How to apply antifouling paint correctly

Guide to protecting your boat's hull with Hempel antifouling paints

Good base work + the right paint = best protection on the water

Applying antifouling paint is not difficult, but it should be done carefully. When you use compatible Hempel products and follow the instructions, you will get long-lasting protection that improves your boat's performance and makes maintenance easier.

Tip: Choose paints and primers from the same manufacturer – Hempel Light Primer, Underwater Primer, and antifouling paints work best together.

Explore our antifouling selection and order products conveniently online:
Hempel Antifouling products at Venemaalit.fi

Why is applying antifouling paint important?

The purpose of antifouling paint is to prevent organisms such as algae, barnacles, and mussels from attaching to the boat's hull. The accumulation of growth increases water resistance, leading to higher fuel consumption, slower speed, and reduced maneuverability.

Correctly applied antifouling paint:

Effectively protects the hull throughout the season
Extends maintenance intervals and reduces maintenance needs
Improves boat performance and saves fuel
Maintains the boat's resale value

If the paint is applied carelessly, its effectiveness will decrease, it may detach during use, or only provide partial protection. Therefore, the quality of application determines the final result – and how carefree your time on the water will be.

Supplies – what you need before starting work

Before you start antifouling painting, make sure you have all the necessary products and tools ready. This will speed up the work and help achieve a smooth, durable finish. Below is a list of supplies by product line:

Product Category	Supplies	Note / Link
Primers	Hempel Light Primer Hempel Underwater Primer	Especially needed for new hull treatment or over old paint
Antifouling paint	Your chosen Hempel Antifouling paint	Explore the selection ›
Tools	Roller or brush Mixing pot and stick	Roller for large surfaces, brush for details
Protective gear	Protective overalls or old work clothes Respirator Safety glasses and gloves	Antifouling paints can irritate skin and respiratory tract – protect yourself carefully

Step-by-step guide – how to succeed in antifouling painting

When preparations are made carefully, the painting itself proceeds efficiently and safely. The following steps will help ensure the best possible result with Hempel's antifouling products.

Step 1: Protect yourself correctly

Antifouling paints contain substances that can irritate the skin and respiratory tract. Wear protective clothing, protective gloves, a respirator, and safety glasses. Work in a well-ventilated area or outdoors.

Step 2: Prepare the hull surface

The condition of the hull directly affects paint adhesion and durability.
Do this:

Wash the boat hull and remove loose dirt, grease, and any salt
Lightly sand the old paint surface to ensure good adhesion for the new paint
Smooth out dents and fill damage if necessary before painting

Step 3: Prime the surface (if necessary)

If it's a new hull, old antifouling has been removed, or the hull material requires special treatment, prime as follows:

Apply a coat of Hempel Light Primer
Allow to dry until the surface is almost dry but still slightly tacky
Apply Hempel Underwater Primer over it
Follow the manufacturer's instructions for coat and drying times

Step 4: Prepare the antifouling paint

Open the paint can carefully and mix thoroughly – pigment settles at the bottom during storage
Pour the correct amount into the mixing pot
Remove excess paint from the roller before application

Step 5: Apply the paint carefully

Use a roller for large surfaces and a brush for tighter spots
Paint in a crosshatch pattern – for example, horizontally then vertically – to ensure even coverage
Avoid too thin or too thick layers

Step 6: Drying and number of coats

The effectiveness of antifouling paint relies on the correct number of coats and drying times:

For a new hull: at least 2 coats
For maintenance painting: usually 1 additional coat is sufficient
Allow coats to dry thoroughly before the next painting or launching – check the paint product data sheet for drying times

Frequently Asked Questions (FAQ) – Antifouling

Can antifouling paint be applied in cold conditions?

Antifouling paint application usually requires a temperature of at least +10 °C and dry weather. Too cold or humid air can reduce paint adhesion and extend drying times. Always check product-specific temperature and climate requirements on the can label or technical data sheet.

How many coats of antifouling paint are needed?

For a new or completely sanded surface, two coats are generally recommended. For maintenance painting, one additional coat is sufficient if the old paint surface is in good condition. Check the instructions for your selected product.

How long does antifouling need to dry before launching?

Drying time depends on temperature and paint type, but in most cases, the final coat should dry for at least 12–24 hours before launching. Recommendations for Hempel paints may vary – check the instructions for use.

Can antifouling be applied directly over old paint?

Yes, as long as the old paint surface is intact and compatible with the new product. Lightly sand before applying a new coat. If you are unsure about paint compatibility, use a primer or check the manufacturer's instructions.

Is a special primer needed before antifouling paint?

Primer is needed, for example, for a new hull, after removing old paint, or in the case of an aluminum hull. Hempel Light Primer and Underwater Primer are designed to be used as a primer for antifouling and ensure the best adhesion.

Achieve a successful result with the right products

The success of antifouling painting depends on two things: meticulous preparation and the right, compatible products. By using Hempel's system of primers and antifouling paints, you ensure a smooth paint surface, durable protection, and effective growth prevention throughout the boating season.

Our selection includes everything you need for your painting project – from Hempel Light Primer and Underwater Primer to antifouling options for both sea and lake. We also offer non-toxic solutions, such as Silic One, if you prefer a more environmentally friendly option.

Explore products and order easily online:
Hempel Antifouling products ›

 Need help choosing?
Check out our comprehensive guide, which compares different antifouling paints, usage conditions, and application options:
Choosing the right antifouling paint