If you are a boat owner, you know very well that the sea, besides freedom, also hides challenges for your boat’s underwater hull. Biofouling —that is, algae, oysters, and shells that attach to the hull— not only reduces your speed, but also dramatically increases fuel consumption and can cause permanent damage (such as osmosis in polyester boats).

The solution is one: the right antifouling paint (mourovia). But how do you choose the right one among hundreds of options? This guide will help you discover exactly what you need before making your purchase.

1. Main Types

The first and most important decision you need to make concerns the type of antifouling paint. They are divided into two main categories, depending on how they work:

A. Self-Polishing / Soft Antifouling Paints 

• Ideal for: Pleasure boats, sailboats, and boats that develop low to medium speeds (usually up to 25-30 knots).
• Advantage: They do not build up many layers of paint over the years, making scraping and the next maintenance much easier.

B. Hard Antifouling Paints

These paints create a hard, durable film that is not worn away by water flow. They release their biocidal ingredients gradually, while their surface remains stable.

• Ideal for: Speedboats (over 30 knots), racing boats, boats that are frequently trailered, or boats that “sit” in areas with very strong currents.
• Advantage: They withstand friction and high speed without peeling, while allowing you to clean the underwater hull with a sponge if needed.

2. What material is your boat made of?

• Polyester / Wood: Almost all antifouling paints are compatible.
• Aluminum / Light Alloys: Attention! You should never use antifouling paint containing copper oxide on an aluminum boat or on metal parts (e.g. propellers, engine legs), because it will cause galvanic corrosion that will destroy the metal. Look for special antifouling paints for aluminum/propellers.

3. What antifouling paint was used last year?

Compatibility is key.

• Over hard antifouling paint, you can usually apply either hard or self-polishing paint (after sanding it well).
• Over soft/self-polishing antifouling paint, you CANNOT apply hard paint, because it will peel off. If you want to change type or if you do not know what was applied in the past, you should use an insulating primer (Primer) as an intermediate bonding layer.

4. What is the boat’s speed and use?

Check the manufacturer’s specifications. Many brands (such as Vemar, International, Marlin, etc.) clearly state the knot limit (e.g. "Leisure up to 25 knots", "Comfort up to 29 knots", "High Speed 30+").

5. How much do you need?

Do not make the mistake of buying less paint to save money. For the antifouling to work properly, a specific coating thickness is required (usually 2 coats over the entire surface and 3 coats on high-friction areas such as the bow and the waterline).

A simple rule of thumb to calculate the underwater hull area in square meters (m²) is:

Underwater Hull Area = Waterline Length × (Beam + Draft) × 0.75

Once you find the sq. m., check the coverage provided by each product per liter (usually 9-11 m²/Lt per coat) to calculate the liters you will need. On Skroutz you will find packages from 750ml, 2.5Lt up to large containers of 5Lt or 20Lt if you have a larger boat.

6. Useful Tips for Application

• Surface preparation: 80% of success is determined by proper cleaning. Remove old peeling paint, wash with fresh water, and apply a good primer if needed.
• Mixing: The biocidal ingredients (which are heavy) settle at the bottom of the container. Mix the product very well before and during painting.
• Launching time: Every antifouling paint has a minimum and maximum time it must be left to dry before the boat is put in the water. Read the instructions carefully so its properties are not altered.

Whether you are looking for a specialized premium antifouling paint or a value-for-money solution for annual maintenance, use the search filters (by liters, color, or manufacturer) to find the ideal antifouling paint that will keep your boat fast and protected all season long!