This must be a cooper’s (tonnelier’s) plane. It’s huge. That iron is at least 10cm wide. If so, we would be looking at the bottom of the plane beam (edge side faces up). But I don’t see any place for mounting the spindle legs. Granted the length is cut off in this photo. Speaking of which, it seems rather long, even for a cooper’s plane. I’m not totally convinced. Paul Bunyans’s plane, maybe.