One of the most expensive boat maintenance projects is the bottom paint. For the last 13 years we have been using Sea Hawk Island 44 bottom paint which requires a new application, hauling the boat out every 2 years, and endangering the oceans we love. The paint is expensive, the sanding and prep are expensive and the haul out is expensive. but it was a necessary evil. That is until we decided to go with coppercoat.
Coppercoat
Coppercoat is considered a more environmentally responsible choice for antifouling. It is a combination of a solvent free water based two part epoxy resign and high purity (99%) copper (it is not paint). Each liter of resign is packed with 2 kilos of ultra fine copper, the maximum allowed by law, making it the strongest copper based antifouling available.
This product is tin free, non-leaching and much kinder to the ocean than conventional self-eroding anti foul paints. The complete treatment has been approved by Health and safety in UK and EU and complies with International Maritime Organization.
Benefits
Even though the initial outlay of money is more expensive than one time haul out and bottom paint application, it lasts for 8-10 years. So, that is one application vs 5 applications.
It is a lot more environmentally friendly, leaves a smooth surface, and requires the same if not a little less maintenance.
And its repuation and claim shows excellent results.
How does Coppercoat work?
Once in the water, the ocean attacks the exposed pure copper, causing the formation of cuprous oxide. This highly effective anti-fouling agent deters growth until the surface degrades further to become cupric hydrochloride. This final copper form is highly unstable, and is washed away by the movement of the yacht, thereby removing any accumulating silt or slime. This automatically reveals a fresh copper-rich surface whereby the process recommences.
Here is a condensed version of the process:
- Sand the bottom of the hull down past the barrier coat
- Apply new barrier coat or primer
- Sand primer
- Clean with MEK to remove all particles
- Apply Coppercoat (5-6 coats in one sitting)
- Sand to activate coppercoat
Primer / Barrier Coat
We went round and round with what type of primer to use. There are several choices and frankly I am not sure there is a clear proven “winner” or better choice.”
Choice 1 – Water Based Epoxy
Several cruisers that we know used a water-based, solvent-free epoxy primer (such as Hemple). Their thought process was that the water-based expoxy primer would stick better to the water-based coppercoat. Makes complete sense and is very logical. The problem is that these types of primers do not go on flat. They create peaks and valleys which then have to be sanded down making it very difficult to get a smooth surface which is required for the coppercoat application. In addition, they are almost twice as expensive as solvent-based primers.
Choice 2: Interprotect Epoxy
The Norsand boatyard recommended Interprotect High Performance Epoxy Primer which is a solvent-based epoxy primer that has been in the marine industry for over 10 years. The application process is proven to be effective, is applied evenly, and adheres to coppercoat . The downside is that it requires two weeks to “off-gas” before the coppercoat can be applied. You know the saying…time is money?
Choice 3: Coppercoat Barrier
The NZ contact for Coppercoat had his own version of primer which he recommended, CK4261 Ceramic Barrier Coating. However, the yard has had poor results with this primer and recommended we use Interprotect.
I also contacted Coppercoat headquarters, Europe and asked for their advice. I gave them the pros and cons of all three variations. They said the good news is that coppercoat will stick to anything. But the bottom line was “use what the yard is comfortable with as they are doing the application and have to stand by the end result.” That resonated a lot with me.
Primer Winner
We ended up using Interprotect (what Norsand recommended) 27L of Part A, 9L of Part B and 4L of thinner. Ian and Conor applied 6 coats with the first three being white and then they added pigment to make the last 3 coats a light gray.
The overall effect was actual rather nice.
Final Adjustments to Previous Repairs
Once the paint dried we found a few areas that needed more filler. Look for a slightly darker color and or indent in the photos.
It is hard to find these problems when the boat is white and gray but now that it is all one color we could see the imperfections. So, they get filled (wine colored paint), sanded, and recovered in barrier coat.
There is too much for one blog post so tune in for The Low Down on Copper Coat Antifoul Part II coming up next.
Our blog posts run 10-12 weeks behind actual live events. This blog post occured around mid-November. In our last blog post we take Sugar Shack down to the bare bones.