Trim tab zincs

[knotflying]

I keep my 25 Parker on a mooring ball, hence no shore power. I find it unusual that at the end of every season that my zincs are pretty well depleted and gone at times. Anyone else have the same issue? Not sure why that happens. I never had an issue on other boats.

 

[Mpellet]

I keep my 25 Parker on a mooring ball, hence no shore power. I find it unusual that at the end of every season that my zincs are pretty well depleted and gone at times. Anyone else have the same issue? Not sure why that happens. I never had an issue on other boats.

I make it through the season with the trim tab zincs on my Parker 2520SL but they do quite a bit of disintegrating April-November and always need replacing in the Spring.

 

[Lucky John]

By the time I haul out in Dec they are usually the size of a nickel if they are there at all

 

[baker]

You don’t need shore power to create galvanic corrosion. If your zincs are not lasting a full season, then probably need bigger ones

 

[Dleopoldi914]

For some reason the zincs on my trim tabs never make it lol

 

[pelagic2530]

They’re protecting a relatively substantial volume of underwater metal. There’s not that many other underwater metal objects on your boat that have anywhere close to the amount of metal surface area of even a small tab. Think of the shafts and rudders on bigger inboard boats, they usually have pretty beefy anodes. Makes sense that the small ones that you frequently see on trim tabs would corrode away fairly quickly.

 

[gman1001]

Same with me. 2300DV on a mooring. I drilled holes and put 2" under/over annodes that last 1/2 the summer. I was really surprised. Next summer I'll put 4" annodes and see what happens.

 

[knotflying]

I'm circling back on this. Here are my thoughts. For electrolysis type of corrosion to happen, stray current has to be present and this usually happens when plugged into ac at a dock. Hence, bonding of metal components and the use of sacrificial metals is imperative. Now if two dissimilar metals are connected, regardless of stray current, corrosion can still occur. So in thinking this out, isn't the placement of a zinc on a stainless steel trim tab going to cause corrosion on the less noble (zinc) metal? On a similar note, I have a friend who never put zincs on his trim tabs. Same boat for 11 years and no issues. He never even coated them with bottom paint.