Haven't seen any difference with my boats. Got a mod messing with something? Or are you new to boating in general and don't know how it works? (serious question)

No mods on this play through. I also am very good with boats. Its not that I'm new, its that its a new problem.

A week ago, steering the boat was like steering a real boat...now it's a total mess. I wonder why.

Now when I turn left....the entire boat moves right...sideways. Zero moving left. Zero turning towards the left.

It was not that way a week ago.

That's actually the first thing I noticed 20min ingame. I think waves now have more impact on the boat than before. I used to put my hands down while sailing/steering, but now i have to always keep an eye on it

No difference for us - the fact that you can't steer left at all makes me wonder if you don't have a stray mod still installed or someone you're playing with might still have one that is running.

Check on a new world save and see if you still have the same problem - if not, it might be the above.

Failing that, try repairing/validating your files in Steam and see if that makes a difference.

Zero mods this game. I'm really confused. My buddy's computer that we're running the game on, sucks, but it never seemed to make the game not work properly before.

All this started since I updated to the Mistlands. Its weird though that nobody else seems to be experiencing any of it.

A week ago I could steer quite well. Now I can't get it away from shore.

Bummer! I hope you can work it out. It's the first time I've heard of that sort of issue.