Coppercoat Conundrum

robertager1962

robertager1962

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www.sailing-south.com
I have Southerly 105 that was Coppercoated in 2013 professionaly by the previous owner. The coppercoat has adhered well to the fibreglass very well but when diving on her I notice that chunks are coming of around the edge of the metal grounding plate. My intention is to take her out this winter and asses the actual condition. In my mind (and as a worse case scenario) is to remove the CC on the metalwork, apply an epoxy coating (VC Tar) and then anti foul conventionally just the metal plate. I would welcome your thoughts and suggestions.
 
If I read this right you appear to have coppercoat on a grounding plate. (SSB sintered bronze grounding plate? or something else)?
It doesn't seem to be a good idea to coppercoat an SSB ground plate. The resin in the coppercoat would insulate the plate from seawater reducing its effectiveness. It should not have any coating on it, even epoxy tar or whatever.

If you mean some other plate then what I say might not apply.
 
MM5AHO said:
If I read this right you appear to have coppercoat on a grounding plate. (SSB sintered bronze grounding plate? or something else)?
It doesn't seem to be a good idea to coppercoat an SSB ground plate. The resin in the coppercoat would insulate the plate from seawater reducing its effectiveness. It should not have any coating on it, even epoxy tar or whatever.

If you mean some other plate then what I say might not apply.
Click to expand...

It is a Southerly & has a plate it sits on when up a beach
 
robertager1962 said:
I have Southerly 105 that was Coppercoated in 2013 professionaly by the previous owner. The coppercoat has adhered well to the fibreglass very well but when diving on her I notice that chunks are coming of around the edge of the metal grounding plate. My intention is to take her out this winter and asses the actual condition. In my mind (and as a worse case scenario) is to remove the CC on the metalwork, apply an epoxy coating (VC Tar) and then anti foul conventionally just the metal plate. I would welcome your thoughts and suggestions.
Click to expand...

It is difficult to get Coppercoat (or rather the underlying epoxy) to stick to cast iron, but might be worth pursuing recoating it. There was a long thread here earlier this year (sorry can't remember the reference) from another Southerly owner who had exactly the same problem. After discussion with Aquarius he decided to try again with a different epoxy undercoating. Suggest you talk to Ewan Clark at Aquarius. Coppercoat is particularly advantageous on your boat as antifouling the plate and grounding plate is a PITA.
 
sailorman said:
It is a Southerly & has a plate it sits on when up a beach
Click to expand...

Tranona said:
It is difficult to get Coppercoat (or rather the underlying epoxy) to stick to cast iron, but might be worth pursuing recoating it. There was a long thread here earlier this year (sorry can't remember the reference) from another Southerly owner who had exactly the same problem. After discussion with Aquarius he decided to try again with a different epoxy undercoating. Suggest you talk to Ewan Clark at Aquarius. Coppercoat is particularly advantageous on your boat as antifouling the plate and grounding plate is a PITA.
Click to expand...

This may be the thread Tranona refers to .......... including, unbelievably, the same "objection" to coppercoating a sintered bronze ground plate

http://www.ybw.com/forums/showthread.php?491537-Best-primer-for-cast-steel-keel-and-grounding-plate
 
the problem is that if the coppercoat wasn't applied from new - the plate may not have been completely dry (without heating it this is very hard to achieve) and as has been said it's hard to get the epoxy to stick well.

The grounding plate on a 105 is about 2 tons of cast iron (I had a 110 with a similar design - mine was a plate about a meter wide, about 9ft long and 6 inches thick in places!)

It is worth the effort to recoat though, although remember that as it's the 'grounding plate' it will be mechanically abraded every time you dry out on a beach as it's the bit in contact with the beach! so it is likely to need maintenance. Coppercoat is however a huge saving in maintenance effort and this little problem is worth persisting over.

