Anti-fouling paint

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New ship being prepared for launch, showing fresh anti-fouling paint Nordseewerke-Stapellauf-Frisia-Brussel-Helling.jpg
New ship being prepared for launch, showing fresh anti-fouling paint
Ship hull being cleaned of fouling in drydock Dry docking.8.JPG
Ship hull being cleaned of fouling in drydock
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Anti-fouling paint is a specialized category of coatings applied as the outer (outboard) layer to the hull of a ship or boat, to slow the growth of and facilitate detachment of subaquatic organisms that attach to the hull and can affect a vessel's performance and durability. It falls into a category of commercially available underwater hull paints, also known as bottom paints.

Contents

Anti-fouling paints are often applied as one component of multi-layer coating systems [1] which may have other functions in addition to their antifouling properties, such as acting as a barrier against corrosion on metal hulls that will degrade and weaken the metal, [2] or improving the flow of water past the hull of a fishing vessel [3] or high-performance racing yachts. Although commonly discussed as being applied to ships, antifouling paints are also of benefit in many other sectors such as off-shore structures [4] and fish farms. [5]

History

In the Age of Sail, sailing vessels suffered severely from the growth of barnacles and weeds on the hull, called "fouling". Starting in the mid-1700s thin sheets of copper and approximately 100 years later, Muntz metal, were nailed onto the hull in an attempt to prevent marine growth. [6] One famous example of the traditional use of metal sheathing is the clipper Cutty Sark , which is preserved as a museum ship in dry-dock at Greenwich in England. [6] Marine growth affected performance (and profitability) in many ways:

While anti-fouling coatings began to be developed from 1840 onwards, the first practical commercial anti-fouling coatings were established around 1860. [6] One of the first successful commercial patents was for 'McIness', a metallic soap compound with copper sulphate that was applied heated over a quick-drying rosin varnish primer with an iron oxide pigment. [6] The Bonnington Chemical Works began marketing copper sulphide anti-fouling paint around 1850. [8] Other widely used anti-fouling paints were developed in the late 19th century, with some 213 anti-fouling patterns being recorded by 1872. [6] Among the most widely used in the 1880s and 1890s was a hot plastic composition known as Italian Morovian. [6]

In an official 1900 Letter from the U.S. Navy to the U.S. Senate Committee on Naval Affairs, [9] it was noted that the (British) Admiralty had considered a proposal in 1847 to limit the number of iron ships (only recently introduced into naval service) and even to consider the sale of all iron ships in its possession, due to significant problems with biofouling. However, once an antifouling paint "with very fair results" was found, the iron ships were instead retained and continued to be built.

During World War II, which included a substantial naval component, the U.S. Navy provided significant funding [10] to the Woods Hole Oceanographic Institution to gather information and conduct research on marine biofouling and technologies for its prevention. This work was published as a book in 1952, the contents of which are available online as individual chapters. [11] The third and final part of this book includes a number of chapters that go into the state of the art at that time for the formulation of anti-fouling paints. Lunn (1974) provides further history. [12]

Modern antifouling paints

In modern times, antifouling paints are formulated with cuprous oxide (or other copper compounds) and/or other biocides—special chemicals which impede growth of barnacles, algae, and marine organisms. Historically, copper paints were red, leading to ship bottoms still being painted red today. [13]

"Soft", or ablative bottom paints slowly slough off in the water, releasing a copper or zinc based biocide into the water column. The movement of water increases the rate of this action. Ablative paints are widely used on the hulls of recreational vessels and typically are reapplied every 1–3 years. "Contact leaching" paints "create a porous film on the surface. Biocides are held in the pores, and released slowly." [14] Another type of hard bottom paint includes Teflon and silicone coatings which are too slippery for growth to stick. SealCoat systems, which must be professionally applied, dry with small fibers sticking out from the coating surface. These small fibers move in the water, preventing bottom growth from adhering. [14]

Environmental concerns

In the 1960s and 1970s, commercial vessels commonly used bottom paints containing tributyltin, which has been banned in the International Convention on the Control of Harmful Anti-fouling Systems on Ships of the International Maritime Organization due to its serious toxic effects on marine life (such as the collapse of a French shellfish fishery). [15] Now that tributyltin has been banned, the most commonly used anti-fouling bottom paints are copper-based. Copper-based antifouling paints can also have adverse effects on marine organisms. Copper occurs naturally in aquatic systems but can build up in ports or marinas where there are lots of boats. Copper can leach out of anti-fouling paint from the hulls of the boats or fall off the hulls in different sized paint particles. This can lead to higher-than-normal concentrations of copper in the ports or bays.

