How often does antifouling need to be renewed?

When it comes to antifouling, opinions differ: should you apply a new layer every year or only when needed? The truth lies somewhere in between and depends largely on what type of antifouling you use and how you use your boat. In this article, I share my knowledge from years of experience so that you know exactly when and how to best protect the underwater hull.

Self-polishing antifouling: planned layer by layer

There is a real pro trick with self-polishing antifouling: apply several coats in different colors. Why? When the bottom color becomes visible, you know it's time for a new coat. This is particularly useful because this type of antifouling is continuously removed and therefore works evenly. Boats that are often moved benefit particularly from this. Self-polishing antifouling is ideal for sailboats and motorized cruising boats that do not reach very high speeds.

A new layer is usually needed once per season, but with the multi-colour method you can flexibly adjust the intervals.

Hard antifouling: A classic with fixed rules

In contrast to the self-polishing variant, hard antifouling remains completely on the boat hull and releases its active ingredients more slowly. This makes it particularly suitable for fast motorboats or boats that are transported on a trailer. The rule here is: a new layer should generally be applied every year, especially before crane lifting in spring. This not only ensures optimal protection, but also a smooth underwater hull - a must for speed and efficiency.

Biocide-free coatings: more layers, more cleaning

Biocide-free coatings have their strengths, especially in inland waters where environmental protection plays a greater role. However, the antifouling effect is not as strong as with products containing biocides. Therefore, you should:

• Apply multiple coats for longer lasting protection.

• Clean the boat regularly during the season to effectively prevent growth.

Discipline is required, especially for boats that are used less frequently, as these coatings do not offer active protection against growth.

The spring tip: Repaint before craneing

Regardless of the type of antifouling, I always recommend applying a new layer before craneing in the spring. This ensures that your boat is optimally protected for the coming season. Make sure that the surface is cleaned well beforehand and sanded if necessary. A clean start is the key to long-term durability.

Additional tips for care and renewal

• Clean regularly: Even when the antifouling is active, light deposits can form. Remove these during the season with a soft sponge or high-pressure cleaner.

• Check the hull: Visible growth or bumps indicate that repairs are necessary.

• More layers, more protection: If you know your boat will be in the water for a long time, it's worth applying more layers.
  

Conclusion: No magic formula, but clear recommendations

How often antifouling needs to be renewed depends on many factors. With self-polishing antifouling and a multi-colour strategy, you can estimate the need well. Hard antifouling should be reapplied every year, while biocide-free coatings require regular maintenance. One thing always applies: a new layer in spring ensures a perfect start to the season!