, a division of the Marmion Group, Houston, Texas.
Turning now to FIG. 3 , the biofouling ablation vehicle maintenance station 13 of the first embodiment that is securely attached to hull 11 of ship 9 is seen in greater detail. A partially sectioned and cut away perspective view of the interior of the biofouling ablation vehicle maintenance station enclosure 14 reveals forced-convection heating unit 57 having fan 59 to circulate heated air and air intake vent 61, battery recharging unit 54 having first and second recharging receptacles 50 and 52, respectively, cleaning water pressurization and control unit 56 that is connected to liquid flow lines (not shown) leading to a plurality of water jet nozzles 23 used for cleaning the exterior of the biofouling ablation vehicle 12 following its return to the biofouling ablation vehicle maintenance station 13 and after the biofouling ablation vehicle 12 is exposed to forced-convection air heating to enable the removal of any surface accumulation of marine fouling on the exterior surfaces of the biofouling ablation vehicle 12. Power line 48 connected to ship electrical utility source (not shown) supplies electrical power (e.g., 440 volts, 3 cycle power at 60 Hz) to battery recharging unit 54. Water supply line 49 is connected to cleaning water pressurization and control unit 56 at water inlet port receptacle 69 with removably connectable water supply fitment 66 located at distal end of water supply line 49. An openable door 16 that is motor-actuated is pivotably supported by the maintenance station enclosure 14 and is positioned at the entrance 18 (not shown) of the biofouling ablation vehicle maintenance station 13. Door 16 is wirelessly and remotely openable by a control system (not shown) within the biofouling ablation vehicle 12 to enable entrance into and exit from the biofouling ablation vehicle maintenance station 13.
In a preferred embodiment, door 16 is closed during the period of forced-convection air heating of the exterior of the biofouling ablation vehicle 12 to at least 72° C. for the purpose of removing marine organisms from the exterior surfaces of the biofouling ablation vehicle 12. An air gap or other insulative material thickness of at least 0.25 inch is maintained between the inner surfaces of the biofouling ablation vehicle enclosure 14 and the principal components contained within the biofouling ablation vehicle 12 including the battery 40, battery management system 45, power supply 42 and control and wireless communication system 44. A thickness of at least 0.25 inch assures that the principal components contained within the biofouling ablation vehicle 12 are maintained at acceptably low temperatures to prevent any thermal damage to these principal components during the forced-convection heating procedure. The use of forced-convection air heating within the enclosed biofouling ablation vehicle maintenance station enclosure 14 enables the exterior surfaces of the biofouling ablation vehicle 12 to be heated to at least 72° C. within a period of preferably less than 30 minutes.
Still referring to FIG. 3 , a hinged door 27 is seen on the bottom surface of enclosure 14 supported by a plurality of hinges 33. Only hinges 33 a and 33 b are seen in FIG. 3 . The hinged door 27 and the perimeter 39 of the base of the maintenance station enclosure 14 are fabricated using a ferromagnetic material (e.g., steel). The ferromagnetic material (e.g., steel) used to fabricate the perimeter 39 of the base of the maintenance station enclosure 14 enables the magnets 26 within first and second traction belts 24 a and 24 b as seen in FIG. 2 (traction belt 24 b not seen in FIG. 2 ) to remain magnetically attached to the base of the maintenance station enclosure 14 as it enters the biofouling ablation vehicle maintenance station 13. The width the hinged door 27 is less than the width between the inner edges of the first and second traction belts 24 a and 24 b, respectively, on the biofouling ablation vehicle 212 so that hinged door 27 can be opened without the requirement to overcome the attraction forces of the magnets imbedded within the traction belts 24 a and 24 b. The hinged door 27 provides operator access to the bottom surface of support frame 106 to enable access to and replacement of the removably attachable active electrode modules 46 seen in FIGS. 4, 7 through 7B within the array of ablation module assemblies 103 shown in FIG. 10 .
Turning next to FIG. 3A, the biofouling ablation vehicle maintenance station 213 of the second and preferred embodiment that is securely attached to hull 11 of ship 9 is seen in greater detail. A partially sectioned and cut away perspective view of the interior of the biofouling ablation vehicle maintenance station enclosure 214 reveals forced-convection heating unit 57 having fan 59 to circulate heated air and air intake vent 61 and cleaning water pressurization and control unit 56 that is connected to liquid flow lines (not shown) leading to a plurality of water jet nozzles 23 used for cleaning the exterior of the biofouling ablation vehicle 212 following its return to the biofouling ablation vehicle maintenance station 213 and the biofouling ablation vehicle 212 is exposure to forced-convection air heating to enable the removal of any surface accumulation of marine fouling on the exterior surfaces of the biofouling ablation vehicle 212. Power line 48 connected to ship electrical utility source (not shown) supplies electrical power (e.g., 440 volts, 3 cycle power at 60 Hz) to the forced-convection air heating unit 57 as well as the cleaning water pressurization and control unit 56. Water supply line 49 is connected to cleaning water pressurization and control unit 56 at water inlet port receptacle 69 with removably connectable water supply fitment 66 located at distal end of water supply line 49. An openable door 16 that is motor-actuated incorporates slot 7 (to accommodate reinforced electrical power and communication tether 8 attached to biofouling ablation vehicle 212) and is pivotably supported by the maintenance station enclosure 214 and is positioned at the entrance 18 (not shown) of the biofouling ablation vehicle maintenance station 213. Door 16 is wirelessly and remotely openable by a control system (not shown) within the biofouling ablation vehicle 212 to enable entrance into and exit from the biofouling ablation vehicle maintenance station 213.
In a preferred embodiment, door 16 having slot 7 is closed during the period of forced air convection heating of the exterior of the biofouling ablation vehicle 212 to at least 72° C. for the purpose of removing marine organisms from the exterior surfaces of the biofouling ablation vehicle 212. An air gap or other insulative material thickness of at least 0.25 inch is maintained between the inner surfaces of the biofouling ablation vehicle enclosure 214 and the principal components contained within the biofouling ablation vehicle 212 including the back-up battery 41, battery management system 45, power supply 42 and control and wireless communication system 44. A thickness of at least 0.25 inch assures that the principal components contained within the biofouling ablation vehicle 212 are maintained at acceptably low temperatures to prevent any thermal damage to these principal components during the forced-convection heating procedure. The use of forced convection heating within the enclosed biofouling ablation vehicle maintenance station enclosure 214 enables the exterior surfaces of the biofouling ablation vehicle 212 to be heated to at least 72° C. within a period of preferably less than 30 minutes.
Still referring to FIG. 3A, a hinged door 27 is seen on the bottom surface of enclosure 14 supported by a plurality of hinges 33. Only hinges 33 a and 33 b are seen in FIG. 3A. The hinged door 27 and the perimeter 39 of the base of the maintenance station enclosure 214 are fabricated using a ferromagnetic material (e.g., steel). The ferromagnetic material (e.g., steel) used to fabricate the perimeter 39 of the base of the maintenance station enclosure 214 enables the magnets 26 within the traction belts 24 a and 24 b seen in FIG. 2A (traction belt 24 b not seen in FIG. 2A) to remain magnetically attached to the base of the maintenance station enclosure 214 as it enters the biofouling ablation vehicle maintenance station 213. The width the hinged door 27 is less than the width between the inner edges of the first and second traction belts 24 a and 24 b, respectively, on the biofouling ablation vehicle 212 so that hinged door 27 can be opened without the requirement to overcome the attraction forces of the magnets imbedded within the traction belts 24 a and 24 b. The hinged door 27 provides operator access to the bottom surface of support frame 106 to enable access to and replacement of the removably attachable active electrode modules 46 seen in FIGS. 4, 7 through 7B within the array of ablation module assemblies 103 seen in FIG. 10 .
A sectional view of an active electrode assembly 100 including a removably attachable active electrode module 46 and an interconnection terminal array module 72 is shown in FIG. 4 . A plurality of interconnection terminal array modules 72 are secured to support frame 106 and enable the removably attachable active electrode module 46 to be replaced once the active electrodes 55 within the removably attachable active electrode module 46 have become eroded as a result of the ablation process used to molecularly dissociate marine fouling that has become attached to the hull 11 of the ship 9 below the water line. The interconnection terminal array module 72 incorporates a plurality of connector pins 70 that are individually attached to a connector pin base 68. Each a connector pin base 68 is in electrical communication with a cable harness 79 including an individual active electrode lead wire 74 for each connector pin base 68 within the interconnection terminal array module 72. The interconnection terminal array module 72 also supports common electrode connector pin 96. Upon attachment of a removably attachable active electrode module 46 to the interconnection terminal array module 72, the common electrode connector pin 96 removably attaches to a mating receptacle within and the common electrode 92 that surrounds and is electrically insulated from the active electrodes 55 as seen in FIG. 4 . The cable harness 79 is in electrical communication with each interconnection terminal array module 72 and extends to multiplexer 110 within power supply 42 (not shown). In addition, individual electrically isolated electrical lead wires within the cable harness 79 are in electrical communication with each connector pin 70 within the interconnection terminal array module 72. As seen in FIG. 4 , common electrode connector pin 96 is also in electrical communication with common electrode lead 98 that extends to a radiofrequency generator 95 (as seen in FIG. 8 ).
Turning now to FIG. 4A, a detailed sectional view of a portion of the ablation module seen in FIG. 4 reveals components within the removably attachable active electrode module 46 and the interconnection terminal array module 72. As seen in FIGS. 4 and 4A, interconnection terminal array module 72 incorporates a plurality of connector pins 70, each connector pin 70 supported by a connector pin base 68 secured within an electrically insulative connector pin base support member 63. The electrically insulative connector pin base support member 63 may be fabricated by machining holes in an electrically insulative plastic at predetermined locations wherein the machined hole size is selected to receive a commercially available connector pin base 68. In a preferred embodiment, each connector pin base 68 incorporates barbs 67 that secure the connector pin base 68 within the electrically insulative connector pin base support member 63 once inserted. In this regard and by way of example, a suitable machinable plastic material for the electrically insulative connector pin base support member 63 is Ultem 1000, a high strength, rigid thermoplastic polyetherimide material that can withstand continuous use at temperatures up to 170° C. The Ultem 1000 material is available in sheet form from Boedeker Plastics in Shiner, Texas. As seen in FIG. 4A, the bare portion of an individual lead wire 74 is in communication with each individual connector pin base 68 and the portion of each lead wire 74 is proximal to the connector pin base 68 is insulated by electrically insulative covering 76.
Still referring to FIG. 4A, a detailed sectional view of a portion of the removably attachable active electrode module 46 and the interconnection terminal array module 72 reveals individual active electrode 55 secured within active electrode support base 64 by electrically conductive adhesive 62. As seen in FIGS. 4 and 4A, removably attachable active electrode module 46 incorporates a plurality of active electrode support receptacles 65 adhesively secured (e.g., cyanoacrylate adhesive) within an electrically insulative active electrode subassembly support member 60. The electrically insulative active electrode subassembly support member 60 may be fabricated by machining holes in an electrically insulative plastic at predetermined locations that precisely match the locations of the connector pins 70 extending from the bottom face of interconnection terminal array module 72. The size of the plurality of machined holes in the electrically insulative active electrode subassembly support member 60 is selected to receive a commercially available connector receptacle 64 as seen in FIG. 5 . In this regard and by way of example, a suitable machinable plastic material for the electrically insulative active electrode subassembly support member 60 is Ultem 1000, a high strength, rigid thermoplastic polyetherimide material that can withstand continuous use at temperatures up to 170° C. The Ultem 1000 material is available in sheet form from Boedeker Plastics in Shiner, Texas.
As seen in FIG. 4A, each electrode 55 extends by a length, L₅distally from the electrically insulative castable ceramic potting material exterior end face 78 of the removably attachable active electrode module 46. The active electrode support base 64 extends a length, L₁₃beyond the end face 77 of the electrically insulative active electrode subassembly support member 60. An electrically insulative castable ceramic potting material is cast to a thickness of L₁₃beyond the end face 77 of the electrically insulative active electrode subassembly support member 60 to prevent unwanted molecular dissociation of the plastic material (e.g., Ultem 1000) used to fabricate the electrically insulative active electrode subassembly support member 60. In addition, as seen in FIG. 4A, the distal end of the active electrode support base 64 is recessed a distance, L₆from the electrically insulative castable ceramic potting material exterior end face 78 in order to prevent ablative erosion of the active electrode support base 64. In this regard and by way of example, a suitable electrically insulative castable ceramic potting material for the electrically insulative castable ceramic potting material, 75 is a fine-grained aluminum oxide filled potting material 575-N available from Aremco Products, Inc., Valley Cottage, N.Y. The aluminum oxide-filled potting material 575-N is capable of continuous operation at temperatures up to 1650° C.
Turning now to FIG. 5 , a sectional view of an active electrode subassembly 80, as seen in FIG. 4A, is seen in greater detail. Active electrode support base 64 receives active electrode 55. Active electrode 55 is secured within active electrode support base 64 by electrically conductive adhesive 62 that also provides electrical communication between active electrode 55 and active electrode support base 64. An active electrode supports receptable 65 integral with active electrode support base 64 is located at the proximal end of active electrode subassembly 80 for reversible engagement and electrical communication with connector pin 70 or interconnection terminal assembly 90 as seen in FIG. 6 . The active electrode seen in FIG. 5 may be a metal or alloy including tungsten, titanium, molybdenum, tantalum, Monel or Alloy. 400 (65% Ni and 32% Cu), Hastelloy C-276, rhenium, or niobium. By way of example, active electrode seen in FIG. 5 may be tungsten wire having a diameter, D₁in the range from 0.010 to 0.050 inch. Also, by way of example, active electrode support base 64 may be procured from connector company, LEMO USA located in Rohnert Park, California. In addition, by way of example, electrically conductive adhesive 62 may be EPO-TEK H20E available from Epoxy Technology, Billerica, Massachusetts.
An interconnection terminal assembly 90 is seen in FIG. 6 and is designed for electrical connection to the active electrode subassembly 80 seen in FIG. 5 by removable insertion of connector pin 70 into active electrode support receptable 65. The body of connector pin base 68 may include barbs 67 to secure its position within the electrically insulative support member 63 as seen in FIG. 4A. The interconnection terminal assembly 90 receives active electrode lead wire 74 that is bare at its distal end to enable electrical communication with connector pin base 68 and is covered by electrically insulative covering 76 along its length proximal to the connector pin base 68. By way of example, electrical communication and secure attachment between active electrode lead wire 74 connector pin base 68 may be accomplished by the mechanical deformation of a portion of connector pin base 68 that surrounds the bare portion of active electrode lead wire 74. Such mechanical deformation, also known as crimping, may be accomplished using a commercially available crimping tool from Astro Tool Corporation located in Beaverton, Oregon. Also, by way example, connector pin base 68 may be procured from connector company, LEMO USA located in Rohnert Park, California.
Various configurations of active electrodes 55 that extend from the castable ceramic potting material end face 78 of a removably attachable active electrode module 46 are shown in FIGS. 7 through 7D. A frontal view of a single row of active electrodes 55 of diameter, D₁are seen in FIG. 7 . The active electrodes 55 are electrically insulated from each other and from the common electrode 92. The active electrodes 55 are located at a uniform spacing, L₉along the length, L₁₁of the removably attachable active electrode module 46. By way of example and as seen in FIG. 7 , each active electrode 55 is surrounded by a ceramic electrical insulation 78, preferably an electrically insulative castable ceramic potting material as also seen in FIG. 4A. The perimeter of the of the array of active electrodes 55 and the electrically insulative castable ceramic potting material 75 are surround by a common electrode 92 as seen in FIG. 7 . While submerged in sea water, the only path for electrical current flow between the array of active electrodes 55 and the common electrode 92 is through the electrically conductive sea water (not shown) interposed between the array of active electrodes 55 and the common electrode 92. The total combined surface area of the common electrodes 92 that are in contact with sea water. 19 is substantially greater than the total combined surface area of all of the active electrodes 55 that are in contact with sea water 19.
