Additional reporting by Adam Fiander

Back in June 2021 we applied eight different types of antifouling onto the hull of a Hardy 42 called Raymariner. Since then it has been used around the Solent on a weekly basis until it was lifted in January this year.

The aim of the test was to compare the performance of traditional copper-based antifouls with longer-lasting, more eco-friendly alternatives, including Coppercoat and three biocide-free foul-release coatings.

The combination of ever tighter regulations controlling the type and quantity of biocides which antifouling manufacturers are allowed to use and boat owners’ own desire to do their bit for the environment means the search for new ways of keeping fouling at bay is gathering pace.

Article continues below…

Ceramic Pro review: Can this ultra-tough coating seal a boat for life?

Hempel Silic One: Is this the future of antifouling?

Most conventional antifouling paints use copper compounds suspended in a paint matrix that gradually erodes as water passes the hull, releasing the biocide at controlled rates, depending upon whether it’s a hard or soft-eroding type.

Coppercoat is an exception to the rule, because although it counts as a biocide, it uses pure copper particles set in a much harder epoxy resin that gives it a lifespan of ten years and greatly reduces the amount of copper released into the water.

Silicone-based foul-release coatings are another promising alternative, preventing fouling growth through the physical properties of its super-smooth hydrophilic surface.

BEFORE: As Raymariner looked when she was launched in June 2021

We wanted to find out if these alternative coatings perform as well as their traditional counterparts and whether their higher initial cost and fiddly multi-coat application regimes balance out with easier, more affordable annual treatments over time due to their longer lifespans.

Since silicone-based coatings work better on regularly used boats, Raymarine kindly allowed us to use their Hardy 42, Raymariner, as our test boat – although we did paint a static panel too to see how that fared.

Last year’s hot and wet weather may well have contributed to the excessive build-up of slime that greeted us when the boat was lifted in January. As you can see from the pictures, slime coated nearly all of our eight test strips, especially near the waterline.

AFTER – As she looked when she was lifted towards the end of January 2022

However, almost none of them showed any weed or barnacle growth, whereas the uncoated strips we left between some of the products were heavily fouled.

You can see a full table of costs at the foot of the page, but for the individual reviews we have quoted two prices. The first is our estimated price of the initial application to a typical 36ft boat, including any essential preparation costs such as stripping and priming (but not labour or lifting).

The second is an estimated annualised cost calculated over a six-year period. This doesn’t include labour and some coatings may last longer than their specified times, including the traditional ‘annual’ antifoulings, but we believe it gives a fairer reflection of the true cost over the long term.

18-month update

Raymariner was repainted with fresh antifoul after our test ended in January 2022, but the static panel allowed us to see how the coatings fared 18 months since the test began.

It’s important to remember that a boat would not normally sit idle and uncleaned for that length of time, making the test more challenging for all our products but especially the ‘foul-release’ coatings which rely on water movement to help shift any fouling.

Now that the boat-based test has reached its conclusion, the static panel provided a valuable cross-check for the longer term performance of the products based on a visual assessment of the stripes, a finger swipe to see how easily any fouling came away, and a sponge wipe to check if the coating itself came away too.

Like the boat, our static test panel was immersed in a Portsmouth marina location in June 2021. Apart from the effect of the tide sweeping across it, the panel has remained in situ there, fully immersed at all times for the last 18 months.

As you can see from the pictures, the coatings have, by and large, performed extremely well. Apart from silty mud covering the test stripes, there are very few signs of serious fouling having taken hold on any of the coated sections.

Even green slime – highly prevalent when Raymariner was lifted a year ago – appears to have taken a back seat in this case, perhaps because the panel has been lying in a shaded area for most of the time. Proof of how well the coatings have performed can be seen by the growth of weed and up to 10cm long sea-squirts on untreated sections.

BEFORE (left): Copper colour turns a greeny blue once immersed. AFTER (right): Some slime evident but no weed or barnacles

Coppercoat

Type: Epoxy-based non-eroding long-term biocide
Preparation: Hull-blasted back to bare GRP
Initial cost: £1,948 inc blasting & primer
Lifespan: 10 years+
Annualised cost over six years: £324
MBY rating: 4/5

Unlike the annual antifoul paints, which use a compound of copper suspended in eroding paint that gradually leaches out, Coppercoat uses pure copper powder set in a harder epoxy coating that should last for at least ten years.

It also vastly reduces the amount of copper released into the water, helping to prevent the build-up of copper in waterways, harbours and marinas.

Coppercoat can only be applied to hulls that have been stripped back to bare gelcoat and each of the five coats has to be applied wet-on-tacky. This effectively means it all has to be done during the course of a single day.

Lasts for 10 years, but has a high initial cost

Once dry, the surface needs to be burnished with 400-grit paper to expose and activate the copper. In future years, a pressure wash or scrub is all that’s required.

The results show a similar level of protection to the annual copper-based antifouls. There may be a little more slime than others but Coppercoat is a long-term solution and seven months is barely one season’s worth of use.

The initial cost is higher than most, partly because we have included the cost of blasting off the old antifoul (new boats just need sanding) but after six years the annual cost is much the same and it would continue getting cheaper after that. Nor does this take into account the substantial saving on labour time.

