Antifouling Tips

The reason we antifoul our boat is simple - without protection, a number of forms of marine life will attach themselves to the craft and have a significant effect on the boats performance, safety and structure. The type of "fouling" experienced will depend on the environment the boat is kept, but some fouling will occur in ALL water and climate types to some degree. With proper application of an antifoul, these problems are kept to a minimum, ensuring that your boats is efficient, handles correctly and that no damage is done to your hull.

There are different types of antifoul available (hard, self-eroding etc.) so check what is suitable for your particular boat and the area in which you will use it.

Antifoul cannot be applied directly to the hull which must be keyed and primed before the antifoul is applied. If you are re-applying antifoul on top of existing antifoul layers, ensure that the new paint is compatible and if in doubt, apply a layer of primer as a barrier coat. On NEW boats, you will have to "key" the hull by sanding it with wet & dry paper first, before applying a primer and then applying the antifoul.

Check the hull for any signs of cracking, blistering or damage. If necessary, repair any damaged areas using a watertight epoxy filler (GRP), and remove and loose, cracked or separated coating that is not firmly attached to the hull. Wash with a pressure washer or similar and allow the surface to completely dry before commencing painting.

Check the minimum period you need to leave between coats and in some cases the advised time for leaving the boat out of the water between completing the antifoul and re-launching.

Due to the seasonal nature of antifouling, it is often done during the colder months of the year - Keep your cans of paint indoors if possible as it will be much easier to apply if not too chilled.

Always mask off the waterline where you want the antifoul to finish. Use previous marks as a guide, or check other craft of similar design. Good quality masking tape will leave a clean line and be easily removed. Cheaper or household masking tape which is not designed to be used outdoors can become difficult to remove and loose it's adhesion, allowing paint to creep underneath and spoil the finish.

It is advisable to apply an extra coat to leading and trailing edges, such as the waterline, keels, rudders etc. These areas experience more water turbulence than other areas and so are more inclined to suffer from wear on the antifoul.

When applying the antifoul, always stir the paint well before use - this will ensure even application and the proper dispersion of chemicals and substances in the paint.

Do not attempt to antifoul on damp or wet days - the moisture will adversely affect the adhesion of the product.

Do not be tempted to use a large roller to apply the paint, the curves and shapes found on all boats will effect an uneven application as pressure will be applied to certain areas of the roller and not others.

Do not ignore other underwater section of your boat, e.g. out drives, keels, propellers etc. There are specialist products to offer antifouling protection for these areas and these areas specifically will detract from performance of your craft if heavily fouled. (PJ)