Self made Copper-Epoxy-mix as Antifouling? - And the 'same' ready made products?

[Angélique]

Hello all,

I read this Dutch article about an experiment with a self made copper epoxy mix. It should work as antifouling for ten years, even in salt water! And it would be legal in the Netherlands where many antifoulings are prohibited now. The site claims that its cheaper, simpler, more effective and environmental friendly.

Dutch:
http://www.water-experience.nl/joomla/index.php?option=com_content&view=article&id=10:koperpoeder&catid=5:projecten&Itemid=10

Google translation, Dutch > Enlish:
http://translate.google.com/translate?prev=hp&hl=nl&js=y&u=http%3A%2F%2Fwww.water-experience.nl%2Fjoomla%2Findex.php%3Foption%3Dcom_content%26view%3Darticle%26id%3D10%3Akoperpoeder%26catid%3D5%3Aprojecten%26Itemid%3D10&sl=nl&tl=en&history_state0=&swap=1

Are there any experiences here with copper-epoxy as antifouling?

If it's already discused here please give a link.

Regards,

http://images.zaazu.com/img/000612-small.gif (http://images.zaazu.com/img/000612-large.gif) Angel http://images.zaazu.com/img/000612-small.gif (http://images.zaazu.com/img/000612-large.gif)

P.S. added the title a bit (10-24-2009)

[TeddyDiver]

http://www.coppercoat.com/
Should be good I've heard..

[simon]

Would be interesting to hear from someone with experience. All I have read, until now, is about applying the copper epoxy, but no recounts about how it worked over the years.
My boat had copper epoxy applied by the first owners and they wrote on the their website that they needed to clean the hulls way to often.
They also thought that it makes a good base for antifouling. A rather expensive primer.

[AndrewK]

About 15 years ago copper epoxy was being promoted in Australia, I tried two different products on my keel and rudder. One was based on fine copper powder and the other so called coloidal copper flakes. Performance of both was well below convetional self polishing antifoul paints.
Water temperature here is 19 - 26'C.

[Ad Hoc]

Whatever you do, do not use it on aluminium..!!!

[masalai]

It is on my boat, and many other Oram designs and some others too... I will launch in April 2010 so ask me after then... fine copper spheres (dust - almost like heavy talcum powder applied in a mix of about 50% by volume to mixed epoxy/hardner and applied by roller in several layers, almost continuously as the mix goes off quickly so make small batches, mix and apply then move to the next portion to be done... 3 or 4 layers and about 4kg per 40 ft hull for a lightweight cat. - - - Also becomes quite hard and IS NOT sandable and will cut your hand if there are any "sharp bits" where you rub your hand against the cured area... only use on glass/epoxy built boats and be cautious or electrolysis on through hull, prop-shaft, outboard/alloy legs etc... and add one or more of these, on advice, for electronic earthing "Moonraker-eplate-1.pdf" or another version to meet your other electrolysis/earthing needs...

[simon]

but, anyone used it for years with success?

[masalai]

Varying levels, seems related to copper exposed to oceans, earlier commercial products were small flakes, for me the "powder" seems best and "Schools Out" is cruising now, and I think it was on their previous (smaller) cat as well... The "urination" test left a copper oxide "green/blue" stains indicating effective leaching, so it is effective there...:o

[Snabb]

Hi,
I am aware that this thread is quite old, but still want to shre my experience. I applied the 'Dutch' epoxy-copper three years ago and had very good results. Unfortunately, I had to do some repairs last year and found out that the company stopped production due to family circumstances. I was lucky to find one of the last liters of Ecoline coating at a shipyard.
At the time there were different types of coating depending on the type of water, the fresh water kind worked very well. Just had to clean it with a high pressure water jet, a brush and cloth.
Since there is no (0,zero) emission of copper into the water, it is locally (in The Netherlands) not classified as anti-fouling.

[HakimKlunker]

It appears that there is no one-for-all. It depends much WHERE your boat is located.
I had a boat on the Baltic once, with a copper antifouling (von Hoeveling). It worked extremely well. Needed only a little cleaning from slime every now and then.
I am now in the tropics and here copper is seemingly less efficient.
Some local fishermen use dispersion paint with mixed-in chili powder. Sounds weird, but it works. Less durable of course, but extremely cheap.
with winter approaching, you have a good chance to inspect boat bottoms on the dry. Their condition and growth status will give you a good indication of what works well in your region.

