Coppercoat causing corrosion on through hull fittings

[MapisM]

Today I spoke with a guy who experienced problems as per thread title on his boat.
He's now going to strip CC after just one year from its application (which I guess must be a helluva job, btw) for that reason alone, and if it weren't for this side effect he would have been happy with the results.
I didn't see the boat, but I asked him if he couldn't think of other reasons behind the problem - the CC application possibly being just a coincidence.
According to him, there were no other changes vs. the previous years: no changes onboard (like bonding or whatever), anodes replaced as usually, same home berth, similar cruising grounds...
Did anyone ever experienced similar problems, or heard of them? Fiberglass hull, if that matters.

 

[vas]

hm,

so instead of doing the obvious and see it as an opportunity to rip off all the metal thru hulls and replace them with GRP ones (marelon/trudesign) he's ripping the coppercoat?

interesting!

V.

 

[Tranona]

Today I spoke with a guy who experienced problems as per thread title on his boat.
He's now going to strip CC after just one year from its application (which I guess must be a helluva job, btw) for that reason alone, and if it weren't for this side effect he would have been happy with the results.
I didn't see the boat, but I asked him if he couldn't think of other reasons behind the problem - the CC application possibly being just a coincidence.
According to him, there were no other changes vs. the previous years: no changes onboard (like bonding or whatever), anodes replaced as usually, same home berth, similar cruising grounds...
Did anyone ever experienced similar problems, or heard of them? Fiberglass hull, if that matters.

There is no way Coppercoat can cause any galvanic action with skin fittings. Firstly the fittings (if brass/bronze are mostly copper themselves - it is the zinc in them that erodes and secondly the copper is encapsulated in resin.

There is also no logical reason why the skin fittings need an anode, so if they are eroding I would be looking at the bonding system first.

However, if the owner is still convinced it is something to do with the Coppercoat, cheaper and better to follow Vas's advice and replace all the skin fittings and valves with Tru Design composites. that will eliminate all electrolysis problems and he can also then get rid of all the anodes connected to the fittings.

 

[MapisM]

Yup, synthetic fittings are indeed a good idea.
I must admit that even if I'm aware of their existence, I didn't think to suggest that alternative (will do).

That aside, the question still stands: is what I was told - assuming that it didn't happen for some other reason - the only case in the universe, or what?
I know that in theory this couldn't happen, but... hey-ho! :ambivalence:

 

[vas]

maybe the fittings weren't that good quality (DRZ or whatever you call that metal) and were at EOL so just happened...
how old were the fittings?

cheers

V.

 

[jimmy_the_builder]

maybe the fittings weren't that good quality (DRZ or whatever you call that metal) and were at EOL so just happened...
how old were the fittings?

cheers

V.

DZR. Your suggestion about replacing with plastic fittings makes complete sense and is what I would do in this situation.

 

[Elessar]

Today I spoke with a guy who experienced problems as per thread title on his boat.
He's now going to strip CC after just one year from its application (which I guess must be a helluva job, btw) for that reason alone, and if it weren't for this side effect he would have been happy with the results.
I didn't see the boat, but I asked him if he couldn't think of other reasons behind the problem - the CC application possibly being just a coincidence.
According to him, there were no other changes vs. the previous years: no changes onboard (like bonding or whatever), anodes replaced as usually, same home berth, similar cruising grounds...
Did anyone ever experienced similar problems, or heard of them? Fiberglass hull, if that matters.

he's daft if he's removing cc for that reason. Antifoul is porous so there is an electrical connection to the copper, coppercoat is not, put a meter across it and it reads infinity, the copper granules don't touch each other. Coppercoat is better not worse than antifoul (other that the likes of trilux) in this regard.
Get him to take advice from an expert - Vyv Cox would be a good example.

 

[Freeloader]

I have had a look at several Coppercoated boats sat on the hard in Poole and there doesn't seem to be any particular problem with the skin fittings. Interestingly, whilst everyone leaves a gap between the antifoul / Coppercoat and the edges of stern drives, trim tabs etc, we have all been painting right up to and over skin fittings for ever. Perhaps, as mentioned above, the fact that the fittings are largely copper themselves means that the proximity of copper hull coatings does not usually cause a problem.

Maybe, in the case in question, it is not so much the skin fittings themselves that are reacting with the copper but the other metallic items that the skin fittings may also be bonded to (engines, electrical system etc)?

 

[MapisM]

Thanks everybody, in the meantime I already suggested that chap - regardless of whether his problem was driven by CC or not - to replace the corroded fittings with some plastic stuff.
He wasn't even aware of that possibility, and he thought I was joking at first, but he will now investigate the option in more detail.
Also because he has nothing to lose: if he must replace some fittings anyway, he can avoid removing the CC for the time being (which btw I suppose must be quite a job) and see what happens next season...

But actually, my main reason for asking is that I'm oriented to apply CC on my boat, and I wanted to check if this problem can indeed have something to see with CC, and how widespread it can be.
It's nice to have a confirmation that CC can hardly have anything at all to see with that! :encouragement:

 

[petem]

can indeed have something to see with CC

P, not very often that we (I in particular) have to correct your EN but you quite often say "something to see with". Correct English would be "something to do with".

And you're probably more "inclined" than "orientated" to apply CC .

More importantly, will you go for plastic fittings?

 

[Hurricane]

Can someone post a link to the plastic fittings that you are suggesting.
Just interested.