Before a thorough wipe-down (left) and after (right)

18-month update

Even though Coppercoat recommends an annual scrub or pressure wash to remove any surface growth, it still seems to be performing well after 18 months untouched. There was no significant fouling on the exposed copper surface, which has now adopted its characteristic blue/green colour, and minimal resistance from the swipe tests, suggesting any surface growth would fall away on a regularly used hull.

As expected of a tough epoxy based product there was no sign of the coating coming away on the sponge. Coppercoat’s claims of it being more environmentally friendly than erodible coatings.

Buy it now from coppercoat.com

BEFORE (left): Smooth rubbery surface makes it hard for fouling to grip. AFTER (right): Impressive result – no weed, barnacles or even slime

Hempel Silic-One

Type: Non-biocide, silicone based foul-release coating
Preparation: Four coats Hempel Light Primer; one coat Silic One Tie-Coat
Initial cost: £1,045 inc primer and tie coat
Lifespan: 2 years+
Annualised cost over six years: £337
MBY rating: 5/5

Silic One has the most stringent application process of our group and is best applied to a stripped hull, unless the old antifouling is in very good order, when a barrier coat of Silic Seal will enable the switch.

The process starts with four thin layers of Light Primer, a tie-coat (applied while the primer is still tacky) and two coats of Silic One with a minimum of 8hrs in between, the last of which has a 16hr minimum drying time before re-immersion.

If it sounds like an involved process that’s because it is, taking nearly three days from start to finish once drying intervals have been factored in. However, the results speak for themselves.

Best performer, but fiddly to apply

After seven months, Silic One has performed the best of our group, with no signs of weed or shell growth and the least amount of surface slime. It also wiped off exceptionally easily.

Because it has a recommended lifespan of two years (but can last for up to five years) before it needs topping up with two fresh coats, the high initial application cost is offset over time. After six years its annualised cost is similar to many of the biocide products but could prove cheaper if it lasts longer than two years.

Before a thorough wipe-down (left) and after (right)

18-month update

We had expected foul-release coatings to struggle on a static panel without any movement through the water to shift surface fouling. However, the majority of the stripe stayed remarkably clean and any slime was easily swept aside with the swipe test.

Some isolated growth can be seen at the top of the strip but this could have been caused by migration of fouling from the untreated section in-between this and the Seajet Bioclean-Eko (the other products were separated by a strip of white Trilux antifouling). So far there are no signs of any surface deterioration.

Buy it now from Amazon

BEFORE (left): Easy to apply and leaves a smooth finish. AFTER (right): Only a thin layer of slime that wipes off easily

Hempel Tiger Xtra 7100

Type: Soft eroding biocide antifouling
Preparation: Two coats Hempel Underwater Primer
Initial cost: £297 inc primer
Lifespan: 1-2 years
Annualised cost over six years: £166
MBY rating: 4/5

While it might not be the most technically sophisticated formulation out there, for many boat owners Tiger Xtra has become a go-to product – a reliable staple and a firm favourite on the winter maintenance list.

With one of the highest per sqm coverage rates of anything tested here, applying Tiger Xtra will soon have you making decent progress across the hull in a relatively short space of time. The prospect of coating even larger than average hulls needn’t be as daunting or as expensive as you might have first imagined.

But does it work? The answer is yes. Doubtless, the regular, weekly use that Raymariner has been subject to these past seven months has helped get the best from all of our contenders (self-polishing mechanisms need movement of water across the hull) but on this evidence Tiger Xtra has performed as well as many of its more expensive rivals.

Impressive value, but needs applying every year

There was no weed or barnacle growth and the slime was a little easier to release than on some of the others. The only unknown quantity is whether this performance will continue over a longer length of time, especially if you’re cruising in warmer waters with higher fouling.

It represents such good value for money we have given it an extra star over its annual rivals.

Before a thorough wipe-down (left) and after (right)

18-month update

We were pleased to see how well the cheapest of our traditional antifouling coatings coped on the boat and the results from the panel did nothing to change this view. Our initial inspection showed no more fouling growth on this than any of the more expensive products and the finger swipe test easily shifted anything that was there.

Some of the coating surface colour did transfer onto the sponge, which is normal for a soft eroding coating, but over time it might start to wear through on a fast, regularly used boat.

Buy it now from Amazon

BEFORE (left): Another easy to apply coating that leaves a smooth finish. AFTER (right): The usual layer of slime but a bit harder to shift than some

International Ultra 300

Type: Hard eroding biocide antifouling
Preparation: One coat Primacon
Initial cost: £444 inc primer
Lifespan: 1-2 years
Annualised cost over six years: £324
MBY rating: 3/5

Ultra 300 is a hard and relatively slow-eroding formulation that lends itself well to fast or regularly used motor boats that might wear through softer coatings too quickly.

After applying just one recommended coat of primer, we applied two good coats of Ultra 300, (total 120 microns dry), in a straightforward and fuss-free way, making life easy for the DIY applicator. Job done.

The results have been pretty good but marginally less impressive than the Micron 350, which Raymariner was coated with prior to this test, although that could be down to seasonal differences in water temperature and fouling growth rates.

Easy to apply, average performance

As expected, the Ultra was sheathed in a film of slime, thicker near the waterline, and when we tried to wipe the slime away with a damp microfibre towel, it showed quite a lot of resistance, suggesting it had taken hold quite firmly.

