I grabbed three smaller ones years ago. I wanna say they were like 200 to 400 pounds. They came from small sailboats but they had like an epoxy coating on that really sucked. I used a larger portable bandsaw to cut them. When I was melting them down I got a lot of garbage out of them lots of junk, almost like sand Lots of dross. If they were as heavy as they say they were, I yielded probably 65% when I was done.
The large one I helped a friend of mine do where someway between 1000 and 1400 pounds. We used a flatbed to move it and it wasn’t all that heavy just awkward. Didn’t feel like 1000 pounds to me. He used a carbide tipped circular, saw to hacking into pieces and that’s when we started finding the chunks of iron inside. It’s as if they stacked iron blocks in the middle. Same thing with him the fiberglass was a real pain in the ass and all said and done. I think he gave up and only pulled about 600 pounds out of it before he gave up.
Since then I hear they are filled with low grade lead and scrap . Theres often signs up at the scrap yards no boats/keels