Copper Bottom?

[tjg1677]

Hello all. Time to draw on the forum expertise again. My boat was apparently given a copper bottom when built. Can anyone shed any light on what this means,  how it is done and what the advantages are. Never come across this on grp, wood yes but not plastic. 

Thanks in advance

Trev

[marshman]

When moulded copper particles were included in the gel coat, and/or bonded thereto.I have it on my Broom Diamond and it is/was meant to work as an antifouling. Even many years later it still seems to be pretty effective or perhaps the Broads do not cause a build up of growth/dirt except around the waterline.

I still dont bother to antifoul all over as that effectively provides a barrier and I only antifoul around the waterline leaving the underneath bare. There is in any case a strong argument not to bother to antifoul underneath, although it keeps some yards going.

Just give it a good pressure wash as it comes out.

[Vaughan]

This doesn't have anything to do with the Golden Rivet, does it?

[marshman]

As far as I am aware, having crawled all underneath mine on many occasions, I con confirm its all solid glass resin - plus a few zebra mussels and I did not inspect them too closely!!! And equally all boats as far as I am aware, are definitely of the gentler variety!!!

[Polly]

Argh Zebra mussels, nasty little things.

[Viking23]

Re zebra mussels.

I might have the odd one in my water intake of my outboard, when I had the impeller changed, last September,  there were two blighters near the water pump inside the leg, about the size of large salted peanuts, so they got through the strainer and took shelter in the leg. I wonder if one or two of their brothers or sisters made it further up. !! hence the thought of running the engine in some strong vinegar solution. 

Rodding out waterways with an old bicycle brake cable was suggested... that should play havoc with them. I don't want to remove the engine, so some back hosing, remove the strainers, and flush out might help. I am having no cooling issues as yet, but to be fair, we haven't been far during the last 18 months.

Richard

[Polly]

They can cause a lot of damage, they invaded our old outboard, but luckily  were easy to get rid of. 

[tjg1677]

Very interesting all this. I understand it was an expensive option when GK was built. What puzzles me is that the previous owner of seven years used to have her antifouled annually, just seems a bit counter productive, particularly as I am one of the school of thought that subscribes to the non anti fouling fraternity.  Any further input on this subject would  much appreciated.

Trev 

[BroadAmbition]

Every 2 years for 'B.A' we use 'Coastal 037' from Marine Industrial. Wash down, hand scrub then on it goes 

Griff

[LondonRascal]

You can buy a copper rich anti foul - its expensive stuff, as it has a high percentage of actual small copper particles in it and cannot just be slapped on to any other anti foul needing a nice smooth 'virgin' surface.  Usually this would be done with some kind of blasting media like Soda Blasting - http://www.soda-blast.co.uk/sbsuk_011.htm

Anyway, rather than go on have a read of this article in Practical Boat Owner about anti fouling - it is riveting stuff : http://www.pbo.co.uk/expert-advice/antifouling-everything-need-know-17104

[MauriceMynah]

Whatever tightens your rivets Robin, whatever tightens your rivets.!!!

[marshman]

Trev-  I think you will find that when yards have the rollers out, its just a case of bungin' it all over, irrespective!!!! Not really necessary as it does not stick that well to Coppercote and is easily blasted off with a pressure washer  - if you like to get your scuba suit out, all you have to do is jump in at Ferry! After all I think you are only 4/5 boats away!!!

[tjg1677]

This is where I am a bit confused. As I understand it my boat has had the copper treatment blended with the gelcoat at build. Isn't coppercote a retro applied epoxy coating???  I had her out when purchased for the survey and subsequently again when the BT was fitted. It was difficult to look see the bottom properly as there was a lot of anti foul still on it ( it had been re antifouled about 9 months previously ) but I thought it strange at he time as the bottom did seem to have a coppery colour to it and as I had never heared of this process, thought nothing about it.

So please enlighten me, if she has the copper into gelcoat treatment, would I be right in assuming that it is an antifouled for life treatment????  if not , what was the point of it when done???

Marshman, no thanks dont think I will go diving for two reasons. One its too cold and the second is that being an ex stoker, I dont like getting wet !! Anyway, if I| did, FM would probably charge me for the priveledge  . I take it you are moored near me then - what is your boat called? If you see me aboard, please do say hello and have a cuppa!

Trev

[marshman]

Trev - don't be confused!!! Not sure how its applied originally as i wasn't there!! However  I was always led to understand it was part of the build process and certainly even now, it looks pretty permanent!!

I would not worry too much anyway as there are many people in the Broads who do not antifoul under their boats as fouling here is minimal. Some use tar varnish and others leave it with nothing on at all . I personally put on about 2' or so around the waterline and never bother with anything else - if however you ask anyone else to do it for you they always do the lot irrespective.

I think in all the years ( 15?) I have had mine, it has only been done totally twice and generally its all a bit of a waste of money/effort!!

You should be aware that antifouling generally is bad for the Broads building up toxins etc - there are always studies being done to see how much this is and at some time in the future , it could be banned especially as its not really vital!!

[kfurbank]

I am guessing Marshman and Trev, your boats are vintage 1991 / 1992? My boat was built in 1992 and according to the broker would never need to be anti fouled. He explained that a copper material was laid out in the mould first and then the normal lay up process completed on top. It was an experimental material and only used for around 12 months before The BA banned it for being not very environmental, which is a relative term, because in 25 years my boat has never seen a drop of anti foul. Certainly a cost saving, but how much anti foul could have been applied and washed off into the system in 25 years? The broker said that somewhere around the Broads there is a warehouse full of the stuff because as mentioned it was banned, however the BA did agree that those boats that were laid up with it, could keep it, but no new mouldings could be produced with it.

I was told by the broker that the copper would go a dark colour over time and that if I wanted a light buff when out of the water would restore a brighter copper colour, but at the same time there is a risk of it going thin. As my boat is an ex hire boat it had a couple of small scrapes underneath and in these places when clean you can see the normal gel. I was also told that I could treat those small areas with anti foul, or if I wanted the whole hull with anti foul. I have done nothing apart from inspect the underneath when it comes out of the water which has only been three times in 12 years. 

When my boat was lifted for the first time after four years of ownership, the yard said that my boat came out cleaner than they had seen boats go back in the water.

I have noticed that around the waterline and several inches below you can get a limescale build up and this can then allow some growth of material, but once the boat is out of the water this very soon dies off. I find a good application of Harpic toilet cleaner to remove the limescale when out of the water is most effective at cleaning the copper and then the growth stays away for a couple of seasons.

The only slight complaint I have about the coating is that I wish they had gone slightly higher up the side of the hull. The copper coating end very close to the waterline and with the wash etc. I get staining on the hull above the copper. As I understand that anti foul doesn't adhere long term to the copper and that finished gel would need to be abraded for anti foul to adhere properly I would need to create a new boot line higher up and abrade the gel coat below and remove a section of the copper coat and then anti foul a ring around the boat, but then I would be back into regular anti foul maintenance, so instead I will live with regular waterline cleaning.

 

[tjg1677]

Thanks chaps that's great.  Yes GK was built in 91 so falls right in that bracket. I now know everything I wanted to, so much appreciated.

Trev