However, it was nothing that a jet-wash wouldn’t shift of course, and with no long beards of weed or shell growth to worry about. At an annual cost of around £324 for a typical 36ft boat it’s a solid, easy to apply performer that may last two seasons on lightly used boats.

Before a thorough wipe-down (left) and after (right)

18-month update

Although this is a traditional copper-based antifouling, it is a slow eroding hard coating designed for faster planing craft with increased water friction that might wear through softer products.

This didn’t affect its performance on our static test panel with little fouling growth over the 18 months and no sign of it starting to lose its antifouling properties. The swipe test suggests any fouling would fall away on a moving hull used regularly, while the sponge test showed only slight signs of the coating releasing itself.

Buy it now from Amazon

BEFORE (left): Blue is one of several colours available in this range. AFTER (right): A decent result but not noticeably better than cheaper options

Jotun Non-Stop 2

Type: Soft eroding biocide antifouling
Preparation: Four coats Jotun Megacote Epoxy; one coat Megasealer Epoxy Tie-Coat
Initial cost: £464 inc primer
Lifespan: 1-2 years
Annualised cost over six years: £355
MBY rating: 3/5

As we had stripped Raymariner’s hull back to bare gelcoat to ensure a level playing field for all of our products, Jotun decided to send us their full epoxy-primer, epoxy tie-coat and combined anti-osmosis system, prior to applying the two final coats of Jotun Non-Stop 2.

While this belt-and-braces approach would make sense on a brand new hull, we felt that for the purposes of price-comparison, it would be fairer to use the cost of two coats of Jotun Vinyl Sealer – a straightforward, one-component product that we have been assured can also be applied on to bare gelcoat hulls.

As the name suggests, Jotun Vinyl Sealer is ideal for those looking to antifoul an already treated hull in good condition and is a readily available product the DIY user would be more inclined to buy.

Slime is easy to shift, but this antifoul is pricier than most

The results in January 2022 showed a good overall performance, broadly similar to the other copper-biocide products, with no significant weed or shell growth to talk about but a thickish layer of slime that shifted quite easily with the towel test.

Even if you opt to use only the basic vinyl primer for the initial application, the annualised cost still makes this one of the pricier options in our test so it will be interesting to see if it lasts longer than the cheaper options over a longer period of time.

Before a thorough wipe-down (left) and after (right)

18-month update

This premium priced self-polishing coating uses ion exchange technology to ensure a steady release of biocides throughout the year, even when the boat is not being regularly used. While it performed well it wasn’t noticeably better than some of its cheaper competitors.

However, it did have the highest degree of coating surface being released onto the sponge suggesting it was eroding consistently even without regular boat movement – a good thing as long as it has been applied in sufficient quantity.

Buy it now on Amazon

BEFORE (left): Needs a good stir but paint goes on evenly. AFTER (right): Another solid performer with no shell or weed growth

Seajet 033 Shogun

Type: Soft eroding biocide antifouling
Preparation: Two coats Seajet 015 Primer
Initial cost: £489 inc primer
Lifespan: 1-2 years
Annualised cost over six years: £292
MBY rating: 3/5

When we heard about a new non-biocide antifoul release coating from Seajet, it made sense to compare it alongside Seajet Shogun, its best-selling, copper-based formulation.

Backed by the commercial resource of Chugoku Marine Paint, Seajet first appeared in the UK about 20 years ago and carved a niche for technical-quality antifouls.

One thing we found when applying Shogun is that the copper and zinc solids sink to the bottom of the tin so it’s imperative to ensure a good 5-10 minutes of continuous stirring with a wide-bladed stick – not the screwdriver you used to prise the lid off!

Solid performer, but needs regular stirring

The vapour given off made us glad we were outside in the fresh air but the coating itself goes on in a thick and consistent way. In keeping with the other biocide brands on test, close inspection showed a solid performance with no signs of shell or weed growth – just the usual slime, especially around the waterline.

The comparatively high cost of the Seajet primer added a bit to the initial cost of application but in subsequent years the price comes down considerably.

Before a thorough wipe-down (left) and after (right)

18-month update

Sold as a premium self-polishing annual treatment for boats capable of up to 40 knots in areas of high fouling growth, this antifouling treatment still seemed to be performing well after 18 months on our static panel.

There was minimal surface growth and only a light smattering of slime. As expected, a certain amount of blue coating did release onto the sponge when the panel was wiped, suggesting it will eventually wear through and reminding us not to skimp when applying this type of erodible coating.

Buy it now on Amazon

BEFORE (left): Shiny silicone- based foul-release system is available in several colours. AFTER (right): Almost no fouling bar some migration of growth from the dividing strip

Seajet Bioclean Eco

Type: Non-biocide, silicone based foul-release coating
Preparation: Three coats Seajet 117 Multipurpose Epoxy Primer; two coats Seajet Bioclean Tie-Coat; two coats Bioclean Eco
Initial cost: £1,012 inc primers
Lifespan: 3 years
Annualised cost over six years: £269
MBY rating: 4/5

Like Hempel’s Silic One, Seajet Bioclean Eco has a rubbery finish that fouling finds difficult to stick to. It is also a seven-coat system best used on bare gelcoat but can be applied on top of existing antifouling.

