Antifouling paint on yacht bottom

Antifouling paint for your vessel and the waters

By volume, 80% of global trade is conducted on our oceans, and our maritime industry continues to grow; as does our dependence on the vessels that work so hard to achieve it. Biofouling refers to the growth of microorganisms; plants, algae, or animals, that build up on the underwater sections of vessel hulls. This build up decreases the durability and efficiency of a vessel. Antifouling paint works to prevent biofouling, protecting your vessel and your wallet. Anti fouling paint is an essential part of vessel’s coating system due to the fact that it:

  1. Decreases the risk of transfering organisms into foreign waters
  2. Protects against damaging marine growth
  3. Increases the maximum speed of a ship
  4. Lowers fuel consumption
  5. Increases a ship’s durability

This article will describe the variety of antifouling paint available, and take a look at the ever-changing regulations regarding biocides. We will also look at the companies that provide antifouling coatings, and where to find them in the Emirates.

The 2 types of traditional antifouling paint

Traditionally, antifouling coating works through the action of a biocide – a chemical substance intended to destroy, deter, or render harmless, or exert a controlling effect on any harmful organism by chemical or biological means. The current biocide used in most antifouling paints is copper, with 90% of antifoul coatings using copper or its oxide as their active ingredient. The mechanism by which biocidal antifouling coatings leach biocides into the surrounding water varies depending on the coating type. Pairing the right delivery system with the substrate, environment, and use of the vessel is vitally important for the correct functioning of the coating. The two main categories of biocidal antifouling paint are:

1. Eroding antifouling coating

antifouling paint applied on boats, all different types.

Antifouling paint comes in two types: eroding and hard antifouling systems. Choose the right type based on environment, vessel type and use.

As the name suggests, this coating uses erosion to deliver biocides.  This can be caused by the friction of the water passing over the hull, or by a chemical reaction which is localised at the surface of the coating. The biocides are released in a controlled manner, which provides longer and more consistent biofoul protection. Unlike hard film antifouling, boats painted with eroding antifoul can be hauled and relaunched without repainting, since the biocides are chemically bound to the paint and are only active in water.

2. Hard film antifouling paint

The delivery mechanism for these types of antifouling paint is called ‘contact leaching’. The coating is packed with biocide, and contact with water causes these biocides to leach out. As a result, the antifouling protection is not constant – it starts out high, then wanes as the biocides leach away and all that remains is the hard paint film. These coatings also lose their antifouling ability if kept out of water, so they cannot be hauled and relaunched without repainting.

Foul release coating – Sustainability-driven alternative for antifouling paint

Currently, there is a trend away from biocides, and new products are emerging on the market which use different properties to fight biofouling. The biocide free antifouling coatings include experimental surfaces such as teflon or silicone coated, hydrophobic, and textured hulls which may prevent the biofouling from growing.

These coatings are known as ‘foul release paint’ instead of ‘antifouling’ due to the fact that the mechanism does not prevent biofouling from settling, but instead the slipperiness prevents it from attaching. Foul release coatings include silicone elastomers, teflon-based coating and fluoropolymer coatings, ceramic coatings, and wax coatings. The action of the vessel moving through the water is enough to detach biofouling from its tenuous hold.

Another, newer type of foul release measure is biomimetic coating. The name comes from the Greek for “life-imitating”, and these coatings look to the natural world for inspiration. Coatings that imitate the closely scaled skin of a shark, flocked surfaces that resemble plants, or hydrophobic coatings based on the water-repelling surfaces of the lily pad are all biomimetic coatings.

6 factors that contribute to the choice of antifouling paint

Ultimately, the choice of antifouling coating comes down to the best option for the vessel’s substrate, the environment, and the intended use of the vessel. All factors need to be considered to ensure a successful coating. In order to determine which coating is best for your vessel, you should be aware of the six factors that affect the choice:

  1. Local and international regulations – After the banning of TBT, marine authorities have been wary of biocides in general. Though copper is currently the most common antifouling active ingredient, and it is not likely to go anywhere anytime soon, the antifouling industry is broadening. Biocide-free options are becoming more common and better-performing as companies within the industry move away from biocides.
  2. Costs related to the coating and the process – How much does the paint cost? Does the coating lead to greater fuel efficiency? What surface preparation is required? How often will it require repainting, and what cleaning procedures will be required? Prices per litre is not an adequate representation of price when it comes to antifouling, there are many cost factors at work.
  3. The lifespan of the coating – Not all coatings have the same lifespan, especially under differing conditions. Some will protect for 3-5 years, others for the vessel’s lifetime.
  4. Intended lay-up times, time in port, and water conditions – Hard antifouling paints do not maintain their antifouling properties while hauled, where eroding coatings do. Foul release coatings require the ship to move at a certain pace (about 25-30 knots) for the best results, so long times in port or lay up periods would prevent it from functioning effectively. Mooring conditions in warm coastal waters where marine organisms are densest poses an additional biofouling threat, however many ports are now banning copper biocide to combat rising contamination levels.
  5. Abrasion resistance – The abrasion resistance is relevant for racing vessels, vessels on trade routes that might encounter ice, bumps, or scrapes, as well as ships that require polishing. Highly abrasion resistant paints include the hard film coatings, Teflon, and ceramic coatings.
  6. Hull cleaning – Can the coating be cleaned without damaging it? Will underwater cleaning risk environmental damage? Downtime from dry-docking and regulations in certain ports preventing underwater cleaning may be factors you need to consider.

Antifouling paint UAE: find the best product for your vessel

There are many companies operating in the UAE that provide antifouling and foul release products. Among these are AkzoNobel (Intersleek products under the International brand), Hempel, and Jotun. Prices vary across products, but with the range available it is possible to find exactly what you are looking for. Many products are not available for retail markets, and need to be applied by professionals and shipyards. It is always best to consult with professionals when choosing an antifouling paint.

If you would like more information, our experts are happy to help. Just contact us and we will bring you in touch with one of our coating partners to secure a quote for your project. You can do this  through our contact form by clicking the “Request a Quote” button at the bottom of this article. We will help you find the right coating solution for your needs.

Anitfouling Paint ManufacturerProductDescription
Aquarius Marine Coatings Ltd.CoppercoatThe name in copper-based biocidal antifouliing. Suitable for DIY or professional application, by roller or spray and can be used on all surfaces including GRP, iron, steel, wood and aluminium.
AkzoNobelInterlux Micron CSCSelf-polishing biocidal antifouling for multi season protection. No sanding required, even after hauling.
AkzoNobelIntersleek 1001Biocide-free elastomeric foul release coating.
JotunSeaQuantum X200Ultra low friction self-polishing antifouling for aluminium and carbon steel
Rust-OleumBoat Bottom Antifouling PaintA copper-based biocidal antifouling paint for use on fiberglass, wood or steel surfaces, suitable for both fresh and saltwater.

Antifouling coating in local and international waters

Antifouling paint has a rocky history. The wonder product of the 60s and 70s, tributyltin (TBT), turned out to be seriously toxic to the marine ecosystem, even causing the collapse of a French oyster fishery. The substance is now banned, but its far-reaching effects have led to increased diligence and scrutiny on antifouling paints. This has led to coating companies investing increasing effort and money into eco-friendly, biocide-free coating alternatives such as foul release paints. In the US, California and Washington State both have restrictions on copper biocides, and a couple of European countries have also had restrictions, or attempted to have restrictions placed on their use. At the moment in the UAE there are no other restrictions on antifouling coating than those concerning TBT. Note that you may have to be able to prove the antifouling paint of your vessel meets the requirement.