Many articles on steel hulls here:
http://www.geocities.com/alloyed2sea...icalForum.html
Experts located here:
http://www.metalboatsociety.com/
I tell everyone, no matter what kind of boat they are considering buying - get a survey, and go with the surveyor over the boat. They love to show you how much they know and what you are getting into. Make sure yours can and does perform audio-gauging the hull to determine steel plate thickness in those "tender" areas (where water collects inside the hull).
Cheers!
Eric