On bare gelcoat the process involves three coats of epoxy primer to provide a sound base, two coats of tie-coat, during which the colour element is introduced (black, white, navy-blue or red), then two coats of Bioclean-Eco – a transparent, paste-like substance.

When Raymariner was lifted, the majority of the test strip was admirably clean and shiny but there were some patches of fouling that appeared to have migrated across from the untreated dividing line separating this test patch from the neighbouring one rather than starting life on the black surface of Bioclean Eco itself.

3 year lifespan, but some fouling migration

Most of these dividing strips were painted with white International Trilux to avoid this happening but due to the longer application process of the silicone products we ran out of time on this one.

There was less slime than on the biocide products, and the wet microfibre towel test showed that it was easier to remove as well. Seajet expects this treatment to last for at least three years after which another tie coat and top coats should refresh it, although as this is a new product the recommended routine isn’t yet fully established.

Before a thorough wipe-down (left) and after (right)

18-month update

As with our other foul-release coating, this performed far better than expected on our static panel, suggesting it would still provide good protection on a less frequently used boat.

Fouling clearly finds it hard to adhere to its slippery, rubber-like coating even in a static situation like this and the swipe test suggests it would perform even better on a regularly used boat.

There were signs of isolated growth at the top and bottom but this could have been caused by migration of fouling from the untreated section between the two silicone-based coatings.

Buy it now on seajetpaint.com

BEFORE (left): Ceramic Pro looks great above the waterline. AFTER (right): But it didn’t seem to deter fouling below the waterline

Ceramic Pro

Type: Biocide-free ceramic based nano-coating
Preparation: Smooth bare gelcoat
Initial cost: POA
Lifespan: N/A
Annualised cost over six years: N/A
MBY rating: 1/5 – for above-water use only

​​In fairness to Ceramic Pro, they were keen to be included as much for their own research as for ours to see if their protective coating, designed for use above the waterline, would also prevent fouling below it.

We know for a fact that it does a fine job protecting the topsides as Editor, Hugo, has used it to good effect on his own boat.

The super-smooth hydrophobic surface makes GRP easier to clean and it has become a popular treatment amongst professional boat valet companies, who find it provides a tough, permanent barrier against salt deposits, exhaust fumes, surface oxidation, staining, bird-droppings, and that ugly line of filth commonly seen around the boot-top, just above the waterline.

Great for topsides, not so good underwater

It was hoped that this would also prevent fouling from attaching below the waterline, however, the micro-organisms that lurk in the Solent’s tidal waters proved too persistent. Even though the fouling was not too difficult to remove, plant life had clearly taken hold and would have become worse over an even longer period of time.

Ceramic Pro told us pricing for boats is on a case-by-case basis and as a result, a price formula for our results table was therefore not deemed relevant.

18-month update: N/A

Buy it now from ceramicpro.co.uk

Note: We may earn a commission when you buy through links on our site, at no extra cost to you. This doesn’t affect our editorial independence.

The big antifoul test: Conclusions

Almost all of the coatings did an effective job of keeping fouling at bay but there were some notable differences between them, not just in terms of performance but also cost, application time and environmental credentials.

We have based our star ratings on all four factors over a nominal six-year period, albeit with a bias towards how well they fulfil their primary role of keeping your boat fouling-free. However strong the eco-credentials, if it fails to do its job you will end up burning more fuel and releasing more pollutants into the atmosphere.

In the event, the silicone-based biocide-free foul-release coatings performed remarkably well, especially Hempel’s Silic One. If you can put up with the higher initial cost and time taken to apply these products for the first time, they really do deliver on their promise and over six years the annual price is broadly comparable.

They won’t suit every boat, though, as silicone can dry out if left unsubmerged for long periods and may start to wear through if kept on a trailer, dry-stack or drying-mooring, but for most craft they appear to be a very effective alternative to conventional biocides.

Coppercoat’s tough finish is fine to use in any of these situations and has the next best eco-credentials of our group. It performed almost as well as the traditional annual antifouls over a short period but should carry on delivering strong results for ten years or more.

It does have to be applied to bare gelcoat, though, which can push up the initial cost. On our fictional 36ft boat we calculated the break-even point at about six years but this would come down substantially if you included the annual labour cost or were applying it to a brand new boat that didn’t need stripping first.

There was little to choose between the traditional biocide antifouls, which supports the view that if you prepare the surface well and apply it properly, most antifouls will do a decent job of protecting your boat, at least over the course of a single season in UK waters.

Hempel’s budget offering, Tiger Xtra, delivered decent protection at a great value price, while Seajet Shogun, International Ultra 300 and Jotun Non-Stop all gave a solid, reliable performance and were impossible to split during the course of our initial test period.

The panel-back after 18 months without antifoul

18-month update conclusions

While the results of the long-term panel test have helped to back up the findings from our original boat-based test, there was not a big enough difference between the performance of the various different coatings to justify changing any of our original boat-based star ratings.

All seven products provided a good degree of antifoul protection when compared with the growth on even the smallest untreated sections of the panel. The extra fuel cost in dragging a carpet of unsightly fouling like this on the underside of your hull does not bear thinking about.

