Trim tab anodes

gyislander

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Can anyone advise me on the best type of anodes for my trim tabs. The originals disappeared in 6 months !
 

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Your tabs and mechanism look like mine. The boat came from the builder with Technoseal R3. I have to say while I replace them annually they still have a good amount of 'beef' on them.

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If they disappeared in six months, I wonder if you're in brackish water. Zinc doesn't seem to do well in these conditions. Fit aluminium instead and see how they last - the bigger the better.
 
There’s something deeper going on here warranting further investigation as to why they disappeared so quickly.


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Theres one underneath as well .They both easily last 12/12 .
 
If they disappeared in six months, I wonder if you're in brackish water. Zinc doesn't seem to do well in these conditions. Fit aluminium instead and see how they last - the bigger the better.
I'm in seawater. The big anodes on the stern are zinc and have hardly eroded in the same period.
 
Any ideas ? The tabs came from Fairline as old stock, I wondered if sitting in a box for years has a bearing on the wear.
Sorry I missed the big anodes on your initial pic with unremarkable wear on the transom .

So its just the tabs ?

Well try bigger and fit two .One each side .Maybe cover the plane AL with layers of AF .
As the yrs build up the layers get thicker an imho some time down the line the working area of metal to dissolve away without anodes decreases .So in a inverse way the sea and chemistry can’t see the acre age of AL .

If you look at the guys ^ who have posted pics in a helpful way the common denominator seems to be ( ok not scientific before a chump on here bites my head off …holster your side arms guys you know who you are ! ) the tabs are caked in anti foul .

If it was shore power leakage or one of your own bilge pump 12 v leakage from a sender or something or a neighbour’s boat with dodgy electrotwackery then all your anodes would degrade together .But you say it’s just the tabs .

So we are reduced to a mass of zinc ratio to the mass of metal it’s supposed to protect .
Correct the balance / ratio to go 12/12 by either , or increasing the mass of zinc or decreasing the area of Al flap = cover it with AF .

My 0.2 cents worth .
 
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