VC 17 Bottom Paint electrolysis

[Brickbat]

Put VC17 over primer on a new hull. After first year of use, the VC 17 wore very well except around the two zinc anodes. I need to replace these with magnesium, but have not gotten that accomplished as yet. Any thoughts on the finish to use around these anodes? Thanks in advance.

[senormechanico]

That's pretty severe ! Are you sure you don't have positive voltage leakage to the zinc from the boat's wiring? Possibly a bilge pump wiring broken?

Are all your thruhulls bonded and if so, are they showing similar symptoms?


I installed a sheet of vinyl between zinc and hull on my boat.

The vinyl doesn't need to extend past the zinc, just prevent the zinc from contacting the paint.

[Tetepare]

Wow. I have never seen that. A zinc should erode, not expand through paint. I too would guess electrical stimulation, be it AC or DC.