Our tests prove that even a moderately priced traditional copper biocide can provide all the short-term protection you need. But be prepared to keep an eye on soft, self-polishing and erodible coatings such as Seajet Shogun, Hempel Tiger Xtra or Jotun NonStop 2, because they will need topping up each year or re-applying in full every two seasons.

The fact that our test panel wasn’t moving may have helped extend the life of these products. Hard coatings such as Coppercoat or International Ultra 300 lend themselves to the extra friction from faster hulls but may need occasional scrubbing to maintain their performance when the surface layer starts to lose its potency.

The sponges used for the wipe test

They are designed to withstand being scrubbed and should not get damaged if you keep your boat on a trailer or in a dry-stack. However, on the basis of this long-term panel test, they seemed to maintain their performance for the full 18 months without any intervention and in the case of Coppercoat should carry on doing so for years to come.

If you’re willing to invest the extra time and cost of applying a silicone-based foul release coating, either of the two that we tested will, on the evidence of this test, do a very good job for you, even if your boat isn’t used that regularly.

The fact that they do this without the use of biocides can only be a good thing for the long-term health of our rivers and seas. You do need to follow the instructions carefully, because each of the three stages of primer, tie-coat and top-coat need correct application for the coating to perform well as a whole.

However, once applied, they should last for several years but tread cautiously with your annual maintenance routines, because a powerful pressure-washer can dislodge the layers if held too close.

First published in the April 2022 and May 2023 issues of MBY.

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This article The big antifouling test 2023: The full results of our 18-month showdown appeared first on Motor Boat & Yachting.

Contrary to many boat owners, antifouling is one of my favourite off-season jobs. If done well, it will ensure you get a full season’s boating with very little fouling and minimal loss of performance or fuel economy – even a small amount of fouling can increase fuel use by 20% or more.

Most (but not all) antifoulings are toxic to certain forms of marine life but they can also be harmful to humans, so you will need personal protective equipment before starting.

How to antifoul: Equipment

At a minimum I’d suggest overalls, gloves, a face mask and a hat and goggles for working under the boat, but make sure you read the paint tin and hazard sheets for further guidance.

Most boatyards pressure-wash the bottom of the boat for you when they lift it. This will remove most of the growth from the hull, props and drives but make sure you wash off any barnacles or slime they may have missed, especially in awkward to reach areas such as bow thruster tunnels and behind chines.

Our test boat came out reasonably clean and simply needed a good scrape with a sharp-edged scraper around the waterline to remove irregularities from the previous year’s antifoul, followed by some 40-grade sandpaper to key the surface for the new paint.

Article continues below…

The big antifouling test 2023: The full results of our 18-month showdown

Hempel Silic One: Is this the future of antifouling?

This is the moment when the mask and goggles are very important, due to the dust it produces. You need to be extra thorough around rough patches of old paint or areas that may have been missed, such as where the lift’s slings or support chocks were.

If the previous layer of antifouling has started to lift or flake off, you will need to scrape it right back to the gelcoat and key and prime it again. Lastly, rinse off any areas you have sanded and allow it to dry properly.

The next task is to mask off the waterline, so as to leave a nice clean edge, and around any metal outdrives or outboard mountings, taking care to leave a 1in gap between the paint and the metal to prevent the copper compounds in the antifouling causing galvanic corrosion of the aluminium alloy.

How to antifoul: Method

Before applying the antifouling, I leave the pots upside down for 30 minutes so that all the heavier active ingredients aren’t stuck at the bottom, then give it a really good stir for 5-10 minutes, making sure the stirrer reaches right to the bottom of the pot. I also re-stir it each time I fill the paint tray.

I find that a small paint roller with a high-density foam head is best for the main underwater sections as it gives me more control than a large roller but is still quicker, smoother and gives a more even thickness than a brush.

However, I use a brush for greater accuracy along the waterline (working away from the edge of the tape), around the hull fittings and along the inside edge of the chines.

Unless the boat is huge, I go around the whole waterline first, working down to the first chine, then complete the hull underneath, by which time the paint around the waterline is dry enough for its second coat.

A good even coat that hasn’t been rollered out too thinly is essential. The tin will say what the coverage should be so use it exactly as recommended – don’t skimp.

Most advise at least two coats (antifoulings are designed to wear away gradually over time to reveal fresh biocide beneath) but I often add an extra coat around the waterline and other areas of high wear.

I like to lift the tape off after coat one to check that I have a good edge before applying more tape for coat two. This is also a good time to ask the boatyard to reposition the support chocks so you can fill in any areas that you couldn’t get to during the first coat, although some yards prefer to touch these in when they lift the boat for re-launch.

Once complete, and having used up any paint left in the tray, I dispose of the brushes and roller heads safely, then go about removing the waterline tape.

My sneaky tip here is to pull the tape from the end you started taping with first so that all the overlaps are picked up and you end up with one continuous piece that you can roll into a ball, then tuck into the centre of your glove as you remove it ready for convenient disposal.

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This article How to antifoul your boat: The best way to protect your hull from fouling appeared first on Motor Boat & Yachting.

As with many more experienced boat owners Harry and Vikki Metcalfe decided to make the switch from sail to power when the appeal of beating into the wind at an angle for hours on end began to lose its appeal.

