yachtcare antifouling aluminium

Yachting Monthly

• Digital edition

How to antifoul your boat: a step by step guide

• Theo Stocker
• April 23, 2021

No one likes to antifoul their yacht, but keeping a boat free of the harmful growth is vital. Adam Fiander shares how to get it right

Using the right kind of paint, properly applied, will give you faster sailing, reduce fuel consumption and help reduce your environmental impact. Credit: Theo Stocker

How to antifoul your boat

No one likes the annual effort and cost of antifouling, but keeping the underside of a yacht free of the unsightly, costly and potentially harmful effects of aquatic fouling has challenged and vexed owners for decades.

Apart from a few exceptions where water is at its coldest, almost no matter where you keep your yacht in the UK, sailors are faced with some of the harshest and most virulent underwater fouling in Europe.

Green and brown seaweed, slime, kelp, sponges, sea squirts, worm casings, barnacles and mussels are vying to take hold and build an entirely natural but unwanted community on your hull and appendages.

This incurs lacklustre sailing performance, unresponsive handling and increased fuel burn.

Protective equipment is vital during the application of antifoul. Credit: Graham Snook

But it’s not just about keeping the hull and propeller clean .

If the risk of transferring harmful non-native species from one region to another wasn’t a good motive, then the fact that health and safety authorities are currently reviewing antifoul product approvals should be.

Since the Biocidal Products Regulation (528/2012) was introduced in 2012, European antifoul paint manufacturers have worked hard to maintain performance from a reduced list of approved active substances they can now use.

Some products have remained unchanged, others have been dropped from product lines completely, and others have received some ‘tweaking’.

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Correct procedures to protect the environment and personal safety risks to applying these paints are being considered at the same time.

If the process of applying those highly effective pesticides is not given approval for continued DIY use, then applying antifoul as a ‘professional-only’ application may become a reality.

Being seen to adequately protect yourself, the environment and those around you in the coming months is key.

The British Coatings Federation, trade body for the coatings industry, set up the Protect, Collect, Dispose campaign ( www.thegreenblue.org.uk ) to educate boat owners in the correct procedures to follow, which, happily, will also help your new layer of antifoul adhere better and last longer.

Different antifoul types

The type of antifouling product to use depends upon your hull material, where you use your boat, how much money you want to spend on it and how often you plan to maintain the underwater coating.

By far the most common choice of DIY-applied paints are normally either a hard (self-polishing), or erodible (ablative) type.

Applied by either roller or brush, these types contain sufficient active ingredients – organic and non-organic compounds such as copper, zinc and booster biocides suspended in a resin or a solvent-based formulation that will last for one, possibly two, or even up to three seasons’ protection, depending upon boat use, quality, type and whether enough coats have been applied correctly to the required film-thickness.

Hi-tech solutions

Other ideas known to work well either as stand-alone solutions, or when used in conjunction with ‘traditional’ types, are sonic transducers that emit specific frequencies that prevent fouling from attaching.

Having sailed since the early 1990s, Adam Fiander cruised and raced a variety of yachts. He has years of experience working with antifoul products and produced the video for the BCF’s Safe Antifouling Initiative. www.safeantifouling.com

More well-known are long- term, copper-rich, durable solutions that have more lengthy application procedures, but offer up to 10 or more years’ protection, though these need to be applied under very controlled conditions and are normally professionally done.

Also having emerged in the last few years, vinyl-wrap coverings rely upon the slipperiness of the vinyl and can be easily peeled at the end of their life, though this raises questions about the use of disposable plastics.

Other coatings containing silicone, Teflon and PTFE are available, as are coatings using nanotechnology, but these are more geared towards high-end racing boats.

The science behind antifouling is changing all the time.

As copper is the predominant force in the majority of coatings, it’s important to check compatibility with the hull substrate you intend to antifoul.

Aluminium hulls, for example, require a different copper formulation to that found in the majority of copper-based antifouls.

Most existing coatings can be overcoated, but there are exceptions to this rule and those exceptions must be respected.

If you’ve recently bought a brokerage yacht, for example, and don’t know the make or type of the existing coating you have on, then a full barrier/primer coat is your best option.

Or if you want to be totally sure, full removal of the existing coating will give you that complete peace of mind.

How much antifouling paint will you need?

There’s nothing worse than realising two-thirds of the way in that you don’t have enough antifoul to finish the job.

Antifouls generally have a coverage-rate- per-litre on the label or technical data sheet, brochure or website.

Once you’ve established the surface area of your hull, keel and rudder combined, divide this number by the coverage rate for the product you have chosen, giving you the number of litres required per coat.

Some manufacturers offer a simple formula for you to work amounts out easily per each product based upon boat keel type.

For Yachting Monthly ‘s editor Theo Stocker’s 29ft Sadler, we used 4.5 litres of antifoul for two good coats, which suggests that some manufacturers’ tables are a little too cautious in their estimates.

In any event, don’t forget to factor in some extra paint to cover areas such as where the supporting props have been.

And if you spill some paint, you’ll want to have enough to compensate.

Paint quality formula

Surface area = Waterline Length x(Beam + Underwater Depth) x 0.50 (fin keel) or x 0.75 (long keel) Total litres required = Total surface area (m2) ÷ Coverage rate of paint (m2/lt)

Before you start of antifoul

Choose a still, dry day to apply the antifoul. Credit: Graham Snook

Antifouling contains biocides, so wearing personal protective equipment (PPE) is more than just a formality and it should be worn until the final clean-up procedure is complete.

You’ll need coveralls, eye- protection, a mask, a hat or hood, sturdy work boots and appropriate disposable gloves or sturdy reusable gloves.

