Marlin trim tabs and zinc
- Thread starter Hookster57
- Start date
Hookster57 said:
Zincs are needed if the boat is kept in saltwater to protect the Trim Tabs from galvanic corrosion . If trailered or on a lift they are not necessary, but a good idea if the boat spends an extended time at a dock. My basic rule of thumb is if you need anti-fouling paint on your hull you need zincs on your Trim Tabs.
It is important to note that if your Grady came with the Trim Tabs installed at the factory they will be powder coated. The powder coating must be ground off where the zinc mounts to insure electrical contact between it and the Trim Tab.
The powder coat makes an excellent primer for bottom paint if you choose to paint the Trim Tabs. Scuff it lightly before applying anti-fouling.
Aftermarket Trim Tabs will not have the powder coating.
Tom McGow
Bennett Marine
Thanks for the replies. Yes my boats sits in saltwater so I had them put on the zincs even though they looked pretty clean. By " anti fouling paint " what exactly do you mean?
You are confusing marine growth with galvanic corrosion. Separate animals.
For marine growth the tabs, and other metal parts permanently in saltwater, need to be primed properly and painted with appropriate antifouling paint.
The zincs are sacrificial anodes that capture stray electrical current and erode over time rather than having your expensive metal parts erode. Freshwater zincs are also needed if you berth in freshwater. Different metallurgy than SW zincs.
Your engines also have zincs and should be checked periodically and replaced when they have eroded significantly. Otherwise your lower unit will erode.
Never paint a zinc and always have paint or coatings removed in the area of the zinc to promote proper bonding to the base metal.
For marine growth the tabs, and other metal parts permanently in saltwater, need to be primed properly and painted with appropriate antifouling paint.
The zincs are sacrificial anodes that capture stray electrical current and erode over time rather than having your expensive metal parts erode. Freshwater zincs are also needed if you berth in freshwater. Different metallurgy than SW zincs.
Your engines also have zincs and should be checked periodically and replaced when they have eroded significantly. Otherwise your lower unit will erode.
Never paint a zinc and always have paint or coatings removed in the area of the zinc to promote proper bonding to the base metal.
Ahill is right on target.Hookster57 said:
By anti-fouling paint I mean the stuff you paint on the bottom of your boat to keep barnacles and other marine life forms from growing on it.
Tom
Bennett Marine
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Hi,
Yes, my bad... Not sure what I was thinking confusing the two.
I don't have the zincs on the tabs that I can see, just bottom paint. I've never had any on the last two GW boats either (one new and one used). I checked other larger boats that sit on moorings at the marina (that have not gone in yet) and none have zincs on them either. I'm going to check with the dealer.
Yes, my bad... Not sure what I was thinking confusing the two.
I don't have the zincs on the tabs that I can see, just bottom paint. I've never had any on the last two GW boats either (one new and one used). I checked other larger boats that sit on moorings at the marina (that have not gone in yet) and none have zincs on them either. I'm going to check with the dealer.