After years of cruising and racing a variety of sailing yachts around the Welsh coastline, they took advantage of their retirement to sell up and move to the south coast to be closer to family and friends.

Fresh start

A trip to the Southampton Boat Show in September 2016 got them thinking about a suitable motor boat in which to get afloat again. After browsing the pontoons they settled on a Jeanneau NC9.

It was small enough to manage on their own but big enough to host larger parties on day trips around the Solent. The enclosed wheelhouse would be warm in all weathers and the single-level design would be easy for them to move around and safe for their young granddaughter to join them on board.

Harry and Vikki in front of their Jeanneau NC9

They struck a deal with Jeanneau dealer Burton Waters for delivery in December 2016 to a berth in Swanwick Marina, Hampshire. That just left one more thing to decide — what type of antifoul to go for.

Having spent far too many hours on their knees hand-rolling antifouling onto their previous boats they were determined to find a long-term solution that didn’t involve the hassle and expense of reapplying a fresh coat each season.

They were all set to go the Coppercoat route but before taking the plunge asked their son Ben, CEO of refit specialist Landau UK, whether there were any other long-term antifouling solutions they should consider. Ben had heard good reports about Hempel’s Silic One fouling release system but hadn’t yet had a chance to try it.

Fino hits the water in January 2019 after a long fallow period

As the name suggests it uses a biocide-free silicone coating but with a special hydrogel polymer that forms a special surface with the same properties as water.

According to Hempel this not only ‘tricks’ organisms into thinking it’s not a solid surface but makes it extremely hard for anything to stick to it.

It isn’t marketed as a long-term antifouling but the brochure does say that it doesn’t necessarily need recoating every year provided the boat doesn’t spend more than a month out of the water.

Harry and Vikki were sceptical but agreed to give it a go. “It sounded too good to be true,” admits Harry. “But Ben seemed confident it would work and was keen to use our boat as a guinea pig.”

As a brand new boat Fino’s gel coat needed to be sanded and washed before being given four coats of Hempel Light Primer. Previously antifouled boats only need one.

The application process was a little more complex than normal as it requires a special tie coat in addition to the usual two coats of primer and Silic One. And because it has to be completed in quite a specific time, temperature and humidity window, Landau had to use a tent and heaters to meet the parameters. Harry describes the finished result as, “very smooth and surprisingly tough.”

Year one results

After a full and reasonably busy first season their boat was lifted in September 2017. Other than the usual slime and a small amount of growth along the edges of the spray rails and chines the hull was almost completely free of fouling.

This was all the more remarkable when compared to the state of the uncoated sterndrive and trim tabs both of which were sporting lengthy beards of weed, sea squirts and barnacles.

After a thorough spray down, the boat was returned to the water well within the one-month window. And there it stayed for a further 15 months, this time with relatively little use even during the long hot summer of 2018 due to a health scare.

As Harry points out this proved as much of a challenge for the Silic One as it did for him. Being left static for long periods is the sternest possible test for antifouling, especially one that relies on water movement to help remove any nascent growth.

The big antifouling test 2022: All about our seven-month showdown

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Year two results

When their boat was finally lifted in January this year MBY was there to witness it. Sure enough it was a similar story, with long trails of weed hanging off the trim tabs and a thick crust of barnacles on the sterndrive.

There was only a thin coating of slime on the hull sides and almost nothing on the underside, except for where the hull had been blocked off during the initial application.

A quick spray down to remove the slime and Fino’s hull looks ready for a third season. Note how the water beads on the hydrogel surface

The slime wiped off with a tissue and even the occasional calcified tubeworm could be dislodged with nothing more than a thumbnail. After the usual spray down, with the pressure washer kept at a safe distance to avoid stripping off the top surface, it looked as good as new again with water droplets instantly beading and running off the hydrogel surface.

Harry wanted to fill in the gaps where the blocks had been and touch up one or two small areas of wear along the chine edges, but there was no question of it needing a full recoat for at least another year.

“We are amazed how well it has worked, particularly since this is the second full season,” said Harry. “Our only mistake was not coating the sterndrive and trim tabs too.” Unlike most copper-based antifoulings, which react with metal surfaces, Silic One can be used on alloy sterndrives as well as GRP hulls.

Admittedly, it’s only one test of one boat in one UK location but with ever-tighter restrictions on the use of conventional biocide antifoulings it looks as if Silic One really does offer an effective alternative for a barnacle-free future.

Hempel Silic One recently got a five-star review in our head-to-head test of the best antifouling paints of 2022.

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This article Hempel Silic One: Is this the future of antifouling? appeared first on Motor Boat & Yachting.

Lots of people seem to think that hard antifouling is the way to go for a fast planing boat because its harder finish won’t wear away too quickly. I don’t buy it, partly because it relies on the boat’s motion through the water to wear away the exhausted top layer of antifouling (so it doesn’t work as well when left in a marina) and partly because over the years, you build up countless thick layers of lumpy, part- worn antifouling.

I prefer to use a true self-polishing copolymer antifouling that gradually dissolves in the water, even when the boat is sat on its berth for weeks at a time. Not only does this ensure there is always a fresh layer of biocide-laden paint to keep the critters at bay, but it reduces the buildup of old paint and leaves a smoother, more fuel-efficient finish.

