Trim Tab Zincs. Does size matter? ;)

[danmili]

Hi all- just curious what everyone's thoughts are. I can't remember off hand but I believe I have 3/34" zincs on my trim tabs (salt water boat).

Boatzincs has several different sizes. Does it matter if they are slightly larger (4 inch) or smaller (2 13/16 inch)?

boatzincs.com/rudder

EDIT- I did get off the phone with them just now. The biggest difference is the size of the bolt. R-2's are a 1/4 bolt, R-3's are 5/16th. The question remains-use a different size and modify the bolt hole?

I've also noticed several posts where members either use BOTH halves on top and bottom of their tabs or just a top half. Does that matter?

Finally, they recommended (for a Bravo III 2004) the aluminum zincs. That a problem for gulf coast/ocean boating?

Thoughts? :huh:

Cheers,
Dan

 

[gregkjones]

As usual, size does matter despite what they say for folks with small zincs. Now, in this case small zincs will erode faster but will work just as good while they last. The bigger zinc will give you more time between changes. On the tabs, mine are top and bottom. I dont think it makes any difference how they are mounted as long as the zinc is in direct contact with the metal of the tab (someone correct me if Im wrong); once it is bolted on, the whole tab is protected BUT I have wondered if having that zinc on the bottom of my tab may be disturbing the water flow and hurting tab performance. If it is interfering then a bigger zinc would be even worse. I am having bigger trim tabs made for my boat now and will mount a zinc bar on the top of the new tabs instead of the clamshell type zincs i have now unless I hear its a no no. I know one thing, the bar would last longer. My boat eats up these small tab zincs pretty quick.

 

[danmili]

As usual, size does matter despite what they say for folks with small zincs. Now, in this case small zincs will erode faster but will work just as good while they last. The bigger zinc will give you more time between changes. On the tabs, mine are top and bottom. I dont think it makes any difference how they are mounted as long as the zinc is in direct contact with the metal of the tab (someone correct me if Im wrong); once it is bolted on, the whole tab is protected BUT I have wondered if having that zinc on the bottom of my tab may be disturbing the water flow and hurting tab performance. If it is interfering then a bigger zinc would be even worse. I am having bigger trim tabs made for my boat now and will mount a zinc bar on the top of the new tabs instead of the clamshell type zincs i have now unless I hear its a no no. I know one thing, the bar would last longer. My boat eats up these small tab zincs pretty quick.

Thanks! I was wondering the same thing about hydrodynamics being affected with an anode on the underside.