What is AntiFouling Paint ? July 21, 2007
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Antifouling paints are paints that we apply on the underwater hulls of ships and boats. As the name suggests, it prevents fouling of the hull of the vessel. Antifouling paints come in various colours and types. Price can range from $6 per litre to over $120 per litre.
Before we go deeper into antifouling paints, let us first discuss a bit about ‘fouling’ and why it is critical to apply antifouling paints.. Where does fouling occur? Fouling in our context occurs on the underwater surfaces of marine vessels (ships, boats etc), buoys, offshore structures and any other submerged objects. Fouling can occur in both salt water and fresh water. What is fouling? Fouling is the settlement of marine organisms on the surfaces mentioned above. The marine organism can either be of plant origin such as algae and weeds, or can be of animal origin such as barnacles and tubeworms. However, the first resident in a fouling process is usually slime. Slime is a viscous and syrupy bacteriological layer consisting of billions of single-celled organism. Once this layer is allowed to establish, the surface becomes more conducive for other bigger organisms to anchor themselves. Effects of Fouling Damage Fouling causes damage to the structure. For wooden or fiberglass boats, severe fouling can cause irreparable damage to the underwater hull and can ultimately cause leakage and collapse of the hull Danger Fouling reduces the responsiveness of the vessel. This may be critical in harsh storm conditions where changing of direction speedily is extremely important in preventing capsize of the craft.
Fouling also weighs on the vessel, making it sit lower than usual. Drag Fouling causes drag which in turns reduces speed and increases fuel consumption. For oceangoing liners, this increased in fuel consumption can be very significant. When does fouling occur? Fouling occurs the moment the structure or vessel is submerged. Fouling generally happens when the structure is stationary. Since most boats remain static for 90% of their time in the water, underwater hulls make perfect feeding and breeding ground for fouling organisms. Certain marine organism such as goose barnacles can attach and grow even when the vessel is sailing.
Anti-Fouling Paints Antifouling paints have been developed specifically to combat this problem. Any vessel owner would know that fouling can be a very big problem, so much so that anti-fouling painting is the most common painting job carried out. Antifouling paints function by slowly releasing toxins into the lamellar sublayer of the vessel, protecting and preventing settlements of fouling organisms. Generally, the type of toxins used and the way these toxins are released differentiates the various classes of antifouling paints. The most common types of toxins used in antifouling paints are copper and TBT (tributyltin) or a combination of the two. Of the 2, TBT is found to be more effective. TBT antifoulings based on the co-polymer technology allows the controlled released of the toxin into the surface of the hull. This type of antifouling paint is commonly known as the TBT antifoulings (SPC). Its effectiveness in preventing growth under many varied marine conditions made it the antifouling of choice for many years. It also lasts a lot longer than copper-based antifoulings. A full system can last up to 5 years, compared to the 12 -18 months that one can get from a copper-based system. TBT-based antifoulings can also be used on aluminium hulls, where copper cannot be used. However, more than 15 years ago, the negative effect of TBT on the environment became a matter of great concern. Worst felt were species of shellfish and whelk, among others. 
In 2001, the International Maritime Organisation (IMO) called for a ban of sales and application of TBT-based antifoulings by January 2003. At the same time, the IMO also called for the total prohibition on hulls after January 2008. This means that ships could no longer be coated with TBT-based antifoulings after January 2003 and those vessels coated with it has up to January 2008 to have them removed. When the treaty comes into force next year, all vessel owners or captains must carry signed declaration that the hull is compliant. With the ban on TBT, copper has again become the toxin of choice. Research and development meanwhile has also led to newer forms of antifouling paints. International Paint has Teflon in some of their antifouling paints. Teflon has a coefficient of friction that is lower than ice and is the most slippery material in existence. It is this smoothness that reduces settlement of organisms. Other areas of research look into using organic or herbicidal compounds to counter fouling. All these research require a lot of time and money. It will be a long way more before a replacement can be found for copper.
We’ll talk about a few specific examples in future posts. Meanwhile, the following link will introduce 2 TBT-free antifouling products from International Paints. http://www.yachtpaint.com/superyacht/sy/pdf/TBT_Ban_Info.pdf
Comments»
Nice read! Very informative!
very nice explanation………………
Wonderful piece of information.
I have innovated a herbal anti fouling polymer from the extracts of botanical, abundantly plant available throughout in the world in wild stage. subject experts of departments of scientific and industrial research have recommended this innovation project to govt of India for support
I have got some useful feedback for my project on my project spc anti fouling polymer thanks.
This herbal anti fouling polymer releases the antimicrobial salts with a definite leaching rate.The herbal product naturally contains cationic initiators with counter ions in its extracts -diluted H2SO4and Chlorides) which act as propagators.The microbial salts resembles salts of HOCl The anti fouling polymer is a chlorinated hydrocarbon polymer with moderate toxicity.It can be utilized for manufacturing SPC anti fouling smoothness,disinfectants and pesticides.
Expert committee of DSIR Govt of India has recommended this project for financial support.
Bio anti fouling polymer may have multiple uses. It is a natural chlorinate hydrocarbon polymer ,
Good day Surendra,
Can you further explain this herbal base anti fouling of yours. Sounds interesting. Have you manufacture them in drums or r you only having the formulation. Have immersion test done n how is the efficacy.
Will the leach deposits cause any pollution issues? Does it leave a porous matrix on the body when leach or does it has a characteristics of a self polishing anti fouling.
Brgds
Shaik yamani
Nippon paint marine singapore
excellent description in brief words…
Preparation Of Antimicrobial Inorganic salt - Chlorine Water. - from this chlorinated bio polymer
Chlorine water is extracted from this co polymer by the following process
This chlorinated bio polymer is a rich source of chlorine water.. It is extracted through boiling the polymer in water and leaching, again the polymer is dehydrated and polymerized and the hydrolysis and leaching process is carried out to extract the chlorine water. All these processes can be repeated time and again for the complete recovery of this antimicrobial product from a given quantity of polymer.
To,
Brgds
Shaik yamani,
Nippon paint marine
Dear Sir,
Thank you for the interest shown on the herbal anti fouling polymer developed by me,here are a few replies of the queries asked by you.
1.I have only developed this botanical anti fouling polymer the biocide is naturally present and bonded with the bio molecules of the plant derived extracts so far .immersion test could not be conducted.Subject expert committee of Department of scientific &industrial research Govt of India has recommended this project for financial support for testing &validation
2.Leaching of the antimicrobial salts(inorganic salts)may not cause any pollution issue because the salts are biodegradable and destroyed by the microorganism and sun light after a short period of time
This anti fouling polymer leaches the antimicrobial continuously and have smoothening properties
.
Thanks,
Surendra Duklan,India