I'm afraid Callmecrazy is just wrong to assert that iron "only works in encapsulated keels". (Paint and epoxy
don't count as "ecapsulation").
In fact, iron is better if left unencapsulated and simply bolted to the centerline structures of the boat. It rusts less than steel
in a hostile environment
if unpainted, and makes a terrific grounding plate - in both senses of the word. It is the next-to-last thing I would put into an encapsulated keel
because when it does rust, the expansion properties are within the range of cracking the encapsulating material - especially fiberglass
is the worst thing for encapsulation because its expansive properties when rusting are even more severe.
"Margaretha Tripp" was sailed 30,000 n. mi. in the 1970's with an external iron ballast keel
bolted to the iroko keel and floors, and we never worried about little bumps and groundings, especially in coral
, and after 3 years it sure as hell was not rusting away - it was in very good shape.
Most commentators have it right - lead is the better material because of its density and its inert encapsulation values, but for a cruising boat there's not too much in it; however, race
boats simply must have a lead as their ballast keel.