Boats have been sailing up and down wind long before we as humans have known how they worked. It's not hard, you should try it some time; the Phoenicians did it and you can too. It is still sometimes fun to imagine alternate ways that nature works despite knowing the truth.

We seem to be constantly replacing simple systems with drastically more complex ones. In the old days, to measure your speed in a boat, a sailor would pay out a rope with knots tied in it. With some measure of time and a little math, the sailor could figure out the boat's speed. Then they started putting little spinning wheels in the water under the boat to spin and electronically measure a boat's speed. Today I don't worry about casting knots overboard or a flakey little wheel in the water, sitting in a hole in my hull; I simply turn on my phone, have it converse with satellites orbiting the Earth, and it shows me a map with my current location, heading. I find an irony in the fact that I'm using one of the oldest means of propulsion while being guided by a horde of freaking satellites with maps off the internet!

All of that being said, who knows, maybe the giant under water navigational robot is not that far off.