Most antifouls contain solvents, so if you are working in a boatshed, ventilate the area as much as possible, take regular fresh-air breaks and use a respirator facemask with cartridge filters, as opposed to paper dust masks, which are fairly ineffective.

Even if you are working outside,a respirator mask with filters is still preferable.

Keep pets and children out of the working area and ensure you don’t eat or drink during the process.

Make sure you read and understand the paint labelling, data sheets and product information before starting.

Follow manufacturers guidelines and observe local health & safety recommendations.

You should antifoul outdoors in a safe and secure location and not in a busy or public place, such as a car park.

Locate your boat on a hard-standing, impermeable surface and use a suitable tarpaulin or cover to capture any washings or scrapings.

Weight the tarpaulin down, to avoid tripping up and so it doesn’t blow around in the wind.

Choose a dry day, not too cold or frosty and with as little wind as possible.

Avoid very early mornings or early evening when damp air, dew and condensation might be around.

Upon haul-out take some pictures to compare how your new paint works over the season, then get the hull pressure washed over a bunded catchment area to prevent antifouling entering the sea or ground water.

Surface preparation

The key to antifoul that lasts is ensuring the surface beneath is properly prepared

1. Wash off

Pressure washing is effective but causes a lot of contamination run-off, which needs to be captured. Credit: Theo Stocker

Pressure washing is the easiest way to get the hull clean.

This should be done on a bunded wash-off area, where contaminated water will be collected and stored in a holding tank rather than running back into the sea.

If this isn’t possible, portable bunding is available, or use a tarpaulin to capture removed fouling and paint particles.

2. Scraping

Credit: Graham Snook

Loose or flaking antifoul and small blisters can be scraped.

For removing several layers of old antifouling, gelcoat- friendly chemical removers are useful, as is professional soda-blasting, but never use a blow lamp or heat gun.

If using a scraper, round off the corners to avoid gouging.

3. Keying the surface

Lightly wet-sanding the surface with 60 or 80 grit wet-and-dry paper wrapped over a sanding block will provide a key and help the antifoul to adhere well.

Dry-sanding is not recommended because of the dust it puts in the air which can be inhaled, or get onto other boats’ hulls and decks.

Scrub the waterline and then rinse the hull thoroughly with fresh water.

4. Hull fittings

Protect anodes and skin fittings, exhaust outlets, heater vents and other fittings by wrapping with aluminum foil or taping over and sealing off.

If your anode is due to be replaced , this could be a good time to remove it, but protect the studs from paint.

5. Masking off 

Proceed by masking off the waterline, press the tape down hard to prevent paint or rainwater ingress and ensure a clear masked space around stern gear.

Avoid domestic decorating tape which will leave residue and invest in a good quality, waterproof masking tape – the blue kind will last outside for several weeks if necessary.

6. Patch prime

When you’ve finished rubbing back, bare patches can be ‘patch-primed’ with a suitable primer or barrier coat.

A slap-dash approach simply won’t do it – it’s all in the preparation

1. Paint preparation 

Ensure the antifoul is kept at room temperature so it flows and mixes well, (store in your car, or boatshed with the lids on).

Standing a tin in a bucket of warm water beforehand will do the same job.

Cover the tin completely with an old towel and open the lid carefully to prevent splashbacks from pressure build-up.

2. Stir and pour 

Stir well as the contents, particularly the active ingredients and heavy metal particles, settle and it’s important to achieve a homogenous coating.

Pour into a roller paint tray, or a sturdy paint pot and always re-secure the lid of the tin as solvents will evaporate quickly.

3. Choose your roller carefully 

To ensure a suitably thick coating is applied, use a medium-pile simulated mohair or sheepskin roller, which will avoid slipping across the hull.

Foam rollers disintegrate more quickly, and can slip, causing patches of thin paint.

Don’t spray antifouling paints from a gun – this practice is best left to professionals inside a shed.

If you need a break, cover the roller in cling film to stop it drying out

4. Film thickness 

Load the roller or brush generously and use a small brush where you need a higher degree of accuracy, such as on the waterline.

Try and achieve a minimum dry film- thickness per coat of no less than 60 microns (approx. 120 to 150 microns wet).

Use a Wet Film Thickness Gauge to measure by placing one edge flat on the wet antifoul.

A natural-fibre roller should give roughly the right thickness.

5. Second coat

For the second and successive coats, follow the same procedures as before and observe the correct drying interval times between coats, and the safe-to-relaunch period indicated on the tin.

Make sure you apply extra coverage where friction is greater, such as at the bow and the leading edge of your keel and rudder or skeg, and just beneath the waterline

6. Get the masking off

While the paint still feels tacky, peel back the masking tape for a sharp line that doesn’t stand proud.

Remove the temporary coverings over the anode and skin fittings, and congratulate yourself on a job well done.

Once it’s dry you can mask up again to refresh the boat top if it needs it.

Correct antifoul clean-up

Dispose of antifouling chemicals carefully

Any large spillages should be contained and collected with non-combustible absorbent materials such as sand or earth and disposed of properly as hazardous waste.

All PPE, apart from goggles, should be disposed of in appropriate hazardous waste collection bins.

Contaminated water needs to be poured into a bunded drain. Credit: Graham Snook

Scrapings from your tarpaulin can be emptied into an old tin and disposed of likewise.

Dirty water from washing down the hull should be disposed of in bunded catchment drains.

Please don’t casually discard this in a hedgerow or scatter it across the boatyard as the biocides will leach into the groundwater.

Waste material is gathered up and put into hazardous waste. Credit: Graham Snook

Don’t take any contaminated equipment, half-used tins of paint or soiled PPE off-site.

In particular, don’t retain these in your car and then drive off because the paint and solvent fumes may impair your ability to drive safely, or will at least give you a thumping headache by the time you get home!