International Micron 77 is one of an increasingly small number of true copolymer antifoulings that you’re still allowed to apply yourself. The other big advantage for workshy lackeys like myself is that two thick coats should last a couple of seasons, which goes some way to offsetting the premium pricing.

That’s exactly what I applied on my Karnic 2250 around this time last year and when I pulled it out of the water at the end of October, the results spoke for themselves.

The underside of the hull was completely free of weed and barnacles and even around the waterline where it was exposed to maximum sunlight, there was only a thin layer of slime. You only have to look at the full beard of weed growing from the small unpainted section of topsides at the stern of the boat to see how bad it could have been.
Even more gratifyingly, there still seems to be plenty of life left in last year’s application, so this spring I will be free to plant up my vegetable patch with lots of baby radishes rather than grovel around under my boat with rollers and facemasks. Result!
For more information click here.

Overall score:

Value ****
Rating *****

Price: £199 for 5 litres

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This article Tried and Tested: International Micron 77 Antifouling appeared first on Motor Boat & Yachting.

The antifouling answer depends on a variety of factors including what type of boat you have, how often you use it and where you keep your boat. That’s why we’ve tried to take the guesswork out of it by looking into the science of how they work then testing a wide range of different paints in three different locations around the UK and the Mediterranean, and rating them for durability and colour fastness as well as how they performed against slime, barnacles and weed.

Types of antifouling paint

There are plenty of misconceptions when it comes to antifouling, even the question of whether to choose a hard or soft paint isn’t as straightforward as it seems, as Darren Gittens of Hempel Paint points out: “Motorboat owners often think that they need a hard paint just because their boat is capable of 30 knots but that’s not always the case. If you regularly exceed 25 knots when cruising or 80 hours total use per year, then you need a hard paint, if you don’t then you’re better off with a soft eroding paint.”

Kate Moss, new product chemist at AkzoNobel the company behind the International range of antifouling coatings, shed more light on the subject: “Most antifouling paints for motorboats are designed to use the friction of water passing over the hull to clean the growth off and erode the paint surface, but unless you take your boat out every other weekend, you could be better off with a paint for a sailing boat.”

There are five main types of antifouling paint, and what suits your boat depends on how you plan to use it. Most products use a similar combination of biocides to keep the fouling at bay so the key differences are in the structure of the paint that delivers these biocides. Over time the biocides leach out of the exposed paint surface leaving an inert coating which can no longer repel fouling. The trick is to ensure that layer of dead paint is removed either by a physical or chemical process in order to expose a fresh layer of bicocide laden paint.

 Soft Rosin-based eroding paint

This uses a soft soluble binder that gradually dissolves in water leaving a fresh layer of paint and biocide. This means the thickness of the paint gradually reduces until it eventually disappears altogether. This type of paint suits sailing yachts and displacement motor boats but may wear out too quickly if applied to a fast planning boat that is regularly driven at speeds of 40 knots or more.

Self-Polishing paints

Self-polishing works in a very similar way to the self-eroding paint but uses a mix of soluble and insoluble glues that requires at least a tidal flow of water passing across the paint to wear it down, revealing the fresh layer beneath. This type of paint won’t go off if the boat is out of the water. Stronger binder means that it can be used on fast boats provided they don’t regularly exceed 25 knots.

CoPolymer

CoPolymer paint replaced the notorious tin based TBT that was banned in the 1990s when it was discovered that it caused some microrganisms to change sex. Unlike the previous paints, the acrylic binder reacts to salt in the water continuously exposing a fresh layer of biocide laden paint. This means that it is not reliant on any movement of water and works regardless of whether the boat is lying idle in the marina or cruising regularly.

Hard paint

Hard paint is most effective the first day after launching but as the season passes the bicocides leach out and it gradually becomes less effective. If the boat is removed from the water after launch, it can also form an impermeable layer which prevents any further biocide leaching out even when launched again. Hard paint is popular on racing yachts and fast planning motor boats as it can be sanded smooth for reduced friction and won’t erode too quickly at speed. This also means it’s more prone to paint build up over the years which may need removing at some point to prevent it cracking and peeling.

Silicon paints

Rather than using biocide chemicals to stop growth, they form a super slippery surface that prevents fouling from getting a solid grip on the surface. Some growth will still appear when left unused in the marina but as soon as the boat exceeds eight knots any significant growth should wash off. They also claim to reduce friction in the water, increasing efficiency and speed. The downside is that it has to be applied to a properly prepared gel coat (any old antifouling has to be stripped off) and it can’t be painted over if you ever decide to switch back to a conventional antifouling paint. .

Paint legislation

The UK is currently in the mid-way between Mediterranean and Nordic countries in terms of legislation. Mediterranean countries are far more lax in terms of what can be used, and who can do it. The story is the opposite in the Nordic area, with some paints that are available in the UK being banned. It continues with removal too, with specialist sites that wash, drain and filter all residue being mandatory when working with antifouling. While nothing is set in stone for UK shores, it’s worth noting that changes that affect us all could be just around the corner.

What are we looking for?

