Using a Signal Coat Indicator for Repainting Ablative Antifouling Paint

Anti-fouling paint is a type of underwater hull paint, also known as bottom paint. These specialized coatings are designed for the exterior of the hull of a ship or boat, and combat the growth, as wells as, the detachment of underwater organisms, such as seaweed, algae and barnacles. These aquatic life forms bind to the hull and impact a vessel’s performance and longevity.

Anti-fouling paints are often applied as one component of a multi-layering process which can have other benefits in addition to their antifouling properties, such as acting as a barrier against corrosion on metal hulls that will degrade and weaken the metal, or to improve the flow of water past the hull of a boat or yacht.

Boaters recognized early on it is important to keep the bottom of their craft free of barnacles due to loss of speed and performance. The key is knowing when to pull your boat out of the water for a new bottom paint application. Ablative paints are typically reapplied every 1–3 years. One way to ensure you reapply your ablative antifouling paint when it’s needed is by adding a signal coat or flag coat.

To apply a signal/flag coat, when you are getting multiple coats of ablative bottom paint applied to your hull, make the first coat a different color. For example, if the bottom is going to be painted blue, make the first coat red. When the blue paint wears off and you see the red flag coat, it is time to repaint.

ablative bottom paint
Aquaguard is an excellent antifouling bottom paint

If you need further assistance with your boat painting project feel free to contact our technical team Monday-Friday 8:30-5:00 pm EST.