can not use the boat hook on the boat

Can anyone tell me what I am doing wrong, every time I pick up the boat hook and click on the rope or the sinking orange thing the boat hook return to inventory and nothing happens to the boat.

I have the same problem. I don't know how to untie the boat from the pier and the boat hook goes back into the inventory. I'm pretty sure u have to untie the boat before u can use the hook. Problem is I can't untie it not sure how to do that can anyone HELP!!??