Anti-fouling Your Boat

Antifouling is one of the most important jobs when it comes to boat maintenance. Follow our top tips for straight-forward antifouling and increase the lifespan and the performance of your boat.

Preparation

The first step to a good antifoul job is making sure you’re properly prepared. Once your hull has been lifted out the water, get the hull pressure-washed thoroughly as this will remove most of the grime, weeds and loose barnacles on the bottom of your boat.

For more stubborn problems such as shellfish infestations, use a scraper to remove them.

If your boat has a build-up of old antifoul paint, or antifoul paint that isn’t in great condition, you will want to remove this using antifoul stripper or by getting the hull blasted.

When you’re looking for a base to start from, find a solid layer of antifoul paint to work with as you’ll want to ensure your new paint sticks.

If your current antifouling is peeling, either because of excessive build up or because of poor preparation in previous years, you will need to address these areas first.

A good scraper is essential here as it will remove flaking paint, alternatively, coarse sandpaper will also do the job and flatten any uneven areas.

Remember to always wear protecting clothing when doing these jobs as you don’t want to breathe in any of the toxic antifoul dust. Also avoid eating and drinking in the area that you’re completing the work in.

The majority of antifouling paints can be applied directly over most others, but there are exceptions. If your antifoul paint is failing to stick, you will need to remove all of last year’s paint and give the whole hull a coat of primer.

The same rule applies if your not sure what paint is currently on your boat, after all, you don’t want your hard work falling off the first time you go out sailing.

To be on the safe side, coat the hull with a barrier coat and be confident that the paint will stay put.

Masking off

Once you’ve done all the dirty jobs and got rid of any loose antifoul paint, it’s time to mask up. It’s always worth buying good-quality tape and getting thick tape for the waterline as the extra inch will allow you to be a bit less careful when painting up to it, making the whole job quicker.

If you’re working on a boat that has been painted in the past then it’s just a case of running the tape along the previous line. Make sure there are no gaps in the leading edge of the tape by giving it a good rub with your thumb.

Ensure you don’t paint over any hull anodes as this will render them useless and could cause corrosion problems on your sterngear.

Another word of warning is not to use copper-based paint if you have an outdrive powerboat as galvanic corrosion can occur on the drives.

Painting it on

If you need to, first paint your boat with a primer coat. If you don’t need to, skip this step and crack straight on with your first coat of antifouling.

Make sure you give the tin a good stir before use as most of the active ingredients sink to the bottom while the can has been standing.

Using the manufacturer’s recommendations, figure out how much antifoul paint your boat needs and ensure you use it all. Use our antifoul paint calculator to work out what you’ll need.

Paint thickness gauges will ensure you are putting on the right amount of antifoul for your particular boat.

Small-headed mohair rollers are great for this job as the roller doesn’t get clogged with paint as it does with longer fibres.

You’ll also need a paintbrush on hand for those harder-to-reach areas.

As antifoul paint can be quite messy, make sure you wear protective gloves and clothing.

Once the hard work is done, sit back and enjoy some cruising out on the water.

Find out more about antifouling your boat in our expert advice section.