A guide to choosing the right primers and anti-foul paints for your boat plus product guides

The severity of fouling can vary dramatically depending upon water temperature, salinity, water-flow, time of year and amount of sunlight.

Whether you own a sailing boat of any size or a fast planning motorboat, all Seajet anti-foul products work at hull speeds up to 40 knots so, in this respect your choice remains unaffected.

Yachts moored in hot climates and subject to long periods of sunlight will suffer worse fouling than others in colder climates with less daylight hours of sun and whether your yacht is immersed at all states of the tide or moored on a drying-mooring will influence whether a soft-eroding or hard type coating can be applied.

In general, hard anti-foul types, such as Seajet 037 Coastal, are good for drying-moorings and self-polishing (eroding) types such as Seajet Samurai, Shogun, Emperor and Platinum should only be used for yachts which are constantly immersed at all states of the tide.

Self Polishing (Eroding) – the popular choice
Self-polishing types gradually and scientifically erode away in a highly controlled fashion. Once applied and following re-immersion, a chemical reaction, combined with the physical movement of water across the hull triggers the formulation to start eroding. An analogy would be to think of a bar of soap, and how this constantly wears away through use.

Seajet advanced polishing mechanisms ensure a fresh-layer of effective biocide and co-biocide is constantly exposed to the surface area ensuring fouling is effectively repelled during the life of the product. This is why the number of coats applied from the outset has a significant bearing on performance and consistency.

Due to the relatively soft nature of self-polishing formulations, these types are not recommended for yachts with drying-moorings.

Provided enough film coating has been supplied from the outset, most users find Seajet self-polishing anti-fouling very hard to beat and nothing more than an annual check and jet-wash to clear away slime and revive the coating is normally all that is needed until the time comes to re-apply.

Hard Types – for ultra fast hulls and drying-moorings
Due to the leaching nature of the biocide, hard types, such as Seajet 037 Coastal, are more resistant to abrasion and eroding. Therefore, yachts with drying moorings need hard types to resist the potential for short-lived erosion of the coating. In these rugged conditions, liberal coats from the outset and re-application on an annual basis is recommended.

Owners of racing yachts also find hard types advantageous because they lend themselves to burnishing with wet & dry paper, prior to launching. Equally, owners of fast motor boats find that Seajet 037 Coastal works best for them by staying intact even at high hull planning speeds up to 70 knots.

Non-biocidal types, such as 036 Shogun-Eco, are the popular choice for customers who insist upon copper-free coatings. Likewise, customers who use their boats in countries that have restrictions in place on the use of copper find this technology ideal.

It’s worth noting, however, this technology tends to polish more quickly than other systems so, if in doubt, apply one extra coat from the outset.

Foul Release
As the term suggests, Foul Release types rely upon the ultra-slippery nature of the treated surface on which fouling simply finds it difficult to adhere to. In the case of Seajet Peller Clean – a silicon based eco-friendly coating for props and stern gear – fouling may visibly gather on the surface, but will soon detach itself as the yacht moves through the water and/or the propeller starts to turn.