[Herman]

At this moment I am starting some tests with Copper Powder in different epoxy systems. A solvent free system with very good resistance against water, and a water based system which seemingly would expose more copper.

Will only start in a couple of weeks though.

At this moment I am selling the stuff with solvent free epoxy, which seemingly does work well. However, I would like to do some testing myself.

[Chuck Losness]

The yard in Puerto Escondido has been applying a copper epoxy bottom paint for the past 2 years with very mixed results. I don't know the brand name. It is $500 per gallon and you have to completely strip everything off the bottom down to bare fiberglass/gelcoat. Very expensive to apply. Didn't work at all on one boat until they hauled the boat and sanded the bottom to expose the copper. Somehow the epoxy glazed over and no copper was exposed. They now sand the bottom just before launching to make sure the copper is exposed. Several boats have had major electrolysis problems both in thru hulls and the paint itself.
I did a google search and did not find one boat owner that kept the copper epoxy bottom paint. All had gone back to regular antifouling. But it was a pretty small sample and maybe not representative of other boat owner's experience. The only positive reports I found seemed to come from the people selling the stuff. From a common sense point of view epoxy is pretty waterproof and does not wear away so how does the copper in the paint every come to the surface to provide antifouling. Do you have haul every year just to sand the bottom to expose more copper. I don't know. This stuff has been around for awhile and if it was as great as the salesman are claiming, then everybody would be using it.
IMHO the jury is still out.

[MikeJohns]

I saw a paint patch trial with Epoxy base coat and copper powder on a slow coastal steel vessel with several different approaches.

From memory the best result was using a water based 2 pack epoxy and the copper powder was blown into/onto the wet paint surface with a sand blasting type arrangement.

That worked much better than the loaded pre mixed in copper with the paint which was sanded after application.

That makes the application expensive and it's also hard to obtain reasonably priced copper powder. It worked very well and I saw the patches after 5 years and they were clean and they were scrubbed with a pad but not sanded.

[Chuck Losness]

Mike
I recently bought 2 lbs of very fine copper powder on Ebay for $13.50 per pound plus shipping. I don't know if that's expensive or not. I added it to my Comex bottom paint. Just got out of the yard 2 days ago. Good to be floating again.
Interesting application to blow the copper powder onto tacky epoxy. I wonder if there is a lot of waste or if the copper readily stuck to the epoxy without much waste. Do you remember how much copper they had to use or how thick it was? Is that process similar to powder coating?
Chuck

[pauloman]

google copper powder epoxy

[HakimKlunker]

...with very mixed results.
...Somehow the epoxy glazed over and no copper was exposed.

Similar incident in Thailand: A copper/EP coating was applied before the (new) boat was completed. Until launch there was sort of oxidation on the surface which 'de-activated' the copper.

I am not convinced about the whole idea: Epoxy is very resistent against water penetration, and all the copper particles are embedded in it; so only the copper next to the surface has a chance to be fully effective.

When - a while ago - the British began copper plating their ships they did not cover with wood planks either, did they? ;)

In my eyes all the expensive EP is better used to build up a barrier coating on which copper paint can be applied.

[Herman]

But copper paint also has a matrix, in which the copper particles are held...

And the above is also the reason I will be testing with water based epoxy resins. They create more porosity, at least, I hope. I might even do a test with diluted epoxy resins, although I would love to keep it 0% VOC.

[MikeJohns]

Mike
I recently bought 2 lbs of very fine copper powder on Ebay for $13.50 per pound plus shipping. I don't know if that's expensive or not. I added it to my Comex bottom paint. Just got out of the yard 2 days ago. Good to be floating again.
Interesting application to blow the copper powder onto tacky epoxy. I wonder if there is a lot of waste or if the copper readily stuck to the epoxy without much waste. Do you remember how much copper they had to use or how thick it was? Is that process similar to powder coating?
Chuck

I didn't see them apply it, I was just told how they had applied it. But it was definitely the most successful patch. In consultation with Epirez (I think) they tried the water based 2 pot polyamide cured epoxy as the base. I would never have thought of that myself but apparently it was the best option. Unfortunately I cannot offer any more information at this stage but I'll try and chase up the study.

[Angélique]

Too bad that the links in post #1 have gone dead. The guy applied it on his own boat and also offered copper powder for sale. I guess he stopped selling the powder and therefore took the article off line.