The results

After a season in the water, this coat of antifoul on the editor’s boat had lasted much better than the previous year’s application.

Granted, she had sailed fewer miles, but there were no patches of undercoat showing through on the keel, no rust bubbling up on the keel, and no more than a thin slime on the hull, with no serious weed, barnacles or algae.

Freshly painted, the antifoul looked smart. After a season in the water, there was some slime but no significant growth. Credit: Theo Stocker

Theo realised he had missed painting one of the spots where the props had supported the boat before it was dropped in the water, and this was much more coarsely fouled.

The propeller did not fare quite so well and had been colonised by a thin layer of coral worm and weed, despite the silicone-based antifoul, though it did come off with the pressure washer without much complaint.

Painting in other locations

Not everyone will be antifouling in a fully kitted out boatyard.

Those with boats on more basic hard standings, using scrubbing posts, or cleaning off between tides will need to take responsibility for reducing risk to themselves, others around them and the environment.

To prevent toxic paint waste entering the sea, groundwater, or general environment, a full-length tarpaulin is essential, or for clubs where bunded drainage isn’t available, portable bunding – a tarpaulin with edges and a means to collect waste water – is an inexpensive alternative.

Plan where you will dispose of hazardous waste. Credit: Graham Snook

Clearly signpost the area to keep passers-by from coming close.

A few cones and ‘hazardous area’ protection tape would be a good idea.

Plan beforehand how and where you are going to dispose of your hazardous waste including paint chips, antifoul residue, used paint tins and brushes, either at a nearby marina, or a council recycling centre, though check beforehand which ones accept hazardous waste.

Scrubbing posts

Using scrubbing posts is cheaper than lifting out, but makes it harder to antifoul safely and effectively. Credit: Alamy

Many places around the UK still offer scrubbing grids on which you can dry out between tides, either against freestanding posts, or against a harbour wall, although some harbours are considering doing away with this facility because of the difficulty in preventing antifouling run-off from entering the water.

If you are going to use scrubbing posts, here are a few tips to follow:

• Check the posts are suitable for your boat and at what tidal heights you’ll need to get onto the scrubbing grid. Don’t just use a harbour wall as the base is unlikely to be firm enough to support your boat.
• As the tide ebbs, make sure the boat leans towards the posts with a line from the masthead to a strong point ashore. Lash the boat firmly to the posts fore and aft, and untie only as the tide reaches the waterline.
• You can scrub or scrape your hull clean, but pressure washers are not permitted due to the amount of run-off.
• Use just enough pressure to clean the hull; if the water runs blue beneath the boat, you’re pressing too hard.
• Use a tarpaulin to catch as much debris as possible. Laying a rope around the edge will catch some of the smaller fragments and sediment.
• Applying antifoul between tides is not ideal as the hull needs to be completely dry, and the paint needs time to set properly. If you are doing it, doing so over the course of two tides may give you more time, but the performance of your antifoul may be reduced.

Antifoul top tips

• Don’t forget to patch in where the prop supports were when the boat is in the slings on the way to the water, or ask if the boat can be held in the slings overnight.
• Use masking tape to seal off where your coveralls leave your wrists exposed – antifoul has a nasty habit of finding its way on to any areas of exposed skin, including face, neck and ears!
• Take the opportunity to inspect the hull for any obvious signs of wear and treat any serious issues such as osmosis professionally before proceeding.
• This is also a good time to repair any surface defects. If you have a cast iron keel there may be some surface pitting, which can be filled with epoxy – car body filler epoxy is a good cheap option. Race boats will invest a lot of time ensuring their keels are fared to a perfect, symmetrical aerofoil shape.
• Use a workmate bench or similar – scrabbling around on the floor opening and stirring tins is uncomfortable and encourages spills and accidents to happen.
• Invest in a proper flat-bladed paint stirrer – a thin screwdriver to stir heavy antifoul paint won’t work well enough.
• Wrap masking tape across a new paint roller, then remove it to take off loose hairs that would otherwise come off on to your fresh paint film. Allow yourself enough time and avoid rushing the job at all costs.
• If it is going to rain when antifouling, use the widest blue masking tape to make a gutter. Stick some balls of tape just above the waterline and then stretch the tape across the supports. It will keep the coating below dry while it cures.
• Keep some dermatological hand- wipes or purpose designed cleansers close by, so that the splashes can be dealt with quickly before they are allowed to dry. Should antifoul encounter skin, wash immediately with warm soapy water and don’t use a solvent or paint thinner.

Teamac Antifouling D Plus

We used a navy-blue, self-polishing antifoul from Teamac called Antifouling D Plus, priced at £89.93 inc VAT for 2.5 litres.

This high copper-oxide product with added co-biocides is for sailing yachts and powerboats up to 30 knots speed.

Two good coats gave us a smooth finish and this should last for between 18 to 24 months reliable fouling protection.

Buy Teamact Antifoulung D Plus from Amazon (UK)

For more information visit: The Green Blue, www.thegreenblue.org.uk and the British Coatings Federation www.safeantifouling.com

*Yachting Monthly is not paid by manufacturers for our recommendations. If you click through and buy an item, we may receive a small amount of money from the retailer, at no cost to you.*

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• Repainting the Boat

The Best Antifouling Paints Tested and Compared

Applying antifoul to the underwater hull of your boat is necessary to keep organisms away that could slow it down or cause it to erode. But which antifouling paints really offer reliable protection? Which is the best antifoul? And how do various antifouling products perform when tested and compared directly? Find answers to these questions in this test and comparison guide to antifouling . It also includes important information about the costs of various antifouling products .

• Which antifouling is the best?

Antifouling paints in comparison

• Comparison: Biocide-free and self-polishing antifouling
• Comparison: Hard and thin film antifouling
• Antifouling test
• Antifouling cost

The great SVB antifoul comparison Biocide-free and self-polishing antifouling in comparison

Self-polishing antifouling 2024.

