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The wing keel on my f-38 has developed what appears to be an electrolosis issue on the aft side of the lower portside wing. It started with a small area (3/4 inch) that i stripped, epoxied and painted using a Pettit Paints recommended 3-part process. Each year (last 4 years) I have to repair again prior to spring launch as the area has become larger 2 inches). The only electrical items i have added include a new auto bilge, and smart regular. All ground wires appear to be intact. Other boats within my area of the marina have not experienced any electrolosis issues. However, my anchor and deck lights both died at the same although there is current fed through the wires to the control panel. Any suggestions on what I could be looking for.

1) How are your zincs holding up? They should be the 1st thing that goes instead of your keel.
2) Do you leave the boat plugged in to shore power?
3) Do you have a galvanic isolator?

-- Geoff

Thanks for the input. Actually, the two zincs on my shaft and an additonal one on my prop have held up well. I do change annually. I also leave my shore power plugged in since I keep my refrigeration running. My slip neighbors also keep theirs plugged in for the same reason. I do not have a Galvanic Isolator installed on the boat. Would that resolve the problem? I'm concerned if I install one and the keel electrolosis problem continues, the aft section of the wing (the thinnest part of the keel) will wear through in another year. Would a zinc hung overboard at the slip help?

You actually have to be careful about over-zincing as that can be as bad a under-zincing. What you really need is to use is a corrosion test meter which tells you if you're under/over/properly zinced. Hopefully you're friends with a boat yard that would let you use one.

I always recommend galvanic isolators as they certainly help resolve the issue if it's shore power related.

-- Geoff