However the website with contact info is still on line so he could be asked for his experiences with the system.

Website (http://www.water-experience.nl/joomla/) - - - - Contact page 1 (http://www.water-experience.nl/joomla/index.php?option=com_contact&view=contact&id=1&Itemid=17) - - - - Contact page 2 (http://www.water-experience.nl/joomla/index.php?option=com_content&view=article&id=9&Itemid=6)

As he's Dutch this could be an easy way for Herman to get some info before his tests. After all it's over two years on the boat now so there should be a beginning of experiences of the promised 10 years lifetime + info about the materials sepcs and how it was applied.

The boat it was applied on is a plywood/glass/epoxy Brent Kohler (K-designs) Manta (http://www.ikarus342000.com/MANTApage.htm) 12.65 x 7.10 m (41½' x 23' 3½") cat.

Max amount of copper powder that the epoxy could take was mixed into the epoxy and then brought on to the boat. After curing it was sanded down to expose the copper. In the pictures I saw of it it was shiny like a pure copper bottom. It was applied in several layers so I guess that was for future sanding down.

Boat was kept in Lelystad so I guess she was mostly sailed on the IJsselmeer and sometimes on the North Sea.

Shortly after the works I saw the boat for sale so let's hope this guy will share his own experiences and knows how it's going on now or is willing to give the name of the new owner to get info about the sequel.

I like the idea posted by Mike about blowing the copper powder into/onto the wet epoxy/paint surface, but I'm worried about the losses. Anyhow, good to learn more about that system too.

Good Luck!
Angel

[Herman]

A few comments I can make already:

Although somehow it was recommended to add 80% by weight copper into the epoxy, I would recommend much more, at least 200%. That makes a difference.

I have already done some homework. Most copper powder is basicly the same grade, although what I got offered was roughly 96% pure. The rest is other metals and minerals. I do not feel this makes a lot of difference. I have also been offered more pure material, but the cost went up considerably.

I will only be able to contact the guy above on tuesday, but I will give him a call. The boat indeed was sailed on the IJsselmeer, which is fresh water. My plans are for testing on both fresh water and salt water.

[Chuck Losness]

Another thought on the blow on approach. If it is a new build and the boat is being built upside, before righting the boat maybe you could sprinkle the copper powder on the tacky epoxy just like you sprinkle sand on a deck for nonskid. Might be able to get a really thick coat of copper that way without a lot of mess or wasted copper. But would only work on a new build. Just a thought.
I read a little bit about powder coating. I wonder if you could somehow ground the hull and positive charge the copper like they do in powder coating. Have no real knowledge of how that process works. Just another thought.

[pauloman]

one has to sand the copper epoxy coating after application and every now and then to expose fresh copper to the environment.

[Angélique]

Found here a ‘‘Coppercoat antifouling long term review (http://www.ventspleen.com/?p=1476)’’ owner isn't happy about it.

He is a forum member (http://www.boatdesign.net/forums/profile/benjy1966.html) so I guess he could be invited to the discussion if there are questions...

I'll send a PM to inform him I posted the link here.

Good luck!
Angel

[benjy1966]

Ahoy All,

Yes, I am the forum member unhappy with the Coppercoat. I agree though that the reason it's not particularly efficient is because there is simply not enough copper being exposed. If this is due to the water based epoxy not eroding fast enough or there not being enough copper powder in the original mix I can't say.

What I can tell you is that for every kilo of epoxy (half litre of resin and half litre of hardener) 2 kilos of copper powder is supplied. It is supposed to be 99% pure and it is very fine indeed. This is the maximum allowed by law.

I'm sure that more copper powder in the mix would help this to be an effective antifouling paint BUT and it's a big BUT, the reason why copper is so popular as an antifouling is because it is toxic to aquatic life! So one must question the wisdom of adding a higher ratio of copper to the mix for fear of causing damage to it.

The way I have come to see it now is this: Coppercoat did not work for me on my boat. As an antifouling paint it is far from efficient but that said, no 'normal' paints I have used in the past were much better (except for stuff with TBT in it, that was excellent!). I still have the advantage that I do not have to paint my boat every year and this is better for the environment.

