Antifouling discolours

[SailingDoc]

Each year I apply a boot-topping, using white (the bottom is red); have used MPX in the past, also MicronCSC - they keep changing the names of these products, very confusing. This year it's called something else....Anyway, as the season progresses the white becomes a moderately pale green, except that part of the boot-topping which is under water (when the boat is still), and that remains white.

Why should this happen? And what can be done about it, other than endlessly tipping the boat in order to wet the entire boot-topping constantly. One boat-yard suggested it's due to the copper salts in the antifouling - yes, copper oxide is green; but I'm sure the manufactureres didn't intend this to happen.

Any ideas?

Brian

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[Robin]

That's exactly what it is. We use black (Optima from International) antifoul, even this shows greenish above the waterline. The proper boot top finishes like MPX should not do that, but are not as strong.

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[TargaLout]

Hi,
I have tried different white antifouls over the years and can say that International's Trilux (white) is the only one that does not change colour and is very tough. It is a bit expensive but worth it. Their other products do discolour. (Salt Water use) I have no affiliation to International paints whatsoever.

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[SailingDoc]

Many thanks for replies. Yes, I'd noticed that Trilux contains copper thiocyanate instead of the oxide, so maybe it'll be better. I'll give it a try this year. Or change to a different boot-top colour, though with dark-green topsides and red hull, it needs a bright boot-top.

Brian

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[DMGibson]

The white boot-topping on my boat goes green as well, especially at this time of year.

However, in my case it is the bit under water which discolours, mainly 'cos of the weed which grows on it.

That is with the Blake's tiger boot-top stuff as well - I'm not sure it is any better than undercoat at keeping the weed at bay, but I still plonk it on every year regardless. At least it looks noce at launch time.

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[andy_wilson]

All manufacturers advise that light colours will discolour.

It's in the literature.

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