The method I was given to detremine if a slug of lead casting is inside the encapsulated keel shell, or a dump of concrete & scrap metal had been poured instead 2 different guys told me ,; look how deep is the bilge under the cabin floor, if it is at least 6' the lead slug is below, if it is more like 3"<4" the boat has concrete below. Both are sealed by "a glop of resin" , so with care & luck water could be kept out for a long time, but anyway this story was supplied by a Mr.Manny & another guy named Carl who both worked there in the late 60' early 70's, when I met them while selling machinery, & tooling in the area. I had a love of sailing & buddied up with these 2 naturally , being "on the road" & having mutual interests, I've since failed to keep track of them. I now own a nice old (1960s) Bristol yacht whose bilge cavity is comfortably 6+" below cabin sole and apparently sealed above with "a glop of resin", so perhaps these stories have some merit. I can say the boat is excellent qquality , hull is quite thick, decks strong , no flexing, cabin still watertight,except front o/h hatch , replaced in 2008. She is well designed as she sails to w/in 40 deg. of weather consistantly & can on a reach show 6= kts quite nice ly for her LWL. So I do not say or repaet any of this to defame or disparage , jus that I have know 2 different owners,people, a man & a woman who told me their boat , the same brand as mine, split apart in our deep cold northern winters, this was sad to hear, but I have mine hauled in Nov. each year, she drys in the crib until April or May, gets her bottom coat & back in she goes.