How To Remove Antifouling

Disclaimer: This post is intended as a guide. Updated September 2020

As we come to the end of the sailing season, it’s time to consider laying up your boat for the winter and one aspect is removing the antifoul from your boat if it is in poor condition.

Now, opinions are split on when is best to strip the old antifoul. Some people will wait until next year when they bring their boat out to apply fresh antifoul. However, some suggest that doing it now saves time and effort next year in the lead up to the season as the old antifoul is still soft and easier to strip.

We briefly covered this topic in our Antifouling FAQs post but we have now expanded on it further.

Read on to find out how best to remove antifoul from your boat.

1. Prioritise Health & Safety.

It’s extremely important before you begin this type of work to ensure you are wearing the correct protective gear. This includes safety goggles, nitrile rubber gloves, overalls, and a solvent mask (if working in a confined space).


It is also highly recommended that you work in an area that is sufficiently ventilated.

Although it is more focused on applying rather than removing, it is worth keeping in mind this handy leaflet. It was created by The British Coatings Federation to “inform and educate boat owners with regard to the hazards associated with antifouling their boats.”

2. Remove loose antifouling.

Whether the boat has just come out of the water or out of storage, begin by removing any loose antifouling with a high-pressure fresh-water washer.

Ensure any residue and wash water is contained during this process and disposed of appropriately afterwards. Once complete, mask off all areas that will be stripped.

3. Use an antifouling stripper.


To remove old antifouling, you can use a paint stripper like International’s Interstrip AF. These products have been specially formulated to remove antifouling from all substrates. Interstrip, in particular, won’t harm the gelcoat when used on glass fibre.

Application of the paint stripper should be generous and with an old brush. Ensure you follow further application guidelines provided on the product label.

You should leave the product to work for a minimum of 10 minutes, though the time required will depend on the temperature and the amount of old antifouling on the hull.

4. Remove old antifoul.

Once the appropriate amount of time for the stripper has passed, take off the old antifoul with a blunt scraper while it is still soft. Ensure the product does not dry out by working on small areas at a time.

Interstrip is able to remove several coats of antifoul in one go but heavy build-up might require this step to be repeated several times.

Final Note: Remember that you will need to sand and prime the hull before applying fresh antifouling.

N.B. Due to the strict carriage of dangerous goods regulations, Gael Force can only dispatch antifouling and associated products to addresses on the UK Mainland.

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