I been bit by the Roamer bug and am looking to buy an old beauty as a restoration project. Of course, no use restoring something that doesn't have a sound hull. Problem I'm finding is that the reputable surveyors in my area admit they don't have the expertise to give a proper assessment of the hull. I've found a company that will ultrasound the hull to measure the thickness of the steel. I've heard audio gauge is the way to asses hulls, is ultrasound an acceptable method as well? Question is... what is the original thickness and what would an acceptable thickness be. The boats I am considering are a 1964 - 38' offshore (which I love the looks of) and a 1961 - 31' riviera. Any tips or suggestions on how to identify potential rust spots other than just looking for rust?