Have fun :)
 
Thanks all. I would obviously rather stick with the Coppercoat and it mat be that it is where the fibreglass and cast iron meet that may be causing a little bit of a problem. Trouble is when diving in fairly murky water it is difficult to assess whether it is a major problem or minor. My best case scenario is that it is just the difference in flex/expansion and contraction of the fibreglass and the plate which has caused the epoxy to crack and water to get in and cause a little corrosion on the plate that has caused the water to rust the cast iron and the epoxy to fail, in this case I will grind off just where it has failed and re-apply a new patch of coppercoat epoxy. Never used coppercoat before so it is all a bit new to me. As we are travelling in her for the forseeable future from next May, I would like to get her as sound as possible. One thing I have suffered from on the Coppercoat is sodding great mussels growing. At first I thought they were skin fittings or earthing plates until I attacked them with my scraper and they came off. About 3" in diameter. I also got two of them out of my keelbox.
I really appreciate all your feedback.
 
I had local failure of the coppercoat on the bulb at the bottom of my keel and along the joint between the keel and the hull - similar to where you have breakdown. I ground back and recoated the affected areas a year ago and it has been mostly successful with only one or two small patches that need doing again next winter. Rust does not spread under the coating if the epoxy stays stuck to the iron. It only rusts where adhesion fails.

You need a week of good weather to do it, but it is no more difficult than normal antifoul except you have to be precise about mixing. With your boat you will need to block it up high to be able to work on the plate. As I suggested talk to Ewan as he will run through the process with you.
 
Tranona said:
I had local failure of the coppercoat on the bulb at the bottom of my keel and along the joint between the keel and the hull - similar to where you have breakdown. I ground back and recoated the affected areas a year ago and it has been mostly successful with only one or two small patches that need doing again next winter. Rust does not spread under the coating if the epoxy stays stuck to the iron. It only rusts where adhesion fails.

You need a week of good weather to do it, but it is no more difficult than normal antifoul except you have to be precise about mixing. With your boat you will need to block it up high to be able to work on the plate. As I suggested talk to Ewan as he will run through the process with you.
Click to expand...

Thanks for this and this sounds like a plan. I am lucky in that I bought a purpose designed cradle for our Southerly that allows the boat to be supported with the keel lowered so I should be able to access the plate fairly easily.
 
PCUK said:
Are we talking about two different types of "grounding" plate? One is the sintered bronze used as an earth plate for elkectronics and the other is a plate on which the boat sits when aground?
Click to expand...

Exactly. This thread is about the latter. An enormous metal plate weighing many hundreds of kgs that surrounds the lifting keel and provides ballast as well as protecting the hull when the boat is drying out. Nothing to do with electrickery or radios.
 
Back to my Coppercoat conundrum again. Before our Hols I dried our Southerly 105 out on the scrubbing grid and I had a very healthy crop of barnacles all over. Resorting to a garden hoe to remove them, I am swiftly coming to the conclusion that my Coppercoat is not working at all. I am lifting her this winter so that I can get at the hull and keel properly and need to plan on my possible course of action. This will be the last time I can really work on her before our big adventure where we are up-rooting and sailing south for the for-seeable future and I am not sure what to do. The Coppercoat was applied in 2011. Some advice is to just abrade to the surface (I would love this if it were the answer) and others is to prime the hull and anti-foul with another product (possibly Hempel's Silic One). I also need to do something with the inside of the keel box. I learned to dive so that I could keep the bits clean that I can't get to when she dries out but am very dubious about putting my hand inside the keel box after a horror story of a stuck finger whilst underwater by a friend of mine. Would welcome your thoughts on what you would do in my shoes.
 
This is a bad year for barnacles and few AFs work with them, although my Coppercoat has been unaffected whereas the prop and saildrive were covered after only 5 months.

Abrading the surface is the recommended action after a few years to re activate it. All covered on the CC website and if the coating is still sound then this is the first thing to do. You could also consider adding more coats. Speak to Ewan at Aquarius for advice.
 
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