I cannot blame nature for doing what she does and I for one will happily put up with some fouling if it means aquatic life is unaffected by my presence. You must remember that there are now so many boats afloat that collectively we must be having an effect. No doubt people will argue until they are blue in the face about whether copper in their paint really does effect the aquatic environment but I'm not prepared to take that chance!

My real gripe with Coppercoat was the fact that I was lead to believe all I would have on my hull when I hauled in the spring was a light coating of slime. That has not been the case!

It's been on nearly 7 years and is just as good/bad as it always was so I suspect their claim of 10 plus years is right at least. Despite it's inefficiency I still think it's the best way forward for cost effectiveness and environmental protection. I just wished it worked better as an antifouling!

[Angélique]

Thanks Benjy for the quick and comprehensive response and for the info in the review article http://www.boatdesign.net/forums/images/icons/icon14.gif

Thanks again :cool:

Cheers,
Angel

[MikeJohns]

Unfortuantely I could not get the results of the trial conducted here a few years ago. The academic has gone and the results were for a shipping company that doesn't remember!

Good work Angel.

Benjy
It's odd that there is a legal limit as to the copper powder, full copper hulls or copper-Nickle hulls are legal too. I suspect someone is confusing copper oxide rates with copper.

I thought Copper doesn't leach much into the environment and has a surface contact toxicity rather than a leaching toxicity such as the 2CuO based toxins.

[benjy1966]

Ahoy all,

As far as I can work out Copper in its pure form does not leech into the environment but at high enough levels can cause trout to lose their smell and get lost so they cannot find their spawning grounds and it can cause gill defects and other maladies in fish. Are levels high enough just from boats? I can't answer that.

The problem (as far as I can understand) is that as the copper oxidizes and becomes cuprous oxide and this is highly toxic to aquatic life. If the copper can't oxidize it's probably not a problem but if it doesn't oxidize it's probably not going to work as an antifouling agent!

I found out about the legal limit from Coppercoat when we were discussing why it wasn't working. If there's a limit, there's probably a good reason.

I'm no scientist and I don't understand the finer points of the possible negative effects that copper (or its oxides) can have on the marine environment so until I do, I will live with what I have.

[MikeJohns]

The rate of pure copper dissolving is quite different to the pre-oxidised material.
I really think with your regulatory body there might be some confusion between the copper oxide and pure unoxidised copper.

Rates of loss into the environment from pure copper is extremely low. More copper would be present in a cities waste water from the wide use of copper pipes and particulalry slightly acidic stale water in pipes.

Rates of copper sheathing loss are well documented and as I said before a bare copper or copper nickle hull is not yet considered an environmental concern.

The copper oxide based antifouling is an entirely different case. But it will probably all get wrapped into one case.

Copper Nickle is used extensively in shipping and industrial plants to pipe water and reduce internal fouling, the rates of loss are so small as to be negligable.

I think if you made a case that copper pipes are common and a copper hull is no different then the coppercoat type application is just another type of copper plate.

[Angélique]

Coppercoat recently won this price... (http://coppercoat.com/antifoul-tests/coppercoat-wins-international-award)We are delighted to have won the prestigious ‘Eco Friendly Business’ category of the Asian Marine & Boating Awards 2011, .....

About the max amount of copper law :confused:

Coppercoat Info... (http://coppercoat.com/coppercoat-info)Coppercoat is the combination of a specially developed solvent-free epoxy resin and high purity (99%) copper. Each litre of resin is impregnated with 2 kilos of ultra fine spherical copper powder, the maximum allowed by law, making Coppercoat the strongest copper based anti-fouling available. Indeed no other anti-fouling exposes as much active copper to unwanted marine life.

Maybe someone can ask them what law that is . . ? ?

(If someone does, please tell here, one would be enough I guess, preferably one with better English and more knowledge about the topic than me ;))

And maybe they also have an explanation for this max amount requirement or maybe it can be found in the law itself . . ? ?

Didn't see any info regarding this in the many PDF's on the Technical Specs page (http://coppercoat.com/coppercoat-info/anti-foul-technical-specs), but I'd only time for a quick glance at them for now, also many links to more info on their site, but didn't find the 'max amount of copper law' yet...

Cheers,
Angel

[pauloman]

I send copper powder worldwide for marine applications and copper powder and special epoxies to users across the USA. Have for many years. PM me directly

[Angélique]

google copper powder epoxy

Hi Paul,

Do you know of a max amount of copper powder in the epoxy that is allowed by law..?