In a preferred embodiment, O-ring 94 of diameter, D₈is secured within an O-ring groove (not shown) around the perimeter of the removably attachable active electrode module 46 to provide a water-tight seal between the removably attachable active electrode module 46 and the support frame 106 seen in FIG. 10 to prevent the ingress of sea water into the interface between the removably attachable active electrode module 46 and the interconnection terminal array module 72 as well as its proximal lead wires 74 and cable harness 79. By way of example, the common electrode 92 seen in FIGS. 4, 7-7D and 8 may be an electrically conductive metal or alloy that resists corrosion in sea water 19 such as, brass, stainless steel Type 316, Monel, and titanium or its alloys.
Turning now to FIG. 7A, a frontal view at the working end of a removably attachable active electrode module 46 including multiple rows of active electrodes 55 having a diameter D₁, an inter-electrode spacing between active electrodes of L₉wherein the active electrodes 55 are electrically isolated from each other by electrically insulative castable ceramic potting material 75 as also seen in FIG. 4A. The array of active electrodes 55 and the electrically insulative castable ceramic potting material 75 are surround by a common electrode 92 as seen in FIG. 7A. While submerged in sea water, the only path for electrical current flow between the array of active electrodes 55 and the common electrode 92 is through the electrically conductive sea water (not shown) interposed between the array of active electrodes 55 and the common electrode 92. In a preferred embodiment, O-ring 94 of diameter, D₈is secured within an O-ring groove (not shown) around the perimeter of the removably attachable active electrode module 46 to provide a water-tight seal between the removably attachable active electrode module 46 and the support frame 106 seen in FIG. 10 to prevent the ingress of sea water into the interface between the removably attachable active electrode module 46 and the interconnection terminal array module and its proximal lead wires.
A side view of the removably attachable active electrode module seen in FIG. 7 is seen in FIG. 7B showing an array of electrically isolated active electrodes extending above the surface of the electrically insulative castable ceramic potting material 75 (not seen). A common electrode 92 surrounds and is electrically isolated from the linear array of active electrodes 55 by electrically insulative castable ceramic potting material 75 (not seen). The active electrodes 55 of diameter, D₁seen in FIG. 7B are electrically isolated from one another, extend above the surface of the electrically insulative castable ceramic potting material 75 (not seen) by length, L₅and are positioned at a uniform spacing, L₉along the length, L₁₁of the removably attachable active electrode module 46. In a preferred embodiment, O-ring 94 of diameter, D₈is secured within an O-ring groove (not shown) around the perimeter of the removably attachable active electrode module 46 to provide a water-tight seal between the removably attachable active electrode module 46 and the support frame 106 seen in FIG. 10 to prevent the ingress of sea or other water into the interface between the removably attachable active electrode module 46 and the interconnection terminal array module and its proximal lead wires.
A partial frontal view at the working end of a removably attachable active electrode module 46 is seen in FIG. 7C showing a single row of rectangular electrically isolated active electrodes 55 surrounded at the perimeter of the array of active electrodes 55 by and electrically insulated from common electrode 92. As seen in FIG. 7C, rectangular active electrodes 55 having a major length, L₁₀and minor length, L₁₂are electrically insulated from one another by electrically insulative castable ceramic potting material 75. Each active electrode 55 is surrounded by electrically insulative castable ceramic potting material 75, preferably an electrically insulative castable ceramic potting material as also seen in FIG. 4A. The linear array of active electrodes 55 and the electrically insulative castable ceramic potting material 75 are surrounded by a common electrode 92 as seen in FIG. 7C. The only path for electrical current flow between the array of active electrodes 55 and the common electrode 92 is through the electrically conductive sea water (not shown) interposed between the array of active electrodes 55 and the common electrode 92. In a preferred embodiment, O-ring 94 of diameter, D₈is secured within an O-ring groove (not shown) around the perimeter of the removably attachable active electrode module 46 to provide a water-tight seal between the removably attachable active electrode module 46 and the support frame 106 seen in FIG. 10 to prevent the ingress of sea or other water into the interface between the removably attachable active electrode module 46 and the interconnection terminal array module 72 and its proximal lead wires.
A partial frontal view at the working end of a removably attachable active electrode module 46 is seen in FIG. 7D showing two rows of square electrically isolated active electrodes 55 surrounded at the perimeter of the array of active electrodes 55 by and electrically insulated from common electrode 92. As seen in FIG. 7D, square electrodes 55 having a length, L₁₀on each side are electrically insulated from one another by electrically insulative castable ceramic potting material 75. Each active electrode 55 is surrounded by electrically insulative castable ceramic potting material 75 as also seen in FIG. 4A. The linear array of active electrodes 55 and the electrically insulative castable ceramic potting material 75 are surround by a common electrode 92 as seen in FIG. 7C. While submerged in sea water, the only path for electrical current flow between the array of active electrodes 55 and the common electrode 92 is through the electrically conductive sea water (not shown) interposed between the array of active electrodes 55 and the common electrode 92. In a preferred embodiment, O-ring 94 of diameter, D₈is secured within an O-ring groove (not shown) around the perimeter of the removably attachable active electrode module 46 to provide a water-tight seal between the removably attachable active electrode module 46 and the support frame 106 seen in FIG. 10 to prevent the ingress of sea or other water into the interface between the removably attachable active electrode module 46 and the interconnection terminal array module 72 and its proximal lead wires.
Turning now to FIG. 8 , an enlarged sectional view of the distal end of the removably attachable active electrode module 46 seen in FIG. 7 is shown illustrating a vapor layer 58 formed between the distal end face 71 of active electrode 55 and the layer of marine organisms 21 attached to the marine antifouling coating 25 adhered to the hull 11 of ship. A voltage of V₁is applied between the active electrode 55 and the common electrode 92, inducing an electric field between the active electrode 55 and the common electrode 92 and, thereby, inducing electrical current flow lines 73 a, 73 b and 73 c within the active electrode 55, sea water 19 and common electrode 92, respectively. As seen in FIG. 8 , electrical current flows, in series, from radiofrequency generator 95 through first active electrode lead 97 to its current limiting inductor 108 and from current limiting inductor 108 to active electrode 55 through second active electrode lead 112. The path of electrical current continues through distal end face 71 of active electrode 55 and across the vapor layer 58 and through the sea water 19 to the common electrode 92 to complete its path through lead 98 to the radiofrequency generator 95. Alternatively, other circuitry including one or more inductors and/or one or more capacitors may be implemented to effect the current limiting function for each individual active electrode.
As seen in FIG. 8 , the intensity of the electric field is higher in region 91 adjacent to the distal end face 71 of the active electrode 55 due to the concentration of the current flux lines in the vicinity of the active electrode 55. An electric field of sufficient intensity is applied between each active electrode 55 and the common electrode 92 as seen in FIG. 8 . The applied electric field ionizes an ionizable species present in the sea water, 19 (viz., sodium) within a vapor layer 58 of thickness L₁₃that is formed between the active electrode 55 and the surface of the marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9. The ionization of the ionizable species within the vapor layer 58 creates a plasma. This ionization generates free electrons and photons within the vapor layer 58 that become energized in the presence of the applied electric field. The energized electrons and photons induce the molecular dissociation of marine organisms 21 that are in contact with the ionized vapor layer 58 formed at the distal end face 71 of each active electrode 55. The energy evolved by the energetic electrons that bombard molecules within the marine organisms 21 break their organic chemical bonds thereby dissociating the molecules including the marine organisms 21 into free radicals that combine into nonviable gaseous species 81, solid species and species that go into solution within the sea water. As a consequence, the marine organisms 21 that attach to the antifouling coating 25 adhered to the surface of the hull 11 of the ship 9 are removed and the products of their molecular dissociation are nonviable byproducts.
By way of example of the power supply 42 energizing active electrodes 55, a radiofrequency generator 95 produces an applied voltage, V₁in the range from 200 to 2000 volts (peak-to peak) at a frequency in the range from 10 kHz to 1,000 kHz, preferably in the range from 50 kHz to 500 kHz. A predetermined level of applied voltage, V₁is selected to produce an electric field intensity sufficient to ionize the ionizable species within sea water 19 (viz., sodium) and create a plasma that emits electrons whose energy is sufficient to induce the molecular dissociation of marine organisms 21 attached to the marine antifouling coating 25 adhered to the hull 11 of the ship 9. The thickness of the vapor layer, L₁₆that is formed between the distal end face 71 of active electrode 55 and the surface of the marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9 ranges from about 0.05 to 1.5 mm (0.002 to 0.060 inch).
By way of an alternative example for the current limiting circuitry within power supply 42, each active electrode 55 may be powered by an independent feedback-controlled voltage source within power supply 42 that adjusts the applied voltage in correspondence to the electrical impedance in the circuit including the current path between each active electrode 55 and the common electrode 92.
In a preferred embodiment, an ablation module assembly 102 includes a plurality of removably attachable active electrode modules 46 as seen in FIG. 9 . In the example embodiment seen in FIG. 9 , the ablation module assembly 102 includes four removably attachable active electrode modules 46 a-46 d, as seen in the form of an individual module in FIG. 7A, to from an ablation module assembly 102 having a preferred length, L₁₄and width, W₃. The common electrodes, 92 a-92 d corresponding to each of the individual removably attachable active electrode modules 46 a-46 d, respectively, are in electrical communication with common electrode lead 98 as seen in greater detail in FIG. 4 . Each of the individual removably attachable active electrode modules 46 a-46 d is removably attached to a corresponding interconnection terminal array module 72 shown in FIGS. 4 and 4A but not seen in FIG. 9 . The segmentation of the full-length ablation module assembly 102 having length, L₁₄into shorter-length removably attachable active electrode modules 46 a-46 d having individual lengths, L₃facilitates the removal and replacement of individual removably attachable active electrode modules 46 a-46 d. The removal and replacement of individual ablation modules 46 is required when the elapsed duration of the activation, t₁of the ablation module assembly 102 incorporating multiple removably attachable active electrode modules 46 to effect the intended ablation of marine organisms 21 reaches a predetermined maximum duration of use, t_max. The predetermined maximum duration of use, t_maxis experimentally determined based on the rate of erosion of the active electrodes 55 during the process of molecular dissociation of marine organisms 21 under actual sea water conditions and attached layers of marine organisms 21 having a thickness, L₁₃as seen in FIG. 8 .
In the exemplary embodiment seen in FIG. 10 , the ablation module assembly 102 seen in FIG. 9 is configured into an array of ablation module assemblies 103 including seven individual ablation module assemblies 102 a-102 g. Each individual removably attachable active electrode module 46 within each ablation module assembly 102 is removably attached to a corresponding ablation module assembly 102 (shown in FIG. 4A but not seen in FIG. 9 ) and each ablation module assembly 102 is secured to support frame 106. Support frame 106 is attached to a bottom facing surface 122 of biofouling ablation vehicle 12 (not seen in FIG. 10 but identified in FIG. 2 ) so that the distal ends of all active electrodes 55 are in close proximity to the marine organisms 21 to effect the attended ablation of the marine organisms 21 as illustrated in FIG. 8 . Support frame 106, having length, L₁₅and width, W₇is oriented on bottom facing surface 122 of biofouling ablation vehicle 12 so that front end 118 of support frame 106 aligns with the front end 35 of biofouling ablation vehicle 12. The direction of advancement of the array of ablation module assemblies 103 during the ablation of marine organisms 21 is seen at arrow 104.
Still referring to FIG. 10 , the array of ablation module assemblies 103 enables one individual ablation module assembly 102 (e.g., ablation module assembly 102 a) within the array of seven ablation module assemblies 102 a-102 g to be selectively energized by multiplexer 110 seen in FIG. 11 . Each selectively energized ablation module assembly 102 ablates marine organisms 21 as the biofouling ablation vehicle 12 or 212 (i.e., either the battery-powered or externally, tether powered biofouling ablation vehicle) advances along the hull 11 of the ship 9 until the elapsed duration of its activation, t₁for the intended ablation of marine organisms 21 reaches a predetermined maximum duration of use, t_max. Once the predetermined maximum duration of use, t_maxfor an individual ablation module assembly 102 is reached, then the control system 44 within the biofouling ablation vehicle 12 or 212 suspends the application of a predetermined level of voltage, V₁to that “used” ablation module assembly 102 (e.g., ablation module assembly 102 a) and redirects the application of a predetermined level of voltage, V₁to the next available “unused” ablation module assembly 102 (e.g., ablation module assembly 102 b) using multiplexer 110 seen in FIG. 11 . After all individual ablation module assemblies 102 (e.g., 102 a through 102 g) in the overall array of ablation module assemblies 103 have reached their predetermined maximum duration of use, t_max, then the biofouling ablation vehicle 12 or 212 is programmed to return to the biofouling ablation vehicle maintenance station 13 to enable the replacement of each “used” removably attachable active electrode module 46 within each individual ablation module assembly 102. In this manner, the total duration of the ablation of marine organisms 21, prior to requiring interruption to replace used removably attachable active electrode modules 46, can be advantageously increased in proportion to the number of individual ablation module assemblies 102 within the overall array of ablation module assemblies 103.
Still referring to FIG. 10 , a plurality of front-end digital image or other sensors 130 a-130 i are seen at the front end 118 of the support frame 106 that is attached to the bottom surface of biofouling ablation vehicle 12 or 212. The surface of the hull 11 of the ship within the view of each of the individual front-end digital image or other sensors 130 a-130 i is illuminated by a plurality of adjacent front-end light sources 132 a-132 i as seen in FIG. 10 . Likewise, a plurality of back-end digital image or other sensors 136 a-136 i are seen at the back end 120 of the support frame 106 that is attached to the bottom surface of biofouling ablation vehicle 12 or 212. The surface of the hull 11 of the ship 9 within the view of each of the individual back-end digital image or other sensors 136 a-136 i is illuminated by a plurality of adjacent back-end light sources 138 a-138 i as seen in FIG. 10 . By way of example, the optical images acquired by the plurality of front-end digital image sensors 130 a-130 i and back-end digital image sensors 136 a-136 i can be remotely observed by operator 5 at the command and control center 6 as seen in FIGS. 1 and 1A in real time or recorded for later review to assess the level of marine organisms 21 attached to the antifouling coating 25 on the hull 11 of the ship. For the preferred embodiment wherein the biofouling ablation vehicle 12 or 212 is connected to the reinforced power and communication tether 8, the video signals from digital image sensors 130 and 136 are transmitted to the command and control center 6 through fiber optic and/or data cable 254. The optical images acquired by the plurality of front-end digital image sensors 130 a-130 i can be used to observe the level of marine organisms 21 attached to the antifouling coating 25 prior to molecular dissociation of the attached marine organisms 21 (i.e., the “before” digital images) while the optical images acquired by the plurality of back-end digital image sensors 136 a-136 i can be used to observe the level of marine organisms 21 remaining after the molecular dissociation of the attached marine organisms 21 (i.e. the “after” digital images). In addition, the “before” and “after” digital images can be used dynamically (i.e. in real time) in combination with image-processing software to digitally determine the extent or completeness of the removal of marine organisms 21 and thereby provide dynamic feedback to the control and communication system 44 to adjust the speed of advancement of the marine antifouling vehicle 12 or 212 and/or the level of voltage, V₁applied by the radiofrequency generator 95 as seen in FIG. 11 . The higher the level of voltage, V₁applied by the radiofrequency generator 95, the greater the rate of molecular dissociation of the marine organisms 21 attached to the antifouling coating adhered to the hull 11 of the ship.
Still referring to FIG. 10 and by way of example, front-end digital image sensors 130 a-130 i and back-end digital image sensors 136 a-136 i may be similar to the digital image sensors used in smart phones. By way of example, the plurality of digital image sensors 130 and 136 may be a 13-megapixel image sensor whose individual pixel size is 1.12 microns×1.12 microns (where the unit micron refers to micrometer) in an array of 4224×3136 pixels and available as Model No. OV13853 image sensor available from OmniVision Technologies, Inc., Santa Clara, California. Each commercially available, high resolution 13-megapixel image sensors may be combined with optical lens to enable the close-range acquisition of detailed images of the type and extent of marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9. By way of example, the front-end light sources 132 a-132 i and back-end light sources 138 a-138 i are preferably light emitting diodes similar to the light sources incorporated in combination with the digital image sensors incorporated in smart phones such as the Apple iPhones.
