Antifouling Paint Guide

Antifouling Paint Guide Introduction 

The natural environment that boats live in is harmful to the boat itself. Bodies of water are havens for animals, slime, and plant life that can damage the effectiveness of your boat. Through the season weeds, slime, and animals can bond to your boat's exterior, which can lead to the destruction of your boat's performance and lifespan. The weed and animal life in the water all have free-swimming spores and larvae, which can adhere to an unprotected boat's surfaces. When choosing an antifouling paint you need to keep in mind which fouling agents are in your environment and choose paint accordingly. Temperature and water conditions can all have an effect on which antifouling paint you should choose for your specific application. Once the fouling agent bonds to the surface of your boat, it can be extremely hard to remove them. These agents can cause your boat to sit lower in the water causing a safety issues and lessen the effectiveness of your boat's performance.

Antifouling Paints

Antifouling paints contain biocides, which are used to control any unwanted organisms from growing on your boat. These biocides are meant to kill or control the formation of plants using a biological or chemical action. Antifouling paints often use copper or cupreous oxide to keep little animals, slime, and plant life from attaching to your boat's surface. Different antifouling paints are not all made with same amount of copper. Each type of antifouling paint also releases copper in different ways and have different actions for keeping the copper in suspension (Also know as binders).

Different Kinds of Antifouling Paints 

Ablative/Polishing - Ablative paints are the best choice when the boat is used often. Ablative paints are designed to have a controlled wearing away effect (ex: A bar of soap). Ablative paints release the paint as water flows over the hull. As the water runs over the hull, the paint wears away removing paint and exposing new biocides as you use your boat. Because ablative paints wear away they are only effective if there is paint available, additional coats will add to the longevity of your paint. Some Ablative paints are also Copolymer paints, which work well in high growth areas and can be effective even if you pull your boat out and re-launch it. An ablative paint that is not a copolymer will start to loose effectiveness after being dry for a certain period of time (The amount of time is up to the Manufacturer).

Hard - Hard Antifouling paints are best suited for the boater who keeps their vessel in the water year round. These paints are hard, durable, and have a season long finish. Hard paints are very resistant to abrasion and rubbing and are best suited for high-speed boats. A hard antifouling paint will release biocides at a gradually decreasing rate. This constant release will leave the boat with the original hard coating at the end of the season. If you tend to store you boat out of water, this paint will start to loose its effectiveness. One downside of this paint is that you will have to remove the paint and reapply once the biocides have worn out.

Thin Film / Teflon - Thin film paints contain Teflon in addition to a biocide. Teflon adds a slick surface to your boat's paint, which will keep fouling agents at bay. These paints make a low friction surface that is ultra smooth. Thin film paint will increase speed, improve fuel efficiency, reduce fuel consumption, extend engine life, and minimize paint build-up. These paints are often used for racing and in low fouling areas.

  • Interlux - VC 17m

Aluminum - You do not want to apply antifouling paints with Copper in them to aluminum surfaces. Copper will react violently with aluminum. For this reason, there are special purpose bottom paints that can be used on aluminum surfaces. These paints can also be used on propellers, outboards, and out drives.

Conclusion

Fouling can be detrimental to your boats performance if not protected. There are three types of fouling: animal, slime, and plants. These fouling agents can be blocked with antifouling paints. Different environments and usage call for different types of antifouling paint. Make sure you research the different types of antifouling paint and pick accordingly. Happy Painting!
All information was taken and modified from Pettit and Interlux product manuals.