Should I Coppercoat my Nauticat?
My phone autocorrected Coppercoat to Nauticat in my search! I own a 1986 Nauticat 33 and I am sick of the annual antifouling grind. Should I bite the bullet and Coppercoat her? What are the real costs and pitfalls for a heavy motorsailer?
Answer
Coppercoating your Nauticat is a superb investment if you plan to keep the boat for more than five years, as it eliminates the annual grind of applying traditional ablative antifoul. However, applying it to a heavy-displacement motorsailer requires meticulous hull preparation and a significant upfront cost, usually around £3,500 to £5,000 if done professionally.
Economics for Heavy Motorsailers
Nauticats like the 33, 331 or 38 have substantial wetted surface areas and long keels that consume vast quantities of paint. Stripping old antifoul and applying four to five coats of Coppercoat (a water-based epoxy loaded with copper powder) demands serious labour. A Nauticat 33 typically requires 12 to 14 litres of the product.
DIY costs sit around £1,200 to £1,500 in materials alone. This includes the resin, hardener, copper powder and blasting supplies. Professional slurry blasting and application push this figure over £4,000. Your break-even point arrives around year four or five when compared to hauling out and paying for two coats of premium paint like International Micron 350 every spring.
Hull Preparation and Osmosis
Poor surface preparation remains the single biggest reason Coppercoat fails. You cannot apply it over old antifoul or conventional one-pack primers. The hull must go completely back to bare gelcoat or a compatible two-pack epoxy barrier coat.
- Removal: Slurry blasting with fine glass bead or crushed glass is the best method for a thick fibreglass hull like a Nauticat. It provides the perfect mechanical key. If you choose to sand, use 80-grit discs on a random orbital sander.
- Safety precautions: Always wear a well-fitted respirator and full protective clothing when sanding or slurry blasting. Inhaling old antifoul dust and copper particles is highly toxic.
- Osmosis check: Older Nauticats built in the 1970s and 1980s feature thick solid fibreglass, but they still suffer from osmotic blistering. Once the hull is bare, check the moisture content. If readings are high, let the hull dry out and apply a barrier coat like International Gelshield 200 before applying the Coppercoat.