The plurality of digital image sensors 130 a-130 i and 136 a-136 i on the bottom facing surface 122 (i.e., hull facing surface) of the biofouling ablation vehicle 12 or 212 that are positioned along the front end and back end 35 and 37, respectively, of the biofouling ablation vehicle 12 or 212 enable the inspection of the surface of the hull 11 both immediately before and immediately after the in-water, ablation of marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9. In addition, the biofouling ablation vehicle 12 or 212 can be used for the purpose of inspection of the hull 11 of the ship 9 (e.g., assess the extent and depth of pitting corrosion and associated hull thinning), the condition of its antifouling coating 25 and the extent of biofouling using the plurality of digital image sensors mounted on the biofouling ablation vehicle 12 or 212. This also enables the determination of the extent of biofouling accumulation between hull cleaning cycles using an intelligent image recognition system combined with incremental machine learning to automate the assessment of biofouling and guide the frequency of hull cleaning operations as well as the condition of the ship's hull and antifouling coating. In this regard, refer to Mittendorf, M. et. al., Capturing the Effect of Biofouling on Ships by Incremental Machine Leaning. Applied Ocean Research 2023; 138:1-15. Also refer to Bloomfield, N. et. al., Automating the Assessment of Biofouling in Images Using Expert Agreement as a Gold Standard. Scientific Reports 2021; 11: 2379-2388. In addition, also refer to Chin, C. S., et. al., Intelligent Image Recognition System for Marine Fouling Using Softmax Transfer Learning and Deep Convolutional Neural Networks. Complexity; Volume 2017; 1-9 (published by Hindawi).
As seen in FIG. 10 , each ablation module assembly 102 a-102 g is oriented at an angle, D₁so that the regions 126 of length, L₁₇between the nearest active electrodes 55 in adjacent removably attachable active electrode modules 46 in an individual ablation module assembly 102 do not result in areas (e.g., strips) of marine organisms 21 that are not ablated and removed from the site of their attachment to the antifouling coating 25 adhered to the hull 11 of the ship 9. The required angle, Φ₁is determined by the particular arrangement and spacing of the individual active electrodes 55 and the spacing between adjacent removably attachable ablation modules 46.
A schematic circuit diagram for power supply 42 is seen in FIG. 11 incorporating a total of N current limiting inductors 108, one inductor in electrical communication with each active electrode 55 incorporated in any single removably attachable active electrode module 46, as seen in FIGS. 9 and 10 , combined with a multiplexer 110 to allow the set of N current limiting inductors to be selectively connected by the control system 44 to any one of the individual ablation module assemblies 102. By way of example, seven ablation module assemblies 102 a-102 g are seen in FIG. 11 . Each individual ablation module assembly 102 is in electrical communication with the multiplexer 110 through cable harness 79.
By way of further and more detailed example and referring to FIG. 11 , a single active electrode 55 a in ablation module assembly 102 a is in electrical communication with a corresponding inductor 108 a through lead wires in cable harness 79 a that connects to a multiplexer 110 and continuing to a first inductor 108 a via a second active electrode lead 112 a. For an example case of 100 active electrodes 55 in each removably attachable active electrode module 46 in the individual ablation module array 102 a, the four individual ablation modules arrays 46 a-46 d will incorporate a total of 400 active electrodes 55. Accordingly, a total of 400 inductors 108 will be required in power supply 42 if an individual ablation module array 102 incorporates a total of 400 active electrodes 55. Since only one individual ablation module array 102 is energized by the radiofrequency generator 95 during the period of its use to induce molecular dissociation of marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship, the N inductors (e., 400) can be selectively brought into electrical communication with any one of the other six individual ablation module arrays 102 within the array of ablation module assemblies 103 seen in FIG. 11 .
Once the predetermined maximum duration of use, t_maxfor an individual ablation module assembly 102 is reached, then the control system 44, as seen in FIGS. 2 and 11 , suspends the application of a predetermined level of voltage, V₁to that depleted ablation module assembly 102 (e.g., ablation module assembly 102 a) and redirects the application of a predetermined level of voltage, V₁to the next available unused ablation module assembly 102 (e.g., ablation module assembly 102 b) using multiplexer 110. As seen in FIG. 11 , control system 44 is in communication with radiofrequency generator 95 through lead cable 116 and control system 44 is in communication with multiplexer 110 through lead cable 114 to enable the selection of the individual ablation module array 102 to be energized by the radiofrequency generator 95.
The set of FIGS. 16, 17, 18 and 18A illustrate an alternative embodiment having a U-shaped active electrode assembly 298 comprising an active electrode 300, first support leg 308 of active electrode 300, second support leg 310 of active electrode 300 and common electrode 92. As seen in the sectional view of FIG. 16 , the U-shaped active electrode assembly 298 is formed by a substantially flat active electrode 300 supported at either end by first support leg 308 and second support leg 310. The proximal ends of first support leg 308 and second support leg 310 are mounted within an electrically insulative castable ceramic potting material 75. In this regard, see Aremco 671 alumina oxide castable ceramic supplied by Aremco Products, Inc., Valley Cottage, New York). A seen in FIG. 16 , the surface of the active electrode 300, first support leg 308 and second support leg 310 are covered by a thin, adherent electrically insulative coating 302 except along the leading edge 304 of active electrode 300 (not seen in FIG. 16 but seen in FIG. 17 ). By way of example, the electrically insulative coating 302 may, by way of example, be polyimide having a thickness in the range from 0.0003 to 0.0010 inches. As seen in FIG. 16 , common electrode 92 is also disposed on the surface of the electrically insulative castable ceramic potting material 75. The electrically insulative coating 302 covers the entire surface of the active electrode 300, the first support leg 308 and the second support leg 310 so that electrical current flow the active electrode 300 is confined to only the limited area of the leading edge 304 of the active electrode thereby achieving a current flux sufficient to induce a vapor layer 58 at the interface between the uninsulated leading edge 304 of the active electrode 300 and the marine organisms 21.
A top view of the U-shaped active electrode assembly 298 seen in FIG. 16 is shown in FIG. 17 revealing the leading edge 304 positioned at the front 312 of the active electrode 300 that extends beyond the electrically insulative coating 302 that otherwise covers the surfaces of the active electrode 300, the first support leg 308 and the second support leg 310. The U-shaped active electrode assembly is removably attachable to the underside 109 of biofouling ablation vehicle 12 or 212 as seen earlier in FIG. 10 .
The marine organisms 21 that attach to the antifouling coating 25 on the hull of the ship 9 (antifouling coating and hull of ship not shown) are seen adjacent to leading edge 304 of the active electrode 300 and in the path of the advancing U-shaped active electrode assembly 298 as indicated by the direction of advancement 104 of biofouling ablation vehicle 12 or 212. As the active electrode assembly 298 is advanced along the surface of the hull 9 of the ship, the active electrode 300 is energized to achieve molecular dissociation of the marine organisms 21 adjacent to the leading edge 304 of the active electrode 300 and attached to the surface of the antifouling coating 25 on the hull 11 of the ship 9. As seen at the back 314 of active electrode 300, the marine organisms 21 previously attached to the surface of the antifouling coating 25 have been removed thereby exposing the antifouling coating 25 to the surrounding sea water 19.
A sectional view of the active electrode assembly 298 is seen in FIG. 18 revealing the leading edge 304 of the active electrode 300 as it engages marine organisms 21 as well as the path of electrical current flow lines 73 b through the sea water 19, electrical current flow lines 73 b extending from the exposed, electrically uninsulated surface of leading edge 304 of active electrode 300 to the common electrode 92.
As seen in FIG. 18 , electrical current flows, in series, from radiofrequency generator 95 through first active electrode lead 97 to a current limiting inductor 108 and from current limiting inductor 108 to active electrode 300 through second active electrode lead 112. The path of electrical current continues through distal end face of leading edge 304 of active electrode 300 and across the vapor layer 58 and through the sea water 19 to the common electrode 92 to complete its path through lead 98 to the radiofrequency generator 95. Alternatively, other circuitry including one or more inductors and/or one or more capacitors may be implemented to effect the current limiting function for each individual active electrode.
As seen in FIG. 18 , the intensity of the electric field is higher in region 91 adjacent to the distal end face 71 of the active electrode 300 due to the concentration of the current flux lines in the vicinity of the active electrode 300. An electric field of sufficient intensity is applied between each active electrode 300 and the common electrode 92 as seen in FIG. 18 . The applied electric field ionizes an ionizable species present in the sea water, 19 (viz., sodium) within a vapor layer 58 of thickness L₁₆that is formed between the active electrode 300 and the surface of the marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9. The ionization of the ionizable species within the vapor layer 58 creates a plasma. This ionization generates free electrons and photons within the vapor layer 58 that become energized in the presence of the applied electric field. The energized electrons and photons induce the molecular dissociation of marine organisms 21 that are in contact with the ionized vapor layer 58 formed at the distal end face of the leading edge 304 of each active electrode 300. The energy evolved by the energetic electrons that bombard molecules within the marine organisms 21 break their organic chemical bonds thereby dissociating the molecules comprising the marine organisms 21 into free radicals that combine into nonviable gaseous species 81, solid species and species that go into solution within the sea water. As a consequence, the marine organisms 21 that attach to the antifouling coating 25 adhered to the surface of the hull 11 of the ship 9 are removed and the products of their molecular dissociation are nonviable byproducts.
By way of example of the power supply 42, as seen on FIGS. 2 and 2A that energizes one or more active electrodes 300, a radiofrequency generator 95 produces an applied voltage, V₁in the range from 200 to 2000 volts (peak-to peak) at a frequency in the range from 10 kHz to 1,000 kHz, preferably in the range from 50 kHz to 500 kHz. A predetermined level of applied voltage, V₁is selected to produce an electric field intensity sufficient to ionize the ionizable species within sea water 19 (viz., sodium) and create a plasma that emits electrons whose energy is sufficient to induce the molecular dissociation of marine organisms 21 attached to the marine antifouling coating 25 adhered to the hull 11 of the ship 9. The thickness, L₁₆of the vapor layer 58 that is formed between the distal end face of the leading edge 304 of the active electrode 300 and the surface of the marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9 ranges from 0.05 to 1.5 mm (0.002 to 0.060 inches).
By way of an alternative example for the current limiting circuitry within power supply 42, each active electrode 300 may be powered by an independent feedback-controlled voltage source within power supply 42 that adjusts the applied voltage in correspondence to the electrical impedance in the circuit comprising the current path between each active electrode 300 and the common electrode 92.
Turning now to FIG. 18A, an enlarged sectional view of the leading edge 304 of active electrode 300, as previously seen in FIG. 18 , revealing vapor layer 58 formed between the active electrode 300 and the marine organisms 21. As seen in greater detail in FIG. 18A, the leading edge 304 of active electrode 300 extends beyond the electrically insulative coating 302 by a distance, L₂₃that represents the length of the leading edge 304. The length, L₂₃, of the leading edge 304 ranges from 0.005 to 0.030 inches. The active electrode 300 seen in FIGS. 16, 18 and 18A may be a metal or alloy comprising tungsten, titanium, molybdenum, tantalum, Monel or Alloy. 400 (65% Ni and 32% Cu), Hastelloy C-276, rhenium, platinum or niobium.
The application of a predetermined voltage of 200 to 2000 volts (peak-to-peak), preferably 500 to 1000 volts (peak-to-peak) at a frequency in the range from 10 kHz to 1,000 kHz, preferably in the range from 50 kHz to 500 kHz, combined with a leading edge 304 having a thickness, t₁limited to the range from 0.001 to 0.040 inches, preferably in the range from 0.003 to 0.020 inches, produces an electric field intensity sufficient to ionize the ionizable species within sea water 19 (viz., sodium) and create a plasma that emits electrons whose energy is sufficient to induce the molecular dissociation of marine organisms 21 attached to the marine antifouling coating 25. The generation of energetic electrons within the plasma formed between the leading edge 304 of the active electrode and the marine organisms 21 also causes the erosion of the metallic active electrode 300 and the molecular dissociation of the electrically insulative coating 302 in close proximity to the leading edge 304 of the active electrode 300. The extent of the molecular dissociation of the electrically insulative coating 302 is limited by the range of the energetic electrons within the plasma formed between the leading edge 304 of the active electrode and the marine organisms 21 and determines the length, L₂₃of the leading edge 304 of the active electrode.
Advantageously, the selection of the width, W₉of the active electrode 300 that is substantially greater than the length, L₂₃of the leading edge allows the erosion of the leading edge 304 to occur while continuing to simultaneously remove the electrically insulative coating 302 to maintain the length, L₂₃of the leading edge 304 as the active electrode 300 erodes in the presence of the generated plasma. In this manner, the active electrode 300 is slowly eroded yet continues to provide the dimensions essential to maintain an electric field intensity sufficient to maintain the plasma required for the intended molecular dissociation of the marine organisms.
By way of example, returning to FIGS. 16 and 18 , the width, W₉of the active electrode 300 is preferably in the range from 0.20 to 0.70 inches and the length, L₂₃of the uninsulated leading edge 304 of the active electrode is 0.005 to 0.030 inches. As a result of the substantially greater length, W₉of the active electrode 300 compared to the length, L₂₃of the leading edge 304, the useful life of the U-shaped active electrode assembly 298 for the molecular dissociation of marine organisms is substantially increased.
A perspective view of the active electrode assembly 298 seen in FIGS. 16, 17 and 18 is seen in FIG. 19 revealing the active electrode 300, first support leg 308, second support leg 310, common electrode 92. As seen in FIG. 19 , the proximal ends of the first support leg 308 and the second support leg 310 are positioned within a castable ceramic 75. The common electrode 92 is positioned on the surface of the castable ceramic as seen in FIG. 19 .
Still referring to FIG. 19 , electrical current flows, in series, from the radiofrequency generator 95 through first active electrode lead 97 to a current limiting inductor 108 and from the current limiting inductor 108 to active electrode 300 through second active electrode lead 112. The path of electrical current continues through distal end face of leading edge 304 of active electrode 300 and across the vapor layer (not shown) and through the sea water (not shown) to the common electrode 92 to complete its path through lead 98 to the radiofrequency generator 95. Although not shown in FIG. 19 but previously seen in FIGS. 16, 17, 18 and 18A, active electrode 300, first support leg 308 and second support leg 310 are covered by active electrode electrically insulative coating 302.
Referring now to FIG. 20 , an alternative embodiment of the present disclosure is illustrated wherein the active electrode assembly 298 seen in FIGS. 16, 17, 18 and 19 is combined with a separate liquid delivery conduit 318. Referring now to FIGS. 18 and 20 , the liquid delivery conduit 318 supplies an electrically conductive liquid 316 into the gap 320 between the leading edge 304 of active electrode 300 and the common electrode 92 providing and electrical path for electrical current flow from the leading edge 304 of active electrode 300 and the common electrode 92. The concentration of the sodium chloride in the electrically conductive liquid 316 is preferably in the range from 0.8% to 3.6%, by weight.
As seen in FIG. 20 , the combination of the active electrode assembly 298 with a separate liquid delivery conduit 318 that supplies electrically conductive liquid 316 containing sodium chloride enables the application of a predetermined level of applied voltage, V₁to produce an electric field intensity sufficient to ionize the ionizable species (viz., sodium) within the sodium chloride containing electrically conductive liquid 316 to create a plasma that emits electrons whose energy is sufficient to induce the molecular dissociation of marine organisms 21 attached to a surface that is not submerged in sea water 19. By way of example, the molecular dissociation of marine organisms 21 attached to the marine antifouling coating 25 adhered to the hull 11 of the ship 9 while the hull 11 of the ship 9 is out of the sea water 19, for example, while the ship is in a dry dock for repairs and/or for hull cleaning.
By way of further example, as seen in FIG. 20 , the combination of the active electrode assembly 298 with a separate liquid delivery conduit 318 that supplies electrically conductive liquid 316 containing sodium chloride enables the application of a predetermined level of applied voltage, V₁to produce an electric field intensity sufficient to ionize the ionizable species (viz., sodium) within the sodium chloride containing electrically conductive liquid 316 to create a plasma that emits electrons whose energy is sufficient to induce the molecular dissociation of any organic material in the direction of advancement 104 of the leading edge 304 of the active electrode 300.
In addition to the example dimensions specified earlier, the range of preferred dimensions for the various components seen in FIGS. 1-10 are listed below where all dimensions are in units of inches unless noted otherwise and are labeled as shown in the referenced figures.


