Whither my cathode?

[Greenwichman]

The cathode on the shaft of my Beneteau was replaced in August after the last one fell off. The new one is already in poor shape. Does anyone have experience like this - is this rate of decay normal, or are there snags with the electrics?


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Just one more month and then the days will start to lengthen again .......

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[Shakey]

It doesn't sound normal to me.

Are they the right size anodes? Are they salt water anodes?

Have you posted this on the PBO reader to reader board, 'cos all anyone ever talks about here is hunting, gypsies, the cost of diesel and all sorts of general nonsense.

<hr width=100% size=1>It could have been worse - it could have been me.

 

[Becky]

Most of us use anodes. But nevertheless, what ever it is it isn't right. You could be the anode for all the adjacent boats. Are you on shore power? Or are all the metal bits earthed together properly?
Keep changing the anodes until you find the source, otherwise it is your boat's metal bits that will be vanishing. Or so says HWMBO. So it must be true.

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[Greenwichman]

Re: Whither my Anode?

Thanks for the advice - not on shore power very often, but looks as though I should examine the earthing arrangements.

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[Oldhand]

Put 2 anodes on.

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[boatone]

They're anodes, not cathodes, and theres obviously something a bit odd. Are you sure you have the right type ( zinc/aluminium/magnesium) depending on how salt/fresh the water is ?

Rather than cast around for ideas here I think you need to have a chat with the experts.........

<A target="_blank" HREF=http://www.boatsontheweb.com/> Website, Photo Gallery, Chat Room, Burgees

 

[charles_reed]

I think you mean anode

tho' if your shaft anode is disappearing within a season it isprobably a case of cherché l'anode.

Most shaft anodes are sized to last about 5-8 months in the water - when mine started to disappear more quickly, as well as below-water bits of 316 stainless I traced the problem to the rf earthing plate for the ssb.

You might have one of these fitted for a dgps receiver, being made of gold-plated sintered bronze shot there are few more active kathodes to be found.

The alternative could be heavy metal contamination of the water round your berth or (most likely) stray currents from boats attached to shore-power.

Just thank your lucky stars yours isn't an aluminium boat. Galvanic electrolysis is the greatest weakness of the hull material.

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