Quote Originally Posted by Buffalobiian View Post
I never quite understood the whole compass thing. The unique thing about it seemed to be the fact that it always stayed horizontal (so we're assume that the world already has compasses). How hard is it to keep a compass flat? In fact, it's the first time I've even seen a compass that bothers to stay level.

Even then, can't you float the compass in some water?
As Ark mentioned, actually pretty damn hard. You don't want the needle to hit the casing, because if it bends, twists, or breaks, you're screwed. In heavy seas, it's really important that the needle isn't subject to impacts or inertia spinning it all about.

And you absolutely have, if you have ever been on any boat, or been in a car or RV that has also has one attached to the dash for some reason.
220px-Flush_mount_compass.jpg
This is the next logical step, modernized. You float your gimbaled compass in water. Invented like 300 years after the gimballed compass in our reality. Keeping the water in there is hard because stuff breaks, the high seas are rough on equipment, even today. The water also slows the needle down, so it doesn't twirl around as fast when jostled, and stays on North more steadily.

It's a pretty huge breakthrough in their world, just like it was in ours.