L₁= 24 to 60
L₂= 34 to 70
L₃= 5.0 to 18.0
L₄= 6.0 to 19.0
L₅= 0.010 to 0.080
L₆= 0.020 to 0.040
L₇= 0.6 to 1.6
L₈= 0.8 to 2.0
L₉= 0.010 to 0.050
L₁₀= 0.020 to 0.065
L₁₁= 4.8 to 17.8
L₁₂= 0.010 to 0.060
L₁₃= 0.04 to 0.20
L₁₄= 24 to 60
L₁₅= 23 to 58
L₁₆= 0.002 to 0.060
L₁₇= 0.3 to 0.7
L₁₈= 0.2 to 1.0
L₁₉= 0.2 to 1.0
L₂₀= 100 to 1200 feet
L₂₁= 50 to 250 feet
L₂₂= 0.15 to 0.50
L₂₃= 0.005 to 0.030
W₁= 24 to 60
W₂= 30 to 66
W₃= 0.30 to 0.75
W₄= 0.25 to 0.60
W₅= 0.20 to 0.50
W₆= 0.10 to 0.40
W₈= 0.5 to 3.0
W₉= 0.20 to 1.00
W₁₀= 0.05 to 0.15
H₁= 6 to 24
H₂= 10 to 30
H₃= 0.5 to 1.5
H₄= 0.5 to 1.5
H₅= 0.5 to 1.0
D₁= 0.010 to 0.100
D₂= 0.030 to 0.130
D₃= 0.025 to 0.050
D₄= 0.012 to 0.100
D₅= 0.020 to 0.050
D₆= 0.020 to 0.050
D₇= 0.005 to 0.025
D₈= 2 to 5
D₉= 6 to 20 mm
(0.24 to 0.79 inch)
D₁₀= 0.10 to 0.35
t₁= 0.003 to 0.020
t₂= 0.0003 to 0.0010
t₃= 0.001 to 0.020

