Interlux Fiberglass Bottomkote NT

Interlux Fiberglass Bottomkote NT Antifouling Bottom Paint

Interlux Fiberglass Bottomkote NT is a hybrid hard/ablative antifouling bottom paint that gives you the best of both worlds. Its dual-resin formula combines the durability of a hard coating with the self-polishing benefits of an ablative paint, so the film gradually smooths with use instead of building up heavy layers year after year. The result is a cleaner, more efficient hull and easier maintenance at haul-out.

Designed for both powerboats and sailboats, Bottomkote NT is an excellent choice for boats kept in fresh, salt, or brackish water. It delivers reliable, single-season fouling protection on fiberglass, wood, and properly primed metals hulls (not for aluminum) and can be burnished or scrubbed where extra smoothness is desired.

Available in red, green, blue, and black, it provides a classic antifouling look with modern hybrid performance.

Best Uses

• Fiberglass powerboats and sailboats that are used regularly during the season
• Boats kept in marinas or on a mooring in fresh, salt, and brackish water
• Owners who want durable, scrubbable finish without excessive bottom paint build-up
• DIYers looking for a fast-dry system that allows multiple coats and same-day launch in suitable conditions.

Key features & benefits

• Hybrid hard/ablative technology - Combines hard-coat durability with a controlled polishing action to help prevent premature wear-through while still shedding light growth.
• Smooth, efficient finish - As the surface slowly smooths with use, it helps reduce drag for better speed and fuel efficiency.
• Fast-dry formula - Under normal conditions you can apply multiple coats and launch the same day, making it ideal for tight haul-out schedules.
• Versatile application - Suitable for fiberglass, wood, and properly primed steel or lead underwater areas (not for aluminum hulls or outdrives).
• Universal use - Works for most power and sailboats in fresh, salt, and brackish waters, making it a flexible choice for mixed cruising areas.

How to apply Interlux Fiberglass Bottomkote NT

Interlux Fiberglass Bottomkote NT can be applied with a brush, roller, or spray equipment over most existing antifouling paints that are in good, sound condition. Always make sure the old coating is firmly adhered, clean, and free of loose or flaking material before overcoating.

• Substrates: Fiberglass, wood, and properly primed steel/lead underwater surfaces
• Existing bottom paint: Check the Interlux antifouling compatibility chart to confirm suitability, then clean and sand as required
• Coats: Apply at least two full coats; use an extra coat on bare wood or high-wear areas such as leading edges and the waterline
• Thinning: Thin only if necessary, using the appropriate Interlux thinner, and do note exceed label recommendations

For best results, always stir or shake the paint thoroughly before and during use to keep the copper and resins evenly mixed.

Surface preparation overview

Proper prep is critical to long-term performance. Follow the detailed instructions on the product label and technical datasheet, but in general:

• Previously painted surfaced - good condition
• Wash to remove slime, salts, and contaminants.
• Lightly sand if recommended to provide a clean, dull surface.
• Removes sanding residue and apply the recommended coats of Fiberglass Bottomkote NT
• Previously Painted Surfaces - poor condition
• Strip loose, flaking, or heavily built-up antifouling using appropriate methods (chemical stripper for fiberglass/wood or sandblasting for steel).
• Once the substrate is clean and sound, follow the bare fiberglass, bare wood, or primed metal system as directed.
• Bare Fiberglass
• Remove mold release wax and contaminants with the recommended Interlux fiberglass prep products.
• Fair any imperfections as needed.
• Follow either the no-sand or sanding system detailed in the Interlux datasheet, typically involving a suitable primer or barrier coat followed by multiple coats of Bottomkote NT.
• Bare Wood
• Sand the surface smooth and clean off dust.
• Apply an initial thinned coat of Bottomkote NT to help penetration, then follow with additional full coats as directed on the label.

Application tips

• Use a quality solvent-resistant roller or marine brush designed for bottom paints.
• Work within the temperature range recommended by Interlux, avoiding application in very cold or very hot conditions.
• Respect the specified drying, recoat, and launch times between coats and before launching.
• Always consult the full Interlux technical datasheet for detailed dry-time tables, safety guidance, and complete system recommendations.

For complete application instructions, safety information, and dry-time charts, refer to the Interlux Fiberglass Bottomkote NT technical data sheet (PDF)

Frequently Asked Questions

Can I use Fiberglass Bottomkote NT on aluminum hulls or outdrives?
No. Fiberglass Bottomkote NT is not recommended for aluminum or alloy hulls and should not be used on outdrives. It is designed for fiberglass, wood, and properly primed steel or lead underwater surfaces.

Can I apply Bottomkote NT over my existing bottom paint?
In many cases yes, as long as the existing antifouling is in good condition and firmly adhered. Clean the hull, lightly sand if recommended, remove any loose or flaking areas, and always check the Interlux antifouling compatibility chart before overcoating.

How many coats of Fiberglass Bottomkote NT do I need?
Most boats require at least two full coats for proper protection. Bare wood or high-wear areas such as leading edges and the waterline often benefit from an additional coat.

Is Fiberglass Bottomkote NT suitable for freshwater or brackish water?
Yes. Bottomkote NT is formulated for use on boats kept in fresh, salt, and brackish water, making it suitable for most marinas and mixed cruising areas.

How soon after painting can I launch?
Dry and launch times depend on temperature and conditions, but under normal warm-weather conditions you can typically launch the same day after applying the final coat. Always follow the specific dry-time guidance on the product label and technical datasheet.

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