Antifouling is a special coating applied to ship hulls and propellers. The coating is used to slow the growth of marine organisms such as barnacles, slime, algae and moss weeds.
In addition to being antifouling, the coating also protects the metal hull and propeller from corrosion. It also improves water flow through the hull.
The antifouling paint applied to metal hulls does two things: it prevents corrosion, and it prevents the settling and growth of tiny marine flora and fauna on the hull. Corrosion and fouling are interrelated, as poor corrosion resistance can lead to cracking of the paint film and thus loss of antifouling properties. Poor stain resistance can also lead to corrosion as barnacles cut into the substrate and damage the film.
Typical antifouling paints contain biocides or toxins in the paint that are released into the area around the hull to poison any attached organisms and prevent other organisms from adhering to the paint.
The four basic components of antifouling paint are:
fungicide
resin
solvent
pigment
The three main categories of antifouling coatings are:
Soft Primer - A moderately effective copper-based paint for cooler waters with lower growth potential in warmer climates. It is an inexpensive coating.
Hard primers – Hard antifoulings contain more biocide (cuprous oxide), making them more effective but more expensive. It provides a tough surface and provides a good finish for the bottom of a racing boat.
Ablative Antifouling - Designed to wear down the exterior surface and still retain some amount of biocide in the remaining layer. It is suitable for a variety of environments with single or multi-season options.
Factors to consider when selecting an antifouling paint include:
whether the boat is sailing in fresh, salt, cold or warm water
Whether the hull material is steel, wood or fiberglass
Will the boat run fast or slow
Compatibility with existing paint on the hull
Preventing fouling and corrosion extends vessel life, improves efficiency, reduces operating costs and avoids marine accidents and costly repairs.