Note: Comparing antifoulings directly can be difficult, as even small changes in the boat and the environment can have an influence on possible fouling.

For this reason, in this antifouling comparison, self-polishing antifoulings and biocide-free antifoulings are compared with each other, as are hard antifouling and thin-layer antifoulings . The reason for this is that these types of antifouling work in different ways. Self-polishing antifouling gradually wears off by itself, releasing biocides and thus protecting your boat from fouling. Hard antifouling forms a hard surface that gradually releases bioactive substances to protect against fouling. And thin film antifouling protects your boat from organisms attaching by providing a very smooth surface. This antifouling comparison guide does not compare specific antifouling applications, such as for propeller & sterndrive.

Hard & Thin Film Antifouling Comparison

Hard antifouling is best used on faster boats, such as motor yachts.

Hard & Thin Film Antifouling 2024

I am very happy with Seatec antifouling. Nice priceperformance ratio.

I have used this for years. It discolours at the waterline so I use Trilux which does not , a bit below the waterline up to the cove line. The trilux needs sanded off each year, the VC does not.

Which is the best antifoul?

There is no "best" antifouling that can be used on all boats. Different types of antifouling are more effective depending on the boat itself and where it is sailing. It's also important to know which previous antifouling was used. More information can be found in our guides "How to find and apply the right antifouling" and "How to properly remove antifouling" . In our online shop you will find the best antifouling paints from the brands Seatec, International, Hempel, Boero, Epifanes, Tikal, Yachticon, Jotun and Yachtcare, which are suitable for a wide range of boat and area requirements. Discover SVB's best antifouling for your underwater hull!

We have compared the 10 best antifoulings from the brands International, Seatec, Hempel, Epifanes and Boero.

How do we compare our antifouling paints?

For the best comparison and test results of our products, various factors are taken into account in the evaluations. This includes the features of the respective product, the many years of experience of our SVB experts as well as our customer comments and reviews.

Our assessment categories

• Comparison winner: The product with the best overall result, regardless of price.
• Price-performance winner: The product that gives the best value for money. Good quality at a reasonable price.
• Best-seller: The top seller that is currently our most popular.
• Green aspect: Biocide-free

Antifoulings in practice

The magazine "Boote" carried out an antifouling test for the 3/2017 issue , in which various antifouling paints were tested in practice.

The test focussed on the difference in fouling protection given by cheaper and branded products. For the test, five antifouling products from Hempel, International, Nautical, Epifanes and Yachtcare were applied to a ship in sections at the beginning of the 2016 season. In order to test the anti-fouling protection, the boat was placed in the port of Hamburg-Tatenburg and sailed to various fresh, salt and brackish water regions during the year. At the end of the season, the vessel was taken out of the water and the amount of fouling compared on the different areas.

The test revealed that all antifouling products did their job well. However, antifouling paints from International and Hempel provided the best protection. . It was easy to wipe off the small amount of fouling that had developed there. Hempel Hard Racing excelled with its very smooth surface. The price differences between the antifouling paints in the test were quite significant. Antifouling test winners at the time were more expensive brand-name products. Nevertheless, the somewhat cheaper products such as those from Yachtcare also performed very well in the test.

In Boote's test, antifouling paints for warm and nutrient-rich waters were also looked at. In these kinds of waters, boaters should choose products that are most effective, in order to protect the underwater hull in the best possible way. Hempel and International antifouling paints were the best at the time of the test.

Biocide-free antifouling in the test

Hiswa , the water industry association in the Netherlands, published a study on the effectiveness of biocide-free antifoulings in 2020. For the study, various antifouling products, such as Silic One by Hempel and simple Melkfett were tested on boats and PVC panels in various waters (salt and fresh water) in the Netherlands. The test products were applied to the surfaces for a year and taken out of the water in between for inspection. This meant that interim test results could be documented. In fresh water, all products performed more or less satisfactorily. Silic One by Hempel proved to be a really good anti-fouling product. In salt water, more extensive fouling was found on the boats and PVC panels. Up to now, biocide-free antifouling paints have been less suitable in harsh fouling conditions in salt water, and biocide-containing products have been the only alternative to protect the hull.

These test results cannot be used for other waters. Further antifouling tests would be necessary here, as different conditions (temperature, salinity, etc.) exist depending on the area. This also applies to special antifouling products. For example, an antifouling propeller test would be necessary to determine the best antifouling for propellers.

Our customers have already tested biocide-free antifoulings, as we can read in the following review by Frank S. of the biocide-free antifouling Silic One: „First of all, hats off to SVB. I called on Monday because I needed a can of Silic One. I needed it to be delivered to Enhuizen (Netherlands), as the boat was due to go in the water on Friday. The DHL delivery arrived on time on Thursday. Great stuff. We're very happy with Silic One. We first used it two years ago. After this time in the water, the hull was like new. We rebuilt some areas (the keel) and painted it with a different colour to the previous one. Red on blue, so that we would be able to see in two years exactly where reworking was needed. I have one suggestion on how to improve. Our boat is on props and before it goes into the water, these areas need painting. One whole can is too much for these areas. A quarter of a can would be more than enough."

In comparing antifouling products and carrying out tests, it is clear to see how difficult it is to determine across the board which antifouling is best. The right one for you and your boat depends on various factors that must be determined individually.

Our comparison and test also show that the best antifouling products are not necessarily the most expensive. Own label products and cheaper antifouling that we sell in our range also provide reliable fouling protection and are in no way inferior to better known brand name antifouling products.

Note: The best antifouling will only be effective if it is applied correctly.

