The purpose of antifouling is to prevent marine plants and animals from colonising the hull, and the easiest way to do this is by killing them.
The ocean is brim full of planktonic larvae and planktonic algal spores whose further development depends on their finding a suitable surface whereon to rest their travel-weary selves and develop into something more adult. Flotsam, and most kinds of jetsam, are surfaces quite suitable enough. Ultra-slippery fast moving things escape the grasp of the creatures – and thus glass bottles seem to be immune to colonisation – but few other items can cross an ocean without collecting passengers and surfaces which sit still, whether at anchor or at sea, are even more susceptible to the development of a thriving miniature ecosystem – unless, that is, they are coated with toxic paint.
Ownership of a portable marine ecosystem provides a fascinating site for snorkelling, and it encourages fish (= dinner) to accompany us on our way; but it also makes journeying embarrassingly slow. A luxurious pile-carpet covering of sponges and exotic seaweed, together with a crusting of king-sized barnacles and a cargo of resident crabs and starfish rather spoils a yacht’s performance, to the extent that her ability to get herself out of danger can even be compromised. Extermination of the causative larvae is only reasonable – but it would seem that an effective antifoul does more than this.
Antifouling leaches its biocide into the surrounding environment, damaging or destroying not only those organisms which touch the hull and attempt to settle there but also all others in the vicinity. Biocide means life-killer, and the more biocides we allow into the sea the greater their concentration in the water. They don’t decompose and vanish after they have leached from the hull. Rather, they accumulate in the sea, converting it into a toxic soup.
Thus, it behoves us to find an antifouling which is non-toxic.
What will the ocean be when it is devoid of life?
If we continue to ravage the seabed with trawls, and if we continue to use ever more efficient means of rounding up those few fish which remain, it will soon be as bare as a desert.
And if we continue to use the sea as a waste disposal unit, and we continue to poison its waters through selfish concern for keeping our ships and fish-farm tanks and yachts completely clean and free of any fouling, then it will become utterly toxic.
When we sail, the highlights of our days are encounters with whales and dolphins. We also delight in naming the birds which wheel about our boat or patter along astern, and we are thrilled when we have the pleasure of their company for days or weeks at a time. Our calendar is marked out with these small adventures; they are the stepping stones which carry us from one side of the ocean to the other.
When the fish and smaller fry are dead and the birds have wasted away, then the wind and the waves will seem less kind – will even seem cruel, I think – and traversing the sea will be a lot less wonderful. From a purely personal and selfish point of view, therefore, it is in our interests to avoid damaging the minute organisms which are the basis of the ocean’s web of life.
It is in our interests to find an environmentally safe antifouling.
— from How NOT to Build a Boat
The story so far
In December of 2008 we slipped Mollymawk in a boatyard in Melilla and painted her bottom with Coppercoat antifouling. Coppercoat is the original copper-epoxy paint. It was formerly marketed as Copperbot, and we had used it, many years before, on our previous boat, Maamari.
A few weeks after painting Maamari we took her down through the French canals. She arrived in the Mediterranean with a completely clean hull – as, indeed, did every other boat which had made the same journey. Marine weeds won’t survive in fresh water, and the freshwater ones had not had time to set up camp. Thus, when we moored for the winter in Port St Louis, Maamari and her neighbours were all scrupulously clean.
At the end of our stay Maamari was still entirely weed and barnacle free, but the other boats were all wearing shaggy green carpets on their bottoms, and some were so foul that their props would not turn. Without a doubt, the original Copperbot paint worked – or at least, it worked for us.
When the time came to paint Mollymawk we couldn’t afford to buy the real thing, and so we mixed our own copper-rich epoxy paint. This was only moderately effective. In the early days it was out-performed by the conventional poison which we applied, as a control, to our self-steering rudder. However, after six months the conventional paint had spilled all of its toxins and the seaweed and barnacles were already moving in. Within a year the rudder looked as if it had never been painted with antifouling. Meanwhile, the copper-painted hull was still reason ably clean.
Conclusion: our home brew worked, but not as well as the real thing.
Eight years and several thousand miles down the line we were fed up with diving, every two or three months, to clean the hull, and so we decided to do the sensible thing and invest in some of that super-effective stuff which had protected Maamari; we decided to buy some genuine Coppercoat.
Unfortunately, it didn’t work.
Within a year we were back to the old routine of diving regularly to clean the hull.
When we contacted Coppercoat they suggested that the antifouling would become more effective as the years go by:
Please remember that unlike conventional anti-foul (that starts off at full strength and becomes weaker by the day), Coppercoat is actually quite a mild anti-foul when new. Coppercoat increases in potency as the months and years pass. … It is likely therefore that you will see a further improvement in the performance of the coating in the coming years.
Since we published our Coppercoat review numerous people have written to us asking whether this claim was justified. Have things got better?
Unfortunately, they have not got better. The most we can say is that they have not got much worse.
If you study the photos you will see that the boat is becoming increasingly coated with a residue of barnacle glue and “white coral”. In another four years time she will probably look as she did when we slipped her in Melilla.
3 years later…
While we were in Itaparica (Brazil) we took the opportunity to lean Mollymawk on a quay and scrub her off as the tide fell. The boat had been scrubbed a few weeks earlier when Caesar dived on her (with scuba gear) and yet, despite this, the fouling was such that it took four people the entire tide to thoroughly clean her. We began work as soon as the boat touched the bottom and we continued until she was afloat again, some twelve hours later.
