Well don’t forget that the current/surf are just as important, it’s not just wind. Then there’s also the fact that you don’t really ever stop, unless you’re heaving to or setting anchor. These factors when added together sort of compound the difficulty in programming intelligent decision making, because you can’t avoid accidents by hitting the breaks as easily or just steering out of the way, everything has to work with this universe of waves and wind and (almost) never stopping.

That’s just under fair conditions. Under foul conditions, I can’t really imagine how you can have a program make sense of this stuff, since all the sensors are going to be all over the place, and you sort of need a human to make sense of it all. So under those conditions the it’d probably be easiest to just heave to, but then it’d probably get off course.

Also don’t forget that GPS is unreliable. The ship could probably do dead reckoning better than Columbus, but that’s something it absolutely must be taught in addition to everything.

I think a fair analogy would be to flying. You could make the argument that flying isn’t as complex as autonomous driving, but they’re just different. Sailing is about one degree of freedom more simple than flying.