About your website, Epoxy Products (http://www.epoxyproducts.com/) ---> Copper Epoxy Filler (http://www.epoxyproducts.com/copper4u.html):How much to use? Epoxies weight about 9 or 10 pounds per gallon. A gallon of the copper powder is about 8 - 9 pounds. Add between 3 - 6 pounds of copper per gallon of our Low V epoxy. Three pounds will give you a nice, coppery colored finish without brush marks. At 4 to 6 pounds of copper you will certainly leave behind brush or roller marks, but you can sand these out. Five pounds of copper per 1.5 gal unit of Low Visc Epoxy is a common order - no feedback on there being too much or too little copper. This is enough for boats about 26 feet and smaller.

If using a medium, or standard thickness marine epoxy instead of our thin Low V epoxy, you can probably reduce the amount of copper by 20 or 30%.

What mixing ratios is that in 'kg copper powder per liter* epoxy (resin incl. hardener)' and what mixing ratio do you recomend for use as antifouling and what kind of epoxy do you recomend for this, please give a link to the epoxy..?

Thanks for the info !

Cheers,
Angel

P.S. - * answer in kg would be even better as it all can be weighted then.

[eyschulman]

Just think about the size of the paint industry associated with marine bottom paint and the access to research that industry has. Good luck if you think you can put some copper powder in epoxy and come up with the magic bullet. So far it has not worked not because of lack of effort.

[Angélique]

Regarding to post #31:

Paul answered by PM as he was afraid it was too commercial for him to post it on the forum, but he gave permission to quote if I wanted to share the information, so here it is...

Originally posted as PM by Pauloman:

a pound of copper powder will fill a quart can.

On our epoxy and copper kits - we often sell 1.5 gallons of a very low Visc epoxy with 5 pounds of copper. We don't make claims or give mix directions for legal reasons. Officially we sell copper powder and epoxies not any sort of copper/epoxy bottom coating. Some folks seem to like thin coats with less copper others thicker mixes. Our user feedback page does give comments from users and their mixtures. The comments are all over the place, hard to believe they all start with the same products. note we cannot sell the low v epoxy outside the usa. If you use a thicker epoxy you get a less color smooth surface as the copper flakes don't all line up flat (OK because you have to sand them to expose the copper anyway).

I like the copper added to varnish to make a copper decorative paint!

Note that the copper is very very fine (floats in the air - wear a mask!)

you can add so much copper that you make copper epoxy puttty. the copper is coated with something to keep it 'fresh' and is non conductive as sold. I understand a mild acid removes the 'coating' -

basically we try to stay out of the 'big issues' and just sell the copper powder for folks to use as they wish..

Keeps it simple and keeps expectations low. Some folks just seem to want the copper bottom look, others seem want anti fouling. some folks expect a copper and epoxy mix to be like enamel paint, others want a thick coating and then are unhappy with drips and sags.

so much nicer to just sell the copper powder and let folks use it as they see fit.Thanks for the answer Paul, hope you stay tuned for further questions, I don't think it's too commercial to answer questions here directly though, but I don't rule the roost here, so do it as you like . . . . :)

Cheers,
Angel

[masalai]

As some may be aware, I recently went on the hard for 2 weeks to attend to some minor maintenance and change propellers... I launched mid / late April 2011 so less than 6 months wet, had a good growth of slime and green stuff from the enriched (well fertilised with run-off from domestic gardens etc), water in the marina's... A quick wash with the high pressure gear and the bottom is good...

Whilst travelling very little fouling occurred, what started, was removed easily with a soft broom as the tide went out and the boat settled on the sand-bar... The main application was done in small batches that would cover less than a square metre... Observation and experience indicates thin rolled, (using short fibre rollers about 2" wide were best), on well worked layers of high copper content mix with normal "west" epoxy was best... The powdered pure copper I get in 10kg or whatever pails from ATL on the Gold Coast of SE Queensland... I have 10 to 12 kg of copper on the bottom of my hulls... and I am pleased with the result... http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-121.html#post498524 for a recent image... The effect of the copper may be seen on the mini-keel, (where a dog peed),... 50 or so years ago all wooden plank hulls, (local prawn trawlers etc.), were covered with sheets of copper as anti-foul paint was not readily known or available...

[Angélique]

Whatever you do, do not use it on aluminium..!!!