This excess of copper in the marine ecosystem can have adverse effects on the marine environment and its organisms. In marinas, the river nerite, a brackish water snail, was found to have higher mortality, negative growth, and a large decrease in reproduction compared to areas with no boating. The snails in marinas had more tissue (histopathological) issues and alternations in areas like their gills and gonads as well. [16] Increased exposure to copper from antifouling paint has also been found to decrease enzyme activity in brine shrimp. [17]

Antifouling paint particles can be eaten by zooplankton or other marine species and move up the food chain, bioaccumulating in fish. This accumulation of copper through the food web can cause damage to not only the species eating the particle, but those that are accumulating it in their tissues from their diet. [18]  Antifouling paint particles can also end up in the sediment of harbors or bays and damage the benthic environment or the organisms that live in them. These are the known effects of copper based antifouling paint; however, it has not been a large focus of study so the extent of the effects is not fully known. More research is needed to fully understand how these paints and the metals in them affect their environments.

The Port of San Diego is investigating how to reduce copper input from copper-based antifouling coatings, [19] and Washington State has passed a law which may phase in a ban on copper antifouling coatings on recreational vessels beginning in January 2018. [20] However, despite the toxic chemistry of bottom paint and its accumulation in water ways across the globe, a similar ban was rescinded in the Netherlands after the European Union's Scientific Committee on Health and Environmental Risks concluded The Hague had insufficiently justified the law. In an expert opinion, the committee concluded the Netherlands government's explanation "does not provide sufficient sound scientific evidence to show that the use of copper-based antifouling paints in leisure boats presents significant environmental risk." [21]

"Sloughing bottom paints", or "ablative" paints, are an older type of paint designed to create a hull coating which ablates (wears off) slowly, exposing a fresh layer of biocides. Scrubbing a hull with sloughing bottom paint while it is in the water releases its biocides into the environment. One way to reduce the environmental impact from hulls with sloughing bottom paint is to have them hauled out and cleaned at boatyards with a "closed loop" system. [14] [22]

Some innovative bottom paints that do not rely on copper or tin have been developed in response to the increasing scrutiny that copper-based ablative bottom paints have received as environmental pollutants. [23] [24] [25]

A possible future replacement for antifouling paint may be slime. A mesh would cover a ship's hull beneath which a series of pores would supply the slime compound. The compound would turn into a viscous slime on contact with water and coat the mesh. The slime would constantly slough off, carrying away micro-organisms and barnacle larvae. [26] [27]

See also

Related Research Articles

A biocide is defined in the European legislation as a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism. The US Environmental Protection Agency (EPA) uses a slightly different definition for biocides as "a diverse group of poisonous substances including preservatives, insecticides, disinfectants, and pesticides used for the control of organisms that are harmful to human or animal health or that cause damage to natural or manufactured products". When compared, the two definitions roughly imply the same, although the US EPA definition includes plant protection products and some veterinary medicines.

<span class="mw-page-title-main">Biofouling</span> Growth of marine organisms on surfaces

Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that cause degradation to the primary purpose of that item. Such accumulation is referred to as epibiosis when the host surface is another organism and the relationship is not parasitic. Since biofouling can occur almost anywhere water is present, biofouling poses risks to a wide variety of objects such as boat hulls and equipment, medical devices and membranes, as well as to entire industries, such as paper manufacturing, food processing, underwater construction, and desalination plants.

<span class="mw-page-title-main">Muntz metal</span> Type of brass

Muntz metal is an alpha-beta brass alloy composed of approximately 60% copper, 40% zinc and a trace of iron. It is named after George Fredrick Muntz, a metal-roller of Birmingham, England, who commercialised the alloy following his patent of 1832.

<span class="mw-page-title-main">Fouling</span> Accumulation of unwanted material on solid surfaces

Fouling is the accumulation of unwanted material on solid surfaces. The fouling materials can consist of either living organisms (biofouling) or a non-living substance. Fouling is usually distinguished from other surface-growth phenomena in that it occurs on a surface of a component, system, or plant performing a defined and useful function and that the fouling process impedes or interferes with this function.

