I read an article about electrolysis and decided it was time to replace my 10-year-old thru-hulls, as PM. I started with the one that had the most ambergris and looked worst, and when I cut it out the cross-section of the metal showed it was 100% fine and would have lasted at least another 10 years.

So Max, how long has it worked like that? Has it caused a problem yet? If I were you I'd focus on the O-ring or rubber seal, and look for another project. JMHO