At bedtime, a boat is something like a campsite. The cabins are relatively large but not too much. Anyway the sea tired and probably sleep like a baby. At anchor in a cove is important to pay attention to the sea crossing, it is often preventable pointing the boat down the stream. This can save you spend an uncomfortable night.
Although logically movement depends greatly on the state of the sea. If the sea is busy, it will not let you sleep safety of the ship, so the choice of the night at anchor zone is important. In the port when we are tied to the dock, the boat tends to move very little or nothing.