<span class="mw-page-title-main">Tributyltin oxide</span> Chemical compound

Tributyltin oxide (TBTO) is an organotin compound chiefly used as a biocide (fungicide and molluscicide), especially a wood preservative. Its chemical formula is [(C4H9)3Sn]2O. It is a colorless viscous liquid. It is poorly soluble in water (20 ppm) but highly soluble in organic solvents. It is a potent skin irritant.

<span class="mw-page-title-main">Marine engineering</span> Engineering and design of shipboard systems

Marine engineering is the engineering of boats, ships, submarines, and any other marine vessel. Here it is also taken to include the engineering of other ocean systems and structures – referred to in certain academic and professional circles as “ocean engineering.”

<span class="mw-page-title-main">Tributyltin</span> Group of organotin compounds

Tributyltin (TBT) is an umbrella term for a class of organotin compounds which contain the (C4H9)3Sn group, with a prominent example being tributyltin oxide. For 40 years TBT was used as a biocide in anti-fouling paint, commonly known as bottom paint, applied to the hulls of oceangoing vessels. Bottom paint improves ship performance and durability as it reduces the rate of biofouling, the growth of organisms on the ship's hull. The TBT slowly leaches out into the marine environment where it is highly toxic toward nontarget organisms. TBT toxicity can lead to biomagnification or bioaccumulation within such nontarget organisms like invertebrates, vertebrates, and a variety of mammals. TBT is also an obesogen. After it led to collapse of local populations of organisms, TBT was banned.

Imposex is a disorder in sea snails caused by the toxic effects of certain marine pollutants. These pollutants cause female sea snails to develop male sex organs such as a penis and a vas deferens.

<span class="mw-page-title-main">Copper sheathing</span> Ship hull covering

Copper sheathing is a method for protecting the hull of a wooden vessel from attack by shipworm, barnacles and other marine growth through the use of copper plates affixed to the surface of the hull, below the waterline. It was pioneered and developed by the Royal Navy during the 18th century. In antiquity, ancient Greeks used lead plates to protect the underwater hull.

<span class="mw-page-title-main">Roadstead of Brest</span> Bay in Brittany, France

The roadstead of Brest is a roadstead or bay located in the Finistère department in Brittany in northwestern France. The surface area is about 180 km². The port of Brest and one of the two French naval bases, Brest Arsenal, are located on its northern edge. It is linked to the Atlantic Ocean by the Goulet de Brest, a strait about 1.8 km wide. Three main rivers drain into the roadstead: the Penfeld, the Élorn and the Aulne.

<span class="mw-page-title-main">Copper toxicity</span> Type of metal poisoning

Copper toxicity is a type of metal poisoning caused by an excess of copper in the body. Copperiedus could occur from consuming excess copper salts, but most commonly it is the result of the genetic condition Wilson's disease and Menke's disease, which are associated with mismanaged transport and storage of copper ions. Copper is essential to human health as it is a component of many proteins. But hypercupremia can lead to copper toxicity if it persists and rises high enough.

<span class="mw-page-title-main">Environmental effects of paint</span>

The environmental effects of paint can vary depending on the type of paint used and mitigation measures. Traditional painting materials and processes can have harmful effects on the environment, including those from the use of lead and other additives. Measures can be taken to reduce its environmental effects, including accurately estimating paint quantities so waste is minimized, and use of environmentally preferred paints, coating, painting accessories, and techniques.

<span class="mw-page-title-main">Copper alloys in aquaculture</span>

Copper alloys are important netting materials in aquaculture. Various other materials including nylon, polyester, polypropylene, polyethylene, plastic-coated welded wire, rubber, patented twine products, and galvanized steel are also used for netting in aquaculture fish enclosures around the world. All of these materials are selected for a variety of reasons, including design feasibility, material strength, cost, and corrosion resistance.

A biomimetic antifouling coating is a treatment that prevents the accumulation of marine organisms on a surface. Typical antifouling coatings are not biomimetic but are based on synthetic chemical compounds that can have deleterious effects on the environment. Prime examples are tributyltin compounds, which are components in paints to prevent biofouling of ship hulls. Although highly effective at combatting the accumulation of barnacles and other problematic organisms, organotin-containing paints are damaging to many organisms and have been shown to interrupt marine food chains.

