Some friends of ours recently returned from an extended trip to the Bahamas. Part of their post-cruise maintenance involved (they thought) replacing several heavily rusted nuts and washers on the studs from their lead keel. After soaking the nuts in a bath of penetrating oil for several days, upon placing a box wrench on the first or the damaged nuts and giving it a twist, the stud broke off below the keel stub to which the ballast keel was attached. Upon extracting the broken stud, with nut and washer still attached, they discovered that the stud was severely wasted. Further, no water flooded into the boat through the hole formerly occupied by the stud so the keel bedding was not compromised. Before proceeding any further, they had the boat hauled out at a local yard after which they discovered that 5 more studs or roughly 30% of the number of studs holding the ballast keel to the boat broke off in a similar fashion.
With this, the boat was lifted off the ballast keel--that was well braced and supported--and set on blocks near by. The condition of all of the studs was poor, even though there was no evidence of water penetration through the bedding compound. In summary, the cost of repairing the keel, considering the difficulties, would have far exceeded the cost of purchasing a replacement keel and selling the old keel to a scrap dealer (paying $0.25/lb for 6,000 lbs of clean lead).
Had that keel been made of cast iron, it could have easily been repaired at roughly 1/3rd the cost the owners are having to endure. They are, accordingly, no longer extolling the superiority of lead to iron keels.
The next time you see a boat with a lead keel, and stainless steel studs (or J-bolts as some refer to them) holding it on, ask yourself whether the keel stub/bilge is, might ever, be wet and if so, what might be the consequences for the studs.
For my part, I'll stick with Iron--perhaps with an easily replaced lead shoe if additional ballast is needed down low.
FWIW...