Original post follow-up
Given the comments on stray current, zincs, and galvanic isolators, I might also add this "investigation" started when I noticed what appeared to be some detioration on my standing rigging (turnbuckles) which was new last fall. I sent a photo to the rigging company and they forwarded to the vendor. Here is their response:
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[FONT="]"The rust patches are on our body and the swage stud (which is not ours by the numbers etched on the side.) This suggests a serious electrical leakage on the mast which is acting like a mini electroplating plant."
[/FONT][FONT="]The boat does have an isolator, and zincs were replaced last spring. There are three - two on the shaft and one on the MaxProp. Mast has an anchor light, foredeck light, steaming light, and VHF antenna. When boat is not in use, DC power is off.
Thanks for the comments so far!
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