An antimicrobial surface is coated by an antimicrobial agent that inhibits the ability of microorganisms to grow on the surface of a material. Such surfaces are becoming more widely investigated for possible use in various settings including clinics, industry, and even the home. The most common and most important use of antimicrobial coatings has been in the healthcare setting for sterilization of medical devices to prevent hospital associated infections, which have accounted for almost 100,000 deaths in the United States. In addition to medical devices, linens and clothing can provide a suitable environment for many bacteria, fungi, and viruses to grow when in contact with the human body which allows for the transmission of infectious disease.

Pettit Marine Paint is a manufacturer of marine (boat) coatings, antifouling boat bottom paint, varnish and epoxies for consumer and commercial markets. The company was established in 1861, its headquarters are located in Rockaway, New Jersey.

Ultra-low fouling is a rating of a surface's ability to shed potential contamination. Surfaces are prone to contamination, which is a phenomenon known as fouling. Unwanted adsorbates caused by fouling change the properties of a surface, which is often counter-productive to the function of that surface. Consequently, a necessity for anti-fouling surfaces has arisen in many fields: blocked pipes inhibit factory productivity, biofouling increases fuel consumption on ships, medical devices must be kept sanitary, etc. Although chemical fouling inhibitors, metallic coatings, and cleaning processes can be used to reduce fouling, non-toxic surfaces with anti-fouling properties are ideal for fouling prevention. To be considered effective, an ultra-low fouling surface must be able to repel and withstand the accumulation of detrimental aggregates down to less than 5 ng/cm2. A recent surge of research has been conducted to create these surfaces in order to benefit the biological, nautical, mechanical, and medical fields.

Ultrasonic antifouling is a technology that uses high frequency sound (ultrasound) to prevent or reduce biofouling on underwater structures, surfaces, and medium. Ultrasound is just high frequency sound. Ultrasound has the same physical properties as human-audible sound. The method has two primary forms: sub-cavitation intensity and cavitation intensity. Sub-cavitation methods create high frequency vibrations, whilst cavitation methods cause more destructive microscopic pressure changes. Both methods inhibit or prevent biofouling by algae and other single-celled organisms.

<span class="mw-page-title-main">Ships husbandry</span> Maintenance and upkeep of ships

Ships husbandry or ship husbandry is all aspects of maintenance, cleaning, and general upkeep of the hull, rigging, and equipment of a ship. It may also be used to refer to aspects of maintenance which are not specifically covered by the technical departments. The term is used in both naval and merchant shipping, but naval vessel husbandry may also be used for specific reference to naval vessels.

In-water cleaning, also known as in-water surface cleaning, is a collection of methods for removing unwanted material in-situ from the underwater surface of a structure. This often refers to removing marine fouling growth from ship hulls, but also has applications on civil engineering structures, pipeline intakes and similar components which are impossible or inconvenient to remove from the water for maintenance. It does not generally refer to cleaning the inside of underwater or other pipelines, a process known as pigging. Many applications require the intervention of a diver, either to provide the power, or to direct a powered tool.

