Ship Hull Antifouling
US Patent 7,390,560 & Patents Pending


The present technology comprises a practical system for cleaning the ship hull from fouling on command at any time. The method is particularly useful for energy conservation and reduction of carbon footprint since drag is reduced and power saved with a cleaner hull. The method based on Hull/Hydrodynamics is currently entering small scale manufacturing and can be rapidly transitioned to ship operation within twelve months.

PELís patented Smart Coating Systems US 7,390,560 technology supports this ship application. Array layers composed of selected polymeric sheet material and are readily mounted to the ship hull and activated on command. Suitable array prototypes can be prepared, tested, and transitioned to most vessels including recreational, military, and later the larger cruise ships, and cargo vessels. The method should be suited to modification of existing vessels and inclusion on new ones as well. A simple schematic is shown in Figure I below.

The mechanism involves energetic input across a coating array which releases the fouled layer. A number of prototypes for smaller vessels have been prepared (Figures 1 and 2) and tailoring for selected application should directly follow. The method will allow ships to save fuel, reduce the introduction of dangerous species to our waters, keep our environment cleaner, reduce the laborious need to clean the hull every few months, and no longer require antifouling paint which contains as active ingredients environmentally unfriendly heavy metals such as copper or tributyl tin compounds, and the ships will be easier to handle and maneuver. We estimate about 5-10% fuel and carbon savings translating into millions of dollars saved.

Layer shedding and the accompanying antifouling can be done at will, for example every six months (three times over 1 Ĺ year period) where fouling would go to zero at six, twelve, and eighteen months. The level of fouling would then never pass the six month accumulation level compared to an eighteen month accumulation level with current methods. Assuming a linear fouling rate, median fouling would be at about the three month level, and maximum fouling would be at the six month level over the 1 Ĺ years.

Note that typical layer materials selected will have very low surface free energy and therefore be in the range of fouling prevention as most antifouling paints. Also the release interlayer can be conductive as depicted in Figure I or insulative depending on the materials selected.

PEL Associates has vast experience with materials and processing of polymeric film and sheet materials. We have worked on projects for DARPA, NAVAIR, and ONR on detection, surveillance, and upgrading of ships. Our experience has led to a survey of appropriate coating materials, and preparation of prototype coating arrays (Figures 1 and 2).
Patent US 7,390,560

Figure 1

Technology Demonstration on Ship Hull in Marine Environment

Fouled top layer is removed leaving clean layer exposed. This process is readily done on dry dock or by divers at sea. Energy input facilitates removal. Fouled layer is readily collected and disposed of in an environmentally safe manner. Later we plan in-water service station facilities where a ship can enter and fouled layer automatically removed, collected, and disposed of.
Patent US 7,390,560

Figure 2

Technology Demonstration on Ship Hull in Marine Environment

On removal of the top fouled layer shown above a clean layer is exposed as depicted here. This boat had been in the water about two weeks. It had been moving slowly for over two miles with no adverse effect.

 

During Coating Removal

After Top Coat Removal


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