The set of FIGS. 12A-12C combine, as labeled thereon, to provide a flow chart describing the first embodiment of the disclosed system. Looking to FIGS. 2 and 12A, the procedure starts, as represented at block 150 and line 152 with the selection of the particular biofouling ablation vehicle 12 to be activated for use in the repetitive cleaning of the intended hull 11 of the ship 9 to remove attached marine organisms 21. This selection step is necessary as there may be multiple biofouling ablation vehicles 12 in simultaneous use on the hull 11 of a specific ship 9. The battery 40 within the selected biofouling ablation vehicle 12 is charged and the computer of the control and communication system 44 is activated as represented at block 154 and line 156.
Next, previously acquired topographical map data is entered into the control and communication system 44 for the specific portion of the ship hull to be cleaned by the biofouling ablation vehicle 12 as represented at block 158 and line 160. A preferred method for the mapping of a curved ship hull utilizes an underwater visual mapping method for reconstructing the 3D surface model of the ship hull 11 using a stereo vision system as its primary mapping sensor. In the preferred method, the camera trajectory and surface element map (i.e., map of dense set of points holding lighting information) are optimized through the graph-based simultaneous localization and mapping (SLAM) framework. In this regard, see Chung, D., et. al., Underwater Visual Mapping of Curved Ship Hull Surface Using Stereo Vision. Autonomous Robots 2023; 47: 109-120.
As seen in FIG. 12A, the next step is the insertion of new (i.e., unused) removably attachable active electrode modules 46 into each interconnection terminal array module 72 as represented at block 162 and line 164. Having completed the above listed steps, the biofouling ablation module is positioned on the hull 11 of the ship, being secured to the hull of the hull 11 by permanent magnets 26 within the first and second traction belts 24 a and 24 b, respectively, above the water line 137 seen in FIG. 13 and wirelessly commanded by the control and communication system 44 to proceed to its assigned biofouling ablation module maintenance station 13 as represented at block 166 and line 168. Next, the timers for the elapsed duration of usage for ablation, t_ifor each ablation module assembly 102 within the biofouling ablation vehicle 12 are set to a zero elapsed time (e.g., t₁=0, t₂=0, . . . , t_N=0) where N refers to the total number of ablation module assemblies 102 in the array of ablation module assemblies 103 incorporated with the biofouling ablation vehicle 12 as represented at block 170 and line 172.
Referring now to FIG. 12B, a query is posed at block 174 regarding the state of charge (SOC) of battery 40 as determined by the battery management system 45 within the biofouling ablation vehicle 12. If the state of charge of battery 40 is less than the minimum allowed state of charge, SOC_MIN, as seen at line 176, then biofouling ablation vehicle 12 is instructed to return to the biofouling ablation module maintenance station 13 for automatic recharging as represented at block 178 and line 180. After automatic recharging, the query is posed at block 174 regarding the state of charge (SOC) of battery 40 is repeated. If the state of charge is greater than or equal to the minimum allowed state of charge, SOC_MINas seen at line 182, the biofouling ablation vehicle proceeds to its pre-programmed start and begins programmed hull cleaning path 146 a on hull 11 of ship 9 as seen, by way of example, in a partial view in FIG. 14 and commences ablation of marine organisms 21 attached to the antifouling coating 25 on the hull 11 of the ship 9 as represented at block 184 and line 186.
A query is posed at block 188 regarding the amount of activation (i.e., ablation) time, t₁for the currently used ablation module assembly 102. If the amount of activation (i.e., ablation) time, t_ifor the currently used ablation module assembly 102 is greater than or equal to a predetermined maximum allowed elapsed duration of usage for ablation, t_MAXthen, as seen at line 190, a sequential query is posed at block 192 to determine if the currently used ablation module assembly 102 is the Nth (i.e., last unused) ablation module assembly 102 where N refers to the total number of ablation module assemblies 102 in the array of ablation module assemblies 103 within the biofouling ablation vehicle 12. By way of example, the total number of ablation module assemblies 102, as seen in FIG. 10 , is seven or N=7 in the example array of ablation module assemblies 103 in FIG. 10 . If the currently used ablation module assembly 102 is the last unused ablation module assembly and it has reached its maximum allowed elapsed duration of usage for ablation, t_MAXas seen at line 194, then the biofouling ablation vehicle 12 is instructed to return to the biofouling ablation module maintenance station 13 as represented at block 196 and line 198.
Referring now to FIGS. 12B and 12C, and returning to the query at block 192, and line 200, if the currently used ablation module assembly 102 is not the Nth ablation module assembly within the array of ablation module assemblies 103, then the control and communication system 44 instructs the multiplexer 110 to transfer electrical communication from the array of inductors 108 and the common electrode lead 98, as seen in FIG. 11 , to the next unused ablation module assembly 102 as represented at block 202 and line 204. As seen in query at block 188 and line 206, if the amount of activation (i.e., ablation) time, t_ifor the currently used ablation module assembly 102 is less than a predetermined maximum allowed elapsed duration of usage for ablation, t_MAXthen, as seen at line 206, a query is posed at block 208 regarding the state of charge (SOC) of battery 40 as determined by the battery management system 45 within the biofouling ablation vehicle 12. If the state of charge of battery 40 is less than or equal to the minimum allowed state of charge, SOC_MIN, as seen at line 212, then biofouling ablation vehicle 12 is instructed to return to the biofouling ablation module maintenance station 13 for automatic recharging as represented at block 214 and line 216. After automatic recharging, the query is posed at block 174 regarding the state of charge (SOC) of battery 40 is repeated. If the state of charge is greater than the minimum allowed state of charge, SOC_MINas seen at line 182, then the biofouling ablation vehicle proceeds (or resumes) its pre-programmed sequence of paths on hull 11 of ship 9 as seen, by way of example, in a partial view in FIG. 14 and commences ablation of marine organisms 21 attached to the antifouling coating 25 on the hull 11 of the ship as represented at block 184 and line 186.
As seen in FIG. 12C, if the query at block 208 confirms that the state of charge of the battery 40 is greater than the minimum allowed state of charge, SOC_MINas seen at line 210, then the biofouling ablation vehicle continues along its pre-programmed sequence of paths on the hull 11 of the ship 9, as seen, by way of example, in a partial view in FIG. 14 , to effect the ablation of marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship as represented at block 218 and 220. A query posed at block 222 by the control and communication system 44 within the biofouling ablation vehicle 12 determines whether the biofouling ablation vehicle 12 has completed its entire pre-programmed series of paths on the hull 11 of the ship. If the biofouling ablation vehicle 12 has not completed its entire pre-programmed series of paths on the hull 11 of the ship, then it continues its ablation of marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9 as seen at line 226. As seen at line 224, if the biofouling ablation vehicle 12 has completed its entire pre-programmed series of paths on the hull 11 of the ship 9, then it returns to the biofouling ablation vehicle maintenance station 13 for the replacement of all depleted ablation module assemblies 102, recharging battery 40 and optional cleaning of the exterior of the biofouling ablation vehicle 12 in preparation for the start of the next ship hull cleaning cycle as represented at block 228 and line 230.
The set of FIGS. 12D-12F combine, as labeled thereon, to provide a flow chart describing a second and preferred embodiment of the disclosed system. Looking to FIGS. 2A and 12D, the procedure starts, as represented at block 150 and line 152 with the selection of the particular biofouling ablation vehicle 212 to be activated for use in the repetitive cleaning of the intended hull 11 of the ship 9 to remove attached marine organisms 21. This selection step is necessary as there may be multiple biofouling ablation vehicles 212 in use on hull 11 of a specific ship 9. The back-up battery 41 within the selected biofouling ablation vehicle 212 is charged and the computer of the control and communication system 44 is activated as represented at block 154 and line 156.
Next, as seen in FIG. 12D, previously acquired topographical map data is entered into the control and communication system 44 for the specific portion of the ship hull to be cleaned by the biofouling ablation vehicle as represented at block 158 and line 160. A preferred method for the mapping of a curved ship hull utilizes an underwater visual mapping method for reconstructing the 3D surface model of the ship hull 11 using a stereo vision system as its primary mapping sensor. In the preferred method, the camera trajectory and surface element map (i.e., map of dense set of points holding lighting information) are optimized through the graph-based simultaneous localization and mapping (SLAM) framework. In this regard, see Chung, D., et. al., Underwater Visual Mapping of Curved Ship Hull Surface Using Stereo Vision. Autonomous Robots 2023; 47: 109-120.
The next step, as seen in FIG. 12D, is the insertion of new (i.e., unused) removably attachable active electrode modules 46 into each interconnection terminal array module 72 as represented at block 162 and line 164. Having completed the above listed steps, the biofouling ablation module is positioned on the hull 11 of the ship 9, being secured to the hull of the hull 11 by magnets 26 within the traction belt 24, above the water line 137 as seen in FIG. 13 . A reinforced electrical power and communication tether 8 is attached to biofouling ablation vehicle 212 and biofouling ablation vehicle 212 is wirelessly commanded by the control and communication system 44 to proceed to its assigned biofouling ablation module maintenance station 213 as represented at block 166 and line 168. Next, the timers for the elapsed duration of usage for ablation, t_ifor each ablation module assembly 102 within the biofouling ablation vehicle 212 are set to a zero elapsed time (e.g., t₁=0, t₂=0, . . . , t_N=0) where N refers to the total number of ablation module assemblies 102 in the array of ablation module assemblies 103 incorporated with the biofouling ablation vehicle 212 as represented at block 170 and line 172.
As seen in FIG. 12E at line 172, the biofouling ablation vehicle 212 proceeds to its pre-programmed start and begins programmed hull cleaning path 146 a on hull 11 of ship 9 as seen, by way of example, in a partial view in FIG. 15 and commences ablation of marine organisms 21 attached to the antifouling coating 25 on the hull 11 of the ship 9 as represented at block 184 and line 186.
As seen in FIG. 12E, a query is posed at block 188 regarding the amount of activation (i.e., ablation) time, t_ifor the currently used ablation module assembly 102. If the amount of activation (i.e., ablation) time, t_ifor the currently used ablation module assembly 102 is greater than or equal to a predetermined maximum allowed elapsed duration of usage for ablation, t_MAXthen, as seen at line 190, a sequential query is posed at block 192 to determine if the currently used ablation module assembly 102 is the Nth (i.e., last unused) ablation module assembly 102 where N refers to the total number of ablation module assemblies 102 in the array of ablation module assemblies 103 within the biofouling ablation vehicle 212. By way of example, the total number of ablation module assemblies 102, as seen in FIG. 10 , is seven or N=7 in the array of ablation module assemblies 103 seen in FIG. 10 . If the current used ablation module assembly 102 is the last unused ablation module assembly and it has reached its maximum allowed elapsed duration of usage for ablation, t_MAXas seen at line 194, then the biofouling ablation vehicle 212 is instructed to return to the biofouling ablation module maintenance station 213 as represented at block 196 and line 198.
Referring now to FIGS. 12E and 12F and returning to the query at block 192 and line 200, if the currently used ablation module assembly 102 is not the Nth ablation module assembly within the array of ablation module assemblies 103, then the control and communication system 44 instructs the multiplexer 110 to transfer electrical communication from the array of inductors 108 and the common electrode lead 98, as seen in FIG. 11 , to the next unused ablation module assembly 102 as represented at block 202 and line 204. As seen in query at block 188 and line 206, if the amount of activation (i.e., ablation) time, t_ifor the currently used ablation module assembly 102 is less than a predetermined maximum allowed elapsed duration of usage for ablation, t_MAXthen, as seen at line 210, the biofouling ablation vehicle 212 proceeds along its pre-programmed sequence of paths on hull 11 of ship as seen, by way of example, in a partial view in FIG. 15 and commences ablation of marine organisms 21 attached to the antifouling coating 25 on the hull 11 of the ship as represented at block 218 and line 220.
As seen in FIGS. 2A, 3A and 12F, a query posed at block 222 by the control and communication system 44 within the biofouling ablation vehicle 212 determines whether the biofouling ablation vehicle 212 has completed its entire pre-programmed series of paths on the hull 11 of the ship 9 as seen, by way of example, in a partial view in FIG. 15 . If the biofouling ablation vehicle 212 has not completed its entire pre-programmed series of paths on the hull 11 of the ship, then it continues its ablation of marine organisms 21 attached to the antifouling coating 25 adhered to the hull 11 of the ship 9 as seen at line 226. As seen at line 224, if the biofouling ablation vehicle 212 has completed its entire pre-programmed series of paths on the hull 11 of the ship 9, then it returns to the biofouling ablation vehicle maintenance station 213 for the replacement of all used ablation module assemblies and optional cleaning of the exterior of the biofouling ablation vehicle 12 in preparation for the start of the next ship hull cleaning cycle as represented at block 228 and line 230.