References

  1. ↑ "Coating Systems For Underwater Hull Surfaces". NSTCenter. Naval Surface Treatment Center. Retrieved 2016-07-03.
  2. ↑ "Marine Corrosion Explained". MarineCoatingPaint.com. June 29, 2015. Archived from the original on January 8, 2016. Retrieved 2015-10-31.
  3. ↑ Are foul-release paints for you? Coating calculator Archived 2011-07-17 at the Wayback Machine , National Fisherman
  4. ↑ Mitchell, Mike J. (2005-04-03). Antifouling Coatings For Offshore Structures. OnePetro. S2CID   137437167.
  5. ↑ Braithwaite, R. A.; McEvoy, L. A. (2005). "Marine biofouling on fish farms and its remediation". Advances in Marine Biology. 47: 215–252. doi:10.1016/S0065-2881(04)47003-5. ISBN   9780120261482. ISSN   0065-2881. PMID   15596168. S2CID   19773748.
  6. 1 2 3 4 5 6 King, Peter (2022). "The development of Merchant Ship Composite Hull Construction in Britain". The Mariner's Mirror. The Society for Nautical Research. 108 (4): 439–461. doi:10.1080/00253359.2022.2117459. S2CID   253161460.
  7. ↑ Dafforn, Katherine A.; Lewis, John A.; Johnston, Emma L. (2011). "Antifouling strategies: History and regulation, ecological impacts and mitigation". Marine Pollution Bulletin. 62 (3): 453–65. Bibcode:2011MarPB..62..453D. doi:10.1016/j.marpolbul.2011.01.012. PMID   21324495.
  8. ↑ Ronalds, B.F. (2019). "Bonnington Chemical Works (1822-1878): Pioneer Coal Tar Company". International Journal for the History of Engineering & Technology. 89 (1–2): 73–91. doi:10.1080/17581206.2020.1787807. S2CID   221115202.
  9. ↑ "Letter from the Secretary of the Navy, Transmitting the Views of the Members of the Board on Construction Relative to the Question of Sheathing and Coppering the Three Battle Ships and the Three Armored Cruisers Authorized by the Naval Appropriation Act, Approved March 3, 1899 (p.17, S. Doc. No. 165, 56th Congress, 1st Session)". Google. U.S. Government Printing Office. February 10, 1900. Retrieved 2016-07-06.
  10. ↑ Stetson, Judith (Feb 23, 2011). "Woods Hole in World War II" (PDF). Woods Hole Historical Museum. Retrieved 2016-07-06.
  11. ↑ "Marine fouling and its prevention; prepared for Bureau of Ships, Navy Dept". Woods Hole Oceanographic Institution. United States Naval Institute. 1952. Retrieved 2016-07-06.
  12. ↑ Lunn, Iver (1974). Antifouling: a brief introduction to the origins and development of the marine antifouling industry. Thame, UK: BCA Publications. ISBN   0950129917.
  13. ↑ Collins, Andrew P (13 August 2019). "Why So Many Ships Are Red On The Bottom". Jalopnik. Gizmodo Media Group . Retrieved 15 August 2019.
  14. 1 2 3 "Eco-Friendly Boating". eartheasy.
  15. ↑ "Focus on IMO - Anti-fouling systems" (PDF). International Maritime Organisation.
  16. ↑ Bighiu, M.A. 2017. Use and Environmental Impact of Antifouling Paints in the Baltic Sea. [Unpublished dissertation]. Stockholm University.
  17. ↑ Katranitsas, A.; Castritsi-Catharios, J.; Persoone, G. (November 2003). "The effects of a copper-based antifouling paint on mortality and enzymatic activity of a non-target marine organism". Marine Pollution Bulletin. 46 (11): 1491–1494. Bibcode:2003MarPB..46.1491K. doi:10.1016/S0025-326X(03)00253-4. ISSN   0025-326X. PMID   14607547.
  18. ↑ "Marine pollution from antifouling paint particles". 13 February 2019. Archived from the original on 2021-10-27.
  19. ↑ "San Diego Region - Shelter Island Yacht Basin Copper TMDL". Regional Water Quality Control Board - San Diego. Retrieved 2015-10-31.
  20. ↑ the same in May, 2011.
  21. ↑ "EU expert committee challenges Dutch copper-paint restrictions". Free Online Library. 2009. Retrieved 2015-10-31.
  22. ↑ Selecting an anti-fouling paint Archived 2011-09-28 at the Wayback Machine , West Marine
  23. ↑ http://goliath.ecnext.com/coms2/gi_0199-5573950/Fouling-out-coppers-glory-fades.html [ dead link ] Fouling out: coppers glory fades as new bottom-paint research leads to improved antifouling treatments, National Fisherman, June 2006
  24. ↑ "EPA Reports to Congress on Tributyltin Boat-Bottom Paint" (Press release). EPA. June 20, 1997. Retrieved August 26, 2012.
  25. ↑ http://findarticles.com/p/articles/mi_m0BQK/is_6_10/ai_n15858063/ [ dead link ] Will California terminate copper paint?, BNET, 2005
  26. ↑ Paul Marks (September 2009). "Slimy-skinned ships to slip smoothly through the seas". New Scientist. Retrieved 28 September 2009.
  27. ↑ "Slime-Covered Boats Could Keep Marine Pests at Bay". 28 September 2009. Retrieved 28 September 2009.
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