Tag Archives: antifouling bottom paint

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 improving 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.

What Equipment is Needed to do a Proper Application of Antifouling Bottom Paint?

Antifouling bottom paint is needed if you store your boat in the water. If left in the water without protection, marine growth may attach to your boat’s exposed hull. Marine growth slows a boat down and increases fuel consumption. Here are the items that you will need in addition to the bottom paint for the proper anti-fouling bottom paint application.

60–100 grit – Suitable for the removal of paint or to sand gel coat prior to the application of antifouling paint.
• After sanding remove sanding residue by wiping with a cloth that has been dampened with the proper solvent.
Masking Tape – When it is necessary to mask off areas use a high quality clean edge masking tape, especially when the masking tape will be left on the surface for a long time.
• Brushes – For antifouling paints use a natural bristle brush but not necessarily one of as good quality as you would use to apply topside finishes.
• Rollers – Most solvent resistant rollers will have a phenolic core and will say that they are for use with oil based paints or epoxies. For antifouling paint and epoxy primers, use a 3/8”-1/2” nap roller.