Antifouling frequently asked questions
Antifouling paint is applied to a boat’s hull below the water line. It slows the build-up of microscopic bio-organisms like slime and algae, and the bigger stuff like barnacles and mussels.
Is antifouling necessary?
Too much muck on your hull has an immediate effect on your boat’s performance and its fuel efficiency. On planing powerboats even light fouling can knock five knots off its top speed and increase fuel consumption by 30%.
It also doesn’t look very nice, particularly around the boot top. This is where the hull meets the waterline. Scale builds up where the water sloshes around the hull and over time this turns an orangey-brown.
Without antifouling, muck builds up quickly. As the surface of your hull gets rougher the process becomes faster. Even with antifouling, where the paint is too thin or applied badly the build-up will be quicker.
Should I apply new antifouling every year?
This depends on the type of boat you own and where you keep it. Some of our Norfolk Broads customers need only re-apply antifouling every other year. Our seagoing customers, and those who want maximum performance and efficiency from their boat, prefer to apply a new coat every year.
While your boat is out of the water it’s also a good opportunity to carry out some basic checks. These might include checking the wear on anodes and stern gear and looking for hull damage like osmosis.
It’s common to find obstructions around the stern such as fishing line. We recently lifted a 60ft cruiser and found sticks and muck blocking its exhaust pots. This could have forced the exhaust fumes back into the engine causing damage.
Is one coat of antifouling enough?
In some cases, one is enough, but we usually recommend two. Trying to do a rushed or cheap job will result in a poor finish and the paint won’t last as long.
At Broom we thoroughly pressure-wash every boat, including acid washing along the water line to remove scale. By washing off as much of the old antifouling as possible and preparing the surface we ensure a professional finish.
Sometimes, we won’t know what make of antifouling was used on the boat before so it’s necessary to apply a primer. Some makes can react with each other, which means the new coat will wear much faster.
With one coat and no primer there’s not enough thickness in the paint to have a long-lasting effect, so you’ll have to apply it more often. We also use a higher-end, trusted brand. To keep your boat running efficiently and looking its best all season, we recommend two professionally applied coats of antifouling.
Can I apply antifouling myself?
Yes, but make sure you follow the manufacturer’s guidelines and use the correct protective gear. Also make sure you prevent the scrapings from entering the water as antifouling paint is toxic to aquatic life. The RYA has some useful environmental guidelines on their website.
If you’d like some tips on antifouling or you’d like more information on our Lift – Antifouling – Relaunch service, get in touch.