Originally we had planned to take the opportunity to abrade the entire hull – because this is another thing which is supposed to improve the efficacy of the paint. Unfortunately we didn’t get the chance to do this, but we did find time to abrade certain areas. Some of them are now collecting less growth than the rest of the boat – Caesar can still find the place where he wrote his name – but others have vanished without trace. It would seem that the abrasion needs to be very forceful and thorough:
Don’t waste time sanding back by hand. Use a random orbital with a soft pad and use P120 grade paper. You have to expose a totally bright copper finish, or it just won’t work!
This is probably true, but we were reluctant to do a Lizzie McMullen. Power tools should not be used unless the boat is high and dry.
Are we expecting too much?
The amount of fouling that a boat collects depends, more than anything, on where she is moored. As I write, we are on the Argentinian side of the Rio Plata and since this is a freshwater location – and since there is a high level of pollution – there is absolutely no fouling. By contrast, six months ago when we were on the Rio Paraíba, in northern Brazil, we needed to clean the bottom every fortnight.
On average we need to clean the hull every month or two.
Some folks seem to find this perfectly acceptable:
The coating is not maintenance free – but what coating is? Frankly having to brush off the entire underwater hull isn’t a big deal, and it allows you to monitor your rudder and prop. I’m not sure what kind of miracles you are expecting?
— Chris Kirk, via the contact form
I guess the answer is that we would like to experience the same miracle which occurred when we painted Maamari with the original Copperbot antifouling!
Whilst we would agree that “having to brush off the entire underwater hull” is not a big deal – provided that the water is clear and warm, and provided the crew are fit enough for the job – we find that we have to do much more than this. We find that Coppercoat allows colonisation not only by weed and slime and plant-like hydrozoans, which can be brushed off, but also by barnacles, oysters, and the dreaded “white coral”, none of which can be shifted by brushing; their removal requires the use of a metal scraper and large amounts of force.
Worse still, even after the living creatures have been evicted one is still left with a calcerous deposit. (The glue which barnacle larvae secrete is said to be one of the strongest adhesives known to man.)
This must either be ground back or, if you prefer the easier option, dissolved in nitric acid. Clearly, neither of these methods works underwater; and yet, if you don’t get rid of the deposit the area will quickly be recolonised.
There’s no getting away from it: for us, Coppercoat has not worked. We spent the money, but the result is no better than our own home-brewed version.
The web is plastered with stories from dissatisfied Coppercoat customers:
I applied Coppercoat last winter 2004/2005 and launched the boat in April and hauled it out at the end of September. The result was one of the dirtiest hulls of many hundreds of boats hauled at the end of the season.
We are in a high fouling area and so no antifouling works very well, and Coppercoat is no exception.
Save your money, it doesn’t work. Just ask any yard manager who does boat scrubs.
(All from www.ybw.com/forums/showthread.php?t=217194&highlight=coppercoat)
However, we have recently had a couple of comments from people who rate Coppercoat as effective:
I had Coppercoat applied to a new 48′ catamaran in controlled factory conditions before launch Nov 2010. I am delighted in the results so far – I dived on the hull in Dec 2011, cleaned off a small amount of weed with a hard sponge, and coating was back to new. There was not one single barnacle on the Coppercoat – numerous on the saildrives rubber seals and saildrive legs. … I cannot understand why so many different and unfavourable experiences have been reported.
— Mike Bouch, via the contact form
I applied Coppercoat in April 2005 to my MG Yachts CS40. The boat was based in Portimão, Portugal at the time and the results were initially disappointing. It did improve, however, after the first haul-out for cleaning, when the hull was burnished again. We moved the boat to Cascais, Portugal in 2007 and we have been very pleased with the performance over the past few years. I hauled out this morning and the was little or no growth on most of the bottom since the last scrub, in August last year. On the other hand, there was a generous crop of weed, almost 2 inches long, in a few spots where the antifouling had come off.
— John Duggan, via the contact form
Why doesn’t the new stuff work?
Why would an antifouling be more effective in some cases than in others, one wonders? According to Ewan Clarke, the main man at AMC Coatings, “The performance of any individual application of Coppercoat is determined by many factors such as (but not only) the quantity applied, the application technique, the mixing technique, the climatic conditions during the application, the environment within which the product is used, the age of the product etc.”
That being the case, one wonders what the optimum conditions might be.
The instructions warn against letting the paint get wet before it is cured, but our highly efficient Copperbot was applied during a rainy weekend. Unaware that the coats were supposed to go on wet-on-wet we allowed the first coat to dry overnight, and by the following morning it was attractively streaked all over from the rain pouring down the hull.
The ineffective Coppercoat, on the other hand, was applied in perfectly dry conditions and was painted exactly according to the rules.
On the plus side
The best we can say for Coppercoat is that it is less damaging to the environment than any conventional, poison-leaching antifouling. And that, for us, is a very important factor. The sea is our back-garden – quite literally – and we don’t want to do anything which will harm it. Thus we are willing to put up with a less than perfectly wonderful paint if it means that we will still be able to see fish flying, and dolphins leaping, and funny little bits and bobs of plankton sparkling by.
However, having tried both the genuine thing and our own mix, we can’t see any point whatsoever in forking out a ton of money for something which is so easy to make for yourself. The recipe? Take a reasonably runny epoxy, add pure copper powder, mix until the copper is all in suspension… and enjoy!