The method of cleaning of hull 11 of ship 9 using the marine antifouling system 10 of the present disclosure and incorporating one or more biofouling ablation vehicles 12 or 212 (i.e., either the battery-powered or an externally tether-powered biofouling ablation vehicle) is illustrated in FIGS. 13, 14 and 15 . Turning first to FIG. 13 and by way of example, the starboard side of a ship 9 is seen wherein the starboard side of the hull 11 is divided into first through fourth substantially equal-size cleaning zones 140 a through 140 d, respectively, that are located along the length of hull 11. Likewise, the hull 11 of a ship 9 is also divided into fifth through eighth substantially equal-size cleaning zones 140 e through 140 h, respectively, on its port side (not shown).
Referring first to the starboard side of ship 9 seen in FIGS. 13 and 14 , a biofouling ablation vehicle maintenance station 13 is attached to the topside of the hull 11 well above the water line 137 within each of the four cleaning zones 140 a through 140 d as seen at first through fourth biofouling ablation vehicle maintenance station locations 142 a through 142 d, respectively. Likewise, a biofouling ablation vehicle maintenance station 13 is attached to the topside of the hull 11 well above the water line 137 within each of the four cleaning zones 140 e through 140 h on the port side of the hull 11 at fifth through eighth biofouling ablation vehicle maintenance station locations 142 e through 142 h, respectively (not shown).
A first programmed cleaning path 146 a followed by the biofouling ablation vehicle 12 within first starboard cleaning zone 140 a on the hull 11 adjacent to the bow 141 of ship 9 is seen, by way of example, in greater detail in FIG. 14 for the case of the first embodiment of the present disclosure. As seen earlier in FIGS. 1, 2 and 3 , the biofouling ablation vehicle 12 of the first embodiment of the present disclosure incorporates a rechargeable battery 40 that supplies all electrical power required for power supply 42, control and communication system 44, battery management system 45 as well as first and second hub motors 28 used to actuate first and second drive wheels 22.
By way of example, a first biofouling ablation vehicle maintenance station location 142 a is seen in FIG. 14 and is shown mounted above the upper edge of the hull 11 of ship 9. A first ramp 144 a provides an access pathway between the hull 11 of the ship 9 and the first biofouling ablation vehicle maintenance station 13 a located at first biofouling ablation vehicle maintenance station location 142 a. The ramp 144 a (e.g., a flat metal plate wider than the biofouling ablation vehicle 12 a) is fabricated using steel to enable the magnets 26 within the traction belts 24 a and 24 b seen in FIG. 2 (traction belt 26 b not seen in FIG. 2 ) to remain magnetically attached to the first ramp 144 a as it advances from the steel hull 11 of the ship 9 to the first biofouling ablation vehicle maintenance station 13 a. Upon wirelessly receiving a command to commence the cleaning of the first cleaning zone 140 a, first biofouling ablation module 12 a exits the first biofouling ablation vehicle maintenance station 13 a at the first biofouling ablation vehicle maintenance station location 142 a and proceeds to follow first programmed hull cleaning path 146 a. When the entire first programmed hull cleaning path 146 a has been completed, the biofouling ablation module 12 a is programmed to return to the first biofouling ablation vehicle maintenance station 13 a as seen in FIG. 14 .
A first programmed cleaning path 146 a followed by the biofouling ablation vehicle 212 within first starboard cleaning zone 140 a on the hull 11 adjacent to the bow 141 of ship 9 is seen in greater detail in FIG. 15 for the case of the second and preferred embodiment of the present disclosure. As seen earlier in FIGS. 1A, 2A and 3A, the biofouling ablation vehicle 212 of the second and preferred embodiment of the present disclosure is connected to an external source of power by reinforced electrical power and communication tether 8 that supplies all electrical power required for power supply 42, control and communication system 44, battery management system 45 as well as first and second hub motors 28 used to actuate first and second drive wheels 22. In addition to providing 440 volt, 3-phase, 60 Hz power lines and flexible load-bearing cable, the reinforced electrical power and communication tether 8 also incorporates a fiber optic and/or data cable for transmission of video signals from digital image sensors located on a bottom surface of support frame 106 to command and control center 6 through fiber optic and/or data cable 254 extending from a first tether reel 148 a as seen in FIGS. 10 and 15 .
By way of example, a first biofouling ablation vehicle maintenance station location 242 a is seen in FIG. 15 and a first tether reel 148 a is shown mounted above the upper edge of the hull 11 of ship 9. A first ramp 144 a provides an access pathway between the hull 11 of the ship 9 and the first biofouling ablation vehicle maintenance station 213 a located at first biofouling ablation vehicle maintenance station location 242 a. The ramp 144 a (e.g., a flat metal plate wider than the biofouling ablation vehicle 12 a) is fabricated using steel to enable the magnets 26 within the traction belts 24 a and 24 b seen in FIG. 2A (traction belt 26 b not seen in FIG. 2A) to remain magnetically attached to the first ramp 144 a as it advances from the steel hull 11 of the ship 9 to the first biofouling ablation vehicle maintenance station 213 a. Upon receiving a command to commence the cleaning of the first cleaning zone 140 a, first biofouling ablation module 212 a along with the attached reinforced electrical power and communication tether 8 exits the first biofouling ablation vehicle maintenance station 213 a at the first biofouling ablation vehicle maintenance station location 242 a and proceeds to follow first programmed hull cleaning path 146 a. When the entire first programmed hull cleaning path 146 a has been completed, the biofouling ablation module 212 a is programmed to return to the first biofouling ablation vehicle maintenance station 213 a as seen in FIG. 15 . As illustrated in FIG. 15 , the reinforced electrical power and communication tether 8 is deployed from tether reel 148 a as needed to allow the first biofouling ablation module 212 a to traverse the extent of the first cleaning zone 140 a.
By way of example, if ship 9 (shown in FIG. 13 ) has a length of 800 feet and is divided into four segments of substantially equal length (e.g., 200 feet long segments), then the maximum required length of the deployed reinforced electrical power and communication tether 8 only is about 150 feet, well within the capabilities of tether reel systems as well as the required power transmission to the biofouling ablation module 212 a.
Also, referring to the example illustrated in FIGS. 13, 14 and 15 , in larger ships, a total of eight biofouling ablation vehicles 12 or 212 may be required in combination with eight biofouling ablation vehicle maintenance stations 13 or 213, four on the starboard side of the ship 9 and four on the port side of the ship 9. Since each biofouling ablation vehicle 12 or 212 is powered and independently controlled, any one or up to eight or more biofouling ablation vehicles 12 or 212 can be deployed and can simultaneously remove marine organisms 21 within their respective cleaning zones 140. It is contemplated that ships may include any number of biofouling ablation vehicles 12 or 212 (e.g., any number less than or greater than eight biofouling ablation vehicles 12 or 212) in combination with a corresponding number of biofouling ablation vehicle maintenance stations 13 or 213. In some cases, particularly in larger ships, a total of more than eight more biofouling ablation vehicles or modules 12 or 212 (e.g., ten to twenty or more) in combination with a corresponding number of biofouling ablation vehicle maintenance stations 13 or 213 may also be contemplated wherein half the fleet of biofouling ablation vehicles or modules 12 or 212 treat each side of the hull of the ship.
By way of further example and referring to FIG. 2 or 2A, 8, 13, 14 and 15 , the length of time to remove marine organisms 21 attached to the antifouling 25 of the entire hull 11 of the ship 9 below the water line 137 using biofouling ablation vehicles 12 or 212 of the present disclosure can be estimated. Referring to FIG. 13 , assume for the example time estimate that the total length, L_hullof the hull 11 of the ship 9 below the water line 137 is 800 feet and the maximum depth, D_hullof the hull 11 of the ship 9 below the water line 137 is 40 feet. Further assume that the average shape of the hull 11 of the ship 9 below the water line 137 is semicircular. The total curved vertical distance, H_hullof the curved hull 11 of the ship 9 below the water line 137 on the starboard side of the hull 11 is therefore equal to one-fourth of the circumference of a circle whose radius, R_hullis equal to the depth, D_hullof the hull 11 of the ship 9 below the water line 137 as expressed in the following equation.
$\begin{matrix} H_{hull} = ⁠ (1 / 4) \times (2 \times 3.1416 \times R_{hull}) = (1 / 4) \times (2 \times 3.1416 \times R_{hull}) & [Equation 1] \end{matrix}$ $\begin{matrix} H_{hull} = (1 / 4) \times (2 \times 3.1416 \times 40) = 62.8 feet & [Equation 2] \end{matrix}$
If the total length of the hull 11 of the ship 9 on the starboard side of the hull 11 is divided into four cleaning zones of substantially equal length 140 a-140 d as seen in FIG. 13 , then the length of each individual cleaning zone 140, L_zoneis one-fourth of the total length (e.g., 800 feet) of hull 11 or 200 feet.
As seen in FIGS. 14 and 15 , the total curved vertical distance, H_hullof the curved hull 11 of the ship 9 below the water line 137 can be divided into the number of cleaning paths 146 a required for the cleaning of the total curved vertical distance, H_hullof the curved hull 11 of the ship 9. If we further assume that the width each cleaning path, W_pathachieved by the biofouling ablation vehicle 12 or 212 as seen in FIG. 2 or 2A, respectively, is 3.0 feet, then the number of cleaning paths 146 a, N_pathrequired across the total curved vertical distance, H_hullof the curved hull 11 of the ship 9, as seen in FIGS. 14 and 15 , is given by the following equation (rounded to the next larger whole number of paths).
$\begin{matrix} N_{path} = H_{hull} / W_{path} = 62.8 / 3. = 21 & [Equation 3] \end{matrix}$
The total length, L_pathof all of the cleaning paths 146 a seen in FIGS. 14 and 15 is the product of the length of the cleaning zone 140 a, L_zoneof the hull 11 of the ship 9 below the water line 137 and the number of cleaning paths 140 a, N_pathrequired across the total curved vertical distance, H_hullof the curved hull 11 of the ship 9 seen in FIGS. 14 and 15 and is calculated using the following equation.
$\begin{matrix} L_{path} = L_{zone} \times N_{path} = 200 feet \times 21 paths = 4200 feet & [Equation 4] \end{matrix}$
If we assume the speed of advancement of a biofouling ablation vehicle 12 or 212, S_cleanseen in FIG. 2 or 2A is 1.0 foot per minute, then the total time, T_cleanto complete the cleaning of the first cleaning zone 140 a, as seen in FIGS. 14 and 15 , is given by the following equation.
$\begin{matrix} T_{clean} = ⁠ L_{path} / S_{clean} = 4200 feet / (1. foot / minute) = 4200 minutes & [Equation 5] \end{matrix}$
Hence, for the present example, each of the cleaning zones 140 a-140 d on the starboard side of the hull 11 of the ship 9 below the water line 137 will require a total cleaning time of 4200 minutes or 70 hours or 2.9 days. If four biofouling ablation vehicles 12 or 212 are used simultaneously on the starboard side of the hull 11, then the entire starboard side of the hull 11 of the ship 9 below the water line 137 can be cleaned in 2.9 days for the case of cleaning on a recurring basis. Likewise, for the present example, each of the cleaning zones 140 e-140 h on the port side of the hull 11 of the ship 9 below the water line 137 will require a total cleaning time of 4200 minutes or 70 hours or 2.9 days. If a total of eight biofouling ablation modules 12 or 212 are used simultaneously, then the entire hull 11 of the ship 9 below the water line 137 on both the starboard side and port side require a total cleaning time of 4200 minutes or 70 hours or 2.9 days if cleaning is performed on a recurring basis.
For the case of the first embodiment of the present disclosure, the total time required to remove marine organisms 21 adhered to biofouling coating 25 adhered to the hull 11 of the ship 9 below the water line 137 (i.e., cleaning) within each cleaning zone 140 may be increased according to the number of times that the biofouling ablation vehicle 12 is required to return to the biofouling ablation vehicle maintenance station 13 for recharging battery 40 and/or to replace used removably attachable active electrode modules 46. Likewise, for the case of the second and preferred embodiment of the present disclosure, the total time required to remove marine organisms 21 adhered to biofouling coating 25 adhered to the hull 11 of the ship 9 below the water line 137 (i.e., cleaning) within each cleaning zone 140 may be increased according to the number of times that the biofouling ablation vehicle 212 is required to return to the biofouling ablation vehicle maintenance station 213 to replace used removably attachable active electrode modules 46.
Since certain changes may be made in the above method, system and apparatus without departing from the scope of the present disclosure herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. For example, alternative sources of energy for the ablation of marine organisms attached to the antifouling coating adhered to the hull of the ship may include ultrasound transducers, ultraviolet light emitters, radiofrequency or microwave solid state emitters.
Provided below are various embodiments of the autonomous in-water marine antifouling apparatus, system and method disclosed herein.
