The sine wave equations don’t correspond to precise astronomical measurements; they’re just an approximation that gives you a good-enough graph.
Typical tide ranges around the coastline of Ceannis are 30-35 feet. If anyone wants to calculate what sizes and distances are most reasonable for the moons that create them, go for it. (If they’re narratively inconvenient, I can always come up with a magic-based excuse.)
Thorn: Didn’t they teach you how the tides work in school?
Leif: I guess it’s not something we have any use for . . . Sønheim is effectively landlocked.
Tundra/desert that nobody can go over
Mountains that are hard to go over
Polar ice sheets that nobody wants to go over
Thorn: Okay, so these two sine waves represent the orbits of the moons. Add them together. When they’re aligned so their combined pull is strongest, that’s HIGH TIDE.
The pull gets steadily lower until LOW TIDE.
Then the moons fall out of alignment. While they’re at odds, the tide levels off for a short period — that’s SHELF TIDE.
Moon = 2sin(x+90)
Moonlet = sin(2x-5)
It’s risky to build too close to the ocean . . . but important for sea travel. Usually we build out to the shelf tide line, and elevate. A boardwalk like this gives people something to stand on, even when the tide is highest.
Leif: Ohhh! So this is a “boardwalk” . . . and it’s elevated! I understand the meaning of one of your traditional ballads much better now.