If the boat does not rock forward, you haven’t set your anchor. You have just dragged it along the bottom. To ensure that the anchor is set, you may need to try a few times. Don’t give up! Otherwise, ...

Imagine a boat floating in a lake, and a heavy object such as an anchor (but without a chain ... the more the water level will fall). I put up my thumb and shut one eye, and my thumb blotted ...