Helpful inside tips on antifouling

It’s that time of the year again, time to haul out the boat, and give the bum a clean! But the debate within yards, paint suppliers and independent operators as to what antifoul is the best in market will rage on well after this article is published.

Do I use a depleting grade (Altex No 5), a semi-hard (Jotun Sea Guardian) or a hard antifouling (International Ultra) on my boat?

In this regard, I can only offer advice on my own findings and what has worked for us in our area (Sydney Harbour). Believe it or not, some paints will outpreform others in certain areas or environments.

ANTIFOULING LORE
Antifouling your boat is one of those chores that many boat owners drag out. Too many try and get every last month out of the coverings, but by doing this you could be causing other damage and overlooking key maintenance on anodes, sail drives, running gear and, as previously covered, sterndrives that all require haul-out maintenance.

So my first bit of advice is this — the antifouling will do 12 months of general work regardless of the brand, keep your schedule to the yearly period, and your bottom and budget will benefit.  Keep in mind the paint is there to protect. So no paint means no protection.

HORSES FOR COURSES
The next bit of advice is talk to your yard and ask why they use it? If the answer is because they do me a good deal, you're using the wrong yard.

Over the years, many brands have had to vary their formula to come in under the environmental regulations. The performance of some brands has been affected more than others.

I use Jotun Sea Gaurdian on my own vessel, as it has the highest legal copper levels allowable. It’s not soft, it's not rock hard, but I have found it to be the best all-round performer in my environment.  It’s a coating that can be dived and scrubbed and doesn’t lose performance, too.

ANTIFOULING TIPS
Regardless of brand here are a few good tips to ensure your antifouling is performing to its best:
>> Like all painting applications, surface preparation is key. Most high-pressure water blasters will work at 3000psi, so the need for a full wet rub for bonding is eliminated.  But all hard shell growth needs to be removed and prepared in a proper manner before application.
>> Any areas that are back to the hull surface need to be primed with a compatible primer for the brand of paint you have chosen.
>> A smooth and fair base will allow the antifouling to be applied in a uniform thickness. I find hulls with years and years of build-up and uneven surfaces don’t perform well. A good wet rub from time to time on these hulls prior to application is recommended. (A full antifoul strip is the best option, but very expensive).
>> Antifouling contains solvents, the solvents evaporate and allow the paint to dry, we live in a fast-paced society, with high expenses for yard operators.  Not allowing paints to dry between coats or the launching of the vessel too quickly can affect the paint performance, even causing the paints to not bond due to trapped solvents. Always work to the manufacturer's recommendations. Temperature is another major player and drying times need to be adjusted in winter months.
>> Applying two thinner coats is better than one thick coat, due to the risk of solvent encapsulation as mentioned above. We also recommend that all hard and leading edges have an extra coat.
>> Maintaining the correct anodes and amount of anodes can affect your performance. We covered anodes in a previous article. From the vessels I inspect fitted with the Maddox system I am seeing better performance from their coatings.
>> On the flip side, don’t apply your coating and have it sitting out of the water for over three weeks. We have found the coatings lose performance and become inactive.

Next we will look at coatings on our running gear, propellers, shafts, sterndrives and trim tabs.

*Gavin Clark is a contributor at boatsales.com.au and BoatPoint.com.au who writes under the pseudonym 'The Surveyor'. He is a shipwright and marine surveyor with a business called Slipstream Marine based in Sydney. Gavin has 28 years experience in the boating industry, is an avid boater and owner of a 33ft Sharpie (trawler). Gavin can be contacted at boatsurveying.com.au.