Coppercoat problem?

[gsturgeon]

I had my Bayliner Coppercoated some years ago. Very good it is too and has paid for itself in lift out fees and antifouling long ago.

However...

Something odd is happening around the skin fittings / trim tabs. The Coppercoat has changed colour and doesn't seem so effective for about an inch or two where they meet. The picture of the transom drain plug was taken two years ago and this time it is a bit worse.

Any ideas please as to what is happening? I am worried that the skin fittings might degrade.

The anodes are zinc on the hull and tabs and ally on the drives

 

[rib]

a well known boat manufacture used to leave about a inch gap around fittings !

 

[30boat]

What are the skin fittings made of? Marelon fittings are inert and would solve the problem whatever it is.http://www.forespar.com/what-is-marelon.shtml

 

[Elessar]

I had my Bayliner Coppercoated some years ago. Very good it is too and has paid for itself in lift out fees and antifouling long ago.

However...

Something odd is happening around the skin fittings / trim tabs. The Coppercoat has changed colour and doesn't seem so effective for about an inch or two where they meet. The picture of the transom drain plug was taken two years ago and this time it is a bit worse.

Any ideas please as to what is happening? I am worried that the skin fittings might degrade.

The anodes are zinc on the hull and tabs and ally on the drives

i've not seen this and I've seens lots of coppercoat.

can you sand the furry bit off - is the coppercoat normal and in tact underneath?

you don't have to leave a gap with coppercoat it isn't porous and electically conductive like conventional antifoul.

 

[Sans Bateau]

I had a patch like this appear on the bottom of my keel, no obvious reason at all. Elessar is right, the skin fitting can be covered. Ours have been for 8 years without problems. (he say fingers crossed as the boat has not been lifted since the new skin fittings were fitted last year and re-coated)

 

[Pasarell]

It looks like cathodic chalking to me. Particularly likely to occur if your skin fittings are bonded to an anode and if the boat is left static for some time. The skin fitting will be a cathode in the circuit that is set up and the end result is deposition of calcium from the water around the fitting. The affected area will gradually grow with time.
It happens on any antifouling but is usually only visible on a hard surface as conventional eroding antifoulings will break away.
You need to remove the calcium deposit otherwise your antifouling will not be able to work next season. Remove it with a dilute solution of acid such as 10% hydrochloric. Paint it on or spray with a hand pumped spray and it will fizz as the calcium dissolves. Rinse off with fresh water and the job is done although it may need several goes with the acid.
Acid at this concentration won't harm the boat or skin fittings in the short time it is there but make sure you wear goggles and any exposed skin is covered.

 

[gsturgeon]

Thanks

It seems that it might not be the problem that I thought. Certainly the boat has been little used recently due to the weather (rather than the fuel cost).

I will have a go when I get to the boat at removing it and will report back.

Thank you for the help.