I recently read an article about a boat with a copper-clad hull. I think it said that this is a permanent antifouling treatment, meaning no haulouts for bottom painting once done. I have since looked for information on the costs and how this is done, as well as more on the pros and cons, but couldn't find any. Can you help?
Dan Dickison responds:
Thanks for your question. Copper cladding, as you might imagine, is increasingly rare, but you will find that it's still used occasionally, mostly on work boats and classic sailing ships. The system usually involves applying copper sheets of varying sizes (cut to fit the boat's countour) in an almost shingle fashion. Most likely the boat you read about was a wooden boat. Wood readily accepts the fasteners (usually copper nails) that keep the sheets of copper in place.
I once assisted on a haulout for a friend of mine whose 45-foot bugeye (Chesapeake Bay work boat) had copper cladding on its keel. We inspected all the sheets, replaced any that had been rubbed through and generally worked to ensure that the seams between the sheets were tight. Where there were gaps, we either replaced the sheets with slightly larger ones or simply nailed down the existing copper. In both cases we used copper, ring-shanked nails that were roughly an inch in length.
Did it work for him? Yes. Even though this was in the Caribbean where the water is warm and fertile regarding marine growth, the keel of his boat stayed in fairly good order due to the use of the copper cladding. But, like every other boat owner, he still had to endure annual haulouts to check the condition of the cladding and make sure that all the other areas, like thru hulls and cutlass bearings, were in good orderóall the normal stuff.
What are the drawbacks? Well, bottom paint is initially less labor-intensive than copper cladding, and certainly with paint it's easier to discern if there are problems with the hull. If there are worms working their way into the wood beneath the copper sheets, you likely won't know that, but with paint, you can poke around and find the problem more easily. Also, it's a bit of a trick getting the sheathing to seal properly around thru-hulls, gudgeons and the like.
I can't help you much regarding the specific costs, but I can tell you that it will vary depending upon the thickness of the copper that you choose. Over time, I suspect that it's a bit of a wash. You'll probably pay enough for the initial purchase of the copper to equal four or five haulouts worth of bottom paint. To get a better handle on that issue, why not get in touch with a boatyard that specializes in working with wooden boats? I'm sure they can run down some more specific numbers for you.
Subsequent to scripting the above reply, we heard from a SailNet reader who was aware of a new product that makes applying copper sheets a more simple matter. David Grieme wondered if we were aware of Cupro FF, made by EcoSea, Ltd. We weren't, but according to Mr. Grieme, Cupro FF is made up of sheets of copper applied to a waterproof acrylic backing with its own adhesive. Evidently you peel back a protective layer and apply the "tiles" to your hull as you would vinyl flooring in a house. We'll report in greater detail on this later after we've had a chance to check it out in person.