According to Clause 1, provided is an apparatus for the molecular dissociation and removal of marine organisms (21) attached to a surface on an antifouling coating (25) adhered to a hull (11) of a ship (9) in sea water (19), including: a plurality of active electrodes (55) confronting adjacency with marine organisms (21) attached to the surface of the antifouling coating (25) adhered to the hull (11) of a ship (9); one or more common electrodes (92) in electrical communication with the plurality of adjacent active electrodes (55) through surrounding sea water (19); and, a power supply (42) incorporating a radiofrequency generator (95), a first active electrode lead (97) in series electrical communication between the radiofrequency generator (95) and each current limiting inductor (108) or current limiting circuitry incorporating inductors and capacitors and a second electrical lead (112) in electrical communication between each current limiting inductor (108) or current limiting circuitry incorporating inductors and capacitors and each active electrode within the plurality of active electrodes (55), wherein the apparatus generates a vapor layer (58) in the region of high electric field intensity (91) between the distal end face (71) of each active electrode (55) and the marine organisms (21) attached to the surface of the antifouling coating adhered to the hull of the ship.
According to Clause 2, the apparatus of Clause 1 or any subsequent Clauses, wherein the active electrode (55) including tungsten or an alloy containing tungsten.
According to Clause 3, the apparatus of any previous or subsequent Clauses, wherein the common electrode (92) includes Hastelloy C-276 steel Type 316, Monel or Alloy 400, titanium or a titanium alloy.
According to Clause 4, the apparatus of any previous or subsequent Clauses, wherein the radiofrequency generator (95) applies a voltage between each active electrode (55) and common electrode (92) having a frequency of 50 to 500 kHz.
According to Clause 5, the apparatus of any previous or subsequent Clauses, wherein the radiofrequency generator (95) applies a voltage between each active electrode (55) and common electrode (92) of 200 to 2000 volts (peak to peak).
According to Clause 6, the apparatus of any previous or subsequent Clauses, further including a removably attachable active electrode module (46), wherein the removably attachable active electrode module (46) houses the plurality of active electrodes (55) and the common electrode (92).
According to Clause 7, the apparatus of any previous or subsequent Clauses, wherein the removable attachable active electrode module (46) is in electrical communication with an interconnection terminal array module (72).
According to Clause 8, the apparatus of any previous or subsequent Clauses, further including one or more ablation module assemblies (102) which comprise two or more removably attachable active electrode modules (46).
According to Clause 9, the apparatus of any previous or subsequent Clauses, further including an array of ablation module assemblies (103) which comprise two or more ablation module assemblies (102).
According to Clause 10, the apparatus of any previous or subsequent Clauses, wherein the power supply (42) incorporates a multiplexer (110) to selectively apply power from the radiofrequency generator (95) to any one of the ablation module assemblies (102) within the array of ablation module assemblies (103).
According to Clause 11, the apparatus of any previous or subsequent Clauses, wherein the total combined surface area of the common electrodes (92) in contact with sea water is substantially greater than the total combined surface area of all of the active electrodes (55) in contact with sea water.
According to Clause 12, the apparatus of any previous or subsequent Clauses, wherein power supply (42) incorporates an independent feedback-controlled voltage source within power supply (42) that adjusts the applied voltage in correspondence to an electrical impedance in a circuit including a current path between each active electrode (55) and the common electrode (92).
According to Clause 13, provided is a system for the molecular dissociation and removal of marine organisms (21) attached to a surface on an antifouling coating (25) adhered to a hull (11) of a ship (9) in sea water (19), including: one or more biofouling ablation vehicles (12 or 212) including a power supply (42), a control and communication system (44), a back-up battery (41), a battery management system (45), four drive wheels (22) actuated by hub motors (28) that drive two or more traction belts (24) incorporating a plurality of permanent magnets (26), and a support frame (106) including an array of ablation module assemblies (103), wherein the array of ablation module assemblies (103) comprise two or more ablation module assemblies (102), wherein the ablation module assemblies (102) comprise two or more removably attachable active electrode modules (46), wherein the removably attachable active electrode modules (46) are removably attached to a corresponding interconnection terminal array module (72); a tether (8) supplying electrical power to each biofouling ablation vehicle (12 or 212) that also incorporates a fiber optic cable (254) for transmission of video signals from a plurality of digital image sensors (130 and 136) on a bottom facing surface (122) of the biofouling ablation vehicle (12 or 212); one or more biofouling ablation vehicle maintenance stations (13 or 213) incorporating a forced-convection heating unit (57) and a cleaning water pressurization and control unit (56) to heat an exterior of the biofouling ablation vehicle (12 or 212) and remove marine organisms from its surface; and, a command and control center (6) located on ship (9) for receiving video signal transmissions from the plurality of digital image sensors (130 and 136) and for transmitting wireless communications to both the biofouling ablation vehicle (12 or 212) and the biofouling ablation vehicle maintenance station (13 or 213).
According to Clause 14, the system of Clause 13 or any subsequent Clauses, wherein the biofouling ablation vehicle maintenance station (13 or 213) includes a remotely operable door to allow the biofouling ablation vehicle (12 or 212) entrance into and exit from the biofouling ablation vehicle maintenance station (13 or 213), According to Clause 15, the system of any previous or subsequent Clauses, wherein the remotely operable door (16) is closed during a period of forced air heating convection, wherein during the period of force air heating convection within the biofouling ablation vehicle maintenance station (13 or 213), the exterior of the biofouling ablation vehicle (12 or 212) is heated to at least 72° C. for the purpose of removing marine organisms from the exterior of the biofouling ablation vehicle (12 or 212).
According to Clause 16, the system of any previous or subsequent Clauses, wherein the biofouling ablation vehicle (12 or 212) includes a biofouling ablation vehicle enclosure (14 or 214), wherein the biofouling ablation vehicle enclosure (14 or 214) includes a door (27) positioned a bottom surface of the biofouling ablation vehicle enclosure (14 or 214), wherein the door (27) provides access to a bottom surface of the support frame (106) to allow access to and replacement of the removably attachable active electrode modules (46).
According to Clause 17, the system of any previous or subsequent Clauses, wherein the permanent magnets (26) are housed within a first traction belt and a second traction belt between slots (51) integrated within the first traction belt and the second traction belt.
According to Clause 18, the system of any previous or subsequent Clauses, wherein the door (27) includes a width that is less than a width between inner edges of a first traction belt and a second traction belt to allow the door (27) to be opened without having to overcome attraction forces from the magnets (26) incorporated within the first traction belt and the second traction belt.
According to Clause 19, the system of any previous or subsequent Clauses, wherein the tether (8) includes a buoyancy filler (256) and is positioned at a front end (35) of a biofouling ablation vehicle enclosure (15) and is in electrical communication with an AC to DC converter (38), wherein the AC to DC converter (38) is in electrical communication with backup battery (41), battery management system (45), power supply (42) and control and communication system (44 or 244).
According to Clause 20, the system of any previous or subsequent Clauses, wherein the biofouling ablation vehicle (12 or 212) includes a biofouling ablation vehicle enclosure (14 or 214), wherein an air gap or an insulative material thickness of at least 0.25 inch is maintained between an inner surface of the biofouling ablation vehicle enclosure (14 or 214) and the battery (40), battery management system (45), power supply (42) and the control and communication system (44) of the biofouling ablation vehicle (12) to ensure that the battery (40), battery management system (45), power supply (42) and the control and communication system (44) are maintained at acceptably low temperatures to prevent thermal damage of the battery (40), battery management system (45), power supply (42) and the control and communication system (44) during forced air heating convection of the biofouling ablation vehicle (12 or 212).
According to Clause 21, provided is a method for the molecular dissociation and removal of marine organisms (21) attached to a surface on an antifouling coating (25) adhered to a hull (11) of a ship (9) in sea water (19), including the steps of: a) selecting a biofouling ablation vehicle (12 or 212) to be activated for use in repetitive molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) in sea water (19); b) charging back-up battery (41) and activating a control and communication system (44); c) entering topographical map data into the control and communication system (44) corresponding to a specific portion of the hull (11) of the ship (9) where molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) is being repetitively performed; d) inserting a removably attachable active electrode module (46) into an interconnection terminal array module (72) incorporated in an ablation module assembly (102) within an array of ablation module assemblies (103); e) positioning the selected biofouling ablation vehicle (12 or 212) on the hull (11) of the ship (9) and attaching a reinforced power and communication tether (8) to the biofouling ablation vehicle (12 or 212); f) inputting a command to the control and communication system (44) that activates the biofouling ablation vehicle (12 or 212) to proceed to the biofouling ablation vehicle maintenance station (13 or 213) located on or adjacent to the hull (11) of the ship (9); g) setting timers for each ablation module assembly (102) to zero wherein timers are used for monitoring the activation time for each ablation module assembly (102) thereby determining when each ablation module assembly (102) has reached the pre-determined end of its useful life; h) inputting a command to the biofouling ablation vehicle (12 or 212) that activates the biofouling ablation vehicle (12 or 212) to proceed to its pre-programmed starting location to commence the molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of a ship (9) along the entire sequence of pre-programmed path on hull of ship; i) continuing to compare the activation time for each ablation module assembly (102) within the array of ablation module assemblies (103) with its predetermined maximum allowed activation time; j) re-directing the application of power using the multiplexer (110) within the power supply (42) from an ablation module assembly (102) that has reached its maximum allowed activation time to the next available unused ablation module assembly (102) within the array of ablation module assemblies (103); k) continuing the molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) along the entire sequence of a pre-programmed path on the hull (11) of the ship (9) until all ablation module assemblies (102) have reached their predetermined maximum allowed activation time; l) inputting a command to activate the biofouling ablation vehicle (12 or 212) to return to the biofouling ablation vehicle maintenance station (13 or 213) after all ablation module assemblies (102) have reached their predetermined maximum allowed activation time; m) removing all removably attachable active electrode modules (46) from all ablation module assemblies (102) within the array of ablation module assemblies (103) whose activation times have reached their maximum allowed activation time and replace the removably attachable active electrode modules (46) with new unused removably attachable active electrode modules (46); and n) repeating steps (g) through (m) until the molecular dissociation and removal of marine organisms (21) attached to the surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) along all pre-programmed paths have been completed.
According to Clause 22, the method of any previous Clause further including the steps of: illuminating the hull (11) of the ship (9) by light sources (132 and 138); acquiring optical images of the hull (11) of the ship (9) by a plurality of digital image sensors (130 and 136) attached to the biofouling ablation vehicle (12 or 212); transmitting video signals from the digital image sensors (130 and 136) through the tether (8) to a command and control center (6) through a fiber optic and/or data cable (254); acquiring optical images from the transmitted video signals to observe a level of marine organisms (21) attached to an antifouling coating (25) on the hull (11) of the ship (9); running an image-processing software to digitally determine an extent of completeness of removal of marine organisms (21) by the biofouling ablation vehicle (12 or 212); and adjusting a speed of advancement of the biofouling ablation vehicle (12 or 212) and/or a level of voltage, V₁applied by a radiofrequency generator (95) to the ablation module assembly (102) based on the extent of completeness of removal of marine organisms (21) by the biofouling ablation vehicle (12 or 212) determined by the software to adjust a rate of molecular dissociation of the marine organisms (21) attached to the antifouling coating adhered to the hull (11) of the ship (9).
While the autonomous in-water marine antifouling apparatus, system and method disclosed herein has been described with reference to various embodiments, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope and essence of the disclosure. In addition, many modifications may be made to adapt a particular situation or material in accordance with the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed, but that the disclosure will include all embodiments falling within the scope of the appended claims. In this application all citations referred herein are expressly incorporated herein by reference.

