Put a ship on a scale on dry land and it registers 10 tons. Ok.
Put the scale under the ship while it floats on water and the scale reads zero. Of course, it's floating because the weight of the water displaced by the portion of the ship below the water line is 10 tons.
Now put the ship's anchor on the scale. 500 pounds. Now throw the anchor overboard and go weigh it at the bottom of the ocean. Does the scale say it weighs 500 pounds minus the weight of the water it displaced? So if you could DL 450 pounds you could pull the anchor to the surface, but if you couldn't DL 500 pounds then you couldn't lift the anchor out of the water?
The Falcon just blew my mind.