 

[ICTM]

Where I bought mine from. No connection etc........

https://www.leesan.com/shop/seacock-kits

 

[petem]

Further discussion and link here Mike: http://www.ybw.com/forums/showthread.php?491452-Seacock-Replacement/page2.

 

[MapisM]

More importantly, will you go for plastic fittings?

Thanks for the language tuning P, free EN lessons are one of the reasons why I like the asylum! :encouragement:
Ref your question above, nope, but not because I've anything against them.
It's just that the bronze stuff I've got is still fine - all from 2004 original construction, fwiw.

 

[Bandit]

Ref skin fittings and valves

Do you know for certain whether the fittings are Bronze, DZR or brass?

A lot of fittings used in that era by otherwise good boat builders were brass with nickle coated brass used on occasions especially for the balls of ball valves.
Should you have an incident with a failed skin fitting or valve (fittings) your insurance would inspect all fittings and if your fittings were found to be corroded and this lead to the incident your claim would probably fail unless you could demonstrate a regular and reasonable inspection and replacement programme.

A good rule of thumb is to inspect visually each year for corrosion and leaks and to operate all valves as well as a continuity test for all underwater fittings as well as stern gear to anode system. Then every seven years to remove all skin fittings and valves and to inspect internally and externally, if fully satisfied with condition re fit. To be honest if you are having it done commercialy the cost is in the labour so you may as well fit new DZR fittings from a reputable supplier who can demonstrate they are DZR not that they are a yellow metal and probably bronze or DZR as often they are brass.

If you can demonstrate 7 years all re fitted with DZR and annual inspection you are home and dry ( please excuse the pun).

The RCD calls for fittings to be good for at least 5 years, brass being much cheaper, but lasts for at least 5 years unless there are other factors involved sometimes a bit longer.

If they are original replace all fittings with new DZR.

 

[MapisM]

Do you know for certain whether the fittings are Bronze, DZR or brass?
...
If they are original replace all fittings with new DZR.

Yep, it's all bronze stuff, completely bonded, and in perfect condition upon visual inspection and operation.
I'm not sure to be willing to remove them all for further check, are you saying that some insurances specifically require that?

Besides, why do you suggest DZR for replacement?
My understanding is that bronze is more longlasting, and whenever I should replace something, in principle I'd rather stick to that (or possibly go for plastic instead).
Fwiw, my previous boat also had bronze everywhere, she's by now 21 years old, and still with original fittings.
Btw, they were NOT bonded. I understand that also with regard to bonding there are different schools of thought...

 

[Tranona]

Yep, it's all bronze stuff, completely bonded, and in perfect condition upon visual inspection and operation.
I'm not sure to be willing to remove them all for further check, are you saying that some insurances specifically require that?

Besides, why do you suggest DZR for replacement?
My understanding is that bronze is more longlasting, and whenever I should replace something, in principle I'd rather stick to that (or possibly go for plastic instead).
Fwiw, my previous boat also had bronze everywhere, she's by now 21 years old, and still with original fittings.
Btw, they were NOT bonded. I understand that also with regard to bonding there are different schools of thought...

The life of DZR - at least the bodies and fittings - of DZR and bronze are essentially the same. The weak point is the ball valve itself which are often nickel plated brass and the cheap steel handles on both types (although some bronze have bronze handles. Bronze is generally 25%+ more expensive.

Yes there are different schools of thought on bonding, but the current thoughts from the "experts" such as the specialist manufacturers is that they do not need bonding in GRP or wooden boats. The science and logic of galvanic corrosion supports this view.

 

[jfm]

... the current thoughts from the "experts" such as the specialist manufacturers is that they do not need bonding in GRP or wooden boats. The science and logic of galvanic corrosion supports this view.

I don't want to drift the thread so won't make a technical debate here but, just for anyone stumbling across this, many folk hold the opposite view to the above 2 sentences.

 

[Bandit]

Yep, it's all bronze stuff, completely bonded, and in perfect condition upon visual inspection and operation.
I'm not sure to be willing to remove them all for further check, are you saying that some insurances specifically require that?

Besides, why do you suggest DZR for replacement?
My understanding is that bronze is more longlasting, and whenever I should replace something, in principle I'd rather stick to that (or possibly go for plastic instead).
Fwiw, my previous boat also had bronze everywhere, she's by now 21 years old, and still with original fittings.
Btw, they were NOT bonded. I understand that also with regard to bonding there are different schools of thought...

How do you know its bronze?

Have you undertaken a continuity test to ensure it is all bonded, otherwise you don't know.

I saw a boat this summer with a good condition anode and very heavily corroded props and scabby rudders, the props are being replaced now with new, 12 months ago they were fine. When the anodes were fitted serrated washers were not fitted giving a poor connection. It only takes a poor connection or a corroded wire to cause system failure.

Its difficult to get a good selection of bronze fittings and valves these days where as DZR is is available, don't mix.

Composite fittings such as Trudesign and Marelon are one thing but never fit plastic fittings ( nylon etc) under the waterline.

I fall into the "bond it" school of thought.

 

[MapisM]

How do you know its bronze?
Have you undertaken a continuity test to ensure it is all bonded, otherwise you don't know.

All fittings are Guidi, which don't even make DZR stuff, afaik.
Ref. continuity, I admit that I just trusted the pretty thick cables strongly connected everywhere, which I found upon visual inspection.
I guess it wouldn't hurt making a continuity test as well, though.
Is it sufficient to cross-check different components with an ohmmeter, or what?

PS: yup, I did actually mean composite, by "plastic".