I can't speak for HWWB here, but from personal experience at least, being good at trigonometry requires a certain degree of aptitude in complex algebra, geometry not so much. Being an adept navigator is something of a different story though as it doesn't really require the same kind of fundamental foundation in algebra that "trigonometry" in general does. Navigation, specifically with maps and/or astronomical or landmark based navigation, is a very specific application of trigonometry that doesn't really require knowledge of any actual trigonometry. It's kind of like in Physics how you're supposed to know how to derive the acceleration formula from the velocity formula which you derive from the distance formula, you might learn how to do those things, but have no idea how or why differential calculus actually works. It's also a matter of acquired skills, one could argue that Loviisa has been doing this sort of thing her whole life, learning navigational and survival skills from a young age, and so she doesn't really need to be good a trigonometry necessarily to be good at navigating using methods derived from trigonometry. I'm no cartographer, but I've always hunted with my family and if I had a blank piece of paper and a compass I could probably produce a decent map of the woods behind my grandfather's house.