And here is Burgundy’s explanation for what the whirlpools do. She still might not know everything about the nature of the things, how or why they work, just what they ultimately end up doing. Which is simply to go from one place to another quickly, by traveling through a tunnel in the ocean. Burgundy wants to take her ship to the whirlpool that opens up behind her castle. That’s probably why she knows about them. Because she lives next to one.