In this test we are not necessarily looking for the cleanest panel at the end of the test, but one that is strong enough to withstand use in the real world, while not succumbing to growth when left in the marina. We also wanted to see how the new environmentally friendly silicone paints performed against more traditional biocide based paints. Finally, one of the biggest niggles with antifouling paint is the way the original colour can fade or change over time. This is particularly true of light colours such as white or cream which often turn green around the waterline due to the copper oxide content.

Some of the paints that we’ve tested are for professional application, and wherever that’s the case we’ve made that clear.

Greg Goulding conducts MBY’s antifouling test

How we tested them

To ensure our testing methodology was as accurate and reliable as possible we based it on advice from industry experts both before and during the test.

We picked three different locations to conduct our testing, one on the East Coast, one in the Solent and one in the Mediterranean and prepared separate boards for each area. The boards were made from marine plywood, sealed with oil-based paint to replicate the gel coat of the hull and then primed using an industry standard primer.

The board was marked out with 10 defined areas and a different antifoul paint applied to each strip. The two silicon based paints were applied to two smaller boards as we wanted to monitor these separately. The test panels were then left in our chosen locations over the 2015 season.

The two UK locations are tidal, so had a constant knot or two running past, while the Mediterranean location was a marina on the Spanish coast, giving us real world results.

Once lifted, we studied the colour change, fouling build-up and type of growth. We then ran a finger over each panel to see how securely the fouling was attached and whether it might wash off on a planing boat with regular cruising at 20 knots or more. Finally we washed each board to replicate a scrub and see how well the fouling and the paint lasted.

Static board tests are often criticised for only portraying boats that are left in the marina untouched for the entire season. However, this is still the preferred method of conventional antifouling paint manufacturers as most boats are left in the water all season, only going out a handful of times and rarely being driven hard for more than a few minutes at a time.

This article The ultimate antifouling group test appeared first on Motor Boat & Yachting.

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The makers of a new long-life antifoul called Clearcoat are looking for MBY readers to take part in a trial of the product.

One hundred selected readers will be sent enough Clearcoat to cover a one square metre section of hull and asked to run their boats as normal for a complete season.

If the results are successful, all those taking part will be able to buy enough of the antifoul to cover their entire boat at a 33% discount.

To sign up for the trial, you need to send an email with your name, phone number and boat’s make, model, LOA and location to info@marinetesting.com.

The new antifoul is featured in the June issue of MBY. You can download the feature here, and see the other terms and conditions that apply.

On paper, Clearcoat looks like it could herald a massive advance in boat antifouling.

It works by creating a super-smooth surface on your hull that marine life can’t adhere to, and is said to last for up to five years.

This new surface is so smooth that Clearcoat’s makers say performance is improved, and it’s also environmentally friendly, containing no biocides, metals or volatile organic compounds.

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This article MBY readers needed for long-life antifoul trial appeared first on Motor Boat & Yachting.

In this month’s practical video, Neale looks at antifouling and all the checks you need to do before starting your season

WATCH by clicking the ‘Video’ tab above the picture.

This article Antifouling your boat appeared first on Motor Boat & Yachting.

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Featured in the January 2012 issue of Motor Boat & Yachting

See the first report

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This article 2B Sure antifouling product test - the results appeared first on Motor Boat & Yachting.

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Featured in the October 2011 issue of Motor Boat & Yachting

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This article 2B Sure antifouling test appeared first on Motor Boat & Yachting.

The Environment Agency has given its approval to a UK firm’s antifoul product after a seven year test.

The EA’s 10m RIB was used as a guinea pig to test Coppercoat as a ‘green’ antifoul, with the product applied in 1999 and the boat remaining in the water ever since, except for servicings.

This year the RIB was lifted for the first time and Mark Warmsley, EA transport manager, said: “As the Environment Agency we are keen to use products that minimise the impact on the marine environment and as a result we decided to try Coppercoat.”

He explained the product’s copper is suspended in epoxy resin, which he said gave the hull the necessary protection but did not harm marine life.

“The vessel, a 10m RIB, has been permanently in the water since June 1999 and to date not had the need to have Coppercoat reapplied. When the vessel is removed from the water for maintenance, there is no marine life or growth on the hull.

“If we can minimise the environmental impact of antifouling we will and as a result we will be using Coppercoat on our other vessels in the future.”

Manufactured and distributed by Aquarius Marine Coatings in Dorset, Coppercoat was developed in the 1980s. It is the combination of specially formulated solvent-free epoxy resin and high purity copper (99%). One treatment is said to have a lifespan of at least 13 years.

www.coppercoat.com

This article Antifoul tip from the EA appeared first on Motor Boat & Yachting.

Anyone anti-fouling their boat in preparation for the season ahead may welcome a new DVD giving advice on how best to proceed.

The DVD has been put together by UK firm Coppercoat and looks at the procedure from start to finish.

Jayson Kenny of Coppercoat said: “WeÕve been in the antifoul market for well over a decade and have a unique insight into changing trends. More people are turning to long-term solutions, saving money, time and reducing the impact on the marine environment and this is reflected in the numbers of customers using our product.”

For your copy of the DVD and Coppercoat brochure contact Aquarius Marine Coatings Ltd (AMC) on 01202 888802, email info@coppercoat.com or visit www.coppercoat.com

This article Antifoul DVD appeared first on Motor Boat & Yachting.