Protect your hull and improve efficiency with antifouling paint NZ
New Zealand is an island nation. Our trade imports and exports are mostly conducted by sea, our fisheries and aquaculture contribute hundreds of millions to GDP, cruise ships bring 200,000 people to our shores each year, and the New Zealand boatbuilding industry exports hundreds of millions of dollars of product yearly. Not to mention the national love of having a cast on the weekend. All of these boat-based activities are at risk of biofouling. Biofouling is the buildup and growth of organisms, plants, animals, and algae on the underwater section of vessels. It decreases the durability and efficiency of a vessel, and occurs in both fresh and saltwater. Antifouling paint prevents biofouling, protecting the bottom of boats and the bottom line.
In this article we look at the benefits of antifouling paint, the different types of antifouling paint, how to determine which one is right for you, and some of the antifouling products available in New Zealand.
The advantages of applying antifouling paint
New Zealand relies on its waterways and marine environments for trade, travel, and industry. Antifouling paint has the following benefits, not just for the vessel but also for the environment:
- Lowers fuel consumption – Biofouling increases the resistance of a vessel in the water, increasing fuel usage. Removing biofouling also decreases CO2 emissions.
- Increases the maximum speed of a ship by removing the heavy biofouling impediment.
- Increases a ship’s durability and removes the strain of dragging the weight and impediment of biofouling through the water.
- Decreases the risk of transfering harmful organisms into foreign waters (such as the Mediterranean Fanworm or Clubbed Tunicate Sea Squirt).
- Protects against damaging marine growth such as shipworms.
Antifouling paint types – hard, eroding, and foul release
Antifouling paints can be classified broadly as either biocidal or foul release coatings. Biocidal antifouling paint is the traditional and more common coating type, though the push for more environmentally-conscious green coatings is driving demand for foul release coatings. Below we look at both these coating types and their pros and cons.
Biocidal antifouling paints
A biocidal antifouling paint uses a biocide to prevent the growth of organisms. A biocide is a chemical substance intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism by chemical or biological means. Nowadays the most common biocide used in antifouling paint is copper or its oxide, with over 90% of paints on the market using it as their active ingredient. The two main categories of biocidal antifouling are hard and eroding:
- Hard film antifouling
Hard film antifouling delivers biocides through ‘contact leaching’ – it is contact with water which causes the biocides to leach out and protect the hull. As a result the protection is not constant, it starts out high and then wanes as the biocides deplete, leaving behind a buildup of hard film. They also lose their antifouling ability if kept out of the water, so they cannot be hauled and relaunched without repainting. They are not affected by erosion and so are commonly used on speed boats and racing vessels.
- Eroding antifouling
Also known as ablative antifouling or self polishing antifouling, the delivery mechanism for this antifouling type is erosion. The paint either wears away due to the friction of moving through the water and so releases biocides, or there is a chemical reaction at the surface of the coating which releases biocides. The release is controlled and so they provide longer and more consistent protection than hard film antifouling. As it is only active in water, the boat can be hauled and relaunched without loss of protection.
Foul release coatings
A foul release coating works to prevent biofouling by providing a surface to which the organisms cannot attach and grow. They are made from silicone elastomers, teflon and fluoropolymer coatings, wax coatings, ceramic coatings, hydrophobic materials, or even materials that give the hull a texture. Though the biofouling is not prevented from settling on the hull, the movement of the ship through the water combined with the slipperiness of the coating means they are detached easily, and cannot stick.
What to know to choose the best antifouling paint
Ultimately, the choice of antifouling paint 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, these are some of the questions you should be asking:
- What are the costs related to the coating?
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? Price per litre is not an adequate representation of price when it comes to antifouling, there are many cost factors at work.
- What is the lifespan of the coating?
Not all coatings have the same lifespan, especially under differing conditions. Some will protect for 1-3 years, others for the vessel’s lifetime. It is recommended, whatever the suggested lifespan of the coating, that you take the shortest measure as the lifespan – reapplying yearly is often the best option.
- How abrasion resistant is the coating?
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. If your vessel is intended for speed or abrasive conditions, hard film antifouling is the best option.
- Is the coating suitable for the 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.
- Where, and how frequently will the coating and hull need 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.
- Are there any regulation changes which may affect the suitability of the coating?
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.
New Zealand’s antifouling requirements and regulations
The New Zealand government is cracking down on the introduction of marine pests and diseases to our waters, a major threat to the marine environment and resources. All vessels arriving in New Zealand need to arrive with a ‘clean hull’ and must provide evidence of biofouling management before they arrive. This does not just apply to foreign vessels, either. There are over 60,000 moored launches or yachts in New Zealand’s marinas, any of which could harbour these invasive species.
The problem with antifouling as a solution is simple – it relies on the toxic nature of its ingredients to kill or deter organisms. Copper is now the biocide of choice after tributyltin was revealed to be having devastating effects on aquatic life. A 50ft yacht coated with a copper-based antifouling paint will leach up to 3kg of copper into the water over a two year lifespan. New Zealand marine authorities are careful to monitor copper concentrations in our waterways, but levels are still very high. Copper-free alternatives such as foul release coatings provide a less toxic alternative.
The New Zealand Environmental Protection Agency provides a helpful guideline for safely using antifouling paints, with best practice tips for safe application and removal.
Antifouling paint products and prices
With New Zealand’s love of fishing and reliance on the water, it is no surprise that there are many brands and companies providing antifouling solutions amidst their marine protection ranges. These include hard, ablative, and foul release coatings. If you would like more information regarding antifouling paint, or have a large project that needs the right coating, get in touch! Our experts are here to help. Simply use the “Request a Quote” button beneath this article and tell us a little about your project to get started, and we will do the rest.
|Antifouling Paint Product||Antifouling Type||Antifouling Price/Coverage|
|Altex Coastal Copper Antifouling Paint||Copper-based ablative suitable for 10-12 knots||$200/4L with a coverage of 5m2/L|
|Altex No.5 Ablative Antifouling||Copper-based ablative antifouling – not for aluminium/alloy||$300/4L with a coverage of 7m2/L|
|Hempel Olympic Ablative Antifouling||Cuprous oxide-based self polishing antifouling||$300/5L with a coverage of 5m2/L|
|International Awlcraft||Ablative antifouling with a high strength copper biocide, Not for aluminium.||$200/4L with a coverage of 5m2/L|
|International Bottomkote||Copper-based antifouling, medium strength||$180/4L with a coverage of 8.5m2/L|
|International Micron Extra||A self-polishing antifouling with copper biocide for GRP, wood, steel/iron, lead.||$330/4L with a coverage of 11m2/L|
|International Trilux 33||Copper-based antifouling for aluminium craft||$130/1L with a coverage of 9m2/L|
|Intersleek 1000||Elastomeric foul release coating||Professional application required|
|OceanMax Propspeed||Foul release coating for propellers and running gear||500mL covers 1m2|
|PellerMax||Foul release coating for propellers and running gear||Available in kits, one kit covers a prop size of 35-45cm|
|Pettit Vivid Antifouling||Hybrid antifouling with copper biocide for fibrelass, wood, aluminium and steel||$240/4L with a coverage of 5m2/L|
|War Paint Antifoul||Ablative antifouling using cuprous oxide as the biocide||$190/4L with a coverage of 7-8m2/L|