He's not a woodworker, he just sees a barnacle encrusted hulk, covered in slime and the beginnings of moss. It's a wreck, it's junk. But at the identical time, a woodworker spots the object down there and comes to investigate. He not only sees a boat, but he sees a yacht, and not only does he see a yacht, but he sees a better yacht than the yacht that's out there on the water, cruising past. This example is slightly different than the example of 'mountain', but the notion of 'vagueness' analyzes out as being of the same kind.
Bronze is another matter.
Still, I think you are on the right track. I know little of it either. Bronze was decisive in history, as to who won or lost wars, etc. Unlike iron, it doesn't rust. The problem was that you needed an extensive civilization to support bronze, since it required e.g. tin from England to mix with e.g. copper from Thailand, to produce the stuff.