2016.02.21 - A Surprising Find
The last few weeks have seen little progress on Naiad as my back is giving me some problems and the sanding of the hull is not doing said back any good at all. Instead I’ve been spending my money buying some of the things I am going to need in the next few weeks. Mahogany the correct size for the rubbing strake, oak planks which will form the bridge deck and thwarts. A battery, a solar panel and batter charger, resorcinol glue and more, some of which are shown below.
The surprise however is what I found on the hull. In preparation for the eventual painting and whilst I have the hull upside down, I am removing the antifouling paint. There appear to be two distinct layers of paint but I cannot determine how many layers are in each part. The most recent layers are an ablative paint that slowly wears away during the year so that any weed and growth that starts to grow on the bottom soon falls off. This is the black layer that you can see in the photos below. The second paint under the black layer seems to be a hard racing paint. It’s very tough and is easy to get a really shiny polish on the surface. That’s the blue paint in the photos below. But the surprise is what’s under those two layers.
Now called Coppercoat antifoul.
This is an epoxy coating that is laden with extremely fine particles of pure copper. At some point in her history, Naiad has been treated with this finish. Any old antifouling paint would have been removed right back to the wood and the wood given light sanding. A coat of normal epoxy would be applied in a thin layer. Then several thin coats of the copper laden epoxy would have been rolled on to the new epoxy later before it had fully cured to form the copper antifouling layer.
This puts a whole new slant on what I intend to do with the bottom of the boat. Previously I was going to paint it with the same paint as the part of the hull above the water and after some time in the river I would be able to see where the waterline is. Then, next Winter I would remove the paint below the waterline and apply antifouling.
Now I shall simply remove the layers of old antifouling paint and sand the hull back to the copper layer. In the area where the repair has been carried out I’ll apply some new Coppercoat. Once I have determined where the waterline is as before I shall remove any paint between the waterline and the copper layer, sand the hull back to the wood in this area, lightly sand the entire hull under the waterline, apply thin normal epoxy coat to the newly exposed wood and then apply a fresh copper coating to the entire hull.
I am quite pleased at this find as I have always had trouble with antifouling. It is very toxic to the marine environment at large, search the Internet for the problems that Tri-butyl-tin (TBT) antifouling paints caused a few years ago and I’ve always been ill for several days after application. Presumably it poisoned me while I was applying it. I doubt that the copper epoxy will have the same effect on me but the real advantage is that it is so long lasting. Some boat owners have reported that it remained pretty effective up to 20 years after the application. A light sanding all over every year or two to keep a fresh layer of copper exposed does seem to be required after a few years but the whole idea of a) not polluting the marine environment with a highly toxic poison and b) not having to put more expensive poison paint on the bottom of the boat every year is a very nice one for me.
You can quite clearly see the metallic sheen of the copper here.
This photo shows the three distinct layers. The Most recent black ablative layer, the harder blue layer and underneath the copper layer.
The red layer, by the way, is known as a boot top and is usually a brightly coloured antifouling strip over the join between the paint on the hull out of the water and the antifouling paint under the water.
Repairing the bilge keel. I had thought that I caused the break when I removed the keel before the hull repair started.
But I was wrong about that as you can just see where another break has started in the keel. I presume that Naiad was bumped against something which caused the cracks.
Some of the things I have bought recently for Naiad. A washing up bowl, a bucket with a lid and a kettle.
All collapsible! Here they are expanded.
The kettle is particularly nice for me since it has a stainless steel bottom. I find that aluminium kettles make my cup of tea taste funny so this was a bonus. It holds 1.5 litres or just over 3 pints.
When I saw these items I just had to buy them.
One thing I will be short of in Naiad is space and these necessary items will no longer take up a lot of storage space.