I had to replace both of mine. A sister boat lost its mast because of a chainplate that failed due to crevice corrosion...
Here is the link to the Ugliness...
Note that it did not fail at the actual weld, but where the metal was continuously encased by the deck ...And like mine leaking under the deck base plate. Mine also showed the same kind of crevicing, so they had to go ASAP.
cira 1980's cheap Taiwanese steel.