Antifouling bottom paint is a specialized coating applied to the hull of a boat to prevent marine organisms like barnacles, algae, and slime from attaching. These growths can slow your boat down, increase fuel consumption, and cause long-term hull damage. Applying antifouling paint helps protect your investment and ensures optimal performance.

The frequency of reapplication depends on several factors, including the type of paint used, your boat’s usage, and local water conditions. On average, most boats need a fresh coat every 12 to 24 months. If your boat stays in the water year-round or you’re in warmer climates with high fouling activity, more frequent maintenance may be required.

Hard antifouling paints provide a tough finish that resists abrasion and is suitable for high-speed boats or frequent trailer use. Ablative (or self-polishing) paints wear away slowly over time, constantly exposing fresh biocide to the surface. Ablative coatings are ideal for boats that remain in the water and need consistent fouling protection.

In many cases, yes—but surface preparation is key. If you're using the same type of paint, you may just need to clean and sand the existing coat lightly. If switching paint types, it’s important to ensure compatibility or consider stripping the old paint first. Always check the manufacturer’s recommendations.

The best antifouling paint depends on your boat type, speed, hull material, and local water conditions. For example, a sailboat in saltwater might need a different product than a trailerable fishing boat in freshwater. Visit our Antifouling Bottom Paint collection to browse top products and detailed descriptions tailored to your boating environment.

Not all antifouling paints are safe for aluminum. Some contain cuprous oxide, which is corrosive to aluminum. For aluminum hulls, choose a copper-free antifouling paint specifically formulated for use on metal surfaces.

You can calculate the approximate amount of antifouling paint you need using this formula:

Boat Hull Area (sq ft) = Length x Beam x 0.85

Gallons Needed = Hull Area ÷ Paint Coverage per Gallon

For example, if your boat is 30 feet long with a 10-foot beam:

• 
  255 sq ft
  
• 
  
  
• 
  0.64 gallons per coat
  

For two coats, you'll need approximately 1.3 gallons.

Use our Boat Paint Calculator for a quick, custom estimate.