To paraphrase, when the anchor is in the boat it's pushing the whole boat down, displacing exactly the volume of water that weights the same as the anchor.
When the anchor is on the floor of the lake it's only displacing the exact volume of the actual anchor. Since the anchor is more dense than water, it's less volume.
To paraphrase, when the anchor is in the boat it's pushing the whole boat down, displacing exactly the volume of water that weights the same as the anchor.
When the anchor is on the floor of the lake it's only displacing the exact volume of the actual anchor. Since the anchor is more dense than water, it's less volume.