Don't know if it's correct but this I found in the Coppercoat FAQ (http://coppercoat.com/f-a-q) about the use on aluminium...Does Coppercoat cause any problems with regards to electrolytic/galvanic action?

No. With the resin carrier insulating each copper sphere, the final coating is inert and non-conductive. A current can not pass through Coppercoat and this coating does not cause or promote electrolysis or cathodic decay. Consequently Coppercoat can be safely applied to metal structures such as iron keels and steel or aluminium craft (after the application of an appropriate epoxy primer). The property of electrical non-conduction in metallic powders including copper was first discovered in 1890 by Eduard Branley and is known as the “Branley Effect”. Sacrificial anodes should be fitted in the usual manner.

Sorry a bit late response, just rereading the thread . . . . :o

Cheers,
Angel

[Angélique]

From the quote in post #33:

‘‘ the copper is coated with something to keep it 'fresh' and is non conductive as sold. I understand a mild acid removes the 'coating' ’’

This keeps me wondering . . . . .

- What acid to use ?
- How to apply the acid on a powder so fine it even floats in the air, and how to remove the acid without losing powder ?
- How to be sure that the coating is off ?
- Must one get rid of the acid residues ?
- If so, how to get rid of the residues without losing copper powder ?
- How to dry the copper powder properly before putting it in the mix ?

Does all available copper powder have this coating ?

How is that with the copper powder that comes with Coppercoat (http://coppercoat.com/) . . ? ?

http://coppercoat.com/wp/wp-content/uploads/2009/12/bottles1.jpg
Coppercoat as delivered (http://coppercoat.com/coppercoat-info): epoxy resin + hardener + copper powder.

As to post #32, sure a self-selected mixture has a higher risk of failure.

Rereading the thread, less than half of the responses so far are positive about the working as a good antifouling, Benjy gives good reasons to accept this. Durability, as reported here, is OK.

Cheers,
Angel

[Angélique]

Observation and experience indicates thin rolled, (using short fibre rollers about 2" wide were best), on well worked layers of high copper content mix with normal "west" epoxy was best...

http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-121.html#post498524 for a recent image... The effect of the copper may be seen on the mini-keel, (where a dog peed)

Thanks for the info Mas http://www.boatdesign.net/forums/images/icons/icon14.gif, bottom looks good . . . .

http://www.boatdesign.net/forums/attachments/boat-building/63200d1320191398t-my-little-piece-peace-dscn4568.jpg
click to enlarge (http://www.boatdesign.net/forums/attachments/boat-building/63200d1320191398-my-little-piece-peace-dscn4568.jpg)

But as much oxidation on the waterline as where the dog peed. Both, the oxidation on waterline and on the dog pee sure shows you have your copper exposed . . . .

Btw, must have been a big dog (http://youtu.be/YvzOoj8nGgQ?hd=1) . . . . or one that lifted his behind (http://youtu.be/j6pYgYldDLo) to reach the top of that LAR keel on blocks . . . . :o

Cheers,
Angel

P.S. - Mas, what mixing ratios copper powder vs. epoxy (resin incl. hardener) did you use ?

[Angélique]

General question, is the copper oxide formed on the exposed copper surface less leaching into the environment as the pre-oxidised copper in copper oxide based antifouling paints ?

Cheers,
Angel

[pauloman]

I've tried matching the copper claims of other vendors in their epoxy. They cheat and distort the facts. if you used as much as they claim, you get copper putty. The trick often used is that they don't consider the curing agent as part of the epoxy. Just the resin part A is the 'real epoxy' - so the numbers are before it is 'thinned down' with curing agent.

And of course anyone paying hundreds of dollars (US) per gallon for any sort of epoxy, copper epoxy mix, or LPU coating is a fool...... yet Those vendors are easily making 300-500% profits on each sale and laughing all the way to the bank.. I've been in the marine and industrial coatings business for over 20 years, I know......

[tazmann]

I did two boats in the late 90's a santana 20 and merit 23 with copperepoxy, works great for trailer boats, It will start growing slime in a week or two in the water. Cleans off easy. I still have the merit 23 and the copperpoxy is still in good shape. iT dicolors and turns greenish and with a light wet sand looks new again. I wouldn't use it as an antifouling you wont be happy with it but it does help some. As far as I know it has been outlawed here because of the copper which does not make sense to me it is not ablative and last 10 or more years
Tom