To protect the environment and organisms in the water, it is generally recommended to use biocide-free antifouling products. Until now, these are mainly suitable for use in freshwater areas and, according to tests done by Hiswa, are a good alternative to antifouling containing biocide. You too can do your bit to protect the underwater world!

The costs of antifouling paint: How much does antifouling cost?

Depending on what you plan to do, the costs of your antifouling will be a combination of the amount it will cost to remove old antifouling and apply new paint.

How much does it cost to remove antifouling?

The costs for removing antifouling, like applying, depend on the size of the boat, and whether you intend to use a professional service provider or do the job yourself. It also depends on the method of removal.

If you decide to remove antifouling using stripper, first calculate the size of the area of the antifouling that is to be removed. The amount of stripper required can then be taken from the values given in the respective data sheet. Remember that you may sometimes have to apply stripper several times in order to remove all layers of antifouling present. In most cases, however, it is unlikely that you will be able to remove all traces of antifouling.

In addition to the cost of the stripper itself (if this method is chosen), the costs of removing antifouling will also include the tools that are needed, any equipment that can help, as well as protective equipment, such as clothing or goggles, if you do not already have these.

Note: After removing the old antifouling, new antifouling should be applied. It's a good idea to do a cost breakdown of the new antifouling. You can find plenty of helpful information and advice about choosing and applying antifouling in our guides "How to find and apply the right antifouling for your boat" and "How to properly remove antifouling from your boat" .

Tools & Protective Clothing

How much does it cost to apply antifouling?

The costs for new antifouling depend on various factors: You'll first need to decide whether to let professionals do the job or if you want to do it yourself. In most cases, money can be saved if you do it yourself, but it is not exactly a quick job, so you will also have to invest some time. The other cost influencer is the size of the boat and necessary work steps, i.e., what exactly has to be done and what is needed. Nevertheless, it is possible to roughly calculate the costs of applying new antifouling.

Total costs: Cost calculation of renewing antifouling

The total costs of renewing antifouling consist of the costs of removing the old antifouling paint and of applying the new antifouling paint. In addition to the corresponding amount of antifouling, other cost factors must be included in the calculation:

The various factors show how different an antifouling job can cost, depending on exact requirements. If you only want to treat parts of the antifouling, the costs will, of course, be much lower than if you want to remove all the old antifouling from your boat and apply new antifouling. The antifouling comparison also shows that an effective antifouling does not always have to be the most expensive.

How much antifouling paint do I need?

• Calculate the area of your underwater hull with a formula to work out the correct amount for your surface (see ."Finding & applying antifouling" guide).
• Look at the practical yield (m² per litre) specification of your antifouling product (e.g., for International Cruiser 250 it is 9 m² per/litre)
• Calculate how many litres you need for the total area of your underwater hull.
• Multiply the result by the number of coats you intend to paint (the recommended number of coats is given by the manufacturer and can be found directly on the products).
• You should now know the number of litres needed for your antifouling.
• To calculate the cost of the antifouling paint required, divide the number of litres by the yield of your antifouling paint and multiply this by the price of the antifouling chosen.
• The result is the total cost of the antifouling paint needed.

International has created an antifouling calculator that you can use to work out the number of litres required for your boat. Simply enter details about your boat, which antifouling paint you want and the application method, and it tells you immediately the quantity you need. To open the calculator, click on "How much paint do I need?" at the bottom right of the International website)

Read up on antifouling before you buy so you can find the best antifouling for your boat. Information on removing antifouling and finding & applying the right antifouling can be found in our guides remove antifouling and antifouling . More detailed information on the individual products can be found in the descriptions and data sheets. Protect your boat with antifouling and enjoy your boat trip!

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Fouling protection : All about antifouling systems

Hauke Schmidt

 ·  15.01.2023

In this article:

Antifouling systems and how they work

Biocide-free coatings, how to protect saildrive & prop, how to recognise the antifouling coating.

If you take your boat out of the water after every stroke, you're in the clear because you don't need to worry about fouling. As soon as the boat stays in the water for longer, it's a different story. The underwater hull must be protected from colonisation by algae and organisms to prevent the yacht from suddenly becoming a property covered in mussels and pox.

How quickly the fouling colonises depends on various factors - mainly the territory and the climatic influences on water temperature and salinity as well as the nutrient supply. User behaviour also plays a role. If the yacht lies idle for a long time, it will be colonised more quickly than a frequently moving vessel.

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But even constant sailing does not protect against fouling. At some point, a biofilm forms that is no longer washed away by the incoming current. This serves as the basis for further colonisation by pox and mussels. There are several strategies to prevent their spread. The classic approach is to use biocides, i.e. toxic substances that kill the growth.

It also works without poison

A more environmentally friendly approach would be frequent mechanical cleaning using a boat washing system in combination with a non-toxic coating. However, these techniques are not yet mature or widespread enough to represent a serious alternative to chemical fouling protection for sailing yachts in saltwater areas.

Silicone-based fouling release systems such as Silic One from Hempel or the films from Mactac and Renolit, which work on the same principle, are more promising. They also work without biocides. Instead of killing the fouling, the smooth coating impairs adhesion so that pocks and the like are washed off when sailing. They also create a so-called hydrogel surface, which appears like water to pox and mussel larvae; the hull of the boat is virtually hidden behind it as a base for settlement. However, frequent and sufficiently fast sailing is required for the fouling to dissolve by itself; around seven to ten knots is ideal. The soft silicone surface is also sensitive and can be easily damaged when craning.

For most areas, paints containing biocides are the safest and most convenient way to keep the underwater hull permanently clean. Even if suppliers of non-toxic systems often claim the opposite, a complete ban on products containing biocides is not in sight. It is true that for years there have been EU-wide efforts to restrict the use of biocides in order to reduce the environmental and health impact. This affects insecticides, plant and wood preservatives as well as antifoulings.

