> It's why looking at the horizon on a boat helps.

Yes it helps. As in getting you back to "barely normal". (Also you can't do anything around the boat because you're looking at the horizon)

The theory make sense but some people have the thing turned to 11

Once it starts for me, it's not stopping for at least a couple hours, even if I immediately get back on solid ground.

But I used to get sick playing Quake, so maybe I'm in the 11 group.