Blank, is it?
On my own propshaft, a little trace of corrosion dripped from the stuffing box on to the shaft. I ignored it, for like, two weeks. Man, it's got a hole in it now.
Yes, it's called stainless, and yes it's sold for propshafts, and yes it corrodes like crazy if you starve it of oxygen.
What is the correct grade for keel bolt?
I hope for his sake it's not the same stuff used for my shiny propshaft, a material provided by a big machine shop in a big fishing port.... I mean, they ought to know, shouldn't they?
Just about anything above 12% chrome is sold as stainless, including dinnerware. I look forward to you recommending a stainless grade for keel bolts, in chloride rich, oxygen-depleted environment.
I am all ears.
He could learn it the way I did, all over again, but it is a keel, after all, and not a propshaft.