The procedure is multi-stage and extremely lengthy. Manufacturers must register active ingredients and formulations and have them approved individually. The antifouling products are currently in the registration phase - in other words, only registered biocides may be marketed and used. They are given a registration number and a temporary authorisation until a final risk assessment has been carried out. The list of authorised active substances in product group 21 can be viewed on the website of the Federal Office for Occupational Safety and Health (BAuA).

In order to avoid spreading too much poison unnecessarily, but still get through the season pockmark-free, the first question to ask when choosing a colour is always: What are the fouling conditions in the home area? If you do not yet have your own experience, you can seek advice from the paint manufacturer or a neighbouring mooring. The Federal Environment Agency also provides detailed information on its website contains a vegetation atlas . It lists the creatures from which the hull must be protected in the respective area or harbour and which type of antifouling is recommended.

Long journey or lying down for a long time

The biocide content of the antifouling is one thing, but the colour must also match the owner's usage behaviour. Trailer boats and ships with shore berths that are regularly craned need robust antifouling that can withstand frequent watering; these are usually hard or thin-layer systems. Another decisive factor is how many months the yacht spends in the water. Anyone who sails until late autumn or even wants to leave the boat in the water over the winter should definitely tell the seller, as the manufacturers determine an average service life for boats that does not necessarily correspond to the individual owner's preference.

The same applies to yachts that lie unused in the harbour for a very long time: In this case, paints with even biocide release make sense; self-polishing products are not the first choice. However, these are recommended if the boat is sailed regularly.

Of course, it must also be clarified what material the boat is made of: aluminium yachts in particular do not tolerate many of the common antifoulings, as copper compounds are usually used as biocides. This can lead to electrolysis!

Grind every winter or have peace and quiet for years

There is also the question of how much labour is considered acceptable. With hard antifouling, the old paint layer usually has to be sanded down every year. On the other hand, there are also coatings that only need to be touched up every other winter. A copper epoxy coating such as Coppercoat gives you even longer peace of mind. The manufacturer states a service life of around ten years - in our experience, this is a very realistic figure.

Last but not least, it is important to observe the legal regulations for the respective area. In Germany, only the deviating regulations for inland areas are of interest, where coatings containing biocides are often prohibited. Stricter regulations often apply abroad, but this only affects permanent residents.

In the Netherlands and Sweden, the antifouling must have special authorisation. Theoretically, you can find out which products these are on the websites of the respective approval authorities. In practice, the websites are only helpful for native speakers and you should ask the paint manufacturer for proof of the necessary approval. In Holland at least, the authorities are very active and monitor the use of paints. Recently, they have even gone so far as to check the copper content of the antifouling in the water. If they come across a banned product, they face a fine of 2,500 euros.

The question of correct processing remains. The effect of any antifouling wears off over time. Depending on the product, coating thickness and fouling conditions, repainting is necessary every one to two years. If you know what the hull is painted with and don't want to change the product, you can start preparing immediately. If the old paint is unknown, it is important to ensure compatibility with the new antifouling. To do this, the colour type must first be determined.

Whether a self-polishing or hard antifouling product is present can be determined with a simple test: If the polishing product is rubbed off with a damp cloth or sponge, traces of colour will remain. Hard antifouling shows virtually no removal. Thin-layer or Teflon antifouling can be recognised by the almost lacquer-like, significantly smoother surface.

Self-polishing and hard antifoulings can usually be painted over directly together. If in doubt, however, a layer of primer matching the new paint should be applied. It is more difficult with Teflon paints. These are only compatible, if at all, with another thin-film antifouling. In this case, you must ask the previous owner or shipyard for the exact type of paint.

Preparation and care of the underwater hull

Whatever the choice, the underwater hull must be thoroughly cleaned to prevent the paint from flaking off after just a few seasons. A high-pressure wash in autumn is not enough. Oil residue almost always collects, especially at the waterline. A follow-up wash with a Scotch-Brite or abrasive sponge and clean water will achieve the desired result.

If you want to be on the safe side, add a cleaning additive to the wash water as a grease remover. The rough surface of the sponge is sufficient as a pre-treatment for self-polishing paints. Hard antifouling requires a little longer scrubbing; the washed-out colour surface must be removed. Antifouling should never be sanded dry - the unavoidable dust is harmful to health.

During the wash cycle, you should check the underwater hull: Is the old paint still firmly in place? If there are large areas of damage, a complete repaint is actually necessary. With a special epoxy primer, for example from Vosschemie, even a dilapidated paint structure can be stabilised to such an extent that it will last a few more years. The product is appropriately called Antifouling Anchorage.

Hard antifouling

Self-polishing or self-eroding

Aluminium parts should not be painted with copper-containing antifoulings, otherwise massive corrosion damage can occur. Which alternatives protect the drive

Depending on the antifouling system, the procedure for reworking differs. Furthermore, not all paints are compatible with each other. The colour type can be determined with a simple test

More on the topic:

• Renew antifouling, repair damage to the hull
• Antifouling - an overview for beginners
• How to remove antifouling ' s

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A complete guide to yacht ultrasonic antifouling

Jan 4, 2022 | Antifouling Tips

When it comes to owning a yacht people often dream about the trips they can take in their new vessel but can often forget about the maintenance side of things. One of the biggest maintenance jobs for any boat owner is antifouling – a technique used to prevent barnacles, algae and other marine life from attaching to the hull . This blog is full of advice for when you need to antifoul your boat in order to keep it seaworthy.

Do I need to antifoul my boat?

In short, yes, you need to antifoul your boat if you plan to use it in the water. Antifouling is one of the most important things a boat owner can do, even if it is one of the worst jobs!

