I feel so depressed.How do you think of my kayak coach and my parents?

Your dad is a megalomaniac. You can't change this. You do what you want to do. If you think it's worth getting beat up by your dad then it's the right thing to do. He can't stop you from running your life. You need to take control. I just hope you don't depend on him for money or housing, just in case he cuts you off.