Claims

We claim:

1. An apparatus for the molecular dissociation and removal of marine organisms (21) attached to a surface on an antifouling coating (25) adhered to a hull (11) of a ship (9) in sea water (19), comprising:

a plurality of active electrodes (55) confronting adjacency with marine organisms (21) attached to the surface of the antifouling coating (25) adhered to the hull (11) of a ship (9);

one or more common electrodes (92) in electrical communication with the plurality of adjacent active electrodes (55) through surrounding sea water (19); and,

a power supply (42) incorporating a radiofrequency generator (95), a first active electrode lead (97) in series electrical communication between the radiofrequency generator (95) and each current limiting inductor (108) or current limiting circuitry incorporating inductors and capacitors and a second electrical lead (112) in electrical communication between each current limiting inductor (108) or current limiting circuitry incorporating inductors and capacitors and each active electrode within the plurality of active electrodes (55);

wherein the apparatus generates a vapor layer (58) in the region of high electric field intensity (91) between the distal end face (71) of each active electrode (55) and the marine organisms (21) attached to the surface of the antifouling coating adhered to the hull of the ship.

2. The apparatus of claim 1, wherein the active electrode (55) comprises tungsten or an alloy containing tungsten.

3. The apparatus of claim 1, wherein the common electrode (92) comprises Hastelloy C-276 steel Type 316, Monel or Alloy 400, titanium or a titanium alloy.

4. The apparatus of claim 1, wherein the radiofrequency generator (95) applies a voltage between each active electrode (55) and common electrode (92) having a frequency of 50 to 500 kHz.

5. The apparatus of claim 1, wherein the radiofrequency generator (95) applies a voltage between each active electrode (55) and common electrode (92) of 200 to 2000 volts (peak to peak).

6. The apparatus of claim 1, further comprising a removably attachable active electrode module (46), wherein the removably attachable active electrode module (46) houses the plurality of active electrodes (55) and the common electrode (92).

7. The apparatus of claim 6, wherein the removable attachable active electrode module (46) is in electrical communication with an interconnection terminal array module (72).

8. The apparatus of claim 7, further comprising one or more ablation module assemblies (102) which comprise two or more removably attachable active electrode modules (46).

9. The apparatus of claim 8, further comprising an array of ablation module assemblies (103) which comprise two or more ablation module assemblies (102).

10. The apparatus of claim 9, wherein the power supply (42) incorporates a multiplexer (110) to selectively apply power from the radiofrequency generator (95) to any one of the ablation module assemblies (102) within the array of ablation module assemblies (103).

11. The apparatus of claim 1, wherein the total combined surface area of the common electrodes (92) in contact with sea water is substantially greater than the total combined surface area of all of the active electrodes (55) in contact with sea water.

12. The apparatus of claim 1, wherein power supply (42) incorporates an independent feedback-controlled voltage source within power supply (42) that adjusts the applied voltage in correspondence to an electrical impedance in a circuit comprising a current path between each active electrode (55) and the common electrode (92).

13. A system for the molecular dissociation and removal of marine organisms (21) attached to a surface on an antifouling coating (25) adhered to a hull (11) of a ship (9) in sea water (19), comprising:

one or more biofouling ablation vehicles (12 or 212) comprising a power supply (42), a control and communication system (44), a back-up battery (41), a battery management system (45), four drive wheels (22) actuated by hub motors (28) that drive two or more traction belts (24) incorporating a plurality of permanent magnets (26), and a support frame (106) comprising an array of ablation module assemblies (103), wherein the array of ablation module assemblies (103) comprise two or more ablation module assemblies (102), wherein the ablation module assemblies (102) comprise two or more removably attachable active electrode modules (46), wherein the removably attachable active electrode modules (46) are removably attached to a corresponding interconnection terminal array module (72);

a tether (8) supplying electrical power to each biofouling ablation vehicle (12 or 212) that also incorporates a fiber optic cable (254) for transmission of video signals from a plurality of digital image sensors (130 and 136) on a bottom facing surface (122) of the biofouling ablation vehicle (12 or 212);

one or more biofouling ablation vehicle maintenance stations (13 or 213) incorporating a forced-convection heating unit (57) and a cleaning water pressurization and control unit (56) to heat an exterior of the biofouling ablation vehicle (12 or 212) and remove marine organisms from its surface; and,

a command and control center (6) located on ship (9) for receiving video signal transmissions from the plurality of digital image sensors (130 and 136) and for transmitting wireless communications to both the biofouling ablation vehicle (12 or 212) and the biofouling ablation vehicle maintenance station (13 or 213).

14. The system of claim 13, wherein the biofouling ablation vehicle maintenance station (13 or 213) comprises a remotely operable door to allow the biofouling ablation vehicle (12 or 212) entrance into and exit from the biofouling ablation vehicle maintenance station (13 or 213), and

wherein the remotely operable door (16) is closed during a period of forced air heating convection, wherein during the period of force air heating convection within the biofouling ablation vehicle maintenance station (13 or 213), the exterior of the biofouling ablation vehicle (12 or 212) is heated to at least 72° C. for the purpose of removing marine organisms from the exterior of the biofouling ablation vehicle (12 or 212).

15. The system of claim 13, wherein the biofouling ablation vehicle (12 or 212) comprises a biofouling ablation vehicle enclosure (14 or 214), wherein the biofouling ablation vehicle enclosure (14 or 214) comprises a door (27) positioned a bottom surface of the biofouling ablation vehicle enclosure (14 or 214), wherein the door (27) provides access to a bottom surface of the support frame (106) to allow access to and replacement of the removably attachable active electrode modules (46).

16. The system of claim 15, wherein the permanent magnets (26) are housed within a first traction belt and a second traction belt between slots (51) integrated within the first traction belt and the second traction belt, and

wherein the door (27) comprises a width that is less than a width between inner edges of a first traction belt and a second traction belt to allow the door (27) to be opened without having to overcome attraction forces from the magnets (26) incorporated within the first traction belt and the second traction belt.

17. The system of claim 13, wherein the tether (8) comprises a buoyancy filler (256) and is positioned at a front end (35) of a biofouling ablation vehicle enclosure (15) and is in electrical communication with an AC to DC converter (38), wherein the AC to DC converter (38) is in electrical communication with backup battery (41), battery management system (45), power supply (42) and control and communication system (44 or 244).

18. The system of claim 13, wherein the biofouling ablation vehicle (12 or 212) comprises a biofouling ablation vehicle enclosure (14 or 214), wherein an air gap or an insulative material thickness of at least 0.25 inch is maintained between an inner surface of the biofouling ablation vehicle enclosure (14 or 214) and the battery (40), battery management system (45), power supply (42) and the control and communication system (44) of the biofouling ablation vehicle (12) to ensure that the battery (40), battery management system (45), power supply (42) and the control and communication system (44) are maintained at acceptably low temperatures to prevent thermal damage of the battery (40), battery management system (45), power supply (42) and the control and communication system (44) during forced air heating convection of the biofouling ablation vehicle (12 or 212).

19. A method for the molecular dissociation and removal of marine organisms (21) attached to a surface on an antifouling coating (25) adhered to a hull (11) of a ship (9) in sea water (19), comprising the steps of:

a) selecting a biofouling ablation vehicle (12 or 212) to be activated for use in repetitive molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) in sea water (19);

b) charging back-up battery (41) and activating a control and communication system (44);

c) entering topographical map data into the control and communication system (44) corresponding to a specific portion of the hull (11) of the ship (9) where molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) is being repetitively performed;

d) inserting a removably attachable active electrode module (46) into an interconnection terminal array module (72) incorporated in an ablation module assembly (102) within an array of ablation module assemblies (103);

e) positioning the selected biofouling ablation vehicle (12 or 212) on the hull (11) of the ship (9) and attaching a reinforced power and communication tether (8) to the biofouling ablation vehicle (12 or 212);

f) inputting a command to the control and communication system (44) that activates the biofouling ablation vehicle (12 or 212) to proceed to the biofouling ablation vehicle maintenance station (13 or 213) located on or adjacent to the hull (11) of the ship (9);

g) setting timers for each ablation module assembly (102) to zero wherein timers are used for monitoring the activation time for each ablation module assembly (102) thereby determining when each ablation module assembly (102) has reached the pre-determined end of its useful life;

h) inputting a command to the biofouling ablation vehicle (12 or 212) that activates the biofouling ablation vehicle (12 or 212) to proceed to its pre-programmed starting location to commence the molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of a ship (9) along the entire sequence of pre-programmed path on hull of ship;

i) continuing to compare the activation time for each ablation module assembly (102) within the array of ablation module assemblies (103) with its predetermined maximum allowed activation time;

j) re-directing the application of power using the multiplexer (110) within the power supply (42) from an ablation module assembly (102) that has reached its maximum allowed activation time to the next available unused ablation module assembly (102) within the array of ablation module assemblies (103);

k) continuing the molecular dissociation and removal of marine organisms (21) attached to a surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) along the entire sequence of a pre-programmed path on the hull (11) of the ship (9) until all ablation module assemblies (102) have reached their predetermined maximum allowed activation time;

l) inputting a command to activate the biofouling ablation vehicle (12 or 212) to return to the biofouling ablation vehicle maintenance station (13 or 213) after all ablation module assemblies (102) have reached their predetermined maximum allowed activation time;

m) removing all removably attachable active electrode modules (46) from all ablation module assemblies (102) within the array of ablation module assemblies (103) whose activation times have reached their maximum allowed activation time and replace the removably attachable active electrode modules (46) with new unused removably attachable active electrode modules (46); and,

n) repeating steps (g) through (m) until the molecular dissociation and removal of marine organisms (21) attached to the surface on the antifouling coating (25) adhered to the hull (11) of the ship (9) along all pre-programmed paths have been completed.

20. The method of claim 19, further comprising the steps of:

illuminating the hull (11) of the ship (9) by light sources (132 and 138);

acquiring optical images of the hull (11) of the ship (9) by a plurality of digital image sensors (130 and 136) attached to the biofouling ablation vehicle (12 or 212);

transmitting video signals from the digital image sensors (130 and 136) through the tether (8) to a command and control center (6) through a fiber optic and/or data cable (254);

acquiring optical images from the transmitted video signals to observe a level of marine organisms (21) attached to an antifouling coating (25) on the hull (11) of the ship (9);

running an image-processing software to digitally determine an extent of completeness of removal of marine organisms (21) by the biofouling ablation vehicle (12 or 212); and,

adjusting a speed of advancement of the biofouling ablation vehicle (12 or 212) and/or a level of voltage, V₁applied by a radiofrequency generator (95) to the ablation module assembly (102) based on the extent of completeness of removal of marine organisms (21) by the biofouling ablation vehicle (12 or 212) determined by the software to adjust a rate of molecular dissociation of the marine organisms (21) attached to the antifouling coating adhered to the hull (11) of the ship (9).