It is how you can help prevent barnacles on your boat hull . Antifoul helps to prevent the attachment and build up of marine growth on the hull, particularly along the water line, rudders and propellers. This improves fuel consumption (reducing your running costs), improve water flow and can even increase the top speed of your vessel. Looking after the hull of your boat properly can also improve the lifetime of it and reduce the likelihood of engine issues around the water inlet and outlets.

How often should I antifoul my boat?

The process of antifouling a boat is labour intensive so minimising this is a priority for many boat owners. How often should you antifoul your boat? Typically most boats need antifouling once a year

• Regular scrubbing or power washing the hull can increase the lifespan of your antifouling.
• Using your boat regularly to prevent it sitting in water for too long can also help prevent biofouling accumulation on the waterline.
• Whether your boat is moored in fresh or salt water can also impact the longevity of your antifouling.
• The size of your boat and the type of antifouling paint used can also affect how often you need to do it.

What is the best antifouling for boats?

When deciding on the best antifouling for boats you need to be aware of the different types of antifouling available. The most common types of antifouling are applied as antifouling paint in a gel coat. There are two main types of antifouling paint:

Self Eroding

Often referred to as a ‘soft antifouling’ system, eroding paints works by slowly eroding throughout a sailing season, ensuring that a fresh film of biocide is always present to prevent marine growth. Generally, this is recommended for boats with speeds of less than 25 knots.

Typically suitable for higher-speed vessels such as race boats (30 knots+), hard paints constantly release biocides, and don’t wear away in the same way as soft or self-eroding antifoul options.

However, most antifoul paints contain copper oxide, a chemical substance that acts as a biocide to kill the marine life that tries to attach to it. But, you’ve guessed it, this means that it is also extremely toxic to other sea life and use and disposal of these paints should adhere to strict guidelines laid out by the British Coatings Federation.

Furthermore, if you have a boat with an aluminium hull it is really important that you don’t apply a copper-based antifoul paint as the copper reacts with aluminium hulls causing them to corrode. You will need to purchase a copper-free antifoul and be sure to use a suitable primer beforehand.

A different approach: Foul-release coating system

An alternative to antifoul that works in a similar way to self-eroding paint is use of foul release coating systems. These work without the use of biocides (pesticides) but are still applied as bottom paint and instead create a surface that is difficult for the marine life to adhere to.

Instead of containing copper they use a specially formulated silicone rubber substance from which the top layers sough off, along with any attached marine life, once the boat is moving through the water. However, many still contain toxic additives and catalysts (including silicone) which have unstudied effects on the environment .

An alternative to annual application of antifouling paint

If you are looking for a truly more eco-friendly antifouling solution then ultrasonic antifouling is the best antifouling for boats . Ultrasonic antifouling uses high frequency sound waves, produced by ultrasonic transducers, to prevent barnacles and other marine foul attaching to the hull. This reduces the need for toxic, copper-based paints which can lead to copper build up in the food chain and damage to other organisms than the ones that may try and stick to your boat.

DIY antifouling – how hard can it be?

If you have the time and tools and are not afraid of a bit of hard work, you can antifoul your boat yourself in order to save money.

Getting started -removing the old paint and cleaning the hull

DIY antifouling involves you removing your boat from the water. Once you haul out your boat you then have to scrape down and jet wash the hull of any significant growth before remove existing paint. The old paint should be wet sanded or removed with the help of paint stripper and the hull dried off.

Specialist PPE should be worn when removing antifouling from your boat hull as the paint is extremely toxic to you and the environment. You will also have to do this in dry weather or undercover in a marina so bear this in mind if you are planning to carry out your antifouling in the winter.

Applying the new paint

The new bottom paint can then be applied, the type and how much antifouling paint you need will depend on the hull and what you use your boat for including the water it will be kept in (salt or fresh water and even where in the world you plan to set sail), the size of your boat and its top speed. It is important to speak to your local chandler if you are unsure of the paint you need – their local knowledge of the water temperature and water conditions can be very useful.

Buying enough paint

As well as being sure to buy the right antifoul paint, you need to ensure you buy enough to complete the job (remember that you will likely need multiple coats) and have a little extra paint spare. A lot of paints will have a guide on the tin to help you ensure to buy enough bottom paint to get the job done.

Special attention needs to be paid with the disposal of any excess paint and even the old paint you remove from the hull in order to adhere to new guidelines by the British Coatings Federation . These guidelines from the British Coatings Federation help protect you, others around you as well as wildlife.

How long does antifouling last?

The length of time your antifoul will last will depend on several factors. Traditionally you need to antifoul your boat every 10-12 months, most people do it annually as it can be a laborious and unpleasant task.

Some key factors will affect how long antifoul lasts ;

• The paint type (hard antifouling or ablative, self-polishing or soft) as softer antifoul paint will be more likely to need renewing more regularly as it wears away.
• How often you use your boat – the lifespan of your antifouling can be reduced to just 8-10 months if it is sat on a mooring most of the year as this allows the foul to build up.
• Storage of your boat when you don’t use it, taking it out of the water each time will prevent excessive foul build up that would occur on a mooring.
• Regular maintenance and cleaning of the hull using a pressure washer.

The length of time between antifouling your boat can be significantly increased (up to five times) with the use of electronic fouling systems like our ultrasonic antifouling control products.

Does ultrasonic antifouling work?

Not only is ultrasonic antifouling much better for the environment -reducing the need for regular use of toxic, copper-based traditional antifouling paints – but ultrasonic antifouling does work really well and can be very cost-effective for boat owners!

A series of easy-to-install transducers attach to the hull of your boat with absolutely no through-hull drilling required and the number of which will depend on the size of your boat hull. These connect to a control unit that produce pulses of ultrasonic signals that form a kind of protective shield around the hull of your boat. This pulsating shield prevents marine life from attaching to the hull of your boat.

The signals produced from our ultrasonic antifouling devices aren’t harmful to humans or sea life and provide a much safer and environmentally friendly alternative to traditional antifouling, particularly when powered using the solar panel expansion.

Do you still need to use antifouling paints alongside ultrasonic antifouling technology?

Traditional antifouling does still need to be applied to the hull around the ultrasonic antifouling terminals, however, use of ultrasonic antifouling can increase the lifespan of this to up to five years instead of applying new paint annually – particularly when combined with regular cleaning and regular maintenance of the hull.

How much does it cost to antifoul your boat?

So you’ve paid out for your new vessel but how much does it cost for you to antifoul your boat? Traditional antifouling costs, on average, £300 for a 20 foot boat and around £800 for a 50 foot boat. That is a big expense for boat owners each year.

The correlation between boat length and cost isn’t linear though – more complicated hulls may be more expensive, how well previously looked after your hull is can contribute to the cost if you are paying someone else to do the work for you (or can compound your workload if you’ve opted to do it yourself!).

Is ultrasonic antifouling more cost effective? Well the initial cost is more – £1250, with a solar-powered kit being around £350 on top. But a cleaner hull can increase fuel efficiency by 30% saving you money all year round, on top of the reduced need for annual antifouling. Combined with the eco-friendly credentials of ultrasonic antifouling, we truly believe it is the future of boat care.

What ultrasonic antifouling kits are there?

At EFC we stock a range of ultrasonic antifouling kits available for all sizes of boats. Head straight to our shop if you know which one you need or read on to help you decide which option is best for you and your boat.

For boats less than 10m the EFC200 is recommended, with two required (one per hull) on a catamaran of the same size. For boats between 10 and 20 metres the EFC300 is recommended, again with two required for catamarans of the same size. For any vessels over 20m we recommend getting in contact with us to help determine the best solution for your needs.

Antifouling your boat can be a tedious job but we hope that our handy guides and use of our ultrasonic antifouling systems can make regular antifouling a thing of the past.

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ANTIFOULING

• Antifouling

ANTIFOULING ERODABLE

• Information Produit

YC ANTIFOULING ERODABLE est très efficace contre les salissures. Convient aux bateaux à voiles et à moteur évoluant dans toutes les eaux exceptées les eaux tropicales. Particulièrement recommandé pour les bateaux dont la vitesse n’excède pas 25 nœuds. Peut être appliqué sur tous les supports autres que l’aluminium et les alliages légers.

Caractéristiques:

• Contenance : 750 ml, 2.5 l
• Couleurs : noir, bleu marine, bleu ciel, rouge
• Rendement : 10 m²/l pour 1 couche de 60 microns secs
• Mise à l'eau :  entre 8h et 5 mois max. Efficacité maximale entre 8h et 5 jours après application.

CE PRODUIT CONTIENT DES BIOCIDES - A MANIPULER AVEC PRECAUTION - Prendre connaissance des pictogrammes de danger et de la FDS

YACHTCARE Antifouling Primer

Prices incl. VAT plus shipping costs

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• PDF: Technisches Datenblatt DE
• PDF: Yachtcare Handbuch Antifouling DE
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Causes serious eye damage.

Flammable liquid and vapour.

Repeated exposure may cause skin dryness or cracking.

Toxic to aquatic life with long lasting effects.

Use biocides safely. Always read the label and product information before use.

Very toxic to aquatic life.

Yachtcare Antifouling Action 750 ml - Hartantifouling for Boats

Purchase options and add-ons

• 1. Highly effective hard antifouling as a fouling protection for underwater areas
• 2. Colour: blue
• 3. Especially recommended for motor boats, trailer boats and dry marinas
• 4. Can be used on all boat materials except aluminium
• 5. Yield: approx. 10 m²/tin
• Use biocidal products carefully. Always read the label and product information before use. Registration number according to the biocide notification regulation: N-74365

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• Yachtcare Anti-fouling action blue

From the manufacturer

Antifouling Action - zuverlässiges, leistungsstarkes Hartantifouling

Antifouling Action ist ein wirksames Hartantifouling mit unlöslichem Bindemittel.

Der Bewuchsschutz für den Unterwasserbereich ist geeignet für Segel- und Motorboote in allen nordeuropäischen Gewässern mit mittleren Bewuchsverhältnissen.

Durch die harte, beständige Oberfläche ist es besonders empfehlenswert für schnelle Motorboote, Trailerboote oder Trockenmarinas.

Yachtcare Action erhalten Sie in zwei verschiedenen Gebindegrößen.

Wählen Sie zwischen 0,75L und 2,5L.

Für die passende Optik Ihres Unterwasserschiffes, bieten wir Ihnen 4 verschiedene Farbtöne an:

- Off White - Blau - Schwarz - Rot

ACTION Antifouling kann auf allen Untergründen außer Aluminium verwendet werden.

Antifouling SP - zuverlässiges, leistungsstarkes Antifouling

Yachtcare Antifouling SP ist ein zinnfreies, selbstpolierendes Antifouling.  Beim Auftragen muss der Untergrund sauber, trocken und fettfrei sein. Bei Neuaufbau zuerst lt. Spezifikation grundieren und 2-3 Anstriche Yachtcare SP aufbringen. Pro Saison 1-2 Erneuerungsanstriche.

Zu Wasser nach Min. 6 Std.(20°C) und Max. 6 Mon. (Bei längeren Landliegezeiten sollte das Antifouling leicht angeschliffen bzw. gereinigt werden).  Einsatzgebiet: Süss-, Salz- und Brackgewässer.

Yachtcare Antifouling SP erhalten